Corvair Forum

I'm working thru some issues w/ my '65 Corsa - and - wanted to know how to check if the harmonic balancer had "slipped" and if the TDC mark is truly at the correct position? Thanks in advance - Andy.

There is a scribe mark on the face of the balancer you can see while it is installed. The mark is chiseled across between the center hub and the outer ring. Rotate the engine with a 3/4 wrench and look closely for the mark. If the mark on the hub is not aligned with the mark on the ring then it is slipped.

Wow / it actually appears to be about 5 degrees off! I assume the center mark is what should be trusted / not the outside mark. That will likely explain some of the occasional pinging I hear. I'm going to mark the "new" TDC position and set the timing accordingly and see what happens! Andy.

Here is an old photo of mine.

firstgencamarojunkie wrote:Wow / it actually appears to be about 5 degrees off! I assume the center mark is what should be trusted / not the outside mark. That will likely explain some of the occasional pinging I hear. I'm going to mark the "new" TDC position and set the timing accordingly and see what happens! Andy.

Not a good plan get a new balancer. Next thing that happens after they start to slip is that the outer ring comes off and usually bores a hole in the oil filter causing a loss of oil and oil pressure usually at a very bad time. Could result in major engine damage.

Thanks terrible / hadn't considered that / probably a good idea to replace it - thanks - Andy.

Agree with TT - The harmonic balancer (actually a damper) is a perishable item. As the rubber ages the unit no longer does it job TO PROTECT THE CRANKSHAFT. Once the outer member starts to slip it's only a matter of time before it comes apart.

There are a few rebuilders around and Clark's sells new ones.