Hi, so i picked up a 302 motor and after I disassembled I found out that it's .040 bored and the cylinders have slight ridge/lips on top. Talked to a machine/engine rebuild shop and they said no problem going .060 over. I was thinking of just having it honed to clean it up instead of boring it up to .060.

THOUGHTS????

 

.060 can have a tendency to run hot and that is pretty much it as far as machining goes I think.

 

What is the clearance between your pistons and cylinder walls and does it meet the recommendation still at .040?
If so, I assume you will use new rings...
How is the top end?

 

What is the recommendation of the clearance between the pistons and walls?

 

depends on the type of pistons you are gonna use..as said above i definitely wouldnt go 60 over it try not to go 40 f you can help it

 

A block already .040 over with a top ridge already formed is NOT a candidate for a reliable rebuild. Find another block. The smaller the overbore, the better chance you will have in getting a reliable, cool running engine. All blocks are not the same, and, on occasion, .060 over can be made to work; however, the odds are not in your favor. Casting core shift causes uneven bore thicknesses, which in turn produce hot spots in the thin areas on an overbored block. The thinner walls are prone to flexing, and will break rings rather easily. Lots of downside to too much overbore.
Best,
Al

 

FWIW....I'm running a moderately-built 289 that's bored .040 over. I've had a hell of a time overcoming overheating problems with it. Engine was built by PO who said it also "ran hot" with him. I did a complete cooling system flush (twice!), and then changed to a FlowKooler water pump, a Champion 4-row aluminum radiator, a 17" flex fan with 289 HiPo fan shroud, and a 160 degree thermostat, and then...and ONLY then...would the temp stay below 190 degrees.

Bottomline...IMHO...302 blocks are just too common and cheap to invest a bunch of hard-earned money and time boring one to 60-over and run the risk of a big headache later.

 

I think I will hold off on using this block. At least the heads and crank are good that I can use them on a different block.