1961 Cadillac - engine vibration issue

[Rafa]

Hi!

I have a 1961 Fleetwood 60-S and I'm facing an engine vibration issue.

The engine vibrates when in Park at about 2000 RPM.

The engine was overhauled 6000 miles ago with new pistons and bearings from Kanter, but this same vibration was already present before it was rebuilt.

Some people are saying I'll have to part out the whole engine to have the crankshaft, push rods, pistons etc. balanced.

Others say balancing the flywheel, flex plate, torque converter and harmonic balancer might work. This option would save me a lot of trouble.

What's your opinion?

Thanks,

Rafael Castilho, from Brazil.

[Tim Groves (Cadillac Tim)]

If the engine vibration was there before the rebuild, and is the same with new pistons, etc., I would look outside the engine first.  Have you checked the harmonic balancer and motor mounts?  Is the flywheel damaged?   Next, is the vibration present driving down the road, and at 2000 rpm?  Does the vibration go away after 2000 rpm when driving?  Tim

[Rafa]

Hi Tim,

It's been a long time, nice to hear from you. Thank you for your reply.

That's what I think. Since the vibration is the same as before the overhaul, it's got to be something that wasn't replaced.

Mounts are new and fine, and it's not that kind of vibration.

The vibration is there whether the car is moving or not. I just mentioned that it vibrates in Park to rule out transmission, prop shaft and differential issues.

RAFAEL FELICIANO DE CASTILHO.

[dplotkin]

Had a similar problem with my 60 Electra, turned out to be an out-of-balance fan.

[Rafa]

And this same car once had a problem with an out-of-balance alternator. Unfortunately this time removing the belts did not do the trick. Thanks for the try!

Rafael.

[dplotkin]

Then I think you have to look hard at the balancer & flywheel.


Dan

[TJ Hopland]

Did you do anything with the transmission when you did the engine rebuild?     

Just wondering if there could be an issue with the torque converter.

[Rafa]

Dan,

Yes, I hope there's something wrong with the torque converter, flywheel, harmonic balancer or flexplate, because if that's the case I won't have to part out the whole engine.

Best,

Rafael.

[Rafa]

TJ,

The transmission was rebuilt twice during my 20-year ownership, the problem was present when I bought the car, and it still is, but I never did anything to the torque converter.

RAFAEL FELICIANO DE CASTILHO.

[dadscad]

This may not relate to the 61 but I'll mention it anyway.

If my memory is good, in the 63 shop manual there is a notation that the flex plate may have an "O"  stamped next to the crank flange cut out and the crank may have the same mark stamped in it. If these marks are there, they should be next to one another when the flex plate is installed on the crank. Not doing so could cause engine vibration.

I don't know if other years had the same notation, but it would not hurt to look if you are going to pull the transmission.

HTH,
David

[Rafa]

David,

That's a very good idea, I have the Service Manual and will take a look at this before I do anything.

Thanks,

Rafael Castilho.

[Tito Sobrinho]

Alo Rafa

My 331 engine had an awful vibration every time speed reached over 50 miles/h.  Removed the engine and balanced: New pistons (Metal Leve) ,rods, crankshaft, camshaft, propeller shaft, flywheel and the tires were shaved.
The damn vibration continued, but I found the culprit...harmonic balancer whereas a previous mechanic installed a flat washer between the harmonic and the crankshaft. A trip to a local "junk yard" got rid of the problem with an harmonic balancer cannibalized from a 1951 Cadillac  engine. The washer is conical.
Since your car is fitted with a 390 engine, that it's nothing more than a 331 with an increased bore...look at the washer.
I'm from Curitiba and you?