The Stovebolt Site Forums The Shop Area The HiPo Shop Harmonic balancer with odd TDC mark

Have a crate 350 motor. Bought naked so had to put various parts on it including harmonic balancer. My FLAPS sold me this thing. I installed it, put motor in streetrod and started it. Couldn't find timing mark with timing light when everthing was sorted out. Ended up being about 105 to 115 degree before TDC tab which is at the 1:00 o'clock position. What went wrong? Anything I can do about it? Thanks.

You have a late-model harmonic balancer with the TDC mark close to the 12:00 position. You'll either need to change timing covers, or re-mark the balancer for the conventional timing scale position between 2:00 and 3:00 that was used up until the 1980's or so. It's not that difficult to re-mark the balancer ring accurately once the true TDC is located.
Jerry

Thanks Jerry. The engine is sitting on TDC as I write this. It was running just fine, well the engine was, so I move the engine around till the dist. rotor cap was looking at #1. Pulled drivers side vale cover and made sure #1 pushrods were spining.

To be sure 100% you have top dead center, get a solid stop for the spark plug hole. Rotate the engine by hand till it hits, mark the balancer, then rotate the other direction till it hits again, and mark a second mark. Measure between the two and you have true dead center.

Joe

Good point, Joe. I was about to mention the positive stop method of finding TDC. That's how we do it on the race engines, as the harmonic balancer can be off a little due to production tolerances. I use a spark plug shell with the porcelain knocked out of it, and drill and tap the shell for a 3/8"-16 bolt. screw a long bolt into the plug shell until it contacts the top of the piston a few degrees of rotation from the top, make a mark on the balancer with a felt tip marker beside the TDC mark on the timing cover, then turn the engine backwards until the piston touches the stop again. Mark that point. Measure halfway between the two points and make a permanent mark there. When the new mark lines up with the timing pointer the piston is at TDC.
Jerry

If I might add a tip to Hotrod's post. Pull all your sparkplugs out when hand cranking. Easier to do. No compression to work against.

NEVER NEVER NEVER EVER crank it with a solid in one hole, turn by hand ONLY !!!!!!!

but you knew that already,

Joe

I caught a student with a screwdriver poked into a spark plug hole on a classroom engine, and reaching for the starter button- - - - -wrong move! He got the benefit of my best "drill sergeant" imitation for about five minutes!
Jerry