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bad compression? bad piston rings? help

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Old Aug 14, 2008, 12:06 AM
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bad compression? bad piston rings? help

I compression tested my 02 lancer tonight, and I got cyl1- 180psi , cyl2- 170psi, cyl3- 175psi, cyl 4- 170psi, and I think the engine is supposed to be around 190psi? anyone know, ? ...well i tested because Im burning oil and it comes out in smoke cloud only after boost though and in deceleration, and been through the whole song and dance w the turbo and seals and breathing ..so i replaced it today, well still not it....So im assuming piston rings are going...and can anyone tell me what factors are really affecting the compression test, because I realized i didnt hold open the throttle....and I might have vacuum leaks somewhere, would that affect it? Im going to retest tomorrow if so...and if it is piston rings, has anyone replaced them on a 4g94? If its too hard to do then Ill just throw in a new motor when i get money.. I heard you can pull the pistons and rods from the bottom without pulling off the head...so how hard is putting on rings and reinstalling... any help or advice would be greatly appreciated, and sorry for the long *** paragraph lol! thanks

Last edited by cantcatchme96; Aug 14, 2008 at 12:21 AM.
Old Aug 14, 2008, 12:08 AM
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compression could lower due to age and milage.. but thier within 5% of each other, so im guessing your ok
Old Aug 14, 2008, 12:15 AM
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thats what I thought....and I have no clue how three copies of this posted, Im retarded, can someone tell me how to delete the other two duplicate threads, srry off subject i kno
Old Aug 14, 2008, 12:19 AM
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that compression looks fine. retest it while holding the throttle wide open and have a jump pack on it, then poor a tiny bit of oil through the spark plug hole and wait a minute ....then test , this is called a wet compression test. if your rings are truely bad the oil will help them seal and compression will be much higher. don't be worried if its a little higher, thats because of the oil you poored in taking up a little space in the combustion chamber, you mainly want to watch the ones that are low on compression in the 1st dry test......hope that helps
Old Aug 14, 2008, 12:24 AM
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yea Im going to retest w/ throttle open tomorrow, I just want to see what other same engines got on there compression test results, lol...and I'm trying to find piston ring replacement info ...
Old Aug 14, 2008, 08:25 AM
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compression looks fine. i should test mines too..ha
Old Aug 14, 2008, 01:05 PM
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You are fine.
Old Aug 14, 2008, 11:45 PM
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well I dnt know what else it could be...?
Old Aug 22, 2008, 12:32 PM
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Burning oil can be caused by bad valve guides.
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