s2000Junky

I can only speak from my own experience working on this engine. 240psi is the proper number on a fresh F20/22 from the factory. I had an engine with a scored cylinder read 190psi and the rest were at 225+ psi at 140k miles. So with that, yes 230-240psi is an average good used mileage F series engine. A lower compression engine will yield less cylinder pressure. Most average 9:1 compression engines will see about 200psi I do believe. My built iron sleeved F22 with 9:6.1 comp pistons yielded 225psi when fresh. That being said, there are gauges that can read lower or higher apparently as many seem to report, which makes being fixed on a number confusing. This is where looking for consistency across all cylinders is more of an indication of engine health/troubleshooting then a peak number per say. But most good calibrated gauges will read 240psi on a fresh s2k engine.

Jah2000

Thanks for the clarification.

And great quotes in sig.

Soviet

Pretty much spot on. I have done compressions tests on 3 motors so far and they all ready around 220-245 PSI (when hot).

s2000Junky

Jah2000

I must have the worst luck. Attempted to do another compression test today and the tester got stuck again and broke off.

It felt super tight/stuck on the treads again, even though I only installed it lightly snugly. I even tried Billman’s tip on wrapping it with tape. But, the threaded adapter was stuck on the head.

Before attempting the test, I cleaned off the hose/fitting with glass cleaner to rid of any possible grease (so the tape will stick best), wrapped it super tight around 8-10x, and also lightly smeared motor oil on the O-ring. But, it still got stuck, and I kept jiggling and twisting and twisting, then it snapped off. This time the rubber broke.

I think it’s time to get one of these solid-metal, “long-reach,” compression tester adapter tubes ..like these ones:
http://www.langtools.com/sku-73110-m...ter-extension/
http://www.motorsport-tools.com/seal...ec-vs200a.html
https://www.machinemart.co.uk/p/clar...ion-tester-ad/


I’m kinda over it too. My engine is strong, quiet, smooth, only burns 1 hash-mark of oil on the dipstick per 2k miles, no misfires, no symptoms, no cel, +26mpg, etc., etc.


Obviously, I only had the chance to test Cyl1 before the tester broke, which read a little over 190psi. At least it isn’t <150psi or something super low.

jkelley

How tight are you turning it before running the test? And this may be a stupid or insulting question but just to make sure, you are relieving the pressure from the cylinder before unscrewing it, right?

Jah2000

Not that tight. Hardly hand tight. Def much less tight than say a 10mm bolt for the valve cover or spark plug cover (7-8ftlbs). I'm guessing I am only using a measly 1-3ftlbs when I twist the tube in place (finger tight). I've done countless compression tests in the '90s..never had this problem of getting stuck though. Weird.

Yes, I am relieving the pressure. I also tried unscrewing it with some pressure still there, to see if it did anything differently. Still was stuck either way.

My only guesses left would be that maybe the oil on the O-ring might've made it more stuck (which I doubt and I would think it'd only help and make it easier to remove). Or, that the engine was pretty warm/hot (I tested it within 10 mins of engine shutdown.. which is supposed to be the most ideal anyways for higher numbers). Or, maybe there's carbon build up on the threads, making the adapter stuck.

The rubber hose just did not give enough solidity/rigidity to be able to unscrew the adapter..not even close. It just kept bending and deforming as I tried to twist.

The solid-metal tube, long-reach adapter, is probably the best and fail-safe option for me at this point (making it super easy to remove as it's solid/rigid). Pricey though (for what it is) at $40 from the UK.