I have an engine vibration and I would really appreciate your input on a solution. My 41 Chev has a 1952 or 1953 engine with a 1961 distributor otherwise everything is stock.
So at idle,tranny in neutral, clutch in or out I have a vibration in the floor and it gets worse at higher revs. It has been doing this since I bought the car 1 year ago. While driving it lessens at 60 mph.
It was suggested to me by a knowlegable old car mechanic it might be a flywheel problem. According to online info it could have 1 of 2 flywheels: a 6 bolt mounting pattern
or a 9 bolt mounting pattern
Thank you and looking forward to your suggestions.
John

Could be motor mounts or exhaust hangers.
Flywheel or pressure plate out of balcnce. Dosen't matter which flywheel it has.
You could try rotating the pressure plate to flywheel mounting or placing a weight on a flywheel bolt, one at a time and see if it makes a difference. This could be done without removing any major parts.

Ok I'll check the motor mounts, exhaust system is new. What kind a weight would you attach to the flywheel bolt?

If you try adding weights I would not put more than 15 grams attached under a clutch cover bolt. Run the engine at not much more than idle and compare the vibration, if that makes no difference move the weight to the next bolt.
Tony

I am interested in this too because I have a similar problem. Would a couple of washer be a good starting weight?

I would begin with a 2 or 3 Oz. wheel weight and figure some way, by bending the clamp, to get it attached to a pressure plate bolt.

I put the car up on wheel stands & checked the motor mount bolts today - they were all tight except for one bolt. Tomorrow I work on the pressure plate/flywheel.
I think the trouble is in the flywheel area. I ran the motor up to vibration speed & set the throttle, crawled under and felt more vibration on the lower bell housing cover than other areas.

Hi John,

Because the engine was switched you could have an issue created in the switch. Typically, the flywheel would have had its surface reground and been balanced when the change was made as best practices for the conversion. If you can not find out that this was done then unfortunately, you need to pull the transmission, clutch, pressure plate, and flywheel for confirmation that all are okay.

You can do a SEARCH of our past posts to find directions, but the 41 Manual should be first consulted. This is major surgery so you need to plan accordingly. It is not uncommon for the engine switch to be done by someone with a lack of experience. A lot of us have "been there done that."

Good luck, Mike

P.S. Gene what other places could the vibration be coming from in the engine (harmonic balancer, crankshaft)?

John,

You sure you don't have a plug problem. Seems as though there is no explanation of the vibration going away at 60+ except the revolutions are so fast that the vibration fades.

See about your plugs and wires. At least I would do that before going all in and taking the clutch out. Mercy!

Charlie

Hello everyone, After reading the manual & inspecting the clutch flywheel I found 2 balance problems.
1)The O marks on the driving lug on the pressure plate and the other on the flange of the cover do not line up.
2) The X marks on the clutch cover and the other on the flywheel do not line up.
The transmission will have to come out to reposition parts so that the the O marks line up but 1st I will try rotating the clutch cover on the flywheel so the X marks line up to see if that makes a difference for now.
Thanks for your support.
John

Hi Charlie,
I wish it were that easy but no the plugs, wires & cap are new.
Kind of like banging your head against the wall...feels pretty good when you stop.
John

Also does anyone know the torque setting for the 6 bolts - cover to flywheel. The oldcarmanualproject.com site shows a rated torque capacity of 200ft lbs, but is that for these bolts? Thanks.
John

25 to 30 foot pounds

Hi John,

Here is some help with removing the transmission. First go through your manual for steps, then do a SEARCH using the terms +transmission +removal. For DISPLAY NAME use Mike Buller. Here is one of the posts 41 Transmission Removal.

Yes you will need to remove the front seat and its support system.

Good luck, Mike

Very good results today. I repositioned the pressure plate cover & flywheel so the X's matched up and I feel about 80% less vibration when driving. I had an enjoyable drive to the Bracebridge Cruise Night tonight.
Since the rest of the vibration is minimal I'll just enjoy the car for now and think about taking the transmission out later to line up the O's on the clutch & pressure plate. Thank you everyone for your input.
John

Any out of balance vibration can damage the main bearings.

Thanks Gene, I probably should line up that driving lug on the pressure plate to the flange on the cover sooner rather than later.
John

I'm not sure if lining up the O's on the driving lug on the pressure plate to the flange on the cover will solve my vibration problem. This vibration feels like you were running tires with big lugs down a smooth road.
I get A vibration with the car parked, running at about 2,000 rpm, in neutral & clutch OUT.
I get NO vibration with the car parked, running at about 2,000 rpm, in neutral & clutch IN.
What do you think? Thanks guys.
John

Hello everyone, about a month ago I solved the engine vibration problem. I asked a local mechanic to line up the driving lug on the pressure plate to the flange on the cover. The transmission had to come out to access the clutch. It goes down the road quite smoothly now at 60mph. Thanks for you help.

John

I have heard of the happening after the clutch has been replaced and more common than you think.
Thanks for letting us know of the result.

"Yes you will need to remove the front seat and its support system."

Mike,

Re: Removing the transmission from a 41.

Really? I didn't know that. I've been doing it all wrong all these years. Mercy!

Charlie

Hi Mike, sorry being so late responding to your suggestion, if I am removing the transmission. I’ve been very busy this past summer and decided to have a mechanic remove than transmission. He was successful in lining things up and now my Chev runs down the road just the way it should.
On a funny note he said “thankfully we have evolved in how we remove transmissions now”. He was referring to pulling the rear end back to remove the transmission as you probably know. Thanks for you input though.

John

John
I agree with your mechanic (so am I), the evolution to the easily removed open drive shaft is a good thing. Having to undo the rear suspension is not always fun.
Tony

Thanks Charlie for your advice. My 41 had vibration which balancing the pressure plate\clutch assembly reduced.Replaced the plugs! NOS AC M8's made a big difference. 2 of the old plugs were blowing thru.