Vibration Quandry after New Clutch Installation

[Hamilton]

`49 Plymouth, stock 218

 

Sorry for the length but I'm trying to address some questions up front.

 

New clutch, PP, release bearing, pilot bushing, engine mounts (F&R).  Flywheel looked good and flat - checked with machinist's straight-edge, so I didn't have it re-surfaced.  Upon initial start up noticed quite a bit of vibration upon clutch take-up.  Made a trip around the block, which only served to confirm what I'd already noticed.

 

Pulled everything back out and took the flywheel in for re-surfacing. Machinist said it was in great shape - pretty much what he would've expected in a low mileage car - and that he had to do very little to it.  Re-installed everything again last night and got the same vibration.  My son happened to stop by so I had him sit in the car while I stood underneath and watched and listened.  Drive shaft was spinning perfectly so I eliminated that (plus, it was fine before and nothing changed with it) as a possible culprit.  Moved forward and detected notable vibration from the clutch/flywheel area.  Damn!

 

Pulled the gearbox and removed the release bearing and fork so I could get a look at the clutch assembly with the engine running.  Didn't appear too bad to the naked eye (which, I understand is probably wholly inadequate here, but what the heck, ya gotta look, right?).  That's when I noticed that, although the rear mount bolts are snugged up completely, the tabs on the gearbox appear to be riding just a hair above the large washer that sits on top of the mount.  At idle (which is all I could do since I had no one there this time) the rotating parts I could see appeared smooth but the entire engine was rocking. I grabbed a couple of woodworking clamps and clamped them over the top of the rear mount bolts and the crossmember.  Even though the clamping force is actually quite little when compared with bolts and nuts, it was enough to smooth everything out.  The oil pan stopped rocking side to side, and just sat there, pretty much motionless.

 

I understand that one is advised to not over-tighten the engine mount bolts but I tried snugging them up just a bit more anyway, trying to eliminate the delta between the washer and the gearbox tab.  No joy, the gap remains and the engine still rocks when the clamps are removed.

 

I've searched to see how others have their mounts installed, just to make certain I didn't mix up the assembly order of the parts.  It appears I did not.

 

If this is the way the mounts are supposed to be then I'm left thinking that I'll need to get the flywheel and clutch assembly balanced - something I frankly didn't figure I'd need to do.

 

Any insight or advice is appreciated.

 

 

 

Edited August 29, 2020 by Hamilton
typo

[Dodgeb4ya]

Motor mount or clutch cover/disc issue IMO.

[DJ194950]

Flywheel running true.? It can be mounted slightly cocked if not set straight onto the crank flange.

 

A thought and easy check with inspection cover off. Bolts holding it on still good and tight?

 

DJ

[Hamilton]

4 minutes ago, DJ194950 said:

Flywheel running true.? It can be mounted slightly cocked if not set straight onto the crank flange.

 

A thought and easy check with inspection cover off. Bolts holding it on still good and tight?

 

DJ

I was pretty careful installing the flywheel but I'll remove the inspection cover when I go out again later this evening or tomorrow.  Torqued the bolts, then double-checked them, so they should be fine.

Edited August 29, 2020 by Hamilton

[Sam Buchanan]

Sounds like the infamous engine/transmission mount dragon has reared its ugly head again..................

 

https://p15-d24.com/topic/50844-engine-mounts-p15-caution/?tab=comments#comment-539481

Edited August 29, 2020 by Sam Buchanan

[Hamilton]

Flywheel looks true - my naked eye detects no run-out.

[Hamilton]

Given file size limitations you've gotta look quick but here you can see the engine moving a bit.

Edited August 29, 2020 by Hamilton

[Hamilton]

My imagination, or less movement with the clamps in place?

[Hamilton]

And finally, the mysterious (to me, anyway) "floating" mounts ...

[9 foot box]

      The clutch plate is off center without the transmission input shaft keeping it centered. Line it up and put in the transmission. I think you have to finish your install to get an accurate result.

[Hamilton]

^^^ The install has been completed twice, which is why I finally posted.

 

_

[Sniper]

For videos I put them on Youtube and post a link here, no size limitations then.

[kencombs]

Last video, there is definitely some up/down motion on the mount.  The one with the clamps dampens that.  I'd revisit the mount install as something doesn't look right.

 

You can actually see the washer moving.  That should be firmly clamped during the install.

[Hamilton]

^^^ Thanks, Ken, that is my thought. 

 

And, Sniper, that's a great idea.  Now if I can just remember how to post on YT ...

 

_

[Hamilton]

Here's a link to a longer video of the mounts.

 

https://youtu.be/XGXdHe82sQU

[Hamilton]

Well, I was hoping it was the mounts but am becoming less confident of that, as the vibration remains even after eliminating the "floating" phenomenon depicted in the video.  Still, they could be an issue: I removed them and upon re-installation, found that the mounting holes on the gearbox tabs weren't lined up front-to-back - off by approximately 3/8".  Had to use a come-a-long and loosen the four bolts at the bottom of the front mount horseshoe in order to move the engine forward enough to get the bolts to pass through and had to apply quite a lot of force in order to move it forward the last eighth-inch.  Just seems as something has to be off, as you would think that everything should line up nicely.  Engine, by the way, was not removed, just the gearbox.

 

I'm again leaning toward flywheel/PP/disk balancing issues.

 

_

 

 

 

 

[plymouthcranbrook]

I remember having a difficult time when changing the rear mounts on my 52.  No problems like you have had but a lot of push and pull.  And that was long before I changed the clutch.

Edited September 1, 2020 by plymouthcranbrook

[Tom Skinner]

Just Mash the Clutch Pedal in. It will drop in

[Hamilton]

Solved!

 

Problem was 100% the fault of the cheap Chinese crap I purchased from a well-known classic Mopar vendor about a year ago.  After posting this thread, considering some of the advice offered and trying various things, I pulled the flywheel (which had already been resurfaced), PP and clutch and sent them out for balancing.  Made absolutely zero difference.  Finally decided to search out a factory unit to send in for rebuild.  I got lucky and found a complete set on e**y that had already been rebuilt (many years ago) but that had never been installed.  It arrived this afternoon and I spent a little over an hour installing it and buttoning everything up (ah, the joys of having a lift) before a quick test drive.  No chatter, no vibration, no untoward noises.  Damned near perfect, in fact.

 

If anybody thinks they can find a way to balance a clutch disc and pressure plate (or figure out whatever the hell else might be the issue) that have maybe one mile of use on them, PM me - I'll cut you a long deal.  Otherwise they're going out in next week's garbage.

 

_

Edited September 26, 2020 by Hamilton
typo

[Sniper]

Thanks for following up on this

[Dodgeb4ya]

Chinese..no go...except in trash.

[kencombs]

Just wondering, what could be wrong with the Chinese set that wouldn't have been caught by the rebalance?   Just guessing, but I'd bet the disk hub is not concentric with the lining.  And likely the balancer only did the flywheel with the pressure plate as there is no easy way to mount the disk.  You probably have a good pressure plate.