E compression test results

[240marcuSX]

i did a compression test today and the results are as follows:

#1 - 170#2 - 175#3 - 170#4 - 170

those ARE good results arent they?? if they are im ready to order the "T" for my "KA24ET"

[WDRacing]

Looks good...boost it till she pops.

WD

[TrunkMonkey]

nice and even...go for it.

-demetrius

[project350sx]

i'm not exactly sure about those being good numbers. cuz i just recently did a compression test on my car and got 190psi +/- a couple each cylinder. this is on stock everything. now unless my engine is higher compression for some reason then you may want to check this out....

[TrunkMonkey]

192 psi is standard142 psi is the minumum

how many miles do you have on your car project350sx? keep in mind, high mileage cars with carbon buildup will give higher numbers. as long as the numbers aren't too low (240marcuSX's are fine) and consistent with one another, then the engine is fine.

-demetrius

[andrave]

my compression gauge says that it would take a 10:1 compression ratio to have 180 psi of cranking pressure...so how did you get 190??

[240marcuSX]

sweet. my car has 124,xxx miles on it btw, and i dont have any mods that would alter compression.. looks like ill be sending out checks soon.

[project350sx]

the engine that did 190psi on each cylinder is a near fresh rebuild...only 5000km's on it since i did a complete teardown and rebuild, so i doubt that there's much carbon built up yet

[andrave]

ahh, maybe they cut the head or the block surface during the rebuild, increasing compression ratio?

[TrunkMonkey]

ahh, maybe they cut the head or the block surface during the rebuild, increasing compression ratio?

oem specs for a 1990 ka24e are 8.6:1 compression ratio with 192 psi on each cylinder.

i'm tired and feeling lazy right now, so maybe someone else will explain the difference between static and dynamic compression. i believe you're getting the two mixed up.

bottom line, you can't determine an engine's compression ratio by taking a compression test.

-demetrius

[project350sx]

i did the rebuild myself and the only machining done to the engine during rebuild was on the crankshaft, no head work, no block work....OEM replacement head gasket, OEM replacement pistons and rings....the engine is in 100% OEM specs. the machining done on the crank was just to micro-finish the journals, the journals are at factory specs...i even did a post a while back asking if 190psi compression was correct, cuz i though myself that 190psi is a little high, but dauntless said that 190psi is proper for the KA24E...

[andrave]

static? dynamic?uh oh.yeah I don't know those.

[fiznat]

http://e30m3performance.com/my...o.htm

dont worry about the numbers too much, just read both pages and you'll get it

[andrave]

ahh, I understand now.My manual for my compression tester says what I said before though.

[absolute]

my cylinders read 175 40 165 145

[WDRacing]

Sweet, your ready for boost to...lol.

[PalmerWMD]

i did a compression test today and the results are as follows:

#1 - 170#2 - 175#3 - 170#4 - 170

those ARE good results arent they?? if they are im ready to order the "T" for my "KA24ET"

They're good.

Fred...

[dareo]

dang if 192 is the spec for the motor, i guess my mid 150s numbers are kinda low. That'll happen after 219k miles i guess. i want a swap pretty bad.

[PalmerWMD]

192 is perfect for new motor, but even all new motors dont make that.175-185 is expected for semi- decent rebuilt.It also important that their are all close to each other.

Fred..

[fiznat]

...within 10% of eachother

[TrunkMonkey]

...within 10% of eachother

the fsm says within 14 psi of each other.

-demetrius

[coupe4me]

I read that the lowest should be no less than 75% of the highest psi.

[coupe4me]

Did I read that correctly? You have one cylinder @ 40psi? How well does your car run? Just curious, Mine doesn't run too bad but I'm going to run a check now that I know how.