In Search Of - Vibration

Rats !!!

Looks like I’m going to have to take it out again this weekend and find a place isolated to make a bit of a racket.

I’ll run it at 4000 rpm for a few seconds at idle to see if there’s noticeable vibration.

In the Caprice it wasn’t vibrating. So the damper must be fine.

The clutch kit is also fine.

The flywheel has a weight and is externally balanced.

I can’t imagine anything is off.

I guess I might be in denial.

Running for a few seconds at 4000 should tell a tale but it would still be best to lower the tans first.
 
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Let’s imagine the engine is well balanced. If the trans were in contact with the tunnel... I would be feeling engine rumble and vibration anyway, right ?

Again, it’s not a really big rumbling vibration. But enough to annoy me.

Do high compression engines “rumble and pop” more through exhaust?
 
Thanks Indy. Must... Resist... Temptation... to test drive now :D
 
Tap a couple wooden wedges between the exhaust pipe and something solid to take any vibrations out of the exhaust then run it to see if anything changed but don't forget to remove them after and if that makes you nervous soak the wood overnight in water before installing
 
just listening to the conversation, it sounds like either the damper/balancer on the front of the crank
and/or the flywheel/clutch assembly are not properly balanced
At first I thought so too Grumpy! Could possibly be that and maybe the tranny mount! One of the 2 or maybe both!
 
why not, park the vette with the brake on, and have the wife or a buddy, put the vette in neutral and slowly increase the rpms with the hood open
while you watch the engine vibration/damper etc. for a bit of visual feedback/info
 
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the tilting shifter is what keeps going through my mind but I will bet the farm between us we will get this solved now weather Dorian ever speaks to us again I don't know
 
why not, park the vette with the brake on, and have the wife or a buddy, put the vette in neutral and slowly increase the rpms with the hood open
while you watch the engine vibration/damper etc. for a bit of visual feedback/info
I agree Grumpy that would rule out something in the drivetrain causing it by being out of balance!
 
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So, I took the corvette out for a drive today. Clearly the shifter base is in contact with the shifter console. That has got to be part of the problem.

I pulled over and revved it up to 4000-4500 and the vibration didn’t seem bad. It’s only really annoying in the shifter handle.

Here’s a question for you guys. Let’s assume the rotating assembly is adequately balanced. How much normal vibration would one feel in the shifter knob ?

I think I might be a bit spoiled by the Muncie. On the Muncie, the shifter is bolted to the frame. On the T5 the shifter is in the transmission rear housing.

So, holding the shifter while at 3500 rpm should be like resting your hand on the valve cover. Would one feel some vibration on a normally balanced engine ?
 
Hm. I suppose that transmission mount could also be torn. That would explain a lot.
 
Well, well.

I couldn’t resist climbing under the car.

The rear of the trans is lifted and I released it down.


I don’t think this explains everything. But this needs to be addressed.

I think I’ll weld the bracket on.
 
From what I can tell, I forgot to tighten the side bolts. They aren’t even finger tight. I can’t imagine they shook themselves loose.

I suspect tightening these will get rid of the yanking shifter lever... but not all of the vibration.

stay tuned
 
What perspective are those pictures coming from? Side ? That mount should be solid! I do think there would be slight vibration in the shifter, I drove a friends 03 mustang yesterday and it had slight vibration while holding shifter! Slight vibration, but vibration none the less!
 
I’m on the passenger side slightly aft of the tail housing.

It’s a bracket that bolts to the crossmember and support the transmission mount
 
Good to know. Maybe if it is lowered and clears the body, (+ tighten bolts) it’ll fix things.
 
Ya know looking at it, I thought the mount would be under rather than over. A thinner mount might cause it to be worse.
 
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