#4) 185
#3) 185
#2) 185
#1) 130, 160

these numbers are off of a salvaged 97 b18b1 engine. Any ideas what could be wrong with #1? All of the spark plugs looked the same. IT sounds fine during idle, although it will sometimes fluctuate. I get poor response after 3000 rpm, 5th gear. Which is why I did the test. Is this maybe coming from a slightly stuck valve? any oppinions, info is appreciated.

 

I'm gonna go out on a limb here and say it has bad rings on #1.

If you do a test and let the compression gauge sit for a minute or two.. and the needle starts to drop... then you have valve problems too... but my guess is rings...

anyone can correct me??

 

if you can do a cylinder leakage test, you can tell more accuratley what is bad

 

The needle on a compression tester won't drop if you let is sit... the compression tester has a one way valve in it and will not relieve the built up pressure until you press the release button.

:D

 

i thought ring too, but wouldnt i see some kind of residue on the plug?

 

GSRwBOOST, G3-TEG is right... you can even unscrew the compression tester and it will hold pressure disconnected from the engine until you press the release button.... this is how the tester has to work, since it is a peak hold gauge. Else, the engine would never have consistent compression because the valves are constantly opening!

Dustin

 

A good way to find out if it is the rings or not is to drop a little bit of oil into the cylinder through the spark plug hole and redo the compression test/ leak down..

if the numbers get better (higher) then the rings are bad. Otherwise with just a leak down test, you should hear the air blowing by the rings.

HTH

 

that makes sense.. didnt think about it.. so how would one perform a leakdown test at home?

 

leakdown test... have to get the tester, need a compressor. the tester has two gauges one for how much psi is let in the other how much the engine is holding. You just have to make sure that the piston is TDC and on the compression cycle.

 

I'll be doing a compression test either today or tomorrow.. and I was wondering which is cylinder 1? Driver or passenger side?

So i can accurately report my findings.. and what type of compression should I expect from a 94 GSR with 70k miles in good shape? Around 175-180?

 

driver side is 1 4321 is the way it goes.

Compression numbers for gsr should be 190+


[Modified by b18bturbo, 9:24 AM 7/6/2001]

 

And what numbers should I expect?

 

You should expect around 180-190 on that many miles plus it also depends on the condition of your motor.