Some thoughts on prop vibes

[v-lux]

Just throwing this in the mix...

I've just replaced my clutch (and engine) and I am wondering about the link between engine/clutch/vibrations.
Before I did the conversion I had slight vibrations at around 40mph and awful ringing on pull away if the revs dropped a bit. Since fitting the new engine and clutch this seems to have almost disappeared.

Now, before fitting the fly wheel and pressure plate I had both of them balanced, which at the time I only really did it as I couldn't handle the thought of having to remove it all to have to do it later. (do it right do it once)

However, the fact that things have improved so much with the balanced clutch, im starting to think that the balancing has had a major effect on how the torque pulses are delivered through the drive train.

Thoughts...?

[syncrosimon]

Get a de-coupler and never worry about it ever again!

[v-lux]

The new, bigger, stronger clutch was a fair bit cheaper than a decoupler though, with different advantages to boot...

[jed the spread]

That bush in your prop sounds worn to me if I were to take a guess.

jed

[v-lux]

I think it's because it's got a slip joint in it. Either way, it rings much less now than before.

[Wolfsburg Willy]

I've come to the conclusion that the 'Ways of the Syncro Prop' are many and devious. Being in the throws of fettling mine at the moment,

https://club8090.co.uk/forum./viewtopic.php?f=4&t=73962

I can't see that there is any one definitive defect that will cause vibrations, ringing or clunking in all cases, it seems to be a combination of several things. Do you think that it's possible that balancing the clutch/flywheel assembly (I take my hat off to you for your thoroughness ) means that the engine runs more smoothly and this translates through the transmission? Did you perhaps align the gearbox/front diff more accurately on re-assembly? We've established from earlier threads that we aren't completely clear as to why 'Graz's Best' designed the prop as they did as opposed to a sliding sleeve type, but I suppose that they know best.
The new flexi-coupling arrived from Baxter yesterday and I can't believe how much more solid it is when compared with the old one; I could twist the old one through 90 degrees with my hands, but I can't budge the new one a fraction, but unless you strip the prop and remove the coupling you can't test it, so who's going to pull the whole thing to pieces on the off-chance that it's duff. In my case I think that the vibration was a combination of a knackered coupling, a bush rotating when it was supposed to be a press-fit and possibly UJ circlips on the new UJs that were allowing too much lateral movement on the UJ cross-piece. I'll never know if the vibration goes exactly what it was, that's the frustrating thing about it!

Get a de-coupler and never worry about it ever again!

I've got one, the trouble is that a tight VC feeds back from the front axle, hence the annoying vibration!

[v-lux]

Do you think that it's possible that balancing the clutch/flywheel assembly (I take my hat off to you for your thoroughness ) means that the engine runs more smoothly and this translates through the transmission?

This is my exact thought.

Did you perhaps align the gearbox/front diff more accurately on re-assembly?

the gearbox, prop and front diff stayed exactly where they are/were. I replaced the clutch whilst the engine was out.

It stands to reason (for me at least) that if the flywheel+pressure plate are running more smoothly then its going to transmit far less vibration along the driveline. I'm convinced anyway, not that i hope to do it again in the near future, but if i were to do it again i would definitely spend the extra £60 to get it balanced properly. Just the smoothness of the clutch pick up makes it worthwhile for me. The reduction in vibration is just a bonus!

[syncropaddy]

Do you think that it's possible that balancing the clutch/flywheel assembly (I take my hat off to you for your thoroughness ) means that the engine runs more smoothly and this translates through the transmission?

This is my exact thought.

Did you perhaps align the gearbox/front diff more accurately on re-assembly?

the gearbox, prop and front diff stayed exactly where they are/were. I replaced the clutch whilst the engine was out.

It stands to reason (for me at least) that if the flywheel+pressure plate are running more smoothly then its going to transmit far less vibration along the driveline. I'm convinced anyway, not that i hope to do it again in the near future, but if i were to do it again i would definitely spend the extra £60 to get it balanced properly. Just the smoothness of the clutch pick up makes it worthwhile for me. The reduction in vibration is just a bonus!

Everything said above is correct. Balancing is the way to go and ideally with a blueprinted set up you should have no vibes at all.

I might do that with my spare AAZ ......