what can happen if you have to much piston to bore clearance? And what is quench? I have read about with compression ratios but bont know what it means. thanks

 

too much will cause "piston slap" it will make noise and wear uneven. it is ok to be a LITTLE bigger than specs, as long as you are within the service limit of your engine. Check a repair book for the exact #s.

 

If they're a little bit loose but within specs, it'll just use a little more oil than if it was tighter. My buddy has a 302 that was honed to remove cylinderwall rust, from the block sitting, but he couldn't afford to re-ring...so he's running .030 rings in a .040 block.... Pulls like a beast, but it does have a bit of blowby and uses a bit of oil.

I know quench has something to do with the mixture burning in the cylinder, but I don't know much more than that.... I'm sure someone can chime in with a technical explanation.

 

as others have said it will use a little more oil also will let a little blowby gas into the crank which will lead to gas in the oil and so you might need to change the oil a little more often.

and since your going ot blowing some of the pressure out into the crank your not going to make peak power. doesn't mean you can't make good power but not as good as it could be.

wear might not be as good being the pistons will be slapping against the cylinder wall rather then sliding up and down the wall

why whats up though?


as far as quench goes it is the amount of gap between the top of the piston and the flat spot around the combustion chamber

if you look at a cylinder head around the edges you should notice a little ring that would stick into the cylinder as well as a big flat spot. take note of that area

a tighter quench area (piston closer to the head) will help mix the air and the fuel up creating a much better burn. the results more power, more efficient, more gas mileage, all in all much better on everything

also with a tighter quench area you going to be less prone to detonation so for the same octane rating might be able to bump the compression up a little more.
the problem comes into the piston smacking the head.... NOT GOOD

all in all I think recomended is around .040" quench area but I don't remember for sure

might want to double check that though

 

thanks for the info guys.

 

Well what was said above. Sad thing is if you know about it and dont bore the block and get the correct components your wasting money and will have an engine that doesent last half as long as it should.

 

Your friend is using the same method fNord guys use on 390's. Guess they figure its going to burn oil anyway, why wait?

 

Haha...hey, my engine never burned oil! It just created tremendous blowby until it finally wiped a cylinder out with 95% leakdown and 85 psi compression.