engine vibration

Hello

I have a 56 CJ with a 4.1 buick V6 80-84 vintage
It was bought used and installed so not much info.
Guy I bought it from said it came out of a jeep and it ran, he never ran it because he had changed his mind/direction to 4.3 for fuel injection.

It runs (been using it for 3 years) Vibration just bugs the crap out of me.
I find myself just running on the low side of the R's and never run the R's much higher because of the vibration.

As the idle is increased the vibration increases.
It is not a drive train problem, It vibrates parked with clutch pushed in.
It seems to idle fine then as RPM's increase the vibration increases.

What is the best way to eliminate or determine the cause?
Can an engine be balanced in the vehicle?
How do I know if I have the wrong flywheel?

Maybe?
Wrong flywheel
wrong distributor
wrong/Bad harmonic balancer

Any ideas?
Thanks

 

I can say that I had a harmonic balancer that did that on an F150. Since it is easiest to get to I would try to borrow/beg from junk yard and try it.

 

What flywheel was used when installed? The 4.1 is an even fire motor like the later 231's so either the 225 flywheel must be re-balanced or a 231/252 flywheel must be used.

 

Just sold my grandmothers 1981 Cadillac for her and guess what engine it had?? Thats right, a 4.1 Buick V6. This engine did the same thing you are describing. I don't know what caused it but I do know that the flywheel, etc. were all original so you may want to look for defective parts instead of incorrect parts

 

Just a thought, but what are the body and motor mounts made of? I have seen cars vibrate like hell with urethane mounts, and calm down with stock rubber mounts. A lot of the after market stuff is urethane, and it lasts longer. It just doesn't dampen vibration like rubber.
On another subject......I resurfaced the flywheel on my 3.9 dodge v-6 in my 56. I had to take .015 off to get it flat, it was worn so bad. It is now dead flat, but I wonder if I should get it rebalanced?
And.....can someone explain the differance between an internally balanced motor and an external one?

 

Thanks everyone.

Nickmil
I don't know for sure what flywheel, just bolted up the parts that came with the motor! I don't think it was a OF because it was not 90 pounds?

Did the 231 OF have a light flywheel? I know the 225 OF was a heavy FW.

Yankeefist
Thanks, I've heard V6 eng are prone to Vibrations.
Sounds like a good reason to start with harmonic balancer!

Birddog56
Thier rubber and one is now broke also! That was one of the first things I checked.

W3srl
Thats my thinking also!
I'd planed to start with HB then pull the FW i'fin I have to!

Anyway it might be the electrical?
could it be the odd spacing on the distributor cap?(not equally spaced)

Thanks again everyone,
I think I might wait till spring, its cold outside!
(0llllll0)

 

Birddog
Almost forgot! the internal VS external balance

Some engines were balanced with the flywheel and harmanic balancer. (external)

Some were balanced with the crank shaft (holes drilled into counter weight)

I think the 231 EF was internal balanced
I don't know about 231 OF?
The 225 OF was external balanced.

If I'm wrong someone will correct me...LOL
(0llllll0)

 

If the plug wires on the distributor aren't spaced evenly it's the wrong cap for a even fire. That's your problem.

 

Just to finish the post!

Pulled the flywheel and it was a heavy wheel off an odd fire.
I had it rebalanced at a local machine shop.
I also installed a howell TBI unit at the same time.

All went well!!!
Bumped the key, he fired up and runs GREAT!
Revees up and seems to have lost the bad vibs.

Thanks for everybodys imput!

 

Glad you got it figured out!

 

Good show.