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MG MGA - Judson Installation Questions

Started tearing down the engine bay in preparation for installing the Judson and have a couple of initial questions. Those of you using a Judson...

1) did you set valve tappet clearance as .020-.022 as per the instructions? Sounds like a lot of slop compared to the normal .015-.017.

2) are you using "standard" spark plugs (eg NGK BP6ES) or did you switch to a colder plug (eg BP7ES)?
Andy Bounsall

Andy, the standard NGK plug(as recommended by NGK) for the MGA is B6ES http://is.gd/ZjHq85 Not as prone to pinking and running-on as BP6ES.
Lindsay Sampford

I have used the Bosch plug that cross references to the BP6ES without any problems at all. I have swapped to a hotter plug with the new engine, and will have to look and see which one it is.

As to the valves, I left them where they were, but I suspect even with more slop you won't hear it except at idle - the Judson makes a fair bit of noise.

Have you checked out my page with tips and tricks for the installation? Most important is to rotate the fan blade after installation and before starting to make sure eveything is clear of the blades - there is really very little space for error here.
dominic clancy

You've got a great website Dominic. Yes, I have been checking out the info you mentioned. Thanks for the tip about the fan blade. I'll be sure to do that.

When you say you switched to a hotter plug, do you mean the equivalent of a BP5ES? Wouldn't a hotter plug increase the tendancy for pinking/detonation?

Lindsay, you are right. NGK website does recommend B6ES for the MGA. Interestingly though, they recommend BP6ES for the 1966 MGB engine that is in my car.
Andy Bounsall

I use Bosch R7DC as far as I can read on the plug
dominic clancy

So far so good. I have the crank pulley installed, which was a pain in the butt. Had to jack the engine up to change the harmonic balancer, then nest the new pulley inside it. The good news is that with the engine back in place I've got just shy of 1/4" clearance between the the supercharger drive pulley and the steering rack.

I've mounted the Judson intake manifold on the engine. Haven't installed the compressor yet, but a quick positioning check suggests that I may not have to trim the 4" fresh air cuff either.

Next question...Where does the vacuum advance from the distributor connect to the carb? There is a brass hose barb on the carb-to-compressor manifold driectly below where the carb mounts, but that, I believe, is where the oiler hose attaches.
Andy Bounsall

Andy, The vacuum advance if used attaches to a fitting on the carb. My carb is appart but I will try to post a picture tomorrow of the attachment point.
James Johanski

Andy

You can see the barbed fitting perfectly in this photo

http://clancy.ch/Holley_Carb.html#0

There is more on the carb here

http://clancy.ch/Holley_Carb.html
dominic clancy

Thanks. My carb currently has a plug there so I'll have to source a suitable fitting.
Andy Bounsall

What fuel line/fitting are other folks using?

The instructions say to use the original line that ran between the two SU's. The line looks like it'd be long enough, but the original banjo bolt is bigger than the one George put on the Holley. The banjo is too big for the new bolt. See attached photo - original bolt on right, Holley bolt on left with original banjo. Perhaps I could use the original fuel line if I added an additional washer on either side.



Andy Bounsall

I have two versions

one is a banjo and bolt, the second is a right angle fitting that goes straight into the carb. Both are the same thread as the end of the fixed fuel pipe

Be careful here, there is almost no space between the carb and the back of the supercharger - so if you use too much distance, you will find it impossible to mount.

The right angle fitting seems to work best from a space perspective.

I'll take a photo of both carbs and let you see what I have - I just have to find my camera first, been searching for it for a few days .....
dominic clancy

So you didn't use the original fuel line / banjo fitting from the SU's then. I wondered if it was just something weird about the fittings on my car. I'm interested to know where you got the new fittings and fuel line from Dominic.
Andy Bounsall

Another thing that I'm wondering about. With the Folchi supplied fan spacer on and the radiator mounted with the Judson spacer bars, the fan is extremely close to the radiator (see photo). There is perhaps 1/8" clearance between the blade and the radiator at its closest spot (blade section closest to the center of the fan). Slightly more space toward the outer circumference as the blades appear to be angled back ever so slightly.

I'm wondering if this will be sufficient clearance. Would the blades of a steel fan deflect forward at all at speed? If so there may be contact. Interestingly, Dominic warned me to expect a very close fit between the fan and idler pulley, although I find on my car that there is about 5/8" of space there. I'm wondering if I should do some disassembly and have the fan spacer machined about 1/8" narrower. Opinions?



Andy Bounsall

Here's a photo of the space between the fan and the idler pulley.


Andy Bounsall

You are misplacing the radiator spacers, which move the rad forward by about 1cm. They are solid bars that should mount between the rad and the rad bulkhead, and there's no sign of them in your pictures, see here for how it should be

http://clancy.ch/Judson_Photos_files/117.jpg.

and

http://clancy.ch/Judson_Photos_files/126.jpg

The right angle fitting came from these guys, the banjo too,
http://www.vintagesupplies.com

the banjo bolt came from George (it was my query that made him realise that a banjo was the probable original fitting here)

If you machine the fan spacer, the belts won't align with the different pulleys, and you will have belt wear problems,or they will just be thrown off because of the misalignment
dominic clancy

With one belt only, do you even need the fan spacer? It may be that you have enough clearance for the fan without it
dominic clancy

The recommended plug for the Moss SC is BPR7ES
dominic clancy

Dominic, I do have the Judson spacer bars installed and the radiator moved forward. It occurred to me this afternoon that the nose of the water pump used on the 18GB engine is probably a bit longer than the MGA water pump. That would explain why the fan is so close to the radiator.

