I'm thinking about getting a set of 81mm pistons. How could you ever get the clearances right though. I'm thinking that by the time you hand hone the bores, you'd have too much clearance. What say you guys? Maybe with the 2618 alloy forged pistons needing a little more clearance than the stockers, there's a little room for honing???

 

Measure the cylinders, then measure the pistons. Subtract the piston measurement from the cylinder measurement and that's what you get.

Anything else is just speculation.

 

I understand that. I'm not new to building motors. I've just never used a drop in piston on any motors I've built unless I was just putting the stockers back in on a half assed refresh. I just can't see it working for ****. If the piston (let's pretend it's a JE 81mm) already has the clearance built in, by the time you hand honed the old bores on an old motor that already has more clearance than factory spec just from wear, I just imagine the bores are gonna end up being loose.
I had a LS-vtec about 15 years ago that had drop in pistons. I didn't build it, just bought it that way and they slapped pretty noticeably. Sounded rattly at under certain loads. I think they were a low expansion 4032 piston, though.

 

Buy 81.5mm pistons and you don't need to worry about any of this speculation...

 

Yes to this.

Or, measure your block and see if an 81mm is going to work for you. I built a GSR for a friend last year. He asked if we would be able to stay 81mm, and I told him I would need to look at the block first before I could say yes or no. Ended up measuring out good, and we went with an 81mm CP. Thing gets beat on pretty regularly, even hot lapping at the drag strip. No noise from the engine bay, other than the noisy PTE 1000's.

 

Bore it and go 81.5. I went 81 last time and it took a good while for the rings to totally seat.

 

rent **** hone from autozone,gap rings,toss in. all set

 

I honed my cylinders and tossed in a set of supertech 81mm pistons, and got a little piston slap but three years at 321whp and lots of punishment still running strong.

 

Thanks for the responses guys. I normally go .5mm over for all the reasons that I'm sure we all agree on, but I already have one drag car that I've spent an ignorant amount of money on (93 toyota MR2 best 10.85 @132mph). My EK hatch is just my daily work beater and I'm just trying to half *** something together that I can make 400whp on. I'm trying to keep machine shop expenditures to a minimum.