What did you end up seeing for the valve adjustment? Tight valves?

Note:
If you used a late model harbor freight tester, check if it has a schrader valve at the point where it screws into the cylinder. If not, 150PSI is equal to ~230PSI on a normal tester due to the Compression ratio loss.


You have to calculate the volume in the hose up to the gauge. This is essentially like lowering your compression ratio. The Bore: 87 mm (3.4 in) and Stroke: 84 mm (3.3 in) and the compression ratio of the AP1 is 11.0:1. Calculate the head volume from the ratio, then add the volume of the hose to it. 182 cm^3 head volume, add hose volume, say 10mm x 300mm, 94.25 cm^3, you have almost halved your compression ratio. 2000 / 182+94 now it is 7.23:1. So 1bar * 11^1.4 * 60% Volumetric Efficiency = 17.2bar = 249 psi. so with the lower CR, 1bar * 7.23^1.4 * 60% = 9.57 bar = 140psi. It will depend on the hose volume. this is just an example.
https://en.wikipedia.org/wiki/Compression_ratio

Zui

 

I calibrate equipment for a living. Best bang for your buck gauge is an Ashcroft. A harbor freight gauge WILL give you inaccurate readings. Unless it's calibrated but I wouldn't trust it. For those of you using one It may give you repeatability but not accuracy.

http://www.ashcroft.com/products/pre...uges/index.cfm

 

I did a test on my car today. Had the gas floored but the engine was completely, 100% cold (had been sitting for a day). Does that matter much for the resulting numbers? I think the only difference it could make is possible lower numbers since the piston rings aren't expanded when cold.

All four cylinders were between 210->215, so I'm pretty happy about that.

 

Yep that's fine, ideally you want to do it with the engine warmed up because then the piston crowns expand and seal better.

 

Thanks for the DIY! I am planning on doing a compression test and changing the spark plugs....but I had a question. The compression DIY says to test with a warm engine, but the spark plug DIY says to replace with a cold engine. Would it be advisable to do these activities separately, or would it be ok to replace the spark plugs after the compression test? Maybe its a dumb question, just looking for reassurance on the procedure.

 

I don't see anywhere that it says the engine must be cold.

It is totally OK to replace the spark plugs during the compression test.

 

You don't want to do a compression test immediately after you just drove 45 miles, vtec screaming half way. But it's best to drive a couple miles to get the car warmed up, wait like 10 minutes and then do it. These engines radiate a lot of heat so it won't be that bad.

 

Updated results

1 - 150
2 - 150
3 - 150
4 - 200

@ Zuikan I'll have to check with the guy who did my test (thanks for the heads up)

 

Sorry, to bring back an old thread but are there any recommendations for high quality compression tester?

 

Thanks for the DIY.

Did a compression test on my S (MY2000) and got following.

220, 216, 218 and 221

pretty happy with the result and glad I got around to it. Now my mates with DC2 TRs want me to do a day of compression testing on their cars.