Quote:
Originally Posted by A Cobra guy
Well the good news is it's running much better. I replaced the exhaust manifold gasket on the left side. I'll wait until winter to do the right side unless it breaks up sooner.
I replaced all the wires on the left side and still have the older plugs in on that side. Dave & Max, you were right on about arcing. I have those foil covered heat sleeves on the wires for a couple of cylinders. Those wires are prone to hitting the headers. When I started it up there was arcing from the FOIL to the header. Moving the wire and the sleeve fixed that. I will put the new plugs back in 1 at a time to see if they are all OK.
I did re-do the compresion test. As oldguy instructed all plugs out and throtle held open. The block was cold. 5 cylinders were at 130 psi. 2 were at 120 psi. Cylinder no. 8 is only at 110.
For now I'm just going to drive it. If I have a great fall I'll get in another 750 miles before winter. I go through the car each winter and looking into whats going on with #8 will be on my list this year.
Thanks to all for the help, tips and education.
|
I wouldn't worry about your cold cranking compression numbers, from high to low, it's 15% difference, generally speaking, 10 to 15% is acceptable.... DO pull all 8 plugs and DO hold the throttle wide open when testing, the butterfleis will all be open on the carb and it makes it easier and more uniform for the engine to draw in air...only thing I do differently is I start the engine first and let it run a minute or so to make sure the bearing are all full of
oil before I begin cold cranking on it.....
Go back and "run" the compression test again, this time squirt 2 or 3 squirts of
oil in the cylinder before cranking, if the compression goes up, then the rings are not sealing up, if the compression stays the same and is low, as in # 8 cylinder, then most likely one or both valves are where the compression leak is.... but with your numbers, I would just drive it and enjoy it and not worry about it.........
David