side_fxxx Posted June 1, 2007 Report Posted June 1, 2007 my shee is sometimes pretty testy to start up when cold. i had it apart today and desided to check the compression. left side was 95 psi and the right was 100psi. this is on a cold motor do you think its time for a rebuild? should the first step be to look at the piston walls and piston to see if it just needs rings? also with the brand of tester i was using i had to remove the gas tank to get it in there is there one with a 90 degree bend in it? thanks! Quote
chevrolet banshee Posted June 1, 2007 Report Posted June 1, 2007 my shee is sometimes pretty testy to start up when cold. i had it apart today and desided to check the compression. left side was 95 psi and the right was 100psi. this is on a cold motor do you think its time for a rebuild? should the first step be to look at the piston walls and piston to see if it just needs rings? also with the brand of tester i was using i had to remove the gas tank to get it in there is there one with a 90 degree bend in it? thanks! i wood run it till it don't run at all i ran mine till the compression wos 60,70 psi then you prodley will need to have it board :smile: Quote
blowit Posted June 1, 2007 Report Posted June 1, 2007 my shee is sometimes pretty testy to start up when cold. i had it apart today and desided to check the compression. left side was 95 psi and the right was 100psi. this is on a cold motor do you think its time for a rebuild? should the first step be to look at the piston walls and piston to see if it just needs rings? also with the brand of tester i was using i had to remove the gas tank to get it in there is there one with a 90 degree bend in it? thanks! When you see something poking out of one of the cylinders, it might be time for new rings. If you are near sea level and your gauge is actually right, it is time to take a look. Um, what the guy did above is NOT what you should do. a broke piston will follow shortly after requiring a new crank generally. Trust me, pay now or pay more later. Brandon Quote
side_fxxx Posted June 1, 2007 Author Report Posted June 1, 2007 i was just wondering if you take the top end off and there is no scratches in the piston wall or piston if a simple rehone and new rings is ok? Quote
dajogejr Posted June 1, 2007 Report Posted June 1, 2007 Yeah, run it till it don't run is great advice if you have deep pockets and you don't mind a total tear down... I would pull the top end off. Have the cylinders and pistons measured or mic'd. Just because they have crosshatches doesn't mean they're within spec. Hone and rings along with a top end gasket kit will set you back less than 100. However, for about 200...you could have the top end bored, fresh pistons, rings, wrist pins and all new gaskets and know you have a tight motor. You need to do something now...it really depends on how things actually measure out, not how they "look"... The fact that it still runs is a good thing...don't wait...it only gets more expensive. Quote
blowit Posted June 2, 2007 Report Posted June 2, 2007 Yeah, run it till it don't run is great advice if you have deep pockets and you don't mind a total tear down... I would pull the top end off. Have the cylinders and pistons measured or mic'd. Just because they have crosshatches doesn't mean they're within spec. Hone and rings along with a top end gasket kit will set you back less than 100. However, for about 200...you could have the top end bored, fresh pistons, rings, wrist pins and all new gaskets and know you have a tight motor. You need to do something now...it really depends on how things actually measure out, not how they "look"... The fact that it still runs is a good thing...don't wait...it only gets more expensive. I kinda oppose the visual thing. Lack of grain or crosshatch means lack of oil retention and heating can be an issue. You WANT crosshatches. I would say, measure, and possible ball home and put new pistons in. New pistons does not mean you always have to bore it. Measure it man!! To many people just bore to be safe when all it takes a few minutes and a calculator to save your self .010", about 90 bucks, and a trip to the machine shop. Brandon Quote
yule16met Posted June 2, 2007 Report Posted June 2, 2007 When I measure my cylinder bore and my piston, what kind of tolerance do I need between the two? Im a machinist but never done anything with motors. How tight should the piston fit? Quote
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