1963 FI with engine vibration

[Scott M.]

Re: 1963 FI with engine vibration

Thanks guys for all the help. My Dad lives in Evansville, Indiana but I picked the car up and live in Des Moines, Iowa. I thought all small block chevy's were neutrally balanced except for the 400. So whats the difference in dampers?

[John H.]

Re: 1963 FI with engine vibration

I thought all small block chevy's were neutrally balanced except for the 400. So whats the difference in dampers?

The dampers have nothing to do with engine balance (except on the 400); they damp crankshaft torsional vibrations, and they're tuned differently for specific application groupings, basically by average expected rpm operating ranges. Standard engines use the smaller 6-3/4" damper, and SHP engines use the larger/thicker 8" damper.

[Michael H.]

Re: 1963 FI with engine vibration

Thanks guys for all the help. My Dad lives in Evansville, Indiana but I picked the car up and live in Des Moines, Iowa. I thought all small block chevy's were neutrally balanced except for the 400. So whats the difference in dampers?

That's correct Scott. All small block Corvette balancers from the 60's are balanced to zero.
The size or weight of the balancer has absolutely nothing to do with the balance of the rotating parts of the engine.

I think the most common "out of balance" issue on most engines is the flywheel/clutch. (although I must say, your balancer doesn't look completely healthy)
There's a lot more to the story though. If an engine is out of balance, an unbalanced flywheel can either make the problem/vibration worse, or better. If both components are unbalanced by an equal amount, and the heavy spot of each is positioned opposite the other, radially, one unbalanced component can cancel the other.

Many new production engines are balanced exactly this way. The flywheel is intentionally slightly "out of balance" to cancel the unbalance condition in the engine.
If the original flywheel is replaced, or balanced to zero, it will no longer cancel the unbalance of the engine.

Unfortunately, the only way to be certain that both assemblies are balanced correctly is to balance each separately.

[Cecil L.]

Re: 1963 FI with engine vibration

Another possibility. Years ago I had a 65 365 hp that developed a similar vibratation. I checked all the obvious things and it just got progressively worse, until the waterpump seized on me one day. New fan clutch, waterpump and the problem was gone. I believe the WP failure was actually caused by the fan clutch.

[Scott M.]

Re: 1963 FI with engine vibration

Thats the first thing I thought so I removed the belt but no change. I had a bad feeling after I saw the new oil pan gasket.