Yesterday I decided to finally set the timing on my '84 Chevy C20’s 350 engine. It had been idling rough ever since I brought her up to Houston as my substitute vehicle. An accident left me car-less but it being my second vehicle I took my time with making repairs. That’s not to say I’ve not done anything; I’ve replaced an exhaust manifold, had the carburetor rebuilt, had the exhaust piping and muffler upgraded, changed the spark plug wires and spark plug themselves, replaced the power steering pump and lines, had the gearbox replaced, replaced fuel pump, air filter, and a host of other things.
But I finally got around to the timing yesterday. I warned up the engine, turned it off, found the mark, traced it with a white marker, hooked up the timing light and started her back up. I figured with the backfiring and exhaust problems she’d been giving me that I would need to advance the timing. When I shined the light I found my timing mark was advanced so far off the mark I couldn’t believe it. Then I noticed another mark that was at about 4 degrees ATDC. Two marks? Just to make sure I retarded the timing slightly to try and bring the mark I highlighted closer to range and the engine began to stall. So naturally I began to advance instead and bring the 2nd mark to the factory specs of 4 degrees BTDC. The engine sounded much better but I couldn’t get past 2 degrees ATDC. The vacuum advance hits the intake manifold and I can’t advance it further. I turned off the engine and took a look at the mark. It looks like someone made that mark with a hack saw. It doesn’t run across the entire harmonic balancer, just near the edge. To me it looks like whoever took this engine apart and put it back together didn’t align the #1 piston with the original timing mark at TDC. So they just sawed in a new mark at the new TDC location on the balancer. Thats my guess. How much work is involved in fixing this?