Cylinder Compression Values

SupraSleuth · 08-17-2009, 11:53 AM

I did my first test with the engine warm, and had my helper crank the engine until I obtained a maximum value at each cylinder. This typically occurred after 4 or 5 revolutions. I wanted to do both dry and wet tests. However, I had a lot of oil in the plug wells that found its way into each cylinder after I removed each plug. For practical purposes, I consider the first test a wet test. I repeated the test the next day to see if the numbers would change. The numbers from my second test were consistently less than those from my first test (typically by about 5 psi). I used a Craftsman compression gauge that I purchased from Sears several years ago. This gauge had been used 3 or 4 times and is in "like new" condition. I don't think this gauge gave me erroneous values, but I have not confirmed its accuracy. Because I had so much oil in my plug wells, I am planning to install new cam cover gaskets and a new "number 3 cylinder head cover".

08-17-2009, 11:53 AM	#7
SupraSleuth Stock Join Date: Aug 2008 Location: USA Posts: 9	I did my first test with the engine warm, and had my helper crank the engine until I obtained a maximum value at each cylinder. This typically occurred after 4 or 5 revolutions. I wanted to do both dry and wet tests. However, I had a lot of oil in the plug wells that found its way into each cylinder after I removed each plug. For practical purposes, I consider the first test a wet test. I repeated the test the next day to see if the numbers would change. The numbers from my second test were consistently less than those from my first test (typically by about 5 psi). I used a Craftsman compression gauge that I purchased from Sears several years ago. This gauge had been used 3 or 4 times and is in "like new" condition. I don't think this gauge gave me erroneous values, but I have not confirmed its accuracy. Because I had so much oil in my plug wells, I am planning to install new cam cover gaskets and a new "number 3 cylinder head cover".