Compression Testing - What is Normal

[1990new]

Did a compression test on Rosie today.
Compression Test results:
1 2 3 4
153 150 150 130

Number 4 is the one with the chip out of the top rim of the cylinder.
This is after installing my rebuilt head.
She is still putting out blue smoke at idle after about 2 minutes and lots of blue some on acceleration.
I suspect stuck rings from previously being run hot.

What is normal compression numbers for the B3?

[1990new]

I did some searching and found some information on the Kia owner club about the B3 engine.

Ideal compression appears to be 214 (mint engine). Minimum acceptable compression 145 with no more that 23 PSI difference between pistons.

Looks like I do need a bottom end rebuild.

[ryanprins13]

What? 214psi with oil in the cylinder maybe, but not dry. I just talked to someone today and i think he said he had never seen a b3 above 150psi.
I just looked back in my records and about 200,000km ago my engine had 100,135,100,170. With a little oil added it was 250,225,250,255.
I havent checked since, but it ran perfectly until a spark plug had the porcelain come of and score up the cylinder more recently. Nothing wrong with the way it ran at all before that.


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[WmWatt]

Haynes manual says standard 204, minimum 149. I've read max 5% difference accross cyclinders. After doing a wet comression test with oil still in the cylinders my car has super power for about half a block.

[1990new]

What? 214psi with oil in the cylinder maybe, but not dry. I just talked to someone today and i think he said he had never seen a b3 above 150psi.
I just looked back in my records and about 200,000km ago my engine had 100,135,100,170. With a little oil added it was 250,225,250,255.
I havent checked since, but it ran perfectly until a spark plug had the porcelain come of and score up the cylinder more recently. Nothing wrong with the way it ran at all before that.

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The 100, 135, 100, 170 numbers seem strange. My test was done after I warmed up the engine for about 5 minutes.
I did not add any oil to the cylinders.

Haynes manual says standard 204, minimum 149. I've read max 5% difference accross cyclinders. After doing a wet comression test with oil still in the cylinders my car has super power for about half a block.

I arrived a the 214 and 145 after converting from BAR, as quoted in the posting I read, to PSI. I was a little off.
I trust your Haynes manual on this being the norm.

[ryanprins13]

Testing after only idling for 5 min would give high readings as the oil is still thick. If you drove it until the thermostat opened then it should be good as thats about when the oil reaches operating temp on these cars. My numbers seemed strange to me too, checked it twice dry that day but it was the same each time. Havent checked since because i dont think it would tell me anything but i plan to late this year or early next year. I dont think this compression test alone justifies a rebuild on your car but from the other problems it could. It would be nice to hear what other peoples compression numbers are though. WmWatt- what were the numbers when you tested yours?


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[zoe60]

It is important to hold the gas pedal to the floor while cranking. Mine was like 150 across the board until I did that and then they went up to 195 or so.

[WmWatt]

Last check was 4 Nov 2014 @ 124,436.6 km
Dry 187, 190, 190, 190
Wet 205, 197, 197 200
I have a remote switch to connect to the starter and watch the pressure build on the guage as it cranks and stop cranking when it stops rising.
I read that the speed at which the pressure rises has some meaning but can't remember what it is.

[Greywolf]

Chiltons calls it 204 psi, and 145 psi is the low limit - but that's mighty high compression. Do the math and it comes out to 13:1, which I find hard to believe with the low octane junk we get from gas stops these days.

[1990new]

Did compression test on Rosie today.
Ran the engine until the thermostat opened.
Held accelerator to the floor while turning over until the compression reached a peak.
Not much different that the first time when the engine was just a little warm and I did not hold the accelerator down.
1 – 155 2 – 154 3 – 150 4 - 145