i thinking about rebuilding a 302 it been covered up for about a year now and was ran for a year a the circle track well any someway alot of water has got into the cylinders and rusted up pretty good well its already bored 30 over what if a get it bored to 40 over but still use the 30 over piston or could the block be to far rusted up its going to be used for circle track racing may be a little bit more than stock engine

 

You'll have to have somebody(a machinest) look at it, maybe it just needs a hone job and new rings, maybe it'll need a fresh bore.

 

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First engine rebuild?

 

You could try cleaning it up and honing the bores like if you were stuck in the middle of the desert and it was your only hope of getting out but you might want to get it checked out at a shop if you plan to run it hard.

 

Well I'm sure that I will be flamed for this, but facts are facts!

I have put back together probably a half dozen engines over the years that had severe rust pits in the cylinder walls and guess what? They work perfectly. If the engine had good rings and cylinders before the rust, they will seal up perfectly and you will never know the difference.

Just put it together with fresh cheap oil and have a couple of oil changes including filters handy. Crank it up and let it run no more than a minute or two and drain the oil. If the oil that comes out looks like chocolate milk, then change the filter and oil and run it again for a few minutes. If the oil on the stick looks clean then drive it about 20 miles to get the oil good and hot and then change it and run it normally. If the oil still looks like chocolate milk, then keep changing it until it is clean.

This should not take more than three oil changes at the most.

For some reason rust pits in the cylinder walls just don't cause any trouble if the rings had been seated before hand. In fact my current work car is a driving testimony. There was a problem with the cylinder head that put coolant all through the engine. I had to travel immediately thereafter and didn't get back to it for a few weeks. I then pulled the head and had to leave for another few weeks.

By the time I put it together the cylinders were so rusty you wouldn't believe it. I got the head back on and changed the oil a few times as described. That was at about 176,000 miles. The car now has almost 310,000 miles on it now and runs perfect with no oil usage, compression loss or anything else.

Okay, my flame suit is on and I'm ready. Let it fly!

 

Yea, ok. I used to let the bore in my 2 stroke motorcycle engine rust slightly ("let" heck, it would rust as soon as you clean off the oil) and it seated the rings just fine. Rust from sitting water where the rings are stuck to the cylinder might be an issue....

But hey, have you ever put one together with .030 pistons in a .040 over bore? Now your talkin'!

 

I would just use the ball hone on it and see how it looks. Wide open circle track racing likes loose clearances anyway. A little blow by won't hurt. Just tie socks on the breathers, been there done that. Most smaller tracks its more on handling than on Hp. If you have a lot of Hp. it just spins the tires faster. If its more than 1/2 mile track then you might want to have machine shop check it out. You will need the HP in the straight aways.

 

So what if the motor already had just the right amount of "loose clearance?" In that case, honing it would make it too loose.

I'm telling you, DON'T HONE THE CYLINDERS. After making sure that there is no water in the cylinders, crank it up and go through some oil changes until it's clean!

BTW, blow by doesn't hurt anything in a race engine? Are you saying that losing pressure around the pistons and rings adds power? Sorry, but it doesn't work that way. You need all the cylinder pressure you can get to make power as long as there is not undue ring drag.