Didn't get any good answers from the regular LT1 teck forum, so i thought I would try here. Is a stock LT1 internally or externally balanced. Thanks.

 

Both, internally up front, externally at the rear.

 

Soma07 is exactly correct.

I just went through this with Callies when I ordered my crank. The front harmonic damper is neautral balanced (internal), and the flywheel in counter balanced (external).

Mike

 

that basically means the harmonic damper provides no external balancing. The flywheel is used to balance the rotating assembly externally. So the LT1 stock would be considered an externally balanced motor. If it were to be considered an internally balanced motor the flywheel would also be zero balanced.

 

Not to split hairs, but that is not 100 percent correct. With a full external balance such as a sbc 400, the flywheel, and the harmonic balancer are counter weighted.

Now the LT1 is considered: front internal, and rear external balanced. This is because of the reason I posted earlier.

This information is straight from Callies. Trust me, I just asked them a hundred questions about this same topic not more than 3 weeks ago.

I do however agree that if it were to be considered an internally balanced engine, both flywheel and harmonic dampner would need to be neautral balanced.

Mike

 

This doesn't make much since. Here's what I need. I bought some new Eagle 6" H beams, SRP forged pistons and using the stock crank. What all does the machine shop need to balance the motor. And I need to know for sure internally or externally balanced, I don't understand how it can be both.

Thanks.

 

Like our man Soma said, the LT1 is internally balanced up front and externally in the rear. Since it relies on a counter-weighted flywheel/flexplate to balance, technically the LT1 is considered an externally balanced motor. The only difference between the LT1 and other externally balanced motors such as the 400 is that the damper up front doesn't really do much balancing at all.

In you situation, just take your rotating assembly to the machinist with the flywheel/flexplate and ask him to balance it. Shouldn't cost much more than $100 or so since the weight disparity between the stock rods/pistons and Eagle's/SRP's is not significant. Just leave the damper at home

 

Jim, you're the man. That's what I was looking for.