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MG MGA - One for the Judson crowd
| A while ago I received information from Alan Feast about his conversion of the MGA Judson to using a SU carb, either a HIF6 or HIF44. According to Alan, his car runs much better than with the Holley. See here for information and pictures http://clancy.ch/Judson_MGA_SU.html Because it appears that the Holley 1904 can't be tuned to run with the correct mixture at both slow and high speed, I have been interested in doing this conversion for some time. Replacing the fixed jet in the Holley so it runs with the correct mixture at high speed means it runs like a pig at low speed because it is then much too rich. The variable jet of the SU is the answer to this problem. As I have a second Judson in the garage right now (no it is not for sale, I have to fit it in the spring - there will soon be 4 Judson MGAs in our local club!) I have used it to make up a wooden mockup of the inlet manifold so that I can take a few measurements and make a drawing. I finished the mockup today, and will make the drawing in the next few days. My questions are: 1. Is anyone else interested in one of these manifolds before I start getting quotes 2. Is anyone on here willing / interested in helping out by making the prototype - basically it needs to be made of flat plate or thick walled rectangular tube so it will require welding and milling facilities Dominic |
| dominic clancy |
| Dominic...sounds like an interesting and worthwhile project. I am away from my mga right now and could not really follow the short description given by Alan feast but it seems that what is necessary is an adaptor tube with flanges on each end with one flange mating with the existing Holley mounting flange on the Judson inlet manifold and the other flange located in a space where the SU plus filter etc can fit. Is this what you have in mind? |
| Neil Ferguson |
| Neil I have tried many variations, but there does not appear to be space to make such a simple adapter. The carb / air filter ends up being too far back and fouling the goalpost, or too high and fouling the underside of the hood / bonnet. It seems that the only way to make this work is to replace the entire inlet manifold, which I have now measured and drawn up for an HIF6 or HIF4. As you can see from Alan's pictures, even with a comletely new manifold, it's tight, because the SU has to sit at 20 degrees from vertical. It would also be (just) possible to use a HS6 as long as the float chamber is on the left of the carb. This brings the carb to within 1 cm of the bonnet, so would require great engine mountings to avoid the two coming into contact under hard acceleration |
| dominic clancy |
| After the quote I just received, I'll be taking the drawings with me to Cambodia in a few weeks and I'll get one made up there! |
| dominic clancy |
| Dominic.....are you in contact with Alan Feast ? Would be good if we could get hold of the drawing for his modification as it looks very neat. I presume the local cost for the unit was prohibitive........ My kit is all on my bench and before installation ,a good few weeks away, I will consider this mod. as it sounds a good one but I don't want to butcher any original parts. Also What is your preferred SU carb and why.? Are you on hol. In Cambodia? |
| Neil Ferguson |
| I did get the details from Alan, but he didn't have the drawing available any more. Italked Carbs with Burlen: The carb would need to be the HIF44 or HIF6 with a BAC or BAK needle. The HS6 could also be used with a different manifold arrangement as it has to sit about 3cm higher so that the float bowl clears the chassis diagonal. The HIF44 is available used for GBP50 without looking too hard. Add a recon kit and it's about GBP80. I will be in Cambodia on holiday, and know of a couple of places that will make the manifold for a lot less than the $400 quoted so far. I will need to take the drawing and a cardboard model with me so I can explain what I need. |
| dominic clancy |
| Dominic....looked at eBay and there are a few hif44 in reasonable nick available for reasonable price so I am going to secure one and recondition it for the future installation. thanks for advice and enjoy Cambodia... |
| Neil Ferguson |
| Dominic, I've gone through two Holley bodies, three rebuild kits, and am ready to try something different, tight fit or not ! Count me in as an investor if you need funds up front. I also have my 1622/Judson engine out of the car right now for engine bay cleanup, so I could be a "guinea pig" for parts fit as well. I don't have any fabrication or machining capability, though. Let me know what I can do to help. -Chuck |
| Chuck Mosher |
| So If I understand you Neil, you are up for one too, so that makes a batch of three. Maybe possible to have it made in Europe after all. I have to add some details to the drawings and then I'll try the guys who have been recommended. It occurred to me that it could be made of 60mm rectangular tube with a 4mm wall, which may reduce costs considerably, so I need to go back and make a new model (may use polystyrene this time as it's easier to shape and cut than wood) and see if model 2 fits before drawing it up. Chuck, I have three engines on the floor at the moment as well as a second Judson, so I'm fine on that score. The tightness is not around the engine, but getting everything in the right position between the chassis rails and the goal post |
| dominic clancy |
| Dominic..I certainly will be proceeding with the SU conversion and therefore will need a new manifold. The $400 was a little frightening so I am very interested if you can get a good price. I also now know about 100 times more about Su Hif44 carbs and needles( ie I started from near zero)..after a few hours on the net..thanks for the info.. Look forward to hearing from you. PS I will need to design a smooth profile 1 3/4 inlet stub stack for the single air inlet after choosing the carb and filter..the same suction benefits should apply and get extra air into the Judson compressor. |
| Neil Ferguson |
| An extra thoght just occurred to me and I should ask. I understood that SU carbs needed to be installed effectively at or very near horizontal ( presumably because of float/fuel, extra friction etc) and in the photo of Alans installation it look at about 15 to 20deg to horizontal...this would be additive to normal road/hill angles, especially going downhill......Alan's system obviously works so is above correct or has Alan done something special to the carb? |
| Neil Ferguson |
| Neil The float bowl on an SU should be vertical, but the carb needs to be inclined to about 20 degrees - random picture attached to illustrate the point  |
| dominic clancy |
| Neil- SU can be installed at all sorts of angles; the governing factor is the fuel level in the float bowl needs to be at the correct level for the jet. Some SU carbs were even used in vertical downdraught configuration. H carbs have different float bowls for different mount angles to maintain the bowl vertical but the level correct. (the "H" stands for "horizontal" as the basic orientation.) HS have different float bowl mounting grommets to do the same thing. 0 to about 30 degrees are common. HIF are a concentric design: the fuel level is correct regardless of the installation angle, within reasonable limits. Don't know exactly what "reasonable" is, but up to 20 or so is seen. Dominic- Still waiting for a picture or drawing; the photos are pretty obscure! FRM |
| FR Millmore |
| Fletcher I am going to have another measuring session to see if it could be made from 60mm rectangular tubing, which would make the fabrication much easier. I also have a contact now who could make the prototype if I can make the drawing. I will order the HIF carb tomorrow (will not use the H6 that I was given last year because it won't clear the chassis unless the manifold is very complex compared to my current idea.) As soon as I have a workable and simple concept I'll put the drawing on my website For others, single HIF carbs can be had for GBP50 no trouble, so don't go overboard on the ebay bids. |
| dominic clancy |
| dominic..I have been following HIF44 sales on Ebay uk..and will probably bid for a matched pair coming up that look in good condition in a days time.. I don't want to bid against you ( or others on the site).I have a UK address ( a relative) I can send items to if I win and then forward.. If I do win ( and at a reasonable price )...would you want one... |
| Neil Ferguson |
| Hi Dominic, I would be interested in this adapter. Anything to make the Judson run smoother and morE ecconminal on gas. Jeff Becker 61MGA Judson Supercharged ZZZZZZZZZZOOOOOOOOOOOOOOOOOOOOOOOOOOMMMMMMMMMMMM |
| JEFF BECKER |
| Hi Neil Depends on the condition and the price - one of a split pair will be missing choke and accelerator connections on one carb. Given that a single HIF44 is available for GBP50, anything that is on ebay for more than that is not worth bothering with. But thanks for the offer |
| dominic clancy |
| Neil, there is another downside to the twin setups, there will also be a fuel outlet on the carb to be blanked off. That means that neither carb could be used without modification. That has convinced me that there's too much to fiddle with on a twin set and that a "single" from a Mini is the way to go. It will definitely need a new needle. |
