I posted something a few weeks back about my engine missing. I thought it was the carburetor. After adjusting that carburetor and putting on a different carburetor, I'm not sure that is the problem.
The engine is a 250 in a 1966 Chevy pickup. I did a compression test on it a couple weeks ago and all the cylinders registered around 175. However, a couple of them leaked off as it sat. So, this weekend I'm going to repeat the test.
I replaced the plugs and plug wires a couple of weeks ago to see if that was the problem. It did not change anything.
A year or so ago I replaced the points with a Petronix electronic ignitor and the coil with a Petronix coil. At this same time I replaced the vaccum advance and it still works as it should.
I have adjusted the timing so that the engine runs smoother. It is several degrees more advanced than the manual suggests.
Last night while it was running I pulled the plug wires to see if there was any cylinder that did not cause it to run worse. It seemed that when I pulled #1 and #2 wires the engine did not run any worse. It definitly ran worse on the remaining 4 cylinders.
Another thing that I noticed was that when I reved the engine it backfired through the carburetor.
So, any ideas on what the problem might be or what I should check this weekend? Did my timing jump? Do I have a bad head gasket? Do I have some burnt valves? What are your thought?
Sorry for this long post, but I have been working on this thing most of the summer and have about come to my wits end.
Thanks in advance for any help or suggestions you can give.
Mike K.
