engine rebore

[Clem Z.]

Re: engine rebore

make sure they "step sleeve",leave a "step" at the bottom of the bore that the sleeve rests against so it can not "slip" any farther down into the block and as far as the stamp pad they can trim the sleeve using a special tool in the boring bar. they do not have to "deck" the block. i always left the sleeve .003/.004 above the block surface to make sure that the head gasket had a good seal because you have no idea what happens when the engine is up to temp and expansion takes place and you do not want the sleeve to get below the deck surface. sleeving works well if done correctly. also i would have all the pin fits checked in all the rods. this means removing the piston from the rods but if done correctly and the pin bores in the pistons rehoned there should be no problems doing this. better safe than sorry.

[Dick W.]

Re: engine rebore

Sleeving as Clem states can be very reliable. The #3 1963 Chevy sitting in the museum in Talledega ran it's last few races with 7 sleeves without problems. It had the MK I "Mystery Engine". When GM issued it's infamous racing ban in 1963 there were no more spare blocks in the system. The teams running the engine had to make do with what they had.

[Randy Krohn]

Re: engine rebore

I read this thread with interest, as I've got a '72 big block with about 93K miles. When did GM switch to the dual coils with the flat dampener? Do I need to be concerned?

Randy

[Michael H.]

Re: engine rebore

Randy,

By the time your car was assembled in 1972, most of the valve spring/retainer problems had been corrected. The original 3859911 single wire spring that was released for 65 was used through about late 1969, when it was replaced by the 3970627, a much more durable design. (it has since been replaced, again, with an even better design) Springs and retainers on 65-66 seemed to be the worst, with a slight improvement in mfg for 67-69, even though the part number didn't change.

If I remember correctly, the most current part number valve spring comes with a new retainer. I don't have the number handy but I believe it was completely out of sequence and started with 62xxxxx. Joe Lucia would have the current number, I'm sure.

By the way, the closly coiled end of the spring goes down, toward the cyl head.

[Michael H.]

If You Keep Yellin......

...yer just gunna get yer blood pressure all pumped up again, and it probably ainta gunna help ma spellin any.