I picked up a car with a Goodwrench 260 hp crate 350, with under 1,000 miles on it. I have a comp roller cam conversion and World Sportsman II heads I am putting on the 350 from another project. However, when I pulled the heads on the crate 350, much to my dismay they have the dreaded stock type dish top pistons w/ 4 valve reliefs. I think they are around a 16cc dish, which even with my 64cc World heads, barely puts compression at 9:1 with a thin head gasket. Not good enough. Cam is 0.502/0.510, 224/230 @0.05, hyd roller. 9:1 would work I'm sure but since I have the engine on the stand, I might as well do it right (especially since coated hyper pistons are around $100 on ebay, with rings).

Anyhow here is my dilemma -- do I have to re hone if I use new rings, even w/ the low mileage (my guess is yes, since break in has already semi occurred?). Is it okay to put my less than perfect hand honing (stones) over the still very sharp oem honing?

Here are the cylinders right now:

http://i134.photobucket.com/albums/q...ebuilds007.jpg

http://i134.photobucket.com/albums/q...ebuilds005.jpg

I am no doubt going to make cross hatching over the top of the existing hone, that does not line up.

OR, would I be able to put new pistons in, but re use the rings, in the same holes, so the rings are already seated to the cylinders? Or is this a bad idea waiting to happen

I am not trying to save cost, I really don't care one way or another. I just want to do what is best for ring seal and longevity, and don't know whether hand honing over such low mileage cylinders w/ new rings is better, or re using the rings w/ new pistons, is better.

Thanks guys

Steve

 

I think you are on the right track. The block has already seated the rings so a hand re hone would do nicely. Don't thnk I would reuse the rings since they have already gone thru break-in and heat. Sounds like ya got a plan, go for it..

 

I'd just put in the new pistons and rings, without re-honing - IF you can still see a visible crosshatch. That'll set in new rings.

I can't view those pictures for some reason...

 

THe cross hatch is very sharp, it looks like I just did it. But just because it looks sharp to the naked eye doesn't mean the edges of the cross hatch ridges, at a microscopic level, are as sharp as when they were put in -- the sharp edges have been knocked off at this point to some extent. Hence my being worried. I called a local shop that I trust that builds some $$$$ NHRA type stuff, and the shop owner said either 1) re use the old rings with new pistons, since they are matched to the cylinders (if I can get them out w/o breaking them) or 2) use new rings and re hone. Still not sure which way I'm going to go yet. Probably going to be better off w/ new rings and honing. I should invest in a bottle brush hone!

 

Take the engine completely apart. Have the Nascar shop deck the block so that the stock pistons come right to the top at TDC (approx .025" cut)
shave the 64cc heads to 58cc (approx .050"). Scrub it good and reassemble with all new gaskets. Your cr will be 9.80:1 using a ..038"" felpro gasket.

Measure the present piston/deck clearance at TDC before dissassembley and you'll know how much to cut the block decks.

Pistons, rings, bearings go right back in the same holes.
Unless you're going to be spraying it with nitrous, the stock pistons are fine.

 

I think you'd be better off with the new rings/pistons and a fresh hone. At least you'll have peace of mind at worst..

 

I agree with urban hunter44. The cylinders from GM are poor and out of round. Rehone the block the best they can and your set up for your new pistons and rings.