Hey guys,
Anybody done any compression tests on their engine lately?
I'm getting compression numbers as follows:

#1 ~155psi
#2 ~165
#3 ~150
#4 ~150

Considering "nominal" (according to the shop manual) is 228, this seems REALLY low. Same test last year (~6k miles ago), with the same guage and conditions, read close to 220 all across. I have less that 15k total miles and have had no incidents of any kind (mis-shifts, over-revved, etc.) and oil level checked routinely. No mods.

Thanks for any input.

 

I have tested mine a couple times, and they were all in the 210+ range. Did you warm the engine up before doing the test? A cold engine will probably show low numbers.

Did you have the throttle fully open while cranking the motor?

 

Yes on both counts. I couldn't imagine the need for a valve adjustment would show these low readings. Maybe if one or two valves were out of spec, but the likelihood of valves on all four cylinders, producing the same range of comp readings.
I've got it at the local dealer now for the spark plug TSB. I'm havng him check the compression as well, plus a leak down test. Maybe that will shed some light.
I've been paranoid about the #4 cylinder issue for a while now (for no particular reason other that). And that would be justified if just #4 was low comp. But all four?

 

At 6000 miles, mine were 200 across the board.

-YS

 

What mods do you have? (if any...)
-BS2KT

 

I haven't done a compression test on the S2000 but I assume it's the same as on other cars. You plug it into a spark plug well and crank the engine. Do you need to do anything else?

 

How much oil have you added, to keep it topped up?

 

[QUOTE]Originally posted by turbo_pwr
[B]I haven't done a compression test on the S2000 but I assume it's the same as on other cars.

 

gernby, thanks, here's my extra question. I've heard different opinions. Is it necessary to disconnect the battery?

 

[QUOTE]Originally posted by turbo_pwr
[B]gernby, thanks, here's my extra question. I've heard different opinions.