civic_driver

Hey guys,

I just did a compression test on my d16y7 and the numbers I got are 195, 187, 192, 197. Since they are above 135psi and are within 10% of each other I suppose the compression is good, right?

A note to those doing a compression test on 96-00 civics: All you have to do is remove the "fuel pump/(srs unit)" and "(ign coil)" fuses before doing a compression test. Both fuses are under the dash and both are 15amp.

I did 8 cranks/revolutions per cylinder as per the compression gauge manual's recommendation. Well, actually I did 10 but the manual recommends 8.

civic_driver

At first I thought the numbers were kind of high for a d16y7 with 70K miles on it. What do you think?

mynameisChris

Sounds about right to me.

Targa250R

It's fine.

amtheiceman

iTrader: (1)

just right

civic_driver

Wow, I remembered now, I forgot to hold the gas pedal at WOT while cranking the engine. Hmm. I'll redo it tomorrow and see if the numbers change.

Targa250R

It doesn't matter. It's fine. You're reading way too much into this.

civic_driver

Yeah, I know. I just want to know what proper numbers I should be getting for this engine since I've never done a compression test before.

I'll redo it today just for kicks

Jimster480

the numbers do seem a litlte high. But that is perfectly fine. you have to worry when they are low lol.

civic_driver

Ok, so I did the test again. This time I held the gas pedal at WOT and my numbers are almost the same. Here they are: 195-192-197-199.

The problem I see is that people say, the exact numbers don't matter, what matters is that they are within 10% of each other. Well, my question then is, if the numbers you get from different compression gauges are different then how do you know if it's time to change/rebuild the engine (i.e. when one or more of the cylinders drop below 135psi as is the case for 96-00 d-series engines)?

Sr420Det

Those numbers seem pretty sound to me. Why are you doing a compression test is it running like **** or something? Dont know seems one of those gauges is off

civic_driver

Exactly, that's my question, how do you know when they're low enough to require engine replacement/rebuilding with any particular compression gauge.

civic_driver

No, it's running great. I just did a valve adjustment and changed the spark plugs which were long overdue and it's running like new. I bought a compression gauge recently and wanted to see what the numbers are on a "healthy" engine so that I know when it's time to rebuild the engine (plus it's my first time doing a compression test, I just wanted to do it )

Jimster480

if its below like 120 on a stock motor there is a serious problem. But it varies per motor since different motors have different compression ratios. So they would have higher PSI from the beginning

Targa250R

When the engine is bad, you'll know it. Trust me.

A D16Y7 won't due of gradually lowering compression. If anything, it will die of head gasket failure or catastrophic oiling issues.

Jimster480

nah it can. My original Y8 was beat to ****. I never compression tested it but I know it was low. I got beat by stock DX's and ****, and I couldnt even hit 100 in it until i got a P2P and even then i could barely get to 105. But it didnt burn oil or spin a bearing, it was all stock it just sucked major dick lol.

civic_driver

A headgasket failure would be much easier to fix. I hope it lasts at least until it hits 150K miles. Anything more is bonus.

Jimster480

mine had like 150k on it when i bought it.

Targa250R

Not with higher mileage. If you freshen the head on a worn bottom end, it's going to burn oil like nobody's business. Once the head gasket goes, you might as well tear it down completely to at least re-ring it and hone the cylinders.

jluo_hatchy

sounds fine to me. nthing to worry about

likwid2u

when i worked at c&t japanese engines if the motor was under 150 on compression the motor would smoke customers would come back and complain

Jimster480

wtf are you talking about? A worn bottom end? If you dont overheat your **** then it wont be warped and the bottom end wont be "worn" so you can replace the gasket and its all good. My friend just replaced the gaskets on a motor that had 200k, it doesnt burn oil for **** so dunno what your talkin about.

Targa250R

Okay . . .

Everything obviously went over your head.

That's fine. Once you get a little bit older than 18 and get some experience under your belt, you'll see what I mean.

Jimster480

i already have plenty of experience, thanks.