Not getting a good vibe

[727]

I have a 1966 Charger that was equipped with a 318 poly 3speed manual on the column.
I swapped in a rebuilt 440 with a balanced rotating assembly and an 833 4 speed on the floor.
When I got it all together there was a strange harmonic vibration inside the car at about 2800-3200 rpm's.
I swapped the flywheel and harmonic balancer with no change.
I bolted up and empty 833 case thinking that maybe the transmission input shaft may be causing this. No change.
I swapped in a rebuilt 400 and it has a less pronounced vibration in the same rpm range.
I unbolted the transmission mount and put on a jack stand the vibration went away.
I swapped in a softer transmission mount and it reduced some.
I put in rubber under and over the transmission mount. Still has a pronounced harmonic in the cab.
I've looked, and outside of the z bar I can't see any hard attachments to the body.
Anybody else run into this, or have any ideas?

 

[khryslerkid]

Are you doing this in neutral?

 

[727]

Neutral, in gear, clutch pushed,clutch released, and while driving
Even removed the clutch and ran it. Still shakes!

 

[moparnation74]

Driveshaft out of balance? Pinion angle?

 

[Crider]

Was the 440 cast or steel crankshaft? The cast crank engines are externally balanced and it would explain why the vibration is still there with the 400 as it would be externally balanced too. And if your flywheels are for an internal balance engine it would cause a vibration with both engines

 

[Mike67]

It only happens in that rpm range? with a trans connected, neutral, or in gear.
My question is when you ran it without the trans bolted to it and it subsided was the pressure plate still bolted to the flywheel? If so that could be your culprit... not sure on a mopar pressure plate but I think most can be rotated 120 deg...

 

[727]

Both engines have forged steel cranks.
Have run two different flywheels on both engines.
Have run with and without the clutch and pressure plate on the flywheels.
I put an empty transmission case on the bell housings with both

 

[727]

Both engines have forged steel cranks.
Have run two different flywheels on both engines.
Have run with and without the clutch and pressure plate on the flywheels.
I put an empty transmission case on the bell housings with both
Flywheels and it still gets this rhythmic vibration in the cab

 

[khryslerkid]

Bad harmonic balancer?

 

[Cranky]

What balancer is on it and was it used on both engines?

 

[Crider]

Worn motor mount? Any part of the exhaust making contact with the body?

 

[727]

Used three separate internal balance hormonic balancers.
The motor mounts and transmission mounts are new.
Played with it today and swapped the fan and alternator out. Still vibrating
I pulled the belt off of the alternator/ water pump and much better. I'm going to get a new belt and if that doesn't do it I'll go for a new crank pulley. This is some adventure!

 

[khryslerkid]

Process of elimination. What parts that you used on both engines needs to be gone through. You'll find it. Think simple first. We're not there so it's up to you to do the inspection of each component.

 

[727]

Thanks for the moral and technical support!

 

[moper]

If you have exhausted everything else, only one thing remains - the engine is either NOT internally balanced, or not internally balanced properly. I the vibe comes in at 2K it's out of balance. Changing the rubber is only isolating your senses. Not fixing it. The engine has to come out and be looked at carefully.

 

[WP29440SE]

stick a small block with an automatic in there , open exhaust , no drive shaft , if it still does it check the k member and piss off the neighbors at the same time lol

 

[727]

I had a 318 with a 3 speed manual in there two weeks ago and it didn't do what it's doing now.
I changed the alt/water pump belt and it narrowed the range that the rhythmic hormonic happens. It's still there though.
Next is change out the crank pulley.
I unbolted the console just to see if it was transmitting the sound and no change.

 

[727]

I went through the exhaust and outside of being bolted to the manifolds it isn't touching anywhere on the body without rubber hangers. Isn't rubbing the springs either.
I did connect the flowmaster 40 series that were on my 318 and I remember from another car those had a certain rhythm at a particular rpm range. Not sure if they would cause what I'm experiencing.

 

[dieseldazzle]

I had a 67 318 automatic ac charger that i chased the engine vibration down on. Wasnt until the impeller let go getting on the freeway one day, that the vibration stopped.

 

[727]

Both the 440 and 400 have new water pumps on them.
Of course with Chinese quality control that doesn't mean they are both good.