motor vibration

[70challengerrt]

I have a 440 1975 chrysler newport motor in my challenger. It starts to vibrate at 3000 and up in every gear. I bought the car in pieces so I don't know if the damper is the original. Could this be the the cause? Or the flywheel is new. Any suggestions?

[Chryco Psycho]

the factory balance was not great so it is possible the engine is just unbalanced , or the balancer could be wrong , it should have 440 cast crank cast into teh damper , , is it 4 spd or auto ? the flywheel if 4 spd would be a special application as there were virtually no 440 cast crank 4 spds so you wiould need to have the flywheel balanced with the crank , the auto requires a special balanced converter for the cast crank 440 , if it is not balanced this will definatly be the vibration , this can be solved 2 ways , you can buy a balanced flex plate or get the weight kit & weld a weight on the converter to correct the balance , or replace the converter entirely   

[70challengerrt]

I used a crank mount bearing for a pilot bearing because my challenger is a 4 spd car. Could I bolt on a tci rattler harmonic damper to fix this? or do I have to get the crank balanced with the flywheel?

[tactransman]

Where did the flywheel come from that you are using? The '75 440 should be a cast crank and your problem is probably the flywheel like Chryco said.

[Robb]

there is a special flywheel specifically for 440 cast crank motors.   McCleod (sp?) makes one.
Other companies do to, but you really have to look.

When the sales guy asks about your car, be sure to give the motor date, not the car date.   I had to really work hard with people on mine, they kept wanting to give me one for a six pack motor.

[67Vette427]

You need to run an externally balanced balancer and flywheel. If you have an internally balanced flywheel on the car you're going to have a vibration. I just had a 440 and a 383 balanced. The parts needed were: Balancer, pistons, rods, crank and flywheel. Good luck!

[70challengerrt]

I just went to the local car quest and got one. Would I be able to get a 11" fly wheel to match the 75 motor? I got the 11" to fit the belllhousing.

[tactransman]

Just make sure it is for a cast crankshaft and not a forged one.

[67Vette427]

As long as the pressure plate matches up to the flywheel you should be okay.

[tactransman]

The cast crankshaft flywheel will be weighted to balance the engine , the forged crank flywheel will be neutral balance.

[70challengerrt]

So I will have to get my flywheel balanced to match my motor even if I order a new one for a cast crank?

[tactransman]

No, only if the flywheel you got is for a forged crank.

[67Vette427]

Its confusing... Cast cranks = externally balanced           Forged/Steel = internally balanced.  You need an externally balanced flywheel.

[70challengerrt]

Does anybody make an externaly balanced 11" flywheel or do I have to switch to 10.5"? If I have to switch do I have to switch to a 10.5 bellhousing?

[tactransman]

Chryco can probably answer that for you.