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MG TD TF 1500 - Adjusting the SU's and timing
I am Joop and living in The Netherlands and new here.
I bought my restored TD a few months ago but even the car is in very nice condition I still want to get my hands dirty, Anyway I checked the ignition with a flash-lamp (stroboscoop) and i saw that with the warm engine at 800 rpm the flashing white strip on the pully was at least 4-5 cm in front of the needle and I changed that to 2 cm, because TDC didn't felt good...but maybe it is? So my first question is was it good to change the timing like I did? Second question is about the adjustment of the carburators. I put the 0.8 m/m metal strip between the piston entrance and the rpm went up (too rich?) so the two hexacons one flat clockwise but because it's not a exact science i didn't trust my work and put the hexacons back where they were. Can anyone of you explain me in simple way how to check these carburators for rich/poor? They look to me completly rebuild by the last owner so they are in good condition but i want to figure them out.
Thanks for help :-)
Oh by the way the car is from 1950 and it's chassis# 2590 and engine# 2928, it's a import from USA in the early 90's Body colour is prime rose yellow with darkgreen leather and beige roof and tonneau cover
Best regards, Joop
Where are you in the Netherlands? Maybe you can drop by in Ermelo so we can let my Colortune loose on your SU mixture? That way your 1950 TD can also have a chat with my 1950 YA.
|Willem van der Veer|
|Hi Joop - congrats. on new car and welcome to the 'T' type brotherhood !|
Re. timing, it is best to start with a static method - see Archives for info. but the TDC notch on the crankshaft pulley is too retarded for modern fuels and is the main cause of overheating etc. Assuming distributor bob weight springs are OK ( they are different!) many find 4mm in advance of the pulley notch about right giving around 5 degrees advance static. Even Morris Minors of the time used 4 degrees advance so why MG suggested TDC is beyond me !
As regards your carbs I find the Colourtune as suggested by Villem an excellent method of getting the mixture right.
Good luck, John.
Thanks guys for the response; I feel perfect at home here!
Willem I am in Utrecht (030-2730392 evening) and I could drive to you with the TD, because it runs very sweet. Speaking about sweet running; 60 mph comes up in a moment but my god the rpm's are so high! I was reading somewhere on internet about a pumpkin of 4.55 or 4.22 of a Morris Minor to get the rpm down on a TD, does anyone here has any experience with that? I think that pumpkin needs a little machine-work to get it in the backaxle of a TD? But boy oh boy would it be heaven to wind the engine not so high up...
Thanks for this perfect way of communication to improve TD's and I wish you all a very SAFETY FAST :-)
PS. Willem maybe you can give me a call and get together? 030-2730392 Or write me: firstname.lastname@example.org
|MGA gears of 4.30 can be used.. quite a few here have installed them. Machining is required. The rpm's drop about 800 or so.|
|gblawson - TD#27667|
The Morris Minor pumpkin swap you are talking about concerns the TC back-axle (and I hope the YA axle).
The MGA gear swap is much talked about in the Archive section. I'll call you tonight anyway; let's see how we communicate in Dutch!
|Willem van der Veer|
You can take off the air filters or the standard air inlet (which ever is fitted) and with the blade of a thin screw driver, lift the piston in the carb ever so slightly (about a millimeter will do). If the engine speeds up and then settles back, the mixture is correct. If the engine speeds up and stays there, the mixture is rich, and if the engine drops and stays there, the mixture is lean. Turn each carbureter jet one flat of the hex and try again if needed.
The engines are happy at 4500 RPM, which should be about 65 MPH or about 100 KPH. Unless you need to run faster, you can safely run them at high RPM without concern. Most drivers seem to feel safer at 4000 RPM. In top gear with standard tires and the standard rear end, you should be seeing 14.4 MPH per 1000 RPM. Here in the US with the Interstate Hwys and such, a change to the 4.3:1 is a good idea which gives about 17.2 MPH per 1000 RPM. I'm not sure what kind of highways you have in Netherlands, so you can consider my observations as you see fit!
|JOOP Congratulations on your TD. You will find the best group of guys in the world on this BBS. Just about any problem you can imagine can be solved on this BBS.|
In your case, the colortune spark plug is an excellent way to set your mixture. Just be aware that the color should be set to the blue that the instructions call for then enrichened till it just shows a little yellow. Severel of us have been there, done that. Seems the fully blue color is close to the 14.4 air/fuel ratio that a modern computer controlled engine runs at. Our antiques like something a bit richer.
The engines will stand the high RPM's OK but the wear factor goes way up. You will need to rebuild at 20/30,000 miles. I run a 4.3 set of gears from an MGA. Machining as such is not required but different bearings are required.The pinion shaft is slightly larger than the TD pinion but there is a bearing that fits in the axle housing and can accomedate the larger MGA pinion shaft. I recommend that you look carefully at the axle shafts because they are prone to break at the splines for the differential. Before they break they will show twisting!!
