MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG TD TF 1500 - 4.33 conversion

I need to know the wisdom or not to change out my MGTD Mkll rear end axle. I bought the car, had it delivered and this option is now available. How can I tell what I now have in the 1952 MGTD Markll? I know there are words related to the car coming with a 5.125. We live in Georgia where roads are flat for the most part. I won't be driving this car more than 100 miles away from home. I need guidance on this decision. Own of 4.3 is a garage owner specializing on rebuilding foreign cars. He is asking $1000 for the hub to hub axle.
Plus shipping.
I don't know why the photo is upside down but this is the car.


Paris vonRabenau

Paris - gl;ad to have you here. The Mark II came with a 4.875 differential, while the standard TD came with a 5.125.

The 4.3 swap is useful if the car is driven at higher speeds, where the engine RPMs feel too high for the sustained speeds. If you will be driving only locally, less than 100 miles, and not on highways, I would not consider that you would benefit much from the conversion.

I'm happy to answer any Mark II questions for you.

Tom Laqnge
MGT Repair
t lange

Hello,
I did the conversion on my TD this winter. The engine is a stage 2. With the 5.125, I could never have accelerator fully down, I always stopped when the RPM was reaching 5500. The car was very lively and a pleasure to drive. Now with the 4.3 I can't feel the difference for 1st. Second is quite equivallent Third is great and top is a little soft but the car can reach more than 80mPh whith full power applied.
Remember also that despite the wheel torque is decreased for 4.3, you keep each gear for a longer distance.The time to reach a certain distance starting from stop maybe the same.

I was in the same decision process one year ago and what decided me is the wear-out of the engine which is improved with the lower RPM.
No regret.

Read the Cedarstrand article. Well documented for choosing your option.
http://www.ttalk.info/RingAndPinion.pdf

Laurent.
LC Laurent31

I converted my TD about ten years ago. I then sold the car to someone who lives in the Lake District in England. This area has lots of hills and steep roads. The new owner contacted me to see if I still had the original parts so he could return the car to standard. Apparently the new ratio didn't cope well with inclines.

Jan T
J Targosz

Hello. I have a 1952 TD with a 4.3 rear end and enough engine upgrades to be at least equivalent to a MkII. And, I live in Marietta. I'd be happy to let you take a spin in Lazarus to try it for yourself.

I agree with Tom Lange, considering your anticipated driving, I would not expect you to benefit from the conversion from 4.875 to 4.3.

Bud Krueger
Marietta, GA
email shown above
Bud Krueger

I can only recommend the 4.3. We have hills where I live (probably higher than the Lake District) and it is absolutely fine. I am a low RPM driver an really enjoy the nice sound at 2500-3000 RPMs.
Best modification to the car you can do imho.

1000$ for the conversion is a fair price if the material is included.

Rgds Mike
Mike Fritsch

The English Lake District has a number of extremely steep roads, e.g. 1 in 4, which I imagine is 25%. In my TF I have 4.55:1 in combination with a Ford Type 9 box, so 4th is 4.55:1 and top is much higher (only good for the flat). Its a very flexible and usable combination.
Dave H
Dave Hill

Flatland rural Georgia I believe (as remarked)if I would know the difference. Having an investment is not just about me. There will be the next owner after me thinking ahead. I think the $1k is in the rafters too. Then I have to install it. The core is said to refund $500 but postage for all is at $500. Nuts. How can I tell what is in the car now? Is there a case marking?
Hey, Bud Krueger! too far to drive this little gem. Trailer to a show perhaps. Is there any in Georgia.
Thanks all, eyes wide open. I appreciate the help.
Paris vonRabenau

Sorry to hear that. Some of us think that TD stands for To Drive. Drove mine down here, from Massachusetts, 2 years ago. Planning on driving to College Station, Texas, next May. Guess I won't be seeing you down the road. Cheers, Bud.
Bud Krueger

Ford type 9 box has a fifth gear of 0.82:1, so with a diff of 4.55:1, the overall fifth gear ratio becomes 3.73:1.
R WILSON

To identify the actual ratio is easy. Jack up one rear wheel. Paint a white spot on the prop shaft and turn it for the jacked wheel to do excatly half a turn.

The number of turns of the propshaft directly indicates the ratio.
Approximatly
Between 4 and 4.5 : 4.3
Between 4.5 and 5 : 4.875
A little more than 5 : 5.125

Laurent.



LC Laurent31

Correct. Seems a very high ratio, but I use it all the time on the flat above 40mph. Drop down to 4th and its a very flexible 4.55:1. Just like top in many other TFs.
Dave H
Dave Hill

It is very high - might be better to go for a 4.875:1 diff, in which case the overall fifth gear would be 4:1, which would be much more tractable.
R WILSON

Paris, there are lots of shows and other driving events in Georgia and throughout the southeast. Consider joining the Southeast T register or the Peachtree T register to stay on top of all that's going on.

Jud (South Carolina)
J. K. Chapin

Sorry, Jud, the SEMGTR no longer exists. Bud
Bud Krueger

Trailer a TD..to each his own..but what is the point? I ave been N. Illinois to Dallas twice, Vermont once, around Lake Michigan once to Central Michigan twice, my next trip is to the west coast and the Pacific coast hwy. if people close to me would stop dying I would have covered more ground by now. Regards, Tom
tm peterson

Gents: Lifestyles differ. This Mark ll came with a 4.8. After reading your replies I have decided that the additional work and money to improve driving on an interstate highway is not my idea of a rewarding experience. I won't be driving this to prove anything. Just pure satisfaction. Windshield down, goggles on and hole popped through the tonneau cover sometimes zooming down the country roads as I intended. I learned much here which is really important to know. Limitations especially. This car was built to run at 40-50 miles per hour all day long. That's exactly what I will do. Wine in a basket and a gal by my side. Cheers
Ps: How about the frogs trick to tell what the ratio is by turning a jacked up wheel? Merci beaucoup!
Paris vonRabenau

This thread was discussed between 29/08/2018 and 31/08/2018

MG TD TF 1500 index

This thread is from the archives. Join the live MG TD TF 1500 BBS now