I'm nervous that under hard braking or an emergency manouver, the engine could shift forward on it's rubber mounts enough to cause the fan to contact the back side of the rad. I've measured and removing the fan spacer completely would cause the fan too contact the idler. I'll have to do some disassembly to remove the fan spacer and then find somewhere to have about 1/8 to 3/16" machined off of it. With that, the fan should be about equal distance from the radiator and the Judson idler pulley.

I had a quick look at the web site you mentioned and didn't see anything that looked like the banjo or right angle fitting which you described.

Funny, of all the things I imagined having problems with, neither of these issues ever occurred to me.
Andy Bounsall

Andy, It looks like Dominic beat me to your answer. Sorry, got tied up with family matters the last couple of days.
Thank you for the information on your pulley sizes.
You are correct in regard to the MGB pump. It is just a bit longer than the MGA pump nose. In fact the extra distance is almost equal to the fan spacer in an original Judson MGA kit. Your decision to make the spacer thinner is correct. The fan must clear both the radiator and the supercharger drive belts.
I have not yet completed the engine on my restoration project but hope to do so this summer, so I am most interested in your experience and results.
This is great fun!!
James Johanski

James, thanks for confirming my suspicion about the MGB water pump.
Andy Bounsall

elbow and banjo here (it's a useful site but very badly orgainsed

http://www.vintagecarparts.co.uk/en/list+taps,+pipe+and+fittings~fittings/

I have found my camera, I'll go and take a few pictures now
dominic clancy

Here you go for the elbow




dominic clancy

And the banjo is an even tighter fit

I had issues here too when fitting the Judson the first time. Both of these approaches work well, although a little thread sealer is also a big help in stopping weeping at the thread of either the banjo bolt or the elbow

Hope this helps you out




dominic clancy

Thanks for that Dominic. I'm looking at the fittings on the Vintage Supplies page you pointed me to...I assume what you have there is part #368?
Andy Bounsall

Good news...for me anyway. After removing the radiator I was able to see that I had more clearance behind the fan blade than I thought. Short version of the long story is that I've removed both the fan spacer and the radiator spacer bars. With everything back together there's now about 3/16"-1/4" clearance both infront of and behind the fan. I can live with that.

Now if I can just get the carb, fuel, and vacuum lines sorted out...


Andy Bounsall

Good news...for me anyway. After removing the radiator I was able to see that I more clearance behind the fan blade than I thought. Short version of the long story is that I've removed both the fan spacer and the radiator spacer bars. With everything back together there's now about 3/16"-1/4" clearance both infront of and behind the fan. I can live with that.

Now if I can just get the carb, fuel, and vacuum lines sorted out...


Andy Bounsall

Andy

No idea what part numbers I have, it's all too long ago, but I dare say I could find the bill if pushed

Dominic
dominic clancy

Dominic, The picture of the gauge face looks pretty good. I am playing with the size to use for printing to the gauge face size--looks like close to 57% will work when printing in photoshop. This image is noticebly sharper. When I get the print scaling correct, I will print it on some decal paper, if I can find where I put it. I think I have some white and clear. I will let you and Andy know what results I have.
James Johanski

Andy, Looks like a good fit without the spacer. How close are you to the steering rack? It is inspirational for me to see your supercharger going together, and will be exciting to see the performance results.
James Johanski

Dominic and Andy,
I used Dominic's sharpened guage face image and printed a couple of samples of the guage face on both clear and white decal paper. The white paper was significantly better in the density and sharpness of the black printing. I recommend using only the white decal paper to print a face. I printed from photoshop, and used a 50% reduction in the file size to achieve the correct face size. I used the highest 1200x4800 dpi printer setting on a HP 8200 colorsmart printer. Besure to use either a photopaper or transfer paper setting rather than plain paper to get a dense black backgound on the white paper.
Hope this information is helpful.

James Johanski

Hi Johanski

I can't get that paper here - any chance of you sending me a printed decal?

Dominic
dominic clancy

Dominic,
PM me with your address. I can mil tomorrow or Saturday.
James Johanski

Got the fuel line sorted out. I'll post info later about the fittings I used. Got everything else finished up except the vacuum line, which I'll sort out later. For now, I just have a plug in the vacuum port on the carb.

So...I was ready to give it a whirl. It started up right away. I adjusted the oiler for a drip about every 4-5 seconds, let the engine warm up, and set the carb idle and mixture to get it idling reasonably well. The supercharger was making a bit of noise, sounded a bit like a constant clicking/scraping noise. I assumed that is to be expected.