| dominic clancy |
| Dominic...not sure why there should be an extra fuel outlet. ..but even if there is for me I see no issue. As for the jet..none will have the right jet so any carb I buy ( except if it is new ) I will refurbish and fit new needle. In the end all depends on the price and competition. |
| Neil Ferguson |
| There's an extra fuel outlet because on the first carb the fuel inlet is passed through to feed the second carb. This is normally the carb that has the throttle and choke cable attachment points. The second carb normally has no throttle and choke cable points (these being implemented with a rigid bar like on the MGA setup) and only a fuel inlet. |
| dominic clancy |
| Dominic ....'tis all academic. The price went past my limit. |
| Neil Ferguson |
| Well measuring up indicates that a 60mm square section tube will indeed fit, which makes the job a lot easier. I will try and get the tube from the steel fabrication place across the street from the office, and have a drawing ready this week. On the carb front I have ordered a HIF44 from a mini specialist in the UK for GBP50 complete. The final reason a twin carb setup cannot be split is that only one carb has the takeoff for the vacuum advance. |
| dominic clancy |
| Dominic...sounds good re fabrication of header. Would appreciate if you could share the name of the co. that sold you a HIF 44 for 50 quid? The ones I looked at from suppliers in Uk come in around 5 to 6 times that price. As I said the twin units went past the price i would pay...if they had not I see no issue in fitting both to be functional as single...the issue you mention are easily overcome with little work. |
| Neil Ferguson |
| Progress has been slow because I have been ill and busy too, but yesterday I obtained the square tube from the fabricators. They will cut it for me on Monday (I got there after they had cleaned all the machines for the weekend). As it is 100m from my office, it's no big deal. I also obtained a piece of 10mm flat stock to make the mounting flange for the carb, and a piece to close off the other end of the tube. I plan to mark up the tube for the supercharger cutout on Monday night, and should be able to have it and the carb flange made up over the next ten days. Getting a carb at a sensible price is turning out to be a challenge - all the guys that say they have them seem unwilling to get their backsides in gear and DO something - I have never had such a seres of telephone calls with such a disfunctional set of people. One who put his telephone number in an ebay listing with "call me it's no problem"practically went postal when I did call! such is life, in the end I will win out. I want to make the first manifold before I supply a drawing and tips for others, so please bear with me. So far the material cost is around $20 US plus machining and carb. |
| dominic clancy |
| Dominic..thanks for the update.....hope all is now ok with the health. |
| Neil Ferguson |
| I now have all the bits on the way. I found a HIF44 weld flange on ebay, so I don't have to make that. Carb cost GBP 35 as it was not described as HIF44 in the advert, but all the seller's measurements say that is what it is, Rebuild kit will be an extra 30. I have found the right length bolts for mounting the manifold to the Judson online, and will use wheel studs from a mini to mount the carb to the flange. So everything except the flange is an off-the-shelf item, and the flange may well be as well - the ebay details are in the picture in case anyone wants to watch out and see if he has another.  |
| dominic clancy |
| I have now had confirmation from the ebay seller of the flange that he does make them and can supply anyone - must be cheaper than having one made as a one-off. From his comments, he may also be an option to have the whole thing made up, I will send him a drawing when the first one is complete and I can take the final measurements and finish the drawing: "Hi Dominic, I can supply as many flanges as you want, I also have the flange for the inlet side of the carb and the flange to mount the Eaton M45 supercharger." I'm off to the machining place in the morning to leave the tube with them to machine up for me. Then when the carb arrives, I shall be in a position to measure up the mounting for the flange, cut the tube down to length and weld the flange in place. Getting closer..... |
| dominic clancy |
| Dominic et al.. I have been following this thread keenly as I have a Judson awaiting installation and the SU idea is a great one. I have bought a good nick HIF 44 carb but it is still in Blighty to be shipped soon ( arrival in 1 to 2 weeks !). In the interim I have been keen to progress and have following the purchase and consumption of David Vizard's book of wisdom and rules I have come up with a design proposal for the inlet manifold . GA is shown on Figs 1 and 2 (latter is next thread) and additional bumf as below... 1..Use of standard 60 by 35mm by 5mm hollow rect. aluminium section (i.e. internal section 50 by 25mm) with bolt holes and cut out to match Judson intake ( fig 1). Mating surface to be ground flat and smooth. 2.One end capped with 5mm plate( fig1) 3 End mating with SU HIF44 fitted with flange (fig2) .Sides of hollow section to be cut out for a distance and top to be bent up 20deg and shaped round to match 44mm flange hole. Bottom of section to be rounded to match flange hole. In fill pieces to be installed on sides. 4. The section size was chosen to keep the air/fuel veloc. approx the same as the original judson/holley manifold . I have made no attempt whatsoever to flow profile the inside of the manifold after reading Vizard. High velocity ( higher than through carb body) and turbulence to keep fuel entrainment are more important than head loss. The figs are to scale but rough. I intend to cut, shape and assemble the manifold myself and then have a local shop TIG weld the assembly and grind the mating surface. Particular Queries ... but all comments appreciated ... a)Dominic..do you have the critical dimension 'x' shown on fig2 . On Alan Feasts pics it looks very short but his carb has a long downstream throat. b) Does anyone know where on the net I can get the dimensions of a HIF44 . I have been looking but no luck so far and will not have the real object for a couple of weeks and I hope to progress the above work in parallel.  |
| Neil Ferguson |
fig 2 of inlet manifold..see previous post.
 |
| Neil Ferguson |
| Dominic..on my car I estimate I have about 23cm horizontal distance between the rear end of the judson compressor and the front of the heater /cockpit protruding shelf. This seems a good distance to get the carb plus a decent sized filter in on the upward 20deg plane ....would appreciate your advice re. actual distance you have on your car. This info. plus dimension "x" would mean i could proceed, review options and select a filter( with internal stub stack!) ? How did you select the needle types ( BAC and BAK ) mentioned in previous post.? I have reviewed a number of programmes but none cater for supercharger use. |
| Neil Ferguson |
| Dominic ..further to my last post on filters and distances etc...I have done some rough layouts and as a result have homed in on a K&N conical filter Type 56-9330 to fit on the HIF44. This filter has a mounting offset which throws the filter assembly higher and well clear of the heater shelf/firewall with the top of the unit about 10 cm above the shelf...well below the bonnet. It avoids the tight conflict evident on Alan Feasts pics. I have bought one of these units as using data in David Vizards book K&N filters are capable of passing about 5cfm per in2 even when filthy. The above unit has sufficient area to pass more than enough air for the supercharged engine without any detrimental press. loss.. Would appreciate your comments on this and other posts above? |
| Neil Ferguson |
| Been in Laax skiing for the weekend, so no progress I have used a standard 60mm square tube to avoid any additional machining and fabrication work. I finally took it to the machine shop on Friday, should get it back later this week. The dimension X is the one I am still working on, and I am waiting for my carb to arrive so I can measure it. On the needle front, I have discovered that the Moss SC kit uses a BCA needle on the HIF44, so I reckon that will probably be perfect for the Judson too. But I still have to punch the options into the Needle programme to figure out if I want to think again. The flange for the HIF is available from ebay seller dmx47a I'll have another Judson very soon, so can take measurements using three different units to make sure that the base dimensions are OK but sill give max clearance beween the unit and firewall I was waiting on ordering the air filter until I had measurement X and the carb, so I could be sure that I had clearance. I guess it would be a good idea to use the K&N, and have been looking at the same coned units. If you have a part number that would be great. We are getting somewhere here, and it's going to be interesting to see how the two different tubes behave. I am hoping that my simple approach is OK, because it saves a HUGE amount of other cutting an machining Are you mounting the carb at 20 degrees too? |
