I found a somewhat deep ding in one of my cylinders. The block is already bored .060 over and just ordered new rotating assembly that is non-refundable. I was wondering if i were to rigid hone the cylinder .0005" over with 220 grit stones will i have problems? The bore is exactly 4.060" top and bottom. The ding is slightly deeper than the ball hone crosshatch. I dont want to drop 30psi of compression in that one cylinder if i decide to throw it together. The rings are file fit so i have to fit them either way. Otherwise im going to have to sleeve the cylinder and i dont want to have to spend the cash on that.

Thanks for the help, Chas

 

I've been an automotive machinist for the last 9 years, and I routinely finish cylinders .0010" over, for most domestic V8s that aren't pure-stock rebuilds.

 

Furthermore, 10 years ago all pistons had the necessary piston-to-bore clearance machined into them. But these days, it's becoming more and more common to have to hone the cylinders another .0020-.0040", so wait for your new pistons to arrive before taking the block in for honing.

 

So wait to see how the piston fits? Im not sure how to describe the ding its kind of oval shaped and is about midway down the wall. about 1/8" tall by 3/16 long. I really need to know b/c i have 1 week to finish the clearancing and assembly of the short block. This is a school project for college and need the cam degreeing kit that he wont lend out...

Thanks for the help guys

P.S. this motor is going to be a 388 and is not stock in anyway...XE284 comp cam, port and polished heads, weiand intake, and 700 DP... Its going to be spun up to ~6500.

 

What stupid machinist honed the block without having the pistons in his hand? Or on his bench, to be more accurate. You can't get accurate results otherwise. Yoo must measure the pistons to set the piston-to-bore clearance. Otherwise it;'s a dangerous assumption. This is far more important than degreeing the cam, especially if you're using major-name-brand cam and timing set. If your pistons are too tight, you'll at least scuff the skirts, maybe have galling or even seize the engine.

 

so ill wait for the kit but the next question is how much piston to bore clearance is normally needed?

 

for street fun? cast and hypereutectic like .0015", 4032 forgings like .0025", and 2618 forgings like at least .004", amnd as much as .007" depending on application, manufacturer, et cetera. Hypers are safe at .0025" 4032s are safe at .004"

 

I called around and the piston manufacturer recommends a minimum of .003 and max of .007... Right now i have .002 so im going to rigid hone the cylinders to .004 just to be on the safe side.

Thanks for all the help