viperprime

Hi All,
I've got a 79 with an L48 & HEI
I put the timing light on it today (With vac advance removed and plugged) and I'm very puzzled. It's reading about 16-20* retarded (Best guess). I tried advancing the timing and by the time my timing marks gets to the first (only) retarded notch, the engine putters out and quits. I thought the Harmonic balancers were indexed. Is it possible for it to be off byy that much? Am i missing something?

wcsinx

Once that bonded rubber ring lets go, there's no telling where the timing marks will end up. I think mine were off by nearly 30° before I replaced the balancer.

MelWff

Pardon the dumb question but did you have the timing light connected to the plug wire going to the cylinder closest to the front of the car on the drivers side?

Danish Shark

Perhaps you momentarily got confused and thought it was retarded when it's really advanced? I do that sometimes
What way did you turn the distributor to advance it?

wombvette

Its a very very common problem with those year cars for the balancer to slip.

hugie82

It happens often. Be sure to us an installer if you are replacing the balancer yourself and of coarse replace the seal

larrywalk

It's easy to tell if it has slipped. The key is to note whether or not the TDC line on the HD is inline with the keyway slot, or with later HDs (~1969), the TDC line will be 10 degrees counterclockwise from the keyway.

Unfortunately, one needs to remove the pulleys from the HD to tell, but there is another way... The HD has 3 struts which go to the outer ring; there is a 3/8 bolt in the center of each strut and the keyway aligns with one of these bolts... Therefore, the TDC mark should align with the center of one of these bolts (pre-1969), or be 11/16" CCW from that bolt! And you didn't need to remove any pulleys or bolts at all!