| dominic clancy |
| Dominic..I have been watching the ice age in Europe on the news....at least you guys are used to it and have the right machinery etc. Skiing sounds the right activity..down here it is good swimming weather and my wife and I have been out ocean swimming frequently( but behind a shark net!). Opposite ends of the spectrum....all change in a few months. But onto serious matters..... I attach the calcs. below I used for getting the manifold size and filter selection.....mainly using Vizards data. The filter assembly is a K&N 96 -9330 and is designed to match the HIF6 or 44 ..after looking around the net I got it new from Ebay ex US at a discount..the ref is below... A Russian substitute (Apha ) is available much cheaper..but.....that is roulette. Re. the manifold I think possibly I am a little undersized and you the reverse..at low rpm the veloc. gets down to approx 25 fps in my section and 10fps in yours. So far I have not found a stockist for the section I proposed but have found 60 by 40 ..so I may compromise . I may also cast some material or insert and piece of flat in the bottom of the manifold to get the velocity up ...if I can find a way of doing it. All good fun..... http://www.ebay.com.au/itm/200665923315?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649 Various Calcs. For sizing Judson Manifold and Air Filter (mostly using Vizard book) X-section Areas Existing Judson Manifold (Holley carb) 3cm by 4.5cm =13.5cm2 SU HIF44 =15.2cm2 Vizard Recommendation ( page 142/144) =9.6cm2 Proposed new sections 60mm by 35mm by5mm wt =12.5cm2 60 mm by 60mm (assume 3mm wt) =29 cm2 Flowrates through System Theoretical for 1600cc at say 5000rpm =1.6*5000/4 lt/min = 70cfm Assume supercharger takes 35% more = 95cfm According to Vizard (page51) an engine needs between 1.4 to 1.8 cfm/hp. using the average of 1.6 gives For 1600cc standard (say80 bhp) = 128cfm For assumed 35%boost = 171cfm Using 17cfm gives the following velocities in the system Through SU hif 44 carb bore =174fps Through existing Holley manifold = 195fps Through proposed sections as above... 60mm by 35mm by 5mm wt = 210fps 60 mm by 60 mm (assume 3mmwt) = 90fps Filter Selection Vizard (fig 5.2 page 48) gives the following results for K&N under standard test of max 1.5in water column head loss ) ..the best results of the comparative tests... 6.5 cfm/in2 for clean filter 5.1 cfm/in2 for dust packed Therefore min. filtration area assuming dirty filter =33.5 in2 =216cm2 On basis of above and on space limitations I selected a K&N sports filter conical type with offset carb. Mounting ..my estimation shows this unit to have approx 230cm2 of filtration area . NB One satisfying by product of this selction is the fact that the cone has approx angle of 66deg which when combined with the 20deg angle of the carb makes the filter top nearly horizontal. |
| Neil Ferguson |
| Found some SU dimensions ( incl HS6 on net) see below....I presume HIF6/44 similar to HS6.....except for the reduced inlet bore. Sizes present some interesting problems for the flange as it has dimension of 54 mm between holes and hole dia approx 9mm so distance between the holes is 45mm i.e. the hole are blinded by section size. Even if you use 60 by 40 section and cut at 20deg the X section mating with the flange becomes 60 by about 44 so the holes are clear but the nuts can't be fitted ( especially with a fillet weld in the way) . 60 by 35 seems to work for the flange ..section becomes 60 by 39 mm with a 20deg cut ..but becomes 32 mm on inside and too small for the 44 bore. Nothing straight forward......I think a bit of cutting and fitting of the any section is going to be required to get it to fit flange and bore. http://dl.dropbox.com/u/19278540/pdf%20files/SU_FlangeDimensions.pdf |
| Neil Ferguson |
| One more to scale sketch (full size) ....This is the arrangement I developed for the manifold end flange , carb.(using HS6 dimensions ) and the offset K&N 56-9330 filter.It gave me the confidence ,along with flow performance , to buy it..plus a stub stack insert from APT ( a radiuses plate ). Some of the dimensions are subject to verification ( i.e. 2cm spacing to Judson and 23 cm Judson to firewall. ..but there is still 2.5 cm clearance between the filter and the firewall ..plus good access to the filter and its centre bolt for cleaning/re-oiling etc.  |
| Neil Ferguson |
| Neil The Moss SC setup mounts the carb vertically. Is there any reason for not doing the same- this would make distance X easy to work out if not using a trumpet arrangement like yours |
| dominic clancy |
| Dominic ...Keeping the 2cm top of carb. flange clearance and then using the scale drawing I attached to the last post and rotating the whole flange /carb/filter assembly to horizontal gives about 3.3 cm clearance to a vertical firewall. I went to car and using a tape measure I noted following .... The firewall is not vertical and at the level of the filter will be about 2.5cm further towards filter..ie clearance of 3.3cm is reduced to less than 0.8 cm. It also looks like the filter itself will be an interference fit with the box chassis member coming up into firewall. Above is not definitive ....only eyeballed....but all looks much too tight and constrained for access ..I think Alan feast had it right and believe I will stay with the 20deg ....a lot more space around to cover dimension and assembly inaccuracies. It also gets the filter further away from the exhaust heat. I have also just bought a sheet of the material ref. below to make up a heat shield to further reduce affect of the exhaust on the whole Judson inlet assembly. Read about this on another thread .... Do you have a shield on your existing unit..if so how did you fix between Judson and block? Do you need heat insert spacers between Judson and block? file:///Users/neilferguson2/Desktop/Heat%20shield%20l.webarchive |
| Neil Ferguson |
| The heat deflector on the judson is fitted to the two threaded holes on the manifold that mounts to the head. I made up a smaller plate than the standard MGA one as I get carb icing with the standard one. It's just a tin plate without any insulation. I know it is a tight clearance between the carb and the firewall. Looking for space here is what has pushed me away from the trumpet (which needs length to work) to the larger tube. Similarly, by mounting the carb vertically, I would spare the rearward movement of the bottom of the carb. It also makes the carb sit lower than with the trumpet, which I think will allow the air filter to sit OK. Bit I am waiting to get the carb before I decide and make the cut. I'll probably make up another wooden model to test it first. |
| dominic clancy |
| Carb icing is not too much of a problem down here. Thanks for advice re shield. Did you use thermal isolator inserts between the Judson outlet flanges and the block? Re. the trumpet ..you will notice that my last sketch had a much shorter end development. After a few more sketches my general conclusion is that the ideal lies between the two extremes ( like everything else in life )...my current best arrangement is with a 60 by 35 mm tube and I believe it needs to cut at a shallower angle less than 20deg and bell mouthed at the end to fit between the bolt holes on the flange.and the 44mm carb bore and stay above the chassis member. |
| Neil Ferguson |
| There is just a gasket between the block and the manifold, and also one between the manifold and the Judson. There is no insulation apart from these, and it runs just fine even on 35C days driving hard up mountain passes. There's actually more of a problem in getting the temperature up over 70C, and in winter I need a radiator blind to get over 50C on the gauge. As it has been -18C here i the last few days, I've not been out in the MGA much.... |
| dominic clancy |
| Just a bump to keep active. I haven't had time to collect the manifold yet.... |
| dominic clancy |
| But this morning I did take a photo of all three units that I currently have in my workshop. All are spoken for. Beat, you can come and collect!  |
| dominic clancy |
| Dominic...finished all the calcs. and layout checks and finalised on the attached design made from 60 by 40 by 3mm hollow aluminium section. The carb. mounting flange is set at 10deg to ensure clearance above the car chassis member and gives about 3cm horizontal clearance between the bottom corner of the filter housing and the bulkhead. I had a long chat with a local aluminium fabricator and he will cut the corners off the section for a short distance adjacent to the flange ( also aluminium ) and shape the sloped cut off section to ensure minimum inside dimension of 44mm ( i.e. as per su carb. flange.) and then reweld ...also keeping enough distance clear around the bolt holes..It is tight in this area. I may need to get the top surface and the su flange surface flat skimmed on a surface grinder if any distortion during fabrication......  |
| Neil Ferguson |
Ref. previous post cc of drawing of new manifold was pretty crappy ( a photograph..I handed original to fabricator ). I worked it on Photoshop and attached is a wee bit better
 |
| Neil Ferguson |
just got the inlet manifold back from the fabricator....pic attached ..and it fits. Now have all parts so time soon to get the Judson installed .
