Compression test on Ford 5.0 FL motor

[akfishin]

All,

Previous owner replaced long block. I figured as I was changing the manifolds I might as well do a compression test while it's all torn apart.

My lowest was 115-118 psi, highest was 125 psi. Test was done cold (40 degrees outside).

Are these numbers acceptable? How much do they increase when the engine is hot.

Thanks!

Dan

 

[Bondo]

Re: Compression test on Ford 5.0 FL motor

Are these numbers acceptable? How much do they increase when the engine is hot.

Ayuh,... Barely passable...

Run it, 'n test it again...

 

[jerryjerry05]

Re: Compression test on Ford 5.0 FL motor

Low numbers could be a cheap tester or not done right.Remove all the plugs.Then start again.
There could be as much as 30# difference between testers.
The thing to look for is all the cylinders about the same.Any more that 10% difference look into it.J