Hello there. I just did a an engine compression test on all 8 cylinders a little bit ago and 7 out of 8 cylinders were in the range of 137 to 142 PSI with the exception of cylinder 2 which checked out at 116 PSI. There are a lot of miles on the engine. I'd say almost 100 thousand. It was rebuilt many years ago and properly ran, cared for and looked after. I plan to find out if there is a stuck/bent valve or piston ring problem by pressurizing the problem cylinder and running the proper tests. What is the ideal cylinder PSI range for a 289 A/T 2V engine? I do know with out a doubt the engine was rebuilt to stock specifications. Any advise would be appreciated. Thanks.
If the engine is currently running and appears to be OK(?), then you probably don't have any "stuck/bent" valves. Pressurizing each of the cylinders (engine at op temps) with each piston tested at TDC (valves closed) and listening at the tail pipe, carb intake, and VC breather for any sounds of air leaking. This test will give an indication of each cylinder's ring and valve's sealing condition.
A leak down tool is an excellent tool to use for this test. Another indication of valve, carb, and timing troubles can be had through the use of a vac gauge.
The important point about compression tests, is the range should be somewhat close in numbers. Some folks say 10% as optimum. Compression numbers range from 140-160, with the low end indicating a more worn engine.
Since you know # 2 cylinder is low, concentrate your tests on that cyl. Your 137-142 range is not bad in itself.
As a comparison, my engine (highly modified) is running 10.6 CR. The cranking pressures are in the range of 198 psi with a vac reading of 17 HGs.
If you are unsure how to perform these tests, there are many articles available by "Goggling".
Hope this helps.