 |
| Neil Ferguson |
| Dominic..attached see a pic of the assembly of the manifold on the judson with the SU HIF 44 and K&N cone filter.In the end I had the assembly angled up 10degrees at the manifold flange. The clearances look good and there will be about 2.5 cm clearance from the filter to the firewall and it is clear of the angled member chassis below ( though the depth of the SU carb surprised me ). A horizontal connection would have fouled the latter I believe. The fabricator bell mouthed the end of the aluminium section to fit around the 44mm bore of the aluminium flange but I need to grind a little into the fillet welds to get a good flat seat around the manifold bolt holes for the bolts attaching the SU to the manifold. I have a number of trims to make before I pull the old carb assembly off and install..including how to run the throttle and choke controls. Any more thoughts/calcs on the correct needle or suggestions of a good programme to use.?  |
| Neil Ferguson |
| Hi Neil I've been sidetracked with other things, and am now hoping to get back onto finishing the project - I ordered the last few bits yesterday. Have you fitted the manifold yet? What is the distance on your manifold between the rear mounting bolt to the Judson and the carb flange - I have mocked up one version but am waiting for an abutment plate before I do the final chop and weld. I think I can shorten about an inch from where I am right now. Dominic |
| dominic clancy |
| Dominic.. I am a long way away from my MGA amd my drawings and assembley right now and will not be able to get back onto the job until next week. I have not yet pulled the old carb assembley off and fitted judson as I plan to do a few other mods at same time ( alternator, blower fan in duct, heat shield ,crankcase ventilation to HIF44) and want all the parts together. Other recent threads cover the blower fan and crankcase vent subjects. I will forward details you request as soon as i get my hands on the parts again. |
| Neil Ferguson |
| bump |
| dominic clancy |
| Dominic..back with mga now. I have not fitted the Judson to the car yet . I am still waiting on the stub stacks from Steve to try with standard carbs before pulling the manifold off. Now have all parts for total judson installation incl. 3 inch blower to get cool air to SU air filter..to be put in the duct adjacent to radiator. The best measurement I can give you is the distance from the end face of the judson casing ( not the bearing boss) to the edge of the new manifold flange..this is 3.7 cm ..remember that my flange is set 10 deg up so the rest of the flange is further away. I was conservative to ensure I could get the flange bolts in..it looks like I could have shortened the above by max 1cm. Any advice re the needle selection and programme as per my last post? |
| Neil Ferguson |
| On carb needles, I talked to Burlen, and they told me which needles were used in a Rover 3.5 litre engine setup (I chose this because a 1622 bored out .060 oversize comes to about 1750, half the volume of a twin carb rover setup) They told me also which needles were slightly richer, and also which had a richer progression (important for getting LOTS of fuel when under hard acceleration. These were the BAC or BAK needles I mentioned at the beginning of this project. I also was given info by Moss about the needles in their MGA setup. I assume that the engine requirements are similar, but note that the Moss unit works under higher pressure than the Judson, so that needle is likely to be rather on the rich side. I have bought one of these anyway (BCA) and will give it a try. I am STILL waiting for the plate to mount the throttle cable to the carb. Burlen sent me the wrong one, so I now have to wait till Tuesday to be able to call them and get them to send the right one. Burlen is also the best place to get the needles. As for comparison charts, I used the http://www.mintylamb.co.uk/suneedle/ site. The comparison looks like this: |
| dominic clancy |
Another try to load the picture
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| dominic clancy |
| Dominic..thanks for the bumf on needles..I have a bca and probably will try that first.... I have just trial installed the judson (with SU and new manifold) and it fits well. I attach a photo. My comments are.... 1) the clearance between the filter and bulkhead is about 20mm at bottom of inclined filter ( this not clearly seen on photo ). 2) The carb sits clear and inboard of the angled upcoming chassis member . 3) The fuel inlet nozzle is too close to the exhaust ( about 10mm ) . I intend to increase this distance using a flange spacer and also tape the exhaust ..as well as putting in a heat shield. I believe i may shape my heat shield material to fit partially around the exhaust . 4) The Judson drive pulley is a contact fit with the steel air conduit . So no horrible clashes ..but some minor adjustments ( also my throttle cable is too short) . Do you want any measurements before I take it out ..probably tuesday?  |
| Neil Ferguson |
| Hi Neil Great news. Can you see how it runs with the BCA before taking it out? Also, how much clearance do you have between the carb bottom and the steering knuckle? Interesting about the fuel inlet, wonder how we can get around that - maybe if I braze in a right angled tube to the inlet, I can raise the fuel inlet above the exhaust I still have an second engine and complete Judson still on the garage floor, so will try and experiment a bit today with the fuel inlet issue. I am still waiting on a few axle bits to move on with my friend's installation. Dominic |
| dominic clancy |
| Dominic...I have not lifted the radiator out and done the pulley/belt work yet. I just wanted to check out the local space out around the compressor/new manifold/carb/filter...so need ot do all the front end work before I can fire up. I have an oz drive so steering gear a long way away. Best direction for fuel line is horizontal right angle heading towards bulkhead. I note there is a hole on opposite side of the HIF but no nozzle fitted . Any idea what it takes to move fuel inlet to far side of carb.? I note the two bolts holding the manifold on the downstream side of the carb seem to be hard up against the rocker cover ..is it the same on yours. I need to get the heat shield material under these bolts so will have an interference here..unless the Judson long cover is narrower. |
| Neil Ferguson |
| Hi Neil After a few hours playing, I have just ordered the spacers from Burlen (cheaper than used on ebay). The acorn nut of the air filter is on the plane of the engine backplate, so I have some room to move backwards with the carb to solve the interference issues. I find that the air filter also fouls the exhaust at the moment, so moving the carb back 3/4 inch or so is going to be essential to slve this and get fuel in. I will braze or solder a length of brass or copper tubing to the fuel inlet to create a right angle and get the rubber fuel hose away from the exhaust. The manifold bolts holding the Judson casing to the engine manifold have to be inserted before the cover is fitted. The heat shield should fit to the threaded bosses on the manifold. Here I just use a sheet of thick tin plate - I guess you could glue or rivet some insulation material to the plate, but I have always found that a simple deflector is enough (or even too much in winter, hence the radiator blind I have fitted to prevent carb icing. The Judson cover is the same width as a standard tin or alloy one, and uses the standard gasket. I'll go and take some pics of the installation on the garage floor and mail them to you directly Dominic |
| dominic clancy |
| Dominic..... progressing on the pulley work etc. Two issues you may be able to advise me on.. 1) The instructions say that the judson pulley is fitted to the existing crankshaft pulley and to ensure that the rivet heads on latter line up with the recesses on the new pulley . My crankshaft pulley has no rivet heads to line up with...but there are two small threaded holes in it. Do I drill holes in the new pulley in line with these threaded holes and transfer the load by inserting screws. 2) The pulleys are an interference fit with the steering horizontal...I recollect somewhere reading this could happen...can you point me in the right direction? |
| Neil Ferguson |
| I do not have an HIF to look at, but many carbs, especially those that come in two "hands", have incomplete passages for alternative fittings. They form as much as possible in the casting to reduce material use and machining work/waste. Take the float cover off and check the casting for an opposite side fuel feed boss to the float valve. It is very likely that you can drill the now dead end passage to the valve, and plug the old one. Possibly also for the vent lines etc. The brass nipples are usually just a press fit - sometimes falling out! FRM |
| FR Millmore |
