If youre following my previous post, I decided to pull the motor so, I can
have the engine bay painted when, the rest of the car is refinished. Please,
read this long post, I need help.
I thought I would tune up the engine then, run compression and leak down tests
to check the health. If I have any issues, the time to correct would be while
the engine was out. The engine was rebuilt 20 years ago. I put maybe 5,000
miles on it, then it sat dormant for 15+ years. While it was dormant, it was
garaged. I routinely squirted oil in the cylinders and turned it over by hand
to keep it from seizing up.
I set my dwell and timing, balanced the carbs, and went for a spin. Results
were fantastic. No hesitation. Pulled hard. Idled nicely. With accurate
timing, it was running much cooler, also.
Next, I ran the leak down test while the engine was hot. Initial results
werent bad but, I ran out of time. Next day, I fired the engine up to get it
warm, again for another test. Its running like crap. Backfiring through the
carbs on occasion. Lots of hesitation. I drove it around the block to get it
warm then, ran another test. Results looked good and were repeatable.
1. 100/93 (7%)
2. 110/94 (6%)
3. 100/96 (4%)
4. 100/96 (4%)
During the leakdown tests, all the air was escaping from the crankcase.
Absolutely nothing out of the carbs or tail pipe. Sounds like my valves are
sealing nicely. While it was hot, checked all the valve clearances, 0.017.
All in spec.
Took a break. Warmed up the engine again and ran a compression test. Results
were sporadic, no consistency. I ran each test several times and never got the
same answer. Heres a sampling.
1. 170, 160, 145
2. 160, 140
3. 165, 150
4. 180, 170, 160
Im thinking my valves are sticking open. The leak down test may have forced
the valves fully closed and any goo on the stem is now causing me problems. I
did try swapping plug wires to see if it made a difference. Nothing. I didnt
have a spare cap and rotor.
So. What do you think?
Thanks,
Dan McHatton
66 1600
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