Just my $.02 worth.
|R. K. (Bob) Jeffers|
The most important thing for anyone to learn about SU carbs is this: ONCE THEY ARE SET UP CORRECTLY, KEEP YOUR HANDS (AND TOOLS) OFF THEM UNTIL THEY START LEAKING FUEL FASTER THAN YOU CAN TOLERATE !!!! SUs will stay in tune for YEARS IF they are not messed with or "adjusted" every time the engine "....doesn't seem to be running right" Almost always, people who complain about problems with SUs have actually CREATED the problems themselves by "ADJUSTING" the carbs.
|Carl...you are so right... had mine rebuilt and adjusted on a bench... bolted them on and only had to adjust the idle a touch...that was 4 years ago!|
|gblawson - TD#27667|
|Best sources (besides this board) for specific carb and other tuning: The book put out by the New England MG-T register "The T-series handbook"- the chapter on carb tuning makes it almost idiot-proof, and the NEMGTR's "Scared Octagon" magazine CD, which has all of the bimonthly magazines going back many years until 2004, with a searchable by subjetct data base. You can't use the factory shop manual much, because you just can't trot down the street to your friendly Lucas agent any more! George|
|Ok guys thanks a lot!|
I will keep my fingers off the SU's but that colortune sounds as a good idea, so first i will check the color of the first and last sparkplug (because they are the furthest away on the engine). Willem van der Veer was friendly enough to give me a call lastnight (thank you!) and we talked cars and oil and more cars :-).
I wanted to do differential-change with a 5.44 of a Morris Minor but soon enough I realised that it's not a 'plug and play' mission to swop it for the 5.125 that is original..oh well I will slowly search for a back axle of a MGA. On 13/14/15 July 2007 there is a big classic car concour délegance in Germany (Baden Baden to be precise) so people on the european mainland I can recommend this event because very rare cars turn up there and a very good atmosphere...but I'm telling this because I want to drive the 550 km in the TD, so no trailer! Probably I will take the small roads along the river Rhein...so from Arnhem to Koln and Mainz and so further up the river, loreley etc. Beside checking fluid levels is there more to be looking at with this trip up and down?
|JOOP I don't think you want to change to a 5.44 ratio. That will make your engine rev even higher. You want to get down to say 4.3 0r 4.1 ratio.|
Of course if you are going to do hill climbs exclusively then maybe the 5.44 is going to be what you want.
Are you going to uprate the engine at all?? That makes the lower gear ratio numbers even more attractive.
|R. K. (Bob) Jeffers|
Your description of that trip brings back happy memories. I made it once in a rental car and once on the train. We should all be so fortunate, even with the risk of a breakdown! Be sure to pack a good tool kit with extra plugs, points, condensor, distributor cap and fan belt, just for starters. Also, there is probably the need for weather gear, but we do not need to tell you about that.
|Oh sorry Bob the 5.44 ratio was a error of my pen, ofcourse it should be 4.55 or 4.22. But for now I will stick to the standard ratio 5.125 because first I have to find a MG A backaxle...and good ones are not at every corner:-) The real high reving starts between 65 and 70 mph and to be honest it's rare that I drive such speeds, but the engine handles it fine and surprisingly it doesn't feel stressed at all but I think it would be better for a XPAG of 57 years old not to be winded up too much too often. |
Uhhmm uprates? You mean a judson blower or sharper camshaft? Well maybe in future...
Here a picture of my dream on wheels :-)
|Tom, how nice that you pictured that Rhein river...in the past I drove that road and I would sometimes take my father with me (he is now almost 80 years and is too fragile to repeat that exiting runs) but boy oh boy that was fun and germans on the streets couldn't believe their eyes when we roared through the small streets of every village along the water. I even took my cycle winged MG J2 (1932) ones on that stretch of road and later drove it with a so called voiturette (that's a small french racecar) named AMILCAR and for the connaisseurs among you it was a CGSS (1927), but the car had a sidevalve 1100cc engine which was too sensitive so breakdowns were common, but on the other hand to repair it and step into the cockpit with a black greased up face was a joy :-)|
Another picture of the present beast...
|Welcome on board Joop !|
You'll find this the best and friendliest place for advice regarding the TD/TF on the whole web !
And what a magnificent looking TD you have!!!
If you want more advice on the MGA differential swap you might want to get in touch with another fellow countryman: Erik van Hardeveld, who visits this BBS forum every now and then.
