I bought a new timing light and need a lesson on how to use it. My car has been experiencing hi temps and loss of oil pressure and pinging that I'm associating with too much retarding on the timing. Can anyone give me a lesson on how to use a timing light. I can hook it up, unplug the vac. line. Once I my timing marks on the crank are 0, 6 and 12. I don't know what the timing was set at. Should I get the idle to about 800rpm and then what mark should I point the light to? I need a lesson on what I should be doing from step 1 to the end. Or should I just take it to a garage?
It's a pontiac 400, with a cam (unknown specs). With an idle at about 800-820rpm, and using a timing light at the zero mark, I'm getting a reading of 39.2. Does that seem like an accurate reading or am I doing something wrong? I thought I should have been looking for a reading somewhere near 12.
Sounds like you are using an advance timing light which is good. You are correct, when you adjust the dial or push button, whichever type you have so that the timing is at 0 degrees at the balancer, the reading on the light is your timing. Sounds like your base timing is waaaay too advanced. Back it down to 13-15 degrees to start, with vacuum disconnected. Then make sure the mechanical advance is working(i have a feeling the weights may be stuck out)rev the engine to about 2k and see what the timing goes to. If it doesn't move at all then you have a mechanical advance problem. Need to solve that first and then continue on.
The HEI usally will advance about 24-28 degrees in mechanical.
I would say your initial (idle at 850 ish) will be in the 10-12 degree mark for a warmed over performance motor. Then while you have the motor reving at 3000 rpms you will need to see what the timing is at - this will be your total advance. this should not go over 38 for your Pontiac and probably would be better at 36ish.
the advanced timing light work off the balancer mark lining up with the zero mark on your timing tab on the timing chain cover.
Remember ALWAYS check timing with vacuum advance disconnected and plugged on the carb or manifold vacuum side.
When you hook the vacuum advance back up it WILL make the timing go up and idle too. Do not FREAK this is normal. Just adjust the idle back down a bit and see how it goes after that.
