just out of curiosity if i have a stock bore size on a piston is it necessary to hone the sleeves?

 

You should always do a finish hone (usually 400grit w/ proper cross-hatching) on the bores to give the rings a proper break-in surface. If you don't do it, doesn't guarantee that you'll have ring seating problems with the new rings, but it's good practice and technique to do so.

The other concern is that of the piston skirt-to-cylinder wall clearance. You have to check to see how much clearance you have with the new pistons. I've been in a situation where I've installed a std bore set of JDM ITR pistons in my B18C1 and the clearances were anywhere from .0006" to .0012" too loose of the max specified tolerance (.0016").

You don't want them too tight either, or you'll chew up the skirts, ring lands, and the cylinder walls.

Now, I've heard several recommendations (all from reputable builders) on what clearances to use with OEM Honda cast pistons, but I'm still on the fence as to which way I should lean.

One person says to stay in the new tolerance (he has probably worked extensively with OEM cast pistons) and the other says to go a little looser (~.0020") to keep the piston from overheating, expanding too much and scuffing the cylinder walls. The second guy works almost exclusively with race motors, so I can understand his standpoint of being a little looser to give you more room for error at peak operating conditions (not so much concerned with the lower load/rpm conditions or cold-start piston slapping).

I can tell you that every stock Honda engine I've taken apart always had perfect cylinder wall and skirt wear (even with mileage up to 100k). There were no vertical grooves or any scuffing.

I can also tell you that the looser clearances I had with the JDM ITR pistons did make the motor slap a little on cold starts.

I recommend measuring the clearance of the original pistons and bore when you take them out to see how much clearance it has (before any honing), and try to shoot for the same with the new pistons if you're gonna use OEM Honda cast pistons again.

If you're not gonna use any sort of high-silicone or hypereutectic piston, then you should follow the manufacturer's (and reputable, experienced race engine builder's) recommendations for forged pistons that are typically made of 4032 or 2618 aluminum alloy.

I forget the percentages, but 4032's have slightly more silicone content mixed into the alloy for slightly higher lubricity and less expansion as a function of temperature. I think it's like 7% to 8% silicone.

2618 alloy is something like, no more than 2% to 4% silicone in the alloy. It's less brittle, conducts and absorbs heat better, but they expand more with temperature and usually wear more quickly than 4032 alloy pistons.

 

hey thanks for the info man, i was planning on using some low comp arias pistons. that were used, so i didnt know if i had to take it down a little or maybe sand down the piston or so. its going in a b18b bottom.

thanks again.