I thought he even changed the complete front and rear axles to MGA spec not only because het wanted the faster diff ratio, but the added benefit of having front disc brakes as well.
|Beautiful car... just as mine came from the factory (ivory/green) before being painted black!|
|gblawson - TD#27667|
|Indeed Nick thanks for the support. Yes i will trace Erik van Hardeveld to share ideas about how to get the car down in the revs and make it more enjoyable. But such a big change with front and back axles i wouldn't consider because it should stay with the feeling of a car of 1950 so not too big part swop for my tast. The same reason why i didn't change the engine of the Amilcar back in those days to a more modern Simca-unit because that just didn't feel right...but in the end I was only under the car working and less and less behind the wheel and in the end i was throwing the towel in the ring and sold it to a guy who still works and works on it. No than it's better to have a proper working TD :-)|
Here is a picture of that Amilcar CGSS, 1927, licence PP 87 94
Ones owned by female racedriver Elaine Drake of England and she was with the car on all the racetracks of GB in the early 60's and 70's, now it's somewhere in Italy....
|gblawson - TD#27667 sorry i forgot to thank you for the compliment. |
I think this light yellow or ivory is a rare colour and often mistaken for old english white?
How many people are here that have the same combination of colours?
Would be interesting to know..
I do know that the only thing not original on my car was the ugly small MOTO LITA steeringwheel, but i found already a nice used example of a 1951 car. This particular car was restored 16 years ago and had driven 1650 miles after the rebuild so time stood still on this one, the only thing I did was checking the valve clearance and ignition timing, replaced sparkplugs and a change of engine- gearbox- and backaxle oil and greased-up the chassis and that's it.
Reason for selling it was the fact that the guy I bought it from was 2 meters long and that's just too long to drive such a small twoseater in comfortable way.
The car I'm restoring will also be finished ivory over green. It originally was ivory over red, but until I took the fascia off, and saw the remnent of the red dash covering, I didn't know. When I started restoring my car (and heck, since I've owned it for over 20 years) it has been red over black.
I picked the ivory over green because the ivory was original, and I thought the green would look best for the grille and the interior.
Your car is beautiful. Congratulations.
You need to look at Gordon Lawson's site of forum participants, and perhaps send him a picture of you and your car.
|Thanks for the reminder Dave... JJ...just send a photo of you and the car together to my email address!|
|gblawson - TD#27667|
|Thanks Dave I will send a picture of me and my car to Gordon Lawson's site...very nice to see that slideshow of photos by the way. I even came accross a photo of my good friend Frank van Geldern who is working on a black TD and is now almost finished with the two year restoration, result is splendid!|
Your TD is aboutr 1500 under mine (4139). Mine is also the same color and you now have convinced me to go with the green interior (black currently).
I put the moss 4:50 differential gears in my TD. A bit of a compromise but it still allows me to get some decrease in RPM
|Hi BEC Cunha,|
Oh how nice that I have another TD-compagnion with exactly the same colour combination...flathered and I think you will be happy with the darkgreen interior, I'm sure :-)
Now for my amature thinkering:
After days of rain here in Holland wheather improved yesterday, so after work I drove the TD until warm and returned back to my garage. I still wasn't satisfied about the pulling power...it was better when i bought the car some 300 miles ago. So with my flash lamp I retarded the ignition time from just before TDC to around 4 to 5 centimeters back, and that made it better! I also used the colortune that was on the shelf for some 25 years but never used it. But starting up with that colortune sparkplug in cyl.no.1 I couldn't really see any difference in colour so than I put the hexacon of both SU's IN so against the clock and the colour went from red/orange to a pale orange and than back to the old position (which I marked with some paint) and than turned them both clockwise. The results was rather poor and the real blue colour (which they show on the package of the box) is not appearing...so what is wrong with it, and why is there not so much happening in colour change?
It was already getting dark so i put both SU's back to the old position and thought 'write the BBS guys your experience...maybe you learn something :-)
TD's and TF's seem to run rich whatever you do. I have given up on my colortune and reverted to keeping an eye on the condition of the plugs and the odd tweak on the adjusting nuts. BTW, I have had an MGA 4.3 CW & P fitted in the rear axle. You can buy them new for around £200.
Are you pressing the jets up against the jet adjusting nuts after you turn them as they could stick in the cork seals. The colour should change from orange to light orange and then to blue and the engine revs should rise as you make the adjustment confirming that you are going the right way with the mixture. I would have thought that by retarding the ignition that you would have reduced the performance.
|I have always found very helpful the information posted by Don Tremblay in the MGA archives:|
"SU jet assembly tips"
In particular, the method of starting with a very accurate maeasured depth of venturi to the top of the jet comes very close to the ideal jet setting for a properly operating SU carburetor.
This method of setting up the SU carburetor is also described in the TD-TF archives.
