dont like what i see with my compression test - 120,120,120,120
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dont like what i see with my compression test - 120,120,120,120
i did a test on my ls vtec i have a b16 head on a b18b1 block and im running ls pistion block has been rebuilt only has 9000 mils on it but the test showed 120,120,120,120 dont know why it would be so lowand dont know what to think
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Re: dont like what i see with my compreshion test
Do the test again, and drop a little oil into each cylinder before you test it. Then come back with the new numbers.
EDIT- try another tester if possible.
EDIT- try another tester if possible.
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From: bum-fuk egypt
Re: dont like what i see with my compreshion test
as they seem consistent its not necessarily a bad thing. you should be near 170-180 in ur compression test. did you just install these cam gears or have they been on? what made u to decide to do a compression test?
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Re: dont like what i see with my compreshion test
ok so i did another test put some oil on the oring of the tester first and got 130,130,130,130 then i went back and put some in the cylindars and did the test again and got the same numbers so i got no change except that i was loseing 10 lbs frome the oring on the tester and befor you ask yes i had my foot to the floor and yes the motor was hot
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Re: dont like what i see with my compreshion test
i just went to this other forum, like this one, and they had a whole bunch of calculators. It said it was just a ballpark estimate, but being as how i dont know all that much about the engine its better than nothing. From what he told me - the heads have been "tweeked" but are still stock, its got an aftermarket cam, the cranks been balanced, and the pistons are aftermarket. From what i can see - the heads are still stock with aftermarket springs and rockers, it definitely has an aftermarket cam, the crank is balanced, and theres got to be more than that, so i think the pistons had to have been switched out. I really dont want to tear the engine down, but i know thats the only way to tell for sure. Ive never measured the dome/dish on a piston, so how would i know what that is? The website gave me this (ballpark estimates):
8:1 - > 102.9 psi
8.5:1 - 102.9 > 110.25 psi
9:1 - 110.25 > 117.6 psi
9.5:1 - 117.6 > 124.95 psi
10:1 - 124.95 > 132.3 psi
10.5:1 - 132.3 > 139.65 psi
11:1 - 139.65 > 147 psi
11.5:1 - 147 > 154.35 psi
12:1 - 154.35 > 161.7 psi
thanks,
classic
8:1 - > 102.9 psi
8.5:1 - 102.9 > 110.25 psi
9:1 - 110.25 > 117.6 psi
9.5:1 - 117.6 > 124.95 psi
10:1 - 124.95 > 132.3 psi
10.5:1 - 132.3 > 139.65 psi
11:1 - 139.65 > 147 psi
11.5:1 - 147 > 154.35 psi
12:1 - 154.35 > 161.7 psi
thanks,
classic
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From: MINT BERRRRRRY CRUNCH!!!, WNY
Re: dont like what i see with my compreshion test
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From: Walnut, CA, US
Re: dont like what i see with my compreshion test
U said ur timing is at TDC ? It needs to be at 16 degrees BTDC. timing will defiantly affect ur compression test.. test the cylinders dry all plugs removed then wet test. Compare readings.
Seagull Management
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From: Miramichi, NB, Canada
Re: dont like what i see with my compreshion test
Mechanical timing is at TDC, ignition timing should be at 16° BTDC. Ignition timing has no effect whatsoever on a compression test.
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Re: dont like what i see with my compreshion test
I dont think these are accurate IMHO. my friends Compression was 150psi (stock d15b7) 9.2:1 CR and my built 10.5:1 CR came out to 150psi same tester. tested same way
these are guess' and do not apply to every single motor. other factors may lessen or increase compression. :different cams (bigger-aftermarket), cam not dialed in, valve leaking, rings bad, valve lash etc.
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Re: dont like what i see with my compreshion test
I dont think these are accurate IMHO. my friends Compression was 150psi (stock d15b7) 9.2:1 CR and my built 10.5:1 CR came out to 150psi same tester. tested same way
these are guess' and do not apply to every single motor. other factors may lessen or increase compression. :different cams (bigger-aftermarket), cam not dialed in, valve leaking, rings bad, valve lash etc.
these are guess' and do not apply to every single motor. other factors may lessen or increase compression. :different cams (bigger-aftermarket), cam not dialed in, valve leaking, rings bad, valve lash etc.
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