A TALE OF TWO COMPRESSION TESTERS
Disclaimer - I have never used a compression tester before this project.
Alrighty, so when I started this project, I did buy a compression tester. It was an el cheapo from Amazon. When I used it at the time I just wanted to make sure I was getting similar compression between cylinders, which I did seem to have. Now that I know a little better now. I think I have found where I went wrong.
The service manual says I should be getting 170 PSI.
Here is a comparison of what I would get using my tester with a thread in attachment, my tester with a shorter attachment that you just press into the plug hole, and a borrowed quality tester that has a Schrader valve at the inlet. I did hold the throttle open during these tests.
Cylinder 1
With hose that does not have valve and that adds a ton of volume:
With push in cone attachment
With push in cone attachment and after adding oil to help the rings seal
With good tester when the engine was warm
Cylinder 2
Apparently I forgot to snap a photo of this cylinder with the long hose attachment
With push in cone attachment
With good tester when the engine was warm
Cylinder 3
With push in cone attachment
With good tester when the engine was warm
Cylinder 4
With hose that does not have valve and that adds a ton of volume:
With push in cone attachment
With push in cone attachment and after adding oil to help the rings seal
With good tester when the engine was warm
In summary, I seem to have low compression and that is my issue. My initial compression test was not done well or with good tools, which made me waste time looking at other stuff. The tester I purchased is not useful for this application. At a minimum the piston rings are worn. I will perform leakdown in next post.