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Old 01-10-2013, 05:12 AM
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staleg staleg is offline
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Timing and TDC problem

I have a L05 Chevy small block 350 first gen 1993 model engine rebuilt from TBI to carb in my '34 Ford Roadster.
Since the water pump is short, I can't use the original timing marks that are at 12 o' clock for the harmonic balancer on these.

I bought an after market ignition timer like this:
Summit Racing® Adjustable Timing Pointers SUM-164800 - SummitRacing.com

And an adjustable timing light like this:
Summit Racing® Timing Lights SUM-G1059 - SummitRacing.com

Found a new TDC point for the new pointer, by adding a piston stopper (modified spark plug) on piston No 1, turned the crank until it stopped, made a mark, turned the other way until stop, made a new mark, set the new TDC mark halvfway between the two.

Started up the engine, turned the distributor until the engine run fine, aimed the timing light against the balancer an twisted the switch on the rear of the light until the timing marks stood level.
Trouble is that I read 60 degrees of advance with vacuum! What's wrong?

Of course, I suspect my new TDC mark to be wrong, but the original timing mark on the balancer is app 12 o'clock (impossible to see 100%) when my new timing mark is level with the new pointer, and isn't that correct?

The engine runs fine. No knocking, no ping or anything. But I would like to have a more accurate timing than I have now.

Any suggestions? Could my TDC point be wrong after all?
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