Hi All,

I got my Fall projects done and ready to start working on my Bird. Upon much advice on this board on my 455 blowing blue smoke on acceleration and getting poor gas milege, I did a compression test tonight per my '68 Pontiac Manual. All of the plugs were removed and the choke held open. I let the engine turn over approx. 8 times per each reading. The PSI readings are listed below

*Drivers side front to back
105
11 (tested this 3 separate times)
101
104

*Pass side front to back
98
107
107
110

All of the plugs were equally oily when removed and no build up. The manual suggested 150-170 psi for a standard reading for 9:2 to 1 CR engine. Mine is approx. 9:5 to 1.

I have my suspicions that I have a bad valve but the psi readings all seem low. I'm not sure if I was to have my heads redone it would correct the problem or a full rebuild is in order. Any advice would be greatly appreciated.

Thanks in advance.

A leak-down test will tell you more accurately what's going on in your engine. It works by essentially hooking up an air line to the cylinder being tested, and measuring how much air leaks out past the rings and by the valves. you can tell where the air is leaking by listening at the carb (intake valve), exhaust pipe (exhaust valve), or the oil filler hole in the valve cover (rings).

Very likely that you have a burnt valve from the sound of the compression test, and the oil burning under acceleration suggests worn rings. At your altitude, you should be closer to 130-140 if everything is in good shape.

It needs the full rebuild. My guess is the rings are weak from prolonged inactivity and/or age. If it wasn't using oil there would be a chance you could fix it with just upper end work.
Jim

I'd vote with Jim on that one. Rebuild the whole thing. Do it Right. Do it once.

So the big question is... What reputable engine rebuilder choices do I have close to Idaho?