Compression test correct?

[Dreadnought]

I'm trying to check the condition of my Super 55 engine. I bought a HF compression tester and am wondering if I did the test correctly. I have the oil pan off and the rocker assembly off. The valves and their springs are still in place. I have all the plugs out. I should be getting an accurate reading still, right? Or should the valves be working to get a valid test? Right now I'm getting 66, 55, 30, and 75 for readings which I know is very low. Any thoughts are appreciated.

 

[Blue Jay]

Valves need to be working to let air into the cylinder.

 

[Dreadnought]

Makes sense. I guess I was just compressing and decompressing the same air over and over again. Thanks
I hope I get a better result now.

 

[rustred]

Makes sense. I guess I was just compressing and decompressing the same air over and over again. Thanks
I hope I get a better result now.

five compression puffs per cylinder with a good battery.

 

[wore out]

I'm trying to check the condition of my Super 55 engine. I bought a HF compression tester and am wondering if I did the test correctly. I have the oil pan off and the rocker assembly off. The valves and their springs are still in place. I have all the plugs out. I should be getting an accurate reading still, right? Or should the valves be working to get a valid test? Right now I'm getting 66, 55, 30, and 75 for readings which I know is very low. Any thoughts are appreciated.

I wouldn't be cranking the engine with the oil pan removed.

But you can do a "cylinder leakdown test" and determine if there's leakage past the rings, the valves or the head gasket.

 

[old]

Makes sense. I guess I was just compressing and decompressing the same air over and over again. Thanks
I hope I get a better result now.

No oil pan on the engine can?will cause major damage. You should NEVER spin an engine over with out having the oil pan on a full of oil

 

[Dreadnought]

I posted a little while back about my “new” tractor with a stuck engine. It had a seized rod bearing and less than a quart of oil in the pan.
A crank grind is already in my future.

 

[Dreadnought]

I put the valve train back on and now am getting 150, 160, 144, and 164. Much better. I hope this post helps someone else down the road. Don’t do what this guy did—————and don’t do it with your oil pan off.