comprestion

[fmster]

Hi to all! What should the PSI be on a comprestoin test?

 

[Casey Jensen]

I think around 110-115 psi.

 

[fmster]

I think around 110-115 psi.[/QUOTE

Is that at idle? or rev up.

 

[Casey Jensen]

Just cranking the starter, engine not running.

 

[fmster]

Just cranking the starter, engine not running.

I am only getting 90 psi,The motor only has 50 miles on rebiuld,still not broken in. Is that normal?

 

[notacarlo]

You aren't checking compression with the engine running are you?

 

[fmster]

You aren't checking compression with the engine running are you?

Engine off at crank 90 psi.

 

[notacarlo]

Which cylinder is it? Check the rest and post back.

 

[fmster]

Which cylinder is it? Check the rest and post back.

ALL THE CYLINDERS.

 

[Jerryl]

ALL THE CYLINDERS.

Not to be an arse, but at least they are all equal.
Describe "how" you performed the test (in detail).

Example: Throttle closed vs open will make a difference
Engine hot vs cold will also show a difference.
Weak vs strong battery also shows a difference.
You add all this up, you could potantially be up +40 PSI

 

[Casey Jensen]

I would put a few thousand on it to break it in, then do another test. If all cylinders are at 90, I think you will be right on track. Don't use synthetic oil in it until it is broken in though.