1st Gen 100K+ Compression Test Results

You warmed up the motor prior to this test?

 

Nothing wrong with that compression - the important thing is that it's fairly even across the board and well within spec. #3 is a little low, but not horribly so.....could just be a tight valve that needs adjusting. (Or are those hydraulic in 2004?)

I say drive her another 100K and check it again!

 

You're down somewhat. Did you perform a wet test afterward? Between a wet test comparison and leak down test you'll know if it's time for headwork, rings or both.

 

question

while I am going to google it, what's a wet test? I have 125K on my R53 and had similar numbers and range, so pleased there. This may be a more general question-- I feel I am not getting the HP I once did. Several mods under the bonnet (CAI, 17% supercharger pulley, and air diverter for supercharger). Routine oil changes and filter cleaning, plugs and wires-- keep it in top running condition. Just wondering if valves and/or even rings needs work. Knowing this is all vague, any ideas? Thank you, and I will keep checking around this thread. C.I.

 

:cornut: This thread is 2 1/2 yrs old so you should probably PM k-huevo to be assured of getting an answer and/or drawing his attention back to this thread

Jason

 

Thank you, Jason. New to forums and will be mindful of post dates, Chris

 

A wet compression test is used to indicate if low cylinder pressures are caused by worn piston rings only. The test is done exactly the same as the “dry” test, however a small amount of engine oil (about 1-2 teaspoons) is added into the cylinder to create temporarily seal (to prevent possible blow-by). If compression rises significantly afterwords, then worn piston rings are the culprit.