Vibrations

[wparslow]

Guys, I'm really grateful for all the replies but, and I re-iterate. I have changed tyres twice, and wheels once - no difference. Prop has been balanced and the car is now on TTR solid CVs - no difference.

All I can hope is that having the engine removed for the bottom end rebuild, new engine mounts etc that the problem might go away but I think it won't.

Car vibrates in just the same way whether clutch is in or I am coasting at 70mph+ which would indicate wheels/tyres/maybe a hub problem.

AARRRRRRRRRRGGGGGGGHHHHHHHHHHHHH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Wayne

[wparslow]

Brand new alloys running first on brand new Conti 165/80 x 13s, then Brand new alloys (different set) running brand new Yokohama 185/70 x 13s.

No difference.



W

[JJDraper]

I had an unsettling experience with my +2 a few weeks back. The car is usually quite smooth up to highly illegal motorway speeds, but started some unpleasant vibrations. I then lost the clutch completely (wouldn't disengage) and had to be towed home - most embarrassing. Long story short - the engine/bellhousing bolts had worked loose allowing the whole engine to move forward when the clutch was pressed in. After tightening the bolts, clutch was restored and the vibrations went away (well at least the nasty ones).

Worth a try, just check the tightness of the bolts.

Jeremy

[alaric]

Have you tried jacking the rear of the car up, starting the engine and popping it into gear so that you can watch the wheels spin? Actually that could be a bit dangerous.

A better idea might be to take the car to a garage where they have rollers inset into the floor, secure the car, and run it up to speed. You may be able to tell where the vibration is from. Also, if there is no vibration, then it's from the front wheels.

Good luck.

Sean.

[1964 S1]

Hello Jeremy, great Lotus story! I'm going out to check my bolts now. You've reminded me of what a wise man once told me... Tighten every nut and bolt, go from one end to the other, every two years on any British car you own.

[rgh0]

Wayne

I agree you need to check all the wheels for lateral or radial runout when mounted on the hubs. You can do this by holding something close to the wheel and seeing how the small gap changes as the wheel turns. Any noticeable runout needs careful investigation as to where it is coming from. Also check the rear drive shafts for radial runout . You can do this visually but a dial guage against the wheel or shaft gives a more precise measurement.

Rohan

[tdafforn]

I had my car on the rolling road recently and was amazed at how much wobble there was on the rear wheels...
So much so that I had to check that I had done the wheel nuts up...
Strange thing is that Its as smooth as smooth at any speed.
(Perhaps my wobble has transported itself onto your car )
Tim

[alaric]

If it's not the prop, the wheel rims or the tyres, then surely it must be a hub related problem.

Does anyone else think it could be a worn hub flange? Correct me if I'm wrong, but at the rear, on each side, there's a shaft held by bearings, which rotates. The wheel flange fits onto the end of the shaft, on a taper, which is forced home with a nut. When they have been on and off a few times, do those taper fits get loose / easier to remove? I've been advised to lap my rear flange onto the taper. What if I get it slightly off centre, won't the whole wheel, once bolted to the flange, rotate off true?

Don't the TTR CV driveshafts just fit between the original diff output shaft and outboard hub shaft, leaving any hub related problem untouched.

Hope you find the problem soon - must be really spoiling the whole car for you.

Sean.

[iain.hamlton]

OK a couple of things to try. each contributed to vibration in on my +2

1/ Look at the chassis carefully for cracks. My chassis is in good shape, except there was one small crack (1", without corrosion) on the main rail, just behind the front left suspension tower where the sheet-steel is horizontal. I got this welded.

2/ Check the security of the bolts fixing the diff. Both the ones holding it up to the chassis, and the rods holding it against the drive-shaft torque. I tightened all those, and presto, no more shakes.

best regards, iain