| Hi Neil I'll get the photos done this morning. It sound like you have a later crank pulley, and there are two approaches possible here. Either drill and screw as you suggest, or drill and add pins to the Judson pulley. Mine is pinned, but the second one I am fitting is crewed to the pulley (it's now mounted on the new engine so it may be hard for me to photograph this.) As far as the steering rack casing is concerned, I had to move my rack forward because the pulley rubbed on braking. Having moved it forward, I am able to change belts without undoing the rack..... In standard setup, you can't get a belt between the rack and the pulley, so this is a mod that I would recommend even if you have no issues here. Just remember to get the wheel tracking redone afterwards. I also had to trim the radiator shelf to be able to move the rad forward, and had to move the rad down about 10mm to avoid the front top corners of the header tank fouling the front lip of the bonnet and preventing it from closing. I believe the radiator shelf was an early prototype from NTG so it may have been a little longer than required. The belts supplied with the second unit are also too long, but I'll dig out my old spares (I now rung a B Crank pulley with a harmonic damper and a single thicker belt) and let you know the Gates number of the correct belts. Dominic |
| dominic clancy |
| Fletcher I have a second HIF that I was kindly sent by another member, and was planning on calling Burlen tomorrow to ask if this mod is possible. I did some photo searching yesterday and all the pairs I found have the vents and fuel inlet in the same side, so there does not appear to be a LH and RH version. But asking the experts will soon clarify this. Dominic |
| dominic clancy |
| Dominic - HIF4 as fitted to MGB are not only handed, but have a through feed between carbs. The passage in question (front carb) is drilled straight through. I find it hard to believe that the HIF6/44 is different. What uses HIF6/44 pairs? I have in my head some Volvo maybe, but not US ones as we got FI after 68. At worst you can probably remove the nipple, thread the hole, and use a banjo fitting for the line - closest fit. FRM |
| FR Millmore |
| Fletcher was right, the carb mod is easy, I have just done two carbs. It's really handy having two of everything at the moment, especially with one Judosn in the car and the second one on an engine on a trolley so I can see everything clearly. Having removed the base plate, float and needle valve etc, I drilled out the opposite boss. I used a 10-24 tap to plug the original pipe, and then a piece of brass dowel against the tap to drive the old pipe out. I had a thicker brass dowel that was ideal to plug the now vacant passageway, and then pressed the pipe into the newly drilled hole, using a little of a special sealant to make sure all stays leak-free. Reassemble in reverse order, photo of the finished pair attached, one with fuel pipe in place to check that the choke still operates without interference. I am now just waiting for the spacer and an abutment plate, and then should be ready to have a go on the car instead of on the second engine. I still have to drill and tap the manifold for the marvel oiler hose tail, still waiting for that to arrive as well. Also have a pin hole on one weld that I need to seal. I also have acquired a SU workshop book that describes the setup procedure for the carb in great detail, step by step. Dominic  |
| dominic clancy |
| Inching closer, I just bought some of Lindsay's insulation material after making a new (longer) heat shield that mounts to the standard Judson heat shield mounts. I'll take detailed pictures and make drawings when everything is finished. |
| dominic clancy |
| Progress this end....New Alternator installed, steering rack moved for clearance, judson pulley pinned to existing pulley..... I wrapped the exhaust pipes and then cut and shaped a heat shield from material I learnt about on this site ( Gary Lock? ) . Great stuff and neat installation..see attached pic.. I will secure the bottom of shield to exhaust with a hose clamp. Blower installed in duct and also engine vent piped up to connect to the SU HIF44. Onwards...end in sight ..... |
| Neil Ferguson |
forgot the photo
 |
| Neil Ferguson |
| I'm still waiting for the abutment plate and spacers before I can go further. Otherwise I think I am ready to go once these turn up. May leave it until after next weekend which is the opening outing for the local club. I just need to tickle the Holley a little bit as it is running too rich on the current setup. The second car had its Judson fitted today, but I am going to have to order a new radiator for it before I can fire it up. I also had to use the spare Holley I had because the one that cam with the Judson appears to have had water inside it and is in a very poor state. The plastic cam is also broken, and I am down to my last spare one. The Judson internally is fine, and its new vanes went in fine, and with a new coat of paint it looks great. |
| dominic clancy |
| I have now scanned and compiled the HIF 44 section of he SU Workshop Manual, and also the exploded diagrams and SPL If anyone doing this mod would like a copy, please mail me directly |
| dominic clancy |
| Can anyone tell me the approximate cost of a Judson supercharger kit. What do they sell for?? Frank |
| F. Camilleri |
| All components plus great refurbishment to as new By George Folchi..$3500 to $4000. |
| Neil Ferguson |
| All the ones that have been on ebay or my site during the last few years are listed here http://clancy.ch/Judson_MGA_ebay.html At the end of last year there were four listed simultaneously for sale on my site. They are all now sold. I have a waiting list with two people on it at the moment in case anyone contacts me with a unit for sale - my site is to JMGA Judsons what Steve Gyles is to Shelley jacks Dis anyone else think that the price for the Judson gauge on ebay at $710 was a little over the top? 270951630718 |
| dominic clancy |
| Yeah, I saw that one Dominic. Wow! Over the top is an understatement. |
| Andy Bounsall |
That is a revolting price...someone has too much lucre and is distributing it around to keep the economy going .. I have given up even looking for one for the present and for my Judson installation I have bought a gauge kit from Classic in US and will install under the dash ( i.e. no holes in dash)with a voltmeter of similar design.
 |
| Neil Ferguson |
| Neil, unfortunately there were at least a couple of people who wanted it more than you did. |
| Andy Bounsall |
| Andy..do not have a Ebay search going on for these gauges..all too rich for me. I would have maxed out at $250..... At this price the guy should keep it in his safe at home! |
| Neil Ferguson |
| Or you can buy the modern "official" gauge here, which is identical to the 50 year old gauges and "only" 270 euros ! That includes Belgian VAT at around 20% so it should be cheaper for non EU residents. http://vwjudsonregister.tripod.com/stephs-judson-gauge.htm |
| dominic clancy |
| Dominic..looked at that a long time ago and dismissed it as grossly overpriced for a repro.. and E270 equals $340 so way above my self imposed price limit ( the VAT equiv. is lost in shipping costs). The most expensive reasonable quality gauges without the Judson decorations found were around the $100 mark . You did a face colour change on a Marsh unit I recollect..that sounds a wise move. |
| Neil Ferguson |
| I thought $700 was wonderful. Unfortunately for me, it wasn't mine and I don't have one to sell. Now purchasing it, I wouldn't have gone over $200 myself. I'm working on a look-a-like that won't say 'Judson' on it. It's more in my price range, me being very cheap, and if I can paint halfway well, I will be quite happy. |
| Mike Parker |
| Mike If you are nice to Johanski maybe he will let you have one of his super face transfers |
| dominic clancy |
| I'm trying to paint the face. I will let you know how it comes out. It may not say Judson on it, just depends on my mood when I do it. |
| Mike Parker |
| Now have Judson installed and belts on etc ...attached find a pic of the topside view of the SU HIF 44 and its nozzles ( the Judson casing is to the left of the pic..). They all point into a brick wall ( the heat shield and exhaust pipes) . The lowest nozzle on the right of the pic is the fuel inlet and I will can and will move this to the opposite hand of the carb...so no problem.. The middle one is a fuel overflow so need to route this down towards mother earth.The next larger one moving left is the vacuum for both the advance and the engine crankcase breather . The right one is not a nozzle ..it is the butterfly disc shaft. I need to route the vacuum and the breather through 90 degrees..would appreciate advice on fittings and best way to do this!!  |
| Neil Ferguson |
| Neil You still appear to have no way of attaching the accelerator and choke cables, how are you planning to do this? My setup is now ready to mount, I'll take a pic and upload as soon as I get a minute or two.... |
| dominic clancy |
| I I have been chewing on this but decided to get the precise space out with the carb and its throttle and choke clamps.. The Judson is now installed and just one hour ago I decided the following.. The trajectory of the two mechanisms as they rotate is towards the face of the Judson casing so using various odd pieces of metal ( from my scrap bin ) I assembled two 90 deg angled metal brackets .Both brackets are clamped using the Judson rear end casing studs on the fender side and one bracket ,the lower one, is much longer than the other . Both have cable sheeth stop swivels . I needed a new longer throttle cable and have bought such. The choke cable seems long enough and runs to the swivel in the longer bracket. I hope that makes sense...I intend to use this arrangement and adjust the brackets and swivels etc until I get smooth cable actions and then to make a composite bracket incorporating both the final dimensions. If you wish I should have the brackets assembled late tomorrow and could take a pic.. |
