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So here's the results:

1. 159 PSI
2. 154 PSI
3. 151 PSI
4. 156 PSI

Service manual says should be 135 PSI.

My car has 103,000 miles it.

Why is the compression higher than the book says?

 
Rep Power: 452

probably because you have carbon build-up on the tops of the pistons. but as long as they are all around the same, you are fine.

 
Rep Power: 811

^yup. and good numbers. hey you should be making more power now right? lol

 
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carbon build up? can u explain how that works.

 
Rep Power: 811

well when the engine works, carbon forms in small amounts as a byproduct and gets deposited on the engine parts. well carbon is very hard and essentially for sake of simplicity becomes part of the motor and decreases the size of the combustion chamber hence increasing compression. now if you dont like carbon try some lc20 from www.lubecontrol.com its good stuff.

 
Rep Power: 313

hey gear how would diferent oil change carbon build up?^

 
Rep Power: 811

lc20 emulsifies carbon and suspends it in the oil until it goes to the filter. its an additive not an oil. i used it in the trans and got a bunch of black gunk on the drain plug that i never saw before so i know it does something.

 
Rep Power: 313

But oil never touches the top of the piston, that’s my point.

I don’t know....

I have no dough’s at all the stuff doesn’t work; I just don’t think it will change his compression results...

 
Rep Power: 257

If you have blow by from the rings, then a small amount of oil can get to the piston area.

Try running a good fuel additive like that techron stuff. That won't remove the carbon deposit that is their, but can help in the future.

 
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You might try taking out your spartk plugs and put in a couple table spoons of seafoam. Let it sit for a good six hours then take it out on the highway at night. I say take it out at night because you won't believe the amount of black smoke that comes out of your exhaust. Your nieghbours may make a phone if yu did it in your driveway.