One of the regulars to this BB, Paul Gaynor has an Amilcar he is restoring (also has a TD MkII racer and YA). If you want to get in touch with him, let me know, and I'll send you his coordinates.
|Gordon A. Clark|
|Hi Cord, yes give Paul my e-mail adres regarding the AMILCAR. I would like to know type and year of it.|
My adres is still the same over the years:
Latest news for TD# 2590 is that I want to share with you all, is that I changed the sparkplugs from Champion to 1/2'' NGK BP6HS. And I cleaned out all the brakes this weekend. The drums came off easy and everything looked fine. All is ready for my trip on Friday the 13th to go to Baden Baden in Germany.
Yesterdaymorning I made a test run and the car is flying at almost 70 mph and after an hour of really sportive driving I check the new sparkplugs for colour and a lightbrown on all four indicates that all is well :-)
Thank you all for the answers you gave me and the suggestions (for the diff) I 'll keep it in mind and now I can't wait for my 700 mile trip in this nice little car.
The "real" colors don't appear with modern fuels. I use the Colortune in a darkened garage (with a hose outside the garage for the exhaust fumes) and look for color changes with good results.
My fathers first car was an Ivory/green TD.
Have fun in Baden Baden. In respect of the date you are traveling, before you start you should hop anti-clockwise around the car on your left leg holding a freshly killed rooster in your right hand, chanting "oh Prince of Darkness, protect this undeserving receiver of your goodness". Don't say you haven't been warned! ;-)
|Willem van der Veer|
Ok your way is fine, but I have a different approach.I bought a special handmade carpet in the small streets of the medina of marrakesh/maroc , years ago and normally I use to lay that in front of the car and go on my knees and pray out loud in western direction (Abingdon). By the way the MG means 'My God!'
Oh what fun these cars are (..when they work :-)
Cheers my friends,
So that's the way to do it !
You have to perform some sort of Voodoo act in front of your Lucas headlights !!!
Still; I think I'd like Joop's carpet a lot better....8^)
I did 600 trouble free miles touring Kent and East Sussex two weeks ago without all this witchcraft though. But I have to admit this was in the 1974 MGB.......8^)
Have a safe trip and we look forward to hear the whole story later (including all horrors....)
|The soft handmade wool carpet isn't the only thing I carry around. I have put two badges of St.Christoffel (the protector of the traveller) on the car. One is on the badgebar (next to a small metal bird that is bolted down so he can't plan to fly away) and one St.Christoffel on the dashboard...furthermore I carry the workshop manual, a tuning book of the t-type, a partsbook and lots and lots of tools :-)|
Dear God have mercy on me...!
"... the car is flying at almost 70 mph"!
According to my calculations, with the standard 5.125 CWP ratio of the TD, this means you were turning about 4860 RPM! WOW !! Unless of course, that was the speed of your (magic) carpet.
I suggest you start looking imediatly for a 4.3, or better, 4.1 ratio differential if you intend to run at that speed often, as your engine will not last long at those sustained revs.
A 4.3 will lower revs by 15% and a 4.1 by 20%.
|Gordon A. Clark|
|My magic maroc carpet was put away behind the backrest at that moment when I really hit 70 mph on the dial, I think I was doing 4500 rpm or near that mark..? But just for a moment to be honest because the car still is in the proces of breaking-in so only a few seconds and go back to 65-60 to let it fall untill 50 and than built up the speed again untill almost 65-70. I think that's the way to loosen-up a XPAG...you need to be brave and trust the work that has been done on the bearings, crankshaft and pistons ofcourse.|
But the trip up and down Germany will be in normal way so 50-55 mph not more :-)
|That seem a bit much to break in an engine... seems to me my old MG manuals mentioned not going above 50 mph and varying the rpm constantly (which going through the gears would do)... i wouldn't go above 3500 for a couple thousand miles... you have revved higher then I ever have on a fully broken in engine (well, i did do 4600 the other day for a minute or so), but 3000 to 3700 is about my range!|
|gblawson - TD#27667|
Breaking in an engine hard is perferrable to breaking it in soft. I plan to put a lot of pressure on my rings to bed them well against the cylinder walls, well beyond 4000 RPM on my maiden run, I will vary engine speed by a few hundred RPM every few minutes. This is especially true with a well broken in cam. With a new cam shaft and lifters some care may be exercised, mostly in the lubricants used, and avoiding going full RPM for the first 500 miles. But you can still load up the engine by accelerating hard in spurts.
|This is great. I just bought an mgtf which needs a lot of TLC. I don't have anything to add to this place of knowledge right now but I am getting a lot of info from it. |
|Hi Rick, |
I welcome you and congratulate you on buying a TF...a very wise decision! Besides having a car that needs TLC is it still running/driving? Tell us something about the general condition and how you got your hands on it ;-)
This thread was discussed between 27/06/2007 and 03/07/2007
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