damper balance question

Hi I have recently bought a 40 ford with a blown big block and after rebuiling the carbs and getting it running we were having trouble timing it, I found the damper to be off a little and I presumed spun, so I bought a new damper external balance, so and after putting it on I thought about the fact the engine was balanced and I do not know if it was balanced with the damper on or not, I was thinking about having the new damper weighted and balanced the same as the old but I am more of a bodyman and not a mechanic so I need help with this one is the only way to fix this rebalance the crank and all?

 

I wonder if you could send your old damper to one of those places that rebuilds them. If it was balanced before the ring slipped, maybe just rebuilding it will get it right again? As long as the ring goes back on concentric, it seems like it should be pretty close.

I know the last time I had an engine balanced, they asked for the crank, rods, pistons, rings, bearings, damper, and flexplate. A big block Chevy has an externally balanced damper and flexplate (if I remember right). The center hub part of the damper is what's weighted lopsided, but the outer ring is evenly weighted (unless they drilled it to balance it either at the factory or at the machine shop that balanced it).

I'd call a local crankshaft grinder that knows how to do balancing to get the real answer though unless somebody here has a definitive answer.

 

I think the 454 was externally balanced, but I'm not so sure about 427s or 396s. Maybe they're internally balanced. And I'm just taking a guess that you have a Chevy big block since you didn't say what it was.

On small block Chevys, I think only the 400s were externally balanced.

 

most builders will install a second key way 180 degrees opposite of the original on a supercharged application to prevent this from happening.

 

396 and 427's are internally balanced. 454 is externally balanced. Which motor is it. Also 454's can be internally balanced but it is expensive.

 

Hi it is a 454, does that mean I can balance only the damper?

 

It would be a good idea to have the new one balanced to match the old one.

 

Don't have it rebuilt IMO. I bought one for my boat LS6. DUMB on
my part

 

Problem solved I found paper work telling me a little about the engine and that the damper was not on the crank when balanced
dorve the car today, and other than running a little hot it was great
before getting into it I am going all disc, getting rid of the drum rears and the tiny mustang rotors on the front. Thanks All. Chris

 

on the damper I did replace it, with a stock damper, this winter when I go thru the car I will use a aluminum one.