Vibration
 

Good morning all,

I finally managed to get my Amazon together enough to give it a shakedown run after fixing all of the oil leaks and have noticed a vibration/noise between 20-25 mph and only at that speed, its not the speedo cable I disconnected that and it was still there.
Could it be the propshaft out of phase/balance or a U/J, I've never experienced such a low speed vibration caused by a prop before?
All the wheel bearings are good too!

Thanks in advance Doug.

Is it certainly just speed related?

As in drive at speed. Clutch depressed - vibration still happens.

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On the whole I'd start by looking for something that hasn't been done up / come loose / is missing a spacer.

I advocate systematically checking all the easy stuff first such as missing weights on wheels...

Yes its definitely speed related and it makes no difference what gear I'm in or if the clutch is pressed or not!

Thanks Doug.

Does it do it again at 40 to 50mph?

No only between 20-25mph feels like its coming from the rear but I've been done this path before when I've been convinced a fault is front/rear or left/right and when I eventually find the cause its not where I initially thought!
The plan is to change the tyres very soon so when they're done and the wheels are balanced it will eliminate them!

Is the general thought that a vibration at such a low speed isn't prop related?

Doug.

It is difficult to say for sure it isn't the propshaft though in my experience there is more often than not a difference in propshaft vibration when you apply power. Behaviour of driveline elements is often influenced by loading / unloading.

If you always get the vibration at a particular speed no matter what gear / accelerating / decellerating / turning corner / clutch in or out then I'd be looking for parts that are not directly influenced by propulsion.

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If you get really stuck on this then a detailed list of the work you have done might help. You then systematically check the work you did.

All a bit tedious really - sorry!

Have you adjusted tracking / alignment etc?

I have just changed the front upper wishbone bushes but the vibration was there beforehand and is still there!

Doug.

Engine and in particular, gearbox mounts. The rubber goes brittle and out of shape with age resulting in the engine sitting too low and the gearbox on the wonk. That in itself isn't good, but allows the prop to be on the wonk too. When replacing - and this is a thing that often gets overlooked - you should measure things up to ensure everything is aligned

All of the above is after you've made sure the prop itself is sound

Do the easiest first:~ Tyre Balance.
Bob.