My compression I really low

1- 105
2- 85
3- 85
4- 90

I am going to take apart the motor and replace the rings to boost the compression back up. Could you guys tell me is there anything else I need to do this, besides the head gasket and oil pan gasket.

 

the cylinder walls will need to be honed. if you have never done this before, take it to a machine shop to insure a proper cross hatch

 

Did you hold the gas pedal to the floor when you did that test? Those readings are so low I'm suprised it cranks over.

Your numbers are fairly consistent, tell us how you did the test.

 

might do the bearings also while its apart. def should atleast run a hone through it.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slowcivic2k &raquo;</TD></TR><TR><TD CLASS="quote">Did you hold the gas pedal to the floor when you did that test? Those readings are so low I'm suprised it cranks over.

Your numbers are fairly consistent, tell us how you did the test.</TD></TR></TABLE>

a proper compression test has zero spark plugs installed
this keeps the motor from having to perform work against the compression in the other cylinders during testing.
you disconnect the dizzy to protect the coil
and disconnect the injector clips so no fuel flows
excess fuel in the cylinders can give false results.
use the starter to crank the motor 5-6 times
test each cylinder

 

Well I did the test twice the numbers in my first post were with the spark plugs in.

These are with the spark plugs out

1-130
2-105
3-105
4-110

I didnt disconnect anything else, But I know I have a compression problem. It doesnt start in colder weather and has a rough idle.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by digitalcongo &raquo;</TD></TR><TR><TD CLASS="quote">

a proper compression test has zero spark plugs installed
this keeps the motor from having to perform work against the compression in the other cylinders during testing.</TD></TR></TABLE>

Spark plugs must be in their holes, with the exception of the tested hole. an engine naturally has to fight with the compression of all the other cylinders, that is simply a way to boost your readings, like putting in a heavy oil to compensate for low oil pressure.

Was the engine hot?, and did you hold the throttle to the floor?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slowcivic2k &raquo;</TD></TR><TR><TD CLASS="quote">an engine naturally has to fight with the compression of all the other cylinders</TD></TR></TABLE>

show me one place in the universe where engines exist naturally
how does the compression of one cylinder have anything to do with another
remove as many of the influencing factors to yield the most conclusive results of any single component of a system.
this isn't about forging a compression value
this is getting an unaffected test result to the best of your immediate ability.

 

Why don't you read my post before you post asking the same question I just answered.

Engines have to fight the strokes of the other pistons in the engine during startup, so what would be the sense to remove all the plugs. All this does is allow the engine to crank faster, and does not give a valid result because the engine will still have to fight the strokes of the engine with the plugs reinstalled. This way the engine builds the same compression the engine would normally build during a normal startup. Therefor I affirm that a more accurate result will be obtained with them installed.

I don't care what Mitchell has to say about it. 40% of the information on there is garbage anyways. You go by a manual, I go by experience/common sense.

 

shut up

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by digitalcongo &raquo;</TD></TR><TR><TD CLASS="quote">

show me one place in the universe where engines exist naturally
how does the compression of one cylinder have anything to do with another
remove as many of the influencing factors to yield the most conclusive results of any single component of a system.
this isn't about forging a compression value
this is getting an unaffected test result to the best of your immediate ability.

</TD></TR></TABLE>

Thanks funny I ended up getting the exact same print out, I decided that its easier and cheaper to just put another motor in. Since my throttle body is done also.

Thanks alot tho