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Posted by D Sherman [72.47.9.228] on Saturday, July 10, 2010 at 03:27:37 :
In Reply to: Dave posted by copey [206.80.248.216] on Saturday, July 10, 2010 at 03:00:31 :
All good suggestions
1) May try compression test, but with valves adjusted it idles smooth and even.
2) Ignition sparks on all cylinders and fires the timing light even when the engine appears to miss.
3) Wires are in correct order, have not checked resistance. Plugs, cap, and rotor are new.
4) There is a little play in the shaft, not sure how much is too much.
5) Vacuum at idle is about 12". Tweaked idle mix for best idle at max vacuum. Did not check at open throttle.
6) Vacuum advance hose at distributor has suction. I should have tried sucking on it with the vacuum pump to make sure it advances, but I didn't do that.
7) Did the propane test, with a rubber hose on the torch body and blowing propane all around the intake manifold and carb. Pinched off each vacuum hose, including brake booster, to eliminate any downstream leak. No effect on idle speed or vacuum.
8) Will try that tomorrow.
10) Adjusted the valves twice today, once with the engine stopped and once with it running (final adjustment) Also had the whole head into the shop for the valve grind. Rockers and push rods looked good when I had them out and still look good and work smooth. I'm slightly concerned about #4 exhaust (the one that was burned before) because the rocker works its way to one side of the valve stem, whereas on the others the rocker stays pretty close to the center of the stem. I think this means the machinist didn't get the new valve guide aligned perfectly.
11) Will have to check with the boss on that
All in all, I'm pretty sure it's the jumpy timing that's the problem. I just have to figure out exactly what's causing it.
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