| Neil Ferguson |
| I have gone with a so-called abutment plate from a Mini Here's a photo of the setup. The choke cable clips in place using a metal spring to clamp the casing to the bracket. This spring fits in the slot on the silver bracket. The accelerator is adjustable a bit at the bracket, but I will just use a rear cable for a bicycle brake, and will do the adjustment at the pedal assembly in the footwell. This is the tube with a threaded lower section leaning back at 45 degrees. I still have not checked if this will clear the Judson body but can easily shorten or add a curve if necessary. The brown plastic stub on the top of the carb downstream flange is the connection for the vacuum advance. The takeoff is tiny, diameter about 0.5mm, and uses a special right angle rubber connector to a small bore nylon pipe. I have retained this, but added an outer sleeve so that my standard vac advance hose will fit.  |
| dominic clancy |
| Neil- "next larger one moving left is the vacuum for both the advance and the engine crankcase breather " NO! This is in the constant depression area of the carb; vacuum is low and constant, perfect for breather but useless for advance purposes. Carb vac for advance is always a small hole opening very near the edge of the throttle plate, usually such that it is on the carb side of the plate at idle, but becoming engine side as the throttle is opened. Vac will read zero at idle, jumping to a high as the throttle is first cracked, then decreasing with further opening. If there is no such port, you need to either use manifold vacuum, or you can drill the port once you thoroughly understand the operation - position is critical. Manifold vac will be highest as idle, dropping steadily as throttle is opened. The difference between the two possible vacuum sources for advance means that different distributor curves and timing procedures and settings are required. FRM |
| FR Millmore |
| FRM..thanks for advice and after further reading..I totally agree . The large port is solely for the engine deep breathing. My HIF 44 has no vac. advance port . I think I will try to set the Judson etc up without vac. advance initially . I have a manifold tapping ( for the lube injection to the Judson ) but this will pull a big vacuum even at idle so that will be second trial...I am loathe to drill into the HIF 44 body . I recently fitted electronics into the distributor ( accuspark ) so will play timing, mixture,combustion ( Gunston) and needle tunes when all fitted..what joy! Dominic...thanks for pics... the carb looks angled ..what angle did you use? See my comments above to FRM re vacuum advance. Your throttle connection is a lot more sophisticated than mine....you have the mini cam as well as the abutment plate. Latter does look like it may need some adjusting to avoid the Judson housing.... I see a comment on the standard Judson installation instruction with the Holley that "the vacuum advance is discarded with the supercharged mga'. Was this because there is no vacuum port on the Holley ? |
| Neil Ferguson |
Dominic....This is my Heath Robinson cable assembly.....primitive but seems to work very freely. I have attached the choke cable to make sure it was long enough and will move the choke cable swivel stop to outboard of the bracket ( i.e. same as the throttle) as alignment is better.
 |
| Neil Ferguson |
| Neil- " "the vacuum advance is discarded with the supercharged mga'. Was this because there is no vacuum port on the Holley ?" Vac advance is primarily for economy, with possible secondary benefit in low rpm throttle response. Given that gasoline in the US was c $0.20-0.25 per gallon at the time, nobody cared, especially since any MG would get at least double the mileage of any US car, if all 4 plug wires were on. And the people using Judson fancied themselves as "Racers", so a little low end coarseness was accepted, though it shouldn't have been, and was unnecessary. Add to that the challenge of getting the advance curves right, on what was meant as a "bolt on and drive" accessory, and you throw the advance out. That was the thinking behind most of the cars that did not use vac advance in the 50-60s. Since these were mostly "high performance" cars, the lack of advance also had a certain cachet; witness the great enthusiasm for Cooper S distributors on every kid's Spridget. There are certain advantages to no vac advance in distributor stability at high speed, and race cars rarely run at low throttle openings, so it is just one more thing to go wrong, hence why such cars did not have it. Any street car can use it and should have it, but you can certainly run without, as least to start. After your pay for enough fuel, you might wish you had sorted the vac out! At that point, you can likely devise a suitable manifold vac setup, with the correct vac capsule. Things are different now. FRM |
| FR Millmore |
| The Holley does have a vacuum port, it is usually blanked off with a bolt for the Judson setup. As Fletcher says, it runs much better with the van adv in operation with a correctly curved distributor. My guess is that Judson wanted the marketing blurb to be simple, and didn't want the cost or hassle of stocking distributors that would only make the kit more expensive |
| dominic clancy |
| FRM...'things' have been different for a long long time everywhere but the US and a few ME oil producer countries. Do I also detect a certain distaste for the Judson "bolt on and Drive' accessory ? |
| Neil Ferguson |
| Neil- Well aware that things were always different in most of the world, but it must be recalled that Judson was a US product, marketed primarily in the 50/60s US market. "Do I also detect a certain distaste for the Judson "bolt on and Drive' accessory ?" No, it's a perfectly reasonable business approach, common in the accessory business. Problem is it creates a box; if you then offer a distributor, which would be both an improvement and a profit maker, everybody is mad that you "cheated" them with the earlier instruction. It's a common issue with many things, made worse by incompetent - or dishonest- sales people. I really hate getting a price on something, then getting it home and finding that I need another bit to make it work. Thus another day, another trip, more money to do what I stated as my problem in the beginning. I've been through this several times with welding equipment, taking a week of valuable time and many 30 mile trips, just to do what I stated as my need on day one - and the cost went from $1000 to $2000. I'm perfectly OK if they tell me the options and I make a bad decision that means I have to buy something more. FRM |
| FR Millmore |
| FRM..can't disagree with most of that. I read that the installation of a Judson takes about 4 to 6 hrs...by superman maybe!..but a well made /restored unit. A very recent experience was installing an EFI ( manifold type ) on my 74 Jeep..only 3 hrs work according to the bumf and magic video...took about 5 times that with costs doubling over the package. I don't agree it is good business....I never touch such companies again. Re ignition I set my mga some time ago following Barney's IG-116A and will use same for Judson after I finish...... |
| Neil Ferguson |
| Installed, hosed up and cables installed. It is as tight as a duck's a...e and knuckle blood was spilt. Some comments..... The carb to manifold underside bolts are impossible to get at..a real oversight. I had to take the whole Judson off and install the carb.on the manifold before the Judson . Glad to have the heatshield and manifold pipe wrap on..the exhaust is hard uo to the filter housing. The two hoses are..middle smaller the vent. The larger to the left is the engine vacuum breather . Hose with redline at bottom right is the fuel hose. The APT stub stack did not fit in the filter housing..I had to file about 3mm of two locations to get the filter on. A query..do all new K&N filters come pre oiled?  |
| Neil Ferguson |
| Sorry to forget the tip about mounting the carb manifold before mounting the Judson to the engine - I just assumed it would be obvious when it isn't. Your carb - exhaust clearance is a lot less than the test installation I did. But you left out the most important things - which jet and.... How does it GO? |
| dominic clancy |
| Dominic..fitted the BAC needle ( a little leaner than BCA) but have not fired up yet.but getting closer ....car still up on the high stands.... A few jobs to do incl. exhaust ( new gasket ring required for manifold to pipe) .. steering work .. the radiator top hose/ thermostat and electrical hook up of new inline fan and alternator..then some joy I hope ....if I can keep away from domestic tasks... |
| Neil Ferguson |
