Compression Test
Thread Starter
|
Posting Guru
Joined: Jun 2004
Posts: 1,808
Likes: 0
From: Cincinnati Ohio
Compression Test
Whats the proper way to do a compression check. I am in the process of replacing valve seals, but the old ones dont look bad and want to know why I go through so dang much Oil! What numbers are safe to say that the engine dont need rebuilt. My oil pressure stays around 5-8PSI when warm with 15W40 in it. Around 40PSI when first started.
Lead Driver
Joined: Nov 2003
Posts: 6,900
Likes: 3
From: Campbell River, B.C.
Its basically the same as for a gasser. Just get a comression tester that is intended for a diesel (glow plug hole is usually the easiest), and crank the engine over with the FSS disconnected. Other than that, all the same rules apply.
Lead Driver
Joined: Nov 2003
Posts: 6,900
Likes: 3
From: Campbell River, B.C.
Correct. I mentioned the requirement of a diesel compression tester, but in hindsight it could be interperated that the compression numers are the same between gas and diesel. As you point out, the diesel needs much higher compression. Manual states up to 440 PSI for a healthy engine and a spread between lowest and highest of no more than 25%. 25% sounds high, but it seems to be true. My engine ran smooth before the rebuild even with on cylinder at 500 psi and another one at 400.
