05-08-2006 12:12 PM #1
my timing mark is way off
when I try to time my chevy 350 the mark on the harmonic balancer is flashing about 2 inches before the timing tab. Is the timing wrong, the tab installed on the engine in the wrong place, or just what the heck is going on. when I try to twist the distributor to get the mark closer to the timing tab, it will get about 1 inch away from the begining of the tab and the motor chokes down, wont run there. It has to be about 2 inches away from the beginning of the tab to run. My tab is mounted a little off center of the engine to the drivers side. The mark on the harmonic balancer is flashing on the top about the center of the engine. How can this be?
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Some small blocks had a timing tab straight up,you had to look behind the water pump to see it. You may need to swap out the balancer. Also the outer ring of the balancer can move. If you look closely at it,it is two pieces of metal,with rubber sandwiched in between. If it gives way totally,well you can guess who'll need a new hood,radiator,etc. Hank
I got caught on that one---The timing mark for a 305 is in a different place than the timing mark for a 350. If you use a bolt on timing mark, be sure and get one that matches whatever engine you have.
|Old guy hot rodder|
You also want to match the diameter of the balancer too.
A: Timing marks have changed during time. While most dampers have the mark 10 degrees BTDC (with a timing mark the same way, so it equals out, but you can see the mark past the water pump better) they came with 2°, 8° and 10° over the years (but I'm not sure about the years and exact numbers, just know they changed, could look it up somewhere).
B: The balancer can slip, but that doesn't happen often
C: The engine should be advanced 6°-8° static. That is if you turn over the engine slowly (i.e. with the starter and only clinder no1 spark plug connected so you get the flash, but the engine won't run) you should get those marks. The engine needs more advance than that at idle to run properly, that's what the vacuum advance is for. At idle it will need as much as 20 degrees MORE than the static setting. My engine doesn't idle at all at the static setting, it simply stops. Because the engine doesn't run at this setting, you can leave all spark plugs connected and just disconnect the vac advance. Then have someone bump the starter for you and set the timing (also called initial timing) to 6-8 degrees. Then reconnect the vac line and you should be ready to go.
BUT: Very many people don't do it like this, they set the engine by tach or by ear. If you have one specific throttle setting, then the highest speed achievable by turning the dizzy without getting detonation is the most economical and efficient setting. So connect everything up (also the vac line) and set it to the desired speed. If you should find out that the engine speed at idle is then too high, turn back the throttle stop screw and reset the dizzy. Do this until you get the right idle speed and this is at the best dizzy setting. Then you're done, if you don't want to go further and bother with adjustable vac cans, springs and weights. Then it gets difficult, but this should get you in the ball park.
Hope I could help...