| Dominic..I have got the beastie fired up but have not yet driven as the steering and alignment need work . The steering stiffness is terrible and I will have to work through it to ease...moving the rack forward did something! I have the engine running and set idle high at 1000rpm with 20 degree advance as per Barneys note ..... and been adjusting the mix to get a smooth idle with some success but not yet used the Colourtune . I hooked up a temporary boost gauge to check vac and boost and was getting about 10in vac at 1000 and about 17in at 2000 ..no boost. I was concerned until the obvious occurred to me .. the boost only comes in with load ..is that obvious correct? The unit makes a high whining noise ..I believe this disappears. Grateful for your advice. Adjusting the jet height ( mix ) is a pig as the screw is in an awful position and angle ...next to exhaust and near bulkhead. I had to make a special cut down screwdriver. |
| Neil Ferguson |
| Loosen the clamps at the top and lower end of the column and spin the steering from side to side to let it find itself again. You also need to push the column towards the front of the car by the same amount that you moved the rack forward. |
| dominic clancy |
| did that with front wheels in the air and it did seem to improve slightly..will do again now car is on terra firma ....any advice re vac and whining noise? |
| Neil Ferguson |
| Noise will diminish after a few hundred ks, you only get boost under load |
| dominic clancy |
| Dominic....thanks for that.......I have also just read the Moss Supercharger Installation Instructions and they recommend the connection of the vac. advance and show the nipple. ( looks about 1/8in ) . They also recommend initially trying 15 deg of advance at 900 to 950 rpm ( without vac. connected ) so will adjust to that . What do you use...? |
| Neil Ferguson |
| Dominic..followed your advice and loosened everything,clamps, supports UJ and then turned the steering wheel for a while and fit has loosened up to same state as before mod. ..but still like an early volvo. Fixed alignment with very very slight toe-in. Changed timing to 12deg and at 1000rpm adjusted mix using Colourscope to get reasonable blue..checked at 1500 and 2500 rpm and bright white ..so probably the BAC is too rich. I have 2 more leaner needles , BBA and BGC and will try the next leaner , BBA, next week .I selected all the needles to have similar low stage diameters so hopefully the idle mix will stay correct . Starting needs a load of choke for a while . Took the car for 20km drive up and downhill and it performed well and with much improved torque . .... Away to melbourne for a week so judson fun has been suspended... |
| Neil Ferguson |
| Dominic..followed your advice and loosened everything,clamps, supports UJ and then turned the steering wheel for a while and fit has loosened up to same state as before mod. ..but still like an early volvo. Fixed alignment with very very slight toe-in. Changed timing to 12deg and at 1000rpm adjusted mix using Colourscope to get reasonable blue..checked at 1500 and 2500 rpm and bright white ..so probably the BCA is too rich. I have 2 more leaner needles , BBA and BGC and will try the next leaner , BBA, next week .I selected all the needles to have similar low speed diameters so hopefully the idle will stay correct mix. Starting needs a load of choke for a while . Took the car for 20km drive up and downhill and it performed well and with much improved torque . .... Away to melbourne for a week so judson fun has been suspended... |
| Neil Ferguson |
| Neil, try and make it to the MGCC Concourse at Flemington Racecourse on Sun 29 April. It is part of the RACV Classic Showcase and includes all European and British cars. Mike |
| Mike Ellsmore |
| Another sign of onsetting decrepitude..an email stutter has developed! Mike-- well do just that ..but coming down in an Xtrail..... |
| Neil Ferguson |
| Neil I thought a white flame is too lean, and it would be yellow if too rich. If that is the case, you need a richer needle rather than a leaner one. It's far better to have a needle running a little rich than one that runs lean, as the lean mixture will promote pre detonation under load, even f you cannot feel it yourself, your crank, pistons and con rods certainly will. |
| dominic clancy |
| 'twas definitely too rich .I have used this gunston many times on my mga and jeep and possibly my color description was too cursory...the color changed from blue at idle to mixed yellow blue then yellow as I opened the throttle ...needle/ jet annular area was too big.....ie .fatter needle required. |
| Neil Ferguson |
| Hope to be rid of the visitor in my garage soon and then can get onto finishing this project on my own car. |
| dominic clancy |
Here's a photo of the van advance nipple from above
 |
| dominic clancy |
From the side to show inclination
 |
| dominic clancy |
| and from the manifold side to show where it comes out behind the butterfly. The hole is not 1/8 like the others, I estimate 1/16  |
| dominic clancy |
| Dominic.....those are excellent close photos..thanks. I thought the tapping was just upstream of the butter fly so that at idle the tapping saw no vac.....only when the butterfly opened did the distributor see the vac.. The tapping shown would see vacuum at all speeds.....I am confused ( hope not old age permanent ) |
| Neil Ferguson |
| The tapping is on the body, not the flange, and is at an angle so that it exits on the manifold side of the butterfly. This way it always sees a manifold vacuum. Note the comment below that it must not be on the centre line - that confuses me too because in a circle the centre line is dependent on your perspective. I would just try to copy the original. |
| dominic clancy |
| Neil is correct, this is manifold vac plain and simple. Old school carb vac is upstream of the throttle plate, and the plate sweeps over the port as the throttle is opened. No vac at closed throttle, rising rapidly at throttle opening, decreasing thereafter. "Note the comment below that it must not be on the centre line - that confuses me too because in a circle the centre line is dependent on your perspective." Think that comment was above. It makes no sense whatever with the port located as pictured. If the port were located as in real ported vac, the off center location toward the throttle shaft would modulate the transition characteristics. FRM |
| FR Millmore |
| Hi Neil I've been away for the last week or so, but am now back in the saddle. The guest MGA will be leaving on Friday, so I'll hope to fit the SU if the weather sin't too good on the weekend. Do you have anything more to report on the needle selection? Dominic |
| dominic clancy |
| Dominic..all has been quiet on the Antipodian Judson front. I have just got back from Melbourne and will shortly lay my hands on the car...hopefully tomorrow. |
| Neil Ferguson |
| Dominic..went for another 20 km drive and then pulled a plug out...black!! So for my set up the BAC gives too rich a mix ... replaced with next leaner needle in my stock, BBA ( thank ye gods for one simple change operation.) and adjusted idle reasonable blue with Gunston..higher speeds looked blue/yellow....so will drive tomorrow. |
| Neil Ferguson |
| Hi Neil I tried my setup on another Judson on the bench tonight, and it all seems to fit OK. I'll probably fit it this week. Thanks for the heads up on the needles so far. Dominic |
| dominic clancy |
| Dominic.. I just got back from my standard 20 km circuit using the BBA needle with speeds up top 100kph ( max legal here ) and some good long hills. Car needed choke for quite a time...approx 3 mins... but once warmed up it was a changed beastie...pulled very strongly in high gears..even in 5th... and accelerated well .....a delight! Pulled all four plugs out on return and a pleasant grey colour ...so combustion is consistent with the Gunston colour tune previously reported. The BBA needle is on the mark or pretty close to it . I don't have my APT round entry stub stack in ( needs more fettling to allow the K&N seal to fit around.it ..lousy fit! ) or any vac advance connection yet. Query..is the need for longer choke time normal with the Judson? PS going into darkest coldest winter here..temps down to 7c at night ..15 during daylight...brrrrr! |
| Neil Ferguson |
| Well I have now to officially declare my attempt as unsuccessful. Although it all fits onto the Judson perfectly, and all the controls work nicely, the bottom of the carb just fouls the steering knuckle when the wheel is turned. There's no space at all for motor vibration and I am certain that the float chamber cover will not last more than a few kilometers if I try to drive it. The old Holley setup will go back on tomorrow night. So Neil, if you can convince your guy to give us a good price on three manifolds, or you can let us have the drawing, I'll see about getting a few made up to your design, but modified a little for my cable hook-ups, which are a bit more refined and use standard mini parts. Now we have the definitive design for the manifold, are there any other takers? |
| dominic clancy |
| Dominic...I did not have to contend with the complication of the steering UJ ..here in Oz the steering wheel is on the British Imperial side. I will check the clearances and see if mine has enough for your situation . I kicked mine up at 10deg and I believe Alan Feast had his kicked up even further ,approx 20deg ,looking at his pics. Will advise soonest. |
| Neil Ferguson |