So off I went for a gentle trip around the neighborhood. A minute or two into the drive, it started to make more noise...a LOT more noise. By the time I got back home it was making a terrible clackety-clacking noise. I checked the oiler again and tried increasing it to a drip every 1 or 2 seconds. No change. Still making that LOUD noise. I shut it off and let it sit for a minute. When I started it back up, it sounded OK at idle but as soon as I gave it a touch of throttle the loud clackety-clack noise resumed.

The Judson instructions say that it's normal for the supercharger to make some noise for the first little while and not to be concerned, but this is a LOT more noise than I was expecting. In fact, when I came back in the house my wifes comment was, "That didn't sound very good!"

Help! Any ideas?
Andy Bounsall

Andy, You need to call George. You are either getting detonation or your vanes are making that noise. Check your timing, but it is probably the vanes. What did the rotor vane slots look like before and after rebuild.
James Johanski

Thanks for the reply James. It's defiitely not detonation as the sound is coming from the blower. I just heard back from George as I'd sent him an email last night and included an mp3 of the noise. Georges reply...

"It sounds like a vane is sticking a bit. I believe this will loosen up over a bit of running time. Give it plenty of oil as you are. Put a few miles on it, again around home.

I have had others do this, reopened them up, and found absolutely nothing wrong. Please bear with the racket for a while, as it should diminish in about 50 to 100 miles of use. A lighter rattle is normal."

I guess I'll do as he suggests and drive it some more. As I said, it's more noise than I was expecting so I just wanted to be sure it wasn't self-destructing.
Andy Bounsall

I can confirm what George says. Just on my way to put the Judson back on - engine has about 600 miles on it now, so should be nicely run in.

I also have to change the seal at the crank pulley as it's giving up the ghost (rather too soon for a newly built engine...)
dominic clancy

Mine worked just fine with BP6ES plugs and stock valve clearances.
Bill Spohn

In case anybody is still following this thread...

The rain let up long enough yesterday that I could get out for a bit of a drive. As George Folchi predicted, within 15-20 miles the loud cacophony had lessened. By the time I returned from a 40 mile trip the sound level was down to what I'll assume is normal (based on observing one or two YouTube videos).

I've got lots of fiddling to do now to sort out the vacuum line and get the carb mixture, timing, etc adjusted properly. With the pre-Judson timing setting I could barely even touch the gas pedal on a level road in 3rd or 4th gear without pinking. I did a quick road-side adjustment (i.e. loosen the clamping nut, give the distributor a slight twist, tighten the nut, try it, repeat...). No idea what the timing is set at right now but after 3 iterations I eventually got it to where I could go for a drive. I'm going to try a cooler spark plug to see if that'll allow me to advance the timing a touch. I think there's going to be an on-going trial and error period while I try to get things set up properly.

Here's the info/pictures I promised re the fuel line connection. I checked 3 different fittings as seen in the attached photo.





Andy Bounsall

First fitting is a simple straight hose barb that I found at a local fastener shop. It could work in a pinch, but the fuel hose was touching the side of the blower and was pointing in the wrong direction.


Andy Bounsall

Second is a Holley 90 degree fuel line fitting (Holley part# 26-44). Not good. The fitting couldn't be screwed into the carb far enough to make a tight seal and the pipe was long enough to touch the blower, interfering with the carb mounting.




Andy Bounsall

Third is a Holley banjo fuel fitting (Holley part# 26-25). This comes with a 9/16" banjo bolt, which is too big for the 1/2" fitting on the 1904 carb. However, I discarded the bolt and used the banjo fitting in conjunction with the bolt and fiber washers supplied by George Folchi. George's bolt was just a hair too long, so I added one of the (aluminum?) washers that came with the Holley fitting to space it out and...Bob's your uncle!
Andy Bounsall

Hi Andy,

I'm still following your thread, as I am sure others are as well. I'm really intrested in learning how it turns out and what kind of improvement you seem to have gotten from adding the Judson to you MGA 1800. I've been told by a couple of others that while the Judson works well on the 1500 and 1600 but its a little small for the 1800. Please prove them wrong!
Ed
L Brorein

I see that the photo of the Holley banjo fitting & Folchi supplied banjo bolt didn't show up in my previous post for some reason. Here it is.


Andy Bounsall

I have the vacuum line connected now and have switched to cooler BPR7ES plugs. Adjusted the carb mixture a bit (it was a slightly on the lean side). I was able to advance the timing a bit without any noticable pinking.

I've still got some fiddling to do, but the car is getting to the point of being quite drivable. The weather forecast looks promising so I hope to get out for a good run this weekend to put it through it's paces.

Dominic, I've seen you mention the J&S Safeguard in several threads in the archive. I'm considering one of these units myself. The current version includes settable boost retard and John of J&S tells me that using this feature negates the need to have your distributor recurved for the supercharger. So I'm wondering, are you still using this device on your car? Any problems with it? My concern is whether the somewhat noisy valve train of our engines combined with the inherent rattling of a vane type supercharger interferes with it's ability to properly detect knock. Any comments positive or negative would be appreciated.
Andy Bounsall

This thread was discussed between 06/05/2011 and 20/05/2011

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