Torque Twist

[JonathanK]

Hello fellow wedgies.

 

Just about to get my 8 back on the road for the summer and put it into a garage I know to get it tuned, checked and Motted. It's been off the road for 18 months and runs like a dog.

 

Engine now sweet but they commented on the amount of twist on the back end when changing gear under hard acceleration.

 

I've noticed it in the past and put it down to age of the car design and trying to get about 185 horses down on the tarmac.

 

They seem to think that the axle bushes may be in the wrong way.

 

Can anyone shed any light on this?

 

Thanks

 

JK

[Guest hodgie]

Presumably the trailing arm mounts are ok? You said it was MOT'd so i presume so. I had one almost break off on my 8 a while ago and the back end was pretty much hanging off.

It should be easy enough to check if the trailing arm bushes at chassis and axle end are OK. I have known the bushes to wear and the locating bolt to have widened the hole where the trailing arm mounts to the body. Again, should be able to see that relatively easily. Wouldn't have thought it could be anything else, but an expert i am not. Anyone?

[anthonyt]

If you are still using the original rubber bushes in the control arms i have had the situation where the oval shaped bush at the front of the arm had turned resulting in one arm moving more than the other and a decidedly emabarrising 360 as a result on a hill climb.

 

Poly bushes cured this and the severe axle tramp that went with the problem.

 

If they are referring to the squat under accelleration resulting in the car twisting longitudinally (if it is a convertible) that cannot be cured without a roll cage, stiffer springs mask the problem somewhat but with a big engine you cannot get away from it.

[andrewt]

Johnathan

The standard way the rear rubbers are installed in the bottom arm is with the rubber orientated up & down, otherwise the spring loads would permanently distort it. what this means though is that the axle is efectively located fore & aft by the rubber bridge which in turn is allowed to deflect due to it being a void bush (with air gaps). These voids are designed to give a nice compliant ride, perfect on american boulevards maybe, but hopeless on our roads with a big engine. I have experienced exactly what you describe in a car i did some tuning work on a few years ago. it is easily solved by fitting a competition bush set from one of the usual suppliers. this will make the car much nicer without too big an impact on ride comfort.

I have gone further than this. I replaced all the bushes on all four axle links with spherical bearings (rose joints!) This means there is no compliance at all to deflect the axle. it gives a firm ride that is not excessively noisy as long as you don't drive over too many cats eyes or rumble strips. Whilst i don't recommend this to the average Tr driver, i would recommend you change out your bushes for 'competition' ones, as long as your bulkhead & floor are sound.

Andy

[Maxwell]

You Lot... Have you booked for the TR-Marque Day [sunday 15th May] in Kent yet?  We need as many Wedgies as possible....  Maxwell :laugh:

[andrewt]

Maxwell, you paying my fule costs to drive down from Aberdeen? Otherwise i would love to!

 

Enjoy it anyway :laugh:

[anthonyt]

i need an airfare from austalia and the car air freighted can the budget stretch that far maxwell?

[tr8coupe]

:blues: just add a drag link and no more twist on the axle  

 

 

 

happy

tr8ing