| Dominic..I used the downward sloping adjacent chassis member as ref for height on both sides of the car and got the following approx height clearance dimensions for my steering UJ on one side of the car and the bottom of my HIF44 as installed on the other side.. ...distance down to top of UJ ....5cm ....distance down to bottom of HIF44...5.3cm The reference position on the chassis members was 15.5 cm horizontallly back from the top lip of the heater shelf. Given the inaccuracies of measuring in 3 dimensions using a spirit level, a ruler and the presumption that the chassis and shelf are symmetrical it looks like my set up would most probably foul the UJ. I looked back at Alan Feasts set up and he has a steep angle ( I estimated 20deg) and also is using an SU with a big downstream throat ( much longer than the HIF44 ) ....the combination of these two would throw the SU body up higher above the UJ. His carb had a side fuel bowl as well I believe so probably was not as deep as the HIF44. From my previous drawing I know that an angle of 20deg would raise the bottom of the HIF44 by about 1.7cm compared to the 10deg I have at present so this may be enough. My suggestions.... 1) measure on your car the actual clearance of the knuckle under the chassis member 15.5cm from the shelf edge. 2) if 1) is greater than 5.3 cm my existing design may possibly fit...but probably very sensible to kick the angle up to 20deg.and get the extra clearance. 3) it is possible to move the carb/filter assembly further towards the bullhead and gain height but the steering column is also angled and there is a protruding clamp bolt nut on the column which may interfere. Check above 1) and 2) above for your car and advise . I can easily and quickly make a drawing for the manifold tailored to the needs of a non British Colonial car. |
| Neil Ferguson |
| Stupid me, forgot that you drive on the wrong side of the road in Australia. I'll go and have a measure. |
| dominic clancy |
| Neil The knuckle is 16.5 cm below the level of my heater shelf. If you could just lay a flat plate in the heater shelf and do a measure from the lower edge of the plate down to the bottom of the carb throat, I can do the sums from there. Thanks Dominic |
| dominic clancy |
| Dominic..the UJ top is 15.5cm below the front top of the shelf on my car using a spirit level and rule . I could not easily get the other Carb measurement you proposed so I measured down from the top of the carb to the shelf top ( gives 5cm ) in the same way. I then looked up the total height of the HIF44 , 20.879 cm , on the sucarb.co.uk site and allowing for the 10deg angle ( reduces vertical height to 20.7cm...such precision!) gives the shelf to bottom of carb distance of 15.7cm ...so this gives an interference of 2mm ..very close to my previous measurement (3mm). I have re-calculated and drawn a full scale 20deg kick up and get an increase of 1.4cm from the 10degree ..so believe this would give sufficient clearance. As a check on your car v mine I measured the vertical drop from the top of the rear of the Judson housing down to the same datum, the shelf, and got a distance of 7.9cm...this will obviously affect the height of the carb as well...check on yours. |
| Neil Ferguson |
| Dominic.....an addition to clarify last post.....the reasons I did not use a flat plate lying on the shelf are two fold.... The shelf seems to slope down rearwards ( this could explain the 1cm diff. between your relative UJ height and mine). My shelf is covered with insulation and many other clamp downs....but front edge is accessible. Of all the measurements given the important ones are the vertical distance down to the UJ from the shelf edge and the height of the Judson housing rear above the shelf edge . I took the car for another longish rapid drive and the performance difference AJ ( After Judson) is remarkable and truly enjoyable. I also mentioned previously re the much longer choke time AJ ..is this normal? air temp is about 15degC Doing all these checks with the spirit level I noted the engine had a distinct slope down to the left of the car ( looking forwards from seats )and the body had a slight slope frown in the same direction. The latter would no doubt be corrected by me on the seat...but the former..just due to the Judson!!! ??? |
| Neil Ferguson |
| Thanks Neil Seems like a 20 degree angle may be the resolution, I will have a go at my drawing to see what that would change. I have to confess to never having used the choke in my Judson, but in the one I just fitted, it is needed until the engine warms up. But both are still on the Holley carb, which has to be set to run richer at the lower end in order not to be lean at the top end. With the SU, because of the variable jet, I would expect this behavior to change as you report. That you need a long period of choke suggests to me that the needle at idle is too lean, even though the profile at speed is better. Could I suggest richening a half turn on the screw and see what that brings. I know it is really awkward to get to - maybe we can find an extended screw for this to allow easier adjustment than currently the case. Dominic |
| dominic clancy |
| Dominic..the choke problem was due to a restricted trajectory for the cable interfering with its operation...I adjusted and all is fine. Choke out until engine warmish then in... Took the car out for a 100km fast drive through hilly countryside and it performs well through the range. I was particularly pleased to see the way it could still pull reasonably in 5th going at 50/60 km through a few small towns and it also made many of the hills in 5th that I usually needed to drop to 4th to surmount . Checked one plug afterwards and grey...BBA needle looks pretty good. I also jury rigged up my boost gauge to see what I was getting and it was up to 4psi ....but also noted afterwards that the belts had loosened so tightened them up. |
| Neil Ferguson |
| Last big job for Judson ( I hope) ....installed a boost/vac gauge and a voltmeter under dash under the two stays. It is fitted to a shaped piece of wood (which can't be seen) to lower and angle it and set well back clear of gear stick and leg. Gauges are from Precision Instruments in US, antique style and reasonably priced ( unlike the extortionate Judson gauge..old or new ). Gauge holder is a cheapie from SunPro and cost $16. PS It is square...IPhone pic distortion.  |
| Neil Ferguson |
Mistake in previous post..Gauges were from Classic Instruments...pleasant looking..see photo of boost below..
 |
| Neil Ferguson |
| Dominic.....Pic of the total under bonnet layout. The Judson/SU layout looks logical and access to the filter is easy ( just installed a APT billet stub stack inside the housing...after a major shaping and tailoring job). The car starts,idles and drives really beautifully and I have been using most days. I am getting about 30.2 miles per imp gallon (equiv to 9.3 lit/100km in Napoleon units) and plugs look healthy and grey.. A real pleasure to drive and I can keep up with the modern traffic,overtake on hills etc. I now need the front anti sway bar. Many thanks for the idea of using an SU HIF44 . How are things your end?  |
| Neil Ferguson |
| Hi Neil I've been too busy again to do anything. I'll try and get the drawing doe this week and get the first attempt modified. |
| dominic clancy |
| Dominic..it sounds like all you have to do is cut off the flange - cut the new angle on the mani fold and weld the flange back on again. Good luck..... |
| Neil Ferguson |
| meant to bump this one There are a few issues with the first attempt that I want to correct with v2. I can keep what I have on the main part under the blower, but will have to get a bit more creative to raise the carb and not move it further rearwards. a 20 degree angle will cause issues with cable mountings against the rear of the blower unit. |
| dominic clancy |
| Any news from the Judson crowd regarding SU? I've finished my Judson installation with a Holley, but I've already sourced a SU HIF44 on ebay and plan to build a manifold as a winter project. Until now I've covered about 100 miles without a problem execpt a speed ticket yesterday :( I've the impression that it runs a bit on the rich side with a 62 Jet in the Holley and I think also there should more power! According to my VDO Vacuum Gauge I get about 18 mmHg when ideling, about 12 when cruising and sometimes while shifting it gets up to about 25! WOT shows only 1-2 psi boost!! Dominic, to you have any ideas regarding my low boost reading? I left my settings untouched (valve, plugs, ignition etc.). Tomorrow I plan a 200 miles trip up to about 6000 feet (Klausenpass for the locals) to get more expierence. Beat MGA 1600 |
| Hofmann |
| I have picked this up again during a party for our national holiday. I have to raise the carb about 2cm to make this work, and have agreed an appointment with a friend to modify and weld up the manifold so that it will work dimensionally. the selection of a suitable needle is an independent exercise, after resolving the issues with interferon between the column and the carb. |
| dominic clancy |
| Beat I think you will already ave noticed that the car has a lot more power,even if you see gauge readings that make you want independent confirmation of this. |
| dominic clancy |
This thread was discussed between 02/01/2012 and 01/08/2012
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