High speed vibration

[cavebloke]

Hi Guys,

When I run the car up to high speed a vibration appears first noticed at around 110mph but rapidly trying to shake the car apart by 120mph (discovered on the BNG runway, Officer). It feels like quite a heavy vibration with a low frequency so I'm thinking propshaft but does anyone know anything else that might cause it?

If it is the propshaft - how were they originally balanced? Is there an obvious balance weight that might have fallen off?

Cheers,

Simon

[Hedgehopper]

My prop. has got a little tin patch tack welded on. If the've come off I think you probably would see a sign of where they were.

How about an out of round tyre....has the car been left standing for a long time?

[cavebloke]

Hedgehopper said:

How about an out of round tyre....has the car been left standing for a long time?

It hasn't stood for any time on these tyres. I think you would feel a tyre/wheel weight problem at lower speeds with the frequncy getting higher the faster you go
and that doesn't really happen with this; which is why I thought maybe propshaft.

[Stew Mc]

Have you greased the propshaft UJ's lately? Did my rear UJ but the front looked as though the exhaust needed to come off. Had TVR power sort out the exhaust so asked them to grease the front one while it was off which they did. Would guess not something that gets done all the time due to exhaust removal so may be worth checking?
Cheers, Stew.

[yellowgriff]

My guess is the propshaft,,, tyres and wheel balance problem would be starting at a much lower speed,
If the propshaft has lost a weight you should be able to see we're it's came of from.hope this helps Goldie

[EGB]

Propshaft can be ballanced with two jubilee clips. Did this on a TR7 V8.

[Argent]

May not be a great deal of use but I had a similar problem to thIs that was down to a warped alloy that I'd bought,
Occurred around 65 mph.

A.

[The Red Baron]

I had a similar thing a while back - vibration at higher speed. Turned out to be a bolt on one CV joint from the drive shaft to the diff had sheared. Managed to get the shaft of the bolt out and replaced it and fixed the problem.



The red arrow shows the head of a bolt, the yellow arrow shows where another bolt head should have been. When it sheared it looks like it tore the gator. Of course it depends on the type of diff as to what sort of bolt-thread is required. I can't remember which was which but it told me in the bible which type I needed.

Hope you find the source of your vibration soon.