1959 Caddy Vibration

[John Maglia CLC#23063]

I'm working on a 1959 Caddy Coupe De ville, 390/325, power steering/brakes and A/C. It has a vibration at any rpm above idle from about 1500 rpm and beyond.  It doesn't matter if the car is in Park, Neutral, or Drive, the vibration is constant thru all speeds.  However, after driving for long periods of time at hwy speed, the vibration seems to disappear but when stopping for rest, fuel, or food, the vibration returns when the car is restarted.

Does anyone have any thoughts on what the problem may be or areas where I may start looking for the trouble?

I have ruled out the transmission because the vibration is present in Neutral and Park.
 
Any direction will be greatly appreciated.

John Maglia
CLC 23063

[homeonprunehill]

I'm working on a 1959 Caddy Coupe De ville, 390/325, power steering/brakes and A/C. It has a vibration at any rpm above idle from about 1500 rpm and beyond.  It doesn't matter if the car is in Park, Neutral, or Drive, the vibration is constant thru all speeds.  However, after driving for long periods of time at hwy speed, the vibration seems to disappear but when stopping for rest, fuel, or food, the vibration returns when the car is restarted.
Does anyone have any thoughts on what the problem may be or areas where I may start looking for the trouble?
I have ruled out the transmission because the vibration is present in Neutral and Park.
 Any direction will be greatly appreciated.
John Maglia
CLC 23063
[/quote
02-25-08
John, It could the "Crank-Pully" that has come loose from the rubber. (if it has a rubber mounting)  Do a search concerning "vibration" and I think you will find the problem. HTH
Good Luck,JIM

[John Maglia CLC#23063]

Jim:

Many thanks for your reply. I'll search for that info right now.

John

[walt chomosh #23510]

John,
  Like Jim,the first thing that flashed thru my mind was your harmonic balancer.(crankshaft dampner)(you might grag the dampner and try to twist it to check for play)One must also consider other possible causes. I like to disconnect various motor accessories but removing the belts one at a time. Your generator,power steering pump,water pump,and A/C compressor could cause a vibration also.Good luck finding your problem. Incidently,I've sent two crankshaft dampners out to Oregon(Dale manufacturing I believe)and have been very pleased with his overhaul.(right around $100)Not trying to plug him,I'm sure there are others out there......walt...tulsa,ok

[Big Fins]

Walt, we always appreciate a plug for a good vendor.

There are too many dishonest ones out there waiting to steal your hard earned money.

Fins

[John Maglia CLC#23063]

John,
  Like Jim,the first thing that flashed thru my mind was your harmonic balancer.(crankshaft dampner)(you might grag the dampner and try to twist it to check for play)One must also consider other possible causes. I like to disconnect various motor accessories but removing the belts one at a time. Your generator,power steering pump,water pump,and A/C compressor could cause a vibration also.Good luck finding your problem. Incidently,I've sent two crankshaft dampners out to Oregon(Dale manufacturing I believe)and have been very pleased with his overhaul.(right around $100)Not trying to plug him,I'm sure there are others out there......walt...tulsa,ok

Many thanks Walt. Will be spending the weekend working on all these fine suggestions. The CLC and its members provides an invaluable service for rookies like me.
John, Rolla, MO

[Forrest]

I agree with all the suggestions above. Does the engine visibly vibrate while idling in park or neutral? I would take off  the v belts from accessories one by one and  check for looseness orplay in the various shafts (generator, water pump, power steering, ac, harmonic balancer) I would also check the engine mounts. I'm sure you've already made sure you have good spark, etc. but it's worth mentioning. Make sure all cylinders are firing. Check timing, etc.

I experienced a similar problem with my 1979 F100. Everything seemed to be in proper working order but the vibration wouldn't go away and started getting worse. When I removed the belts and started checking things for looseness, I got to the crankshaft pulley. The harmonic balancer was fine but I was able to lift up on the pulley and the crankshaft moved up and down slightly. Not good. The front journal was worn out. Time for a new engine.

Check also to make sure your exhaust pipes are not vibrating against the frame.

I hope it's something simple. Please write back and let us know.

Forrest

[John Maglia]

I agree with all the suggestions above. Does the engine visibly vibrate while idling in park or neutral? I would take off  the v belts from accessories one by one and  check for looseness orplay in the various shafts (generator, water pump, power steering, ac, harmonic balancer) I would also check the engine mounts. I'm sure you've already made sure you have good spark, etc. but it's worth mentioning. Make sure all cylinders are firing. Check timing, etc.

I experienced a similar problem with my 1979 F100. Everything seemed to be in proper working order but the vibration wouldn't go away and started getting worse. When I removed the belts and started checking things for looseness, I got to the crankshaft pulley. The harmonic balancer was fine but I was able to lift up on the pulley and the crankshaft moved up and down slightly. Not good. The front journal was worn out. Time for a new engine.

Check also to make sure your exhaust pipes are not vibrating against the frame.

I hope it's something simple. Please write back and let us know.

Forrest

Thanks Forrest. I am travelling for a couple of weeks and when I return, I will try all the great suggestions and let you all know if I had any luck.

Regards,

John