Honda Prelude Forum

Does anyone know how to do a compression test or would it just be smarter to get it done by a mechanic?

yup.

first, go rent/buy a compression tester from autozone.
then, either pull your fuel pump fuse, or disconnect the coil wire (to keep the engine from firing)
then pull out your #1 spark plug and wire, and screw the comp tester in. then your either gonna need someone else watching the gauge to tell you when it max's out, or bend it so you can see the gauge under the hood.
first, crank the engine for about 5-8 seconds, then stop. then crank it again for short 2-3 second bursts as many times as needed until the needle stops rising.
then repeat for the other cylinders.

its easy as hell to do, shouldn't take more than 20 minutes.

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N.J.P.O.C.
New Jersey Prelude Owners Club

Boost Club Member #1.....because N/A isn't worth it.

You can do it yourself with a compression gauge. Way up the pro's of buying one yourself to do it or the price for a garage to do it.

Edit: I never realised there was a reply before posting ;) the wonders of the refresh button lol

can you do it with just the engine

you mean without the gauge??

how are you gonna tell how much pressure is in each cylinder then?

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Positive Intake Manifold Pressure Video


N.J.P.O.C.
New Jersey Prelude Owners Club

Boost Club Member #1.....because N/A isn't worth it.

i think he means without the car like a crate motor or somethin. . . correct?

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yea i think so. as long as you can supply some power to the starter, i dont see why not.

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Positive Intake Manifold Pressure Video


N.J.P.O.C.
New Jersey Prelude Owners Club

Boost Club Member #1.....because N/A isn't worth it.

ya i wanted to do a comp test on my h22 i got from hmotorsonline before i put it in..

does anyone know what the compression should be?
i did it and got from cylinders 1 to 4
170 152 142 170 psi
i saw it says in the specs you need to test at 250 rpm and throttle wide open so i wasnt sure how to do this so i just did it all closed.

well not only would it help to tell us what engine you have, but your results are also gonna vary depending on what altitude your at, condition of the motor, as well as other factors.

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Positive Intake Manifold Pressure Video


N.J.P.O.C.
New Jersey Prelude Owners Club

Boost Club Member #1.....because N/A isn't worth it.

sorry, early monday morning syndrome...
1997 prelude base,
h22a4
stock internals
i live in alberta so the altitude is approx 650 m above sea level

650m = 2100 feet, and H22 ~= 10:1 CR, sooo.....

xenocron states approx "healthy" numbers are:
-9.5:1~11:1 compression: 210-275 psi per cylinder

but your at slightly higher elevation so they should be slightly lower numbers. but again, the higher the number doesn't mean your engine is in better condition. its more important that the cylinders don't vary more than 10% from each other, and yours.... do. alot, which isn't good.

did you do both a dry and wet test?
dry is a regular test with the motor cold, you always do this one first.
afterwards once you get the initial results you do a wet test by simply pouring a cap full of oil into the cylinder that you're about to test, then do it again.

__________________


Positive Intake Manifold Pressure Video


N.J.P.O.C.
New Jersey Prelude Owners Club

Boost Club Member #1.....because N/A isn't worth it.

i thought you never wanted to put oil where the gas goes?????

one other thing, when you are crtanking the engine to get a compression reading you should also have the throttle all the way open.