Im doing an lsv turbo with nippon 81mm low comp pistons and looking for 400whp. They are cast pistons so should I run .002" p2w clearance like Honda stated for oem pistons? I think its .0015-.002 is what honda recommend or a bit looser like .003" or .0035" since its gonna be making 4x the power it was intended to make by honda? Its gonna be my daily and a little weekend toy

 

I'd run them at .0035 - .004"

 

id say around .003-.0035 they arent going to expand like a cp piston would. I ran cast vitaras at .0035 and around 18 psi just shy of 300 whp and no issues at all

 

Running 2618 alloy comparable clearance does not mean the engine will survive. Its unecessary, in many cases the piston will melt or crack before tightening up against the wall.

 

so you think pretty tight is the way to go? maybe somewhere around the service limit of oe pistons something like .002?

 

.0022-.0025"
.0035" is gonna be loose. You could get away with .0035" on a standard forged piston for your hp goal

 

.0035-.0040 for sure. You will not have any issues at this clearance as long as its broke in properly. Both my street cars are at .0038 (waiting on dyno) and .0040 @426hp(your goal) with no issues. The .0040 is going on 28k miles. Go loose with that hp. You won't regret it.

 

I went with .003". Its gonna be my daily and im not gonna get on it everytime i drive. Quick question, what ring clock did you guys follow? Honda's oem or endyne cause I went with oem since npr are cast oem pistons

 

Generally for performance motors, endyne. The reality is rings move somewhat so you will be fine but in the future I'd go with endyne.

Have you run the nippons before? I prefer ycp as do many others just curious as to your choice with nippons. Reason being a friend and I built two identical motors in my garage at the same time. He went Nippon, I went ycp with identical clearances. Overall noise was considerably louder with the nippons and are known to be inferior but we are gonna push the limits and find out. You should be fine at that hp level, just thought I'd share some results with you.

 

The motor is not put together yet, i just put the pistons in with that ring clock so I will remove it and go with the endyne setup, they dont make low compression ycp for 81mm bore and people have made over 500 on nippons.

 

That's what I figured. I work with d series in my cars so I didn't know if ycp got into the 81mm yet. That's also why I said you're good at 400whp anyway but the endyne clocking is the way to go on high hp builds. Although on factory rebuilds, OE is the way.

 

You seen this before? I put it back together and everything is torque to spec and this happens.

 

I checked the eagle part number and it is b18a/b18b rods and the pistons are the same as the stock pistons.

 

Why would you use LS/B20