vibration Lotus 5 speed Elite

[Icanfixit]

I have been tracking down a vibration issue with the 76 Elite. Above 60 mph the vibration comes in and gets worse with speed. better in fourth gear ans worse in fifth. Clutch depressed or replaced the same.

 

Drieshaft u-joints replaced

Rear hub bearings replaced

trans mount replaced

rear bushings inspected and replaced as needed

rear diff checked

replaced bad anti-roll bar bushing to lower arm and arm bushing

 

I have a concern it is in the trans. I am thinking about the little needle roller bearing between the shafts. Any test for this or other tests for the trans?

 

Chris

[eclat22]

Propshaft uj?

[johnpwalsh]

I thought this was a documented and well known problem on the older cars, I know several were factory fitted with lead weights to try an counteract the vibration. Starts at about 55/60 and goes about 75/80.

[Icanfixit]

Everything was fine with years of driving without this problem. It started last spring. The propshaft u-joints were also replaced. They were getting bad but that seems to not be the basic problem. When the problem started it would happen at 70 and above.It now comes in at 60. The car has 46k miles on it. I am the second owner. I have replaced almost everything and what is left has been checked out by myself and a shop.

 

I know there is a bearing in the trans that can go bad about 45k. It is between the motion shafts. Five years ago I swapped out a low mileage trans for a Lotus event. The engine was out for repairs and it seemed like a good idea. There was nothing wrong with the trans but a lower mileage unit would give me more time till something else happened. At the 11th hour I just had time to do a short test drive and put it on the trailer for a two day journey to the event. To my surprise a trans out of a 18k mile car was worse than the 40k that was in the car. Once home I swapped the original trans back.

 

Chris

Edited July 7, 2013 by Icanfixit

[johnpwalsh]

Have you checked to see if there are any counter ballance weights missing from the prop shaft

Edited July 7, 2013 by johnpwalsh

[J400GED]

_{might seem daft, but have you actually checked to make sure that your wheels and are balanced?}

 

_Ged

Meant to say wheels and tyres

[Icanfixit]

That was what i just finished today. I had to check that off the list. One tire, left rear had a small imbalance. The other three were still good. Rotated tires and test drove. Vibration still there at 70. Comes and goes at 60 depending on power. Accelerate in 4th to 70 and then push in clutch. No vibration till I push in the clutch and also when I pull it out of 4th and into 5th. Vibration in 5th. I am sure that all the small things had added to the vibration issue and masked what was going on. There is less vibration then yesterday, but it is still there.

 

I took the car on a spirited run through the country roads and it preformed great. Never got above 4th. The car is great till I get to high speed. No noise, just vibration.

 

The mystery continues.

Chris

[korteix]

I don't know if it's the same problem on mine, when I drive sometimes there's a sound like "scraping a knife on a stone", I can feel it when I touch the clutch pedal. All the gearbox:clutch has been rebuilt, I'll check oil level soon.

[Herc]

I just had my 5 speed rebuilt by Alan Voigts.  Mark, the son, seemed to think the bearings where pretty strong and rarely fail.  Indeed, the best part of the box, from what he was saying.  Not a man to mince his words.

 

It you are prepared for a long chat, you could always ring him.  He seems to have decades of experience on this box, and is very friendly.

 

Herc.

[TonyPoll]

I had a problem like this -  the car had been sitting still for a while and the tyres developed flat spots. The cure was to pump them up to about 60 psi for a few days, then reduced to the usual 24 psi. The vibration went away.

[Icanfixit]

 

Part #8 is the bearing I am thinking about. It is a small needle roller bearing that I have had trouble with in one other trans. Two decades go I spent allot of time in a Lotus shop and the owner had an Elite. This bearing was the major problem he saw in the boxes he repaired. This is why I suspect it and I had a trans with that problem five years go.