Vibration Problem

[arcturus]

The initial reason for engine out and rings was to replace the clutch. It seemed that oil had leaked onto clutch and It was shuddering on acceleration and deceleration. The clutch had some oil but not vert much. With new seal and clutch fitted i still have the same symptoms so it looks as though that was not causing the problem. I am now wondering it the vibration is coming through the drive line. center support bearing? UJ? It comes on at low, unlike wheel imballance Any ideas? speed. I know that I can rule out front wheel bearing

[v8250]

Logically, this could be coming from four places

1. Crank, worn end crank bearing
2. Gearbox, front or rear shaft bearings
3. Propshaft bearings
4. Propshaft out of phase https://www.youtube.com/watch?v=dt69zYAcXME

Start with the easiest, check gearbox front and rear shafts for any play, if play present fit new bearings. Next check/change prop bearings and check prop UJ's are 'in phase' meaning 3no UJ faces are in line along prop line. Lastly, check rear of crank.

[arcturus]

I think I can rule out the crank and gearbox as i have just rebuilt the engine with new rings and big end bearings and the crank was fine. The gearbox also has been renovated recently. The vibration started half way through a 1000 km trip so i don't think that is a "phase" problem. Is there any way of checking shaft center bearing in situ?

[arcturus]

B'n reading the manual and it's not too clear. This is on my 144 which will have the same set up more or less. It talks about unfastening the rear UJ from the diff' and sliding it out from center bearing. mentions splines. Am I correct in reading that as the shaft is spline-d into the bearing?

[v8250]

If same as Amazon the prop is supported by bearing in mounting housing. This has a female spline, the male spline slides into female spline as a slider shaft enabling fore/aft position before mounting on to rear diff font flange. If vibration is coming from shaft it could be that the balancer weight/tab has fallen off. Easy way to check is to get prop dynamically balanced at local engineering workshop. It's worth rebuilding any prop if you've invested good time and money with and engine and gearbox rebuild...without it would spoil the new power/driveline experience...always best to sleep at night knowing everything is perfectly assembled; good luck.

PS if on 144 would be worth posting on 144 forum too

[dcthompson]

Why hasn't anyone mentioned the most obvious culprit(s)? The symptoms the author is experiencing are typical of one or more bad u-joints. Before going to the expense of straightening and balancing the drive shafts, I would replace any suspect u-joints (either with play or binding), and check the carrier bearing and support (another prime suspect). The u-joints can be had for about $5 each, as can the carrier bearing support. Thus for $20 the most obvious sources of the vibration can be eliminated.

[arcturus]

Originally Posted by dcthompson

Why hasn't anyone mentioned the most obvious culprit(s)? The symptoms the author is experiencing are typical of one or more bad u-joints. Before going to the expense of straightening and balancing the drive shafts, I would replace any suspect u-joints (either with play or binding), and check the carrier bearing and support (another prime suspect). The u-joints can be had for about $5 each, as can the carrier bearing support. Thus for $20 the most obvious sources of the vibration can be eliminated.

Hi and thanks. That is going to be my next line of investigation. Just trying to rule out any other possible causes.

[arcturus]

Got underneath car and I strongly suspect that this the culprit. Even if it isn't it needs replacing.

[mocambique-amazone]

Hello George, this is the vibration problem with your car.
Follow dcthompson an check carefully the u-joints for play and binding when getting the propshaft out. I wouldn't renew if they are ok.
Check the phase carefully in front of dismantling, do marks, and check after too!
Tryo find a NOS part of the rubber bearing, the new ones won't last 30 years again.
Good luck, regards, Kay

[arcturus]

Originally Posted by mocambique-amazone

Hello George, this is the vibration problem with your car.
Follow dcthompson an check carefully the u-joints for play and binding when getting the propshaft out. I wouldn't renew if they are ok.
Check the phase carefully in front of dismantling, do marks, and check after too!
Tryo find a NOS part of the rubber bearing, the new ones won't last 30 years again.
Good luck, regards, Kay

Thanks, I don't think that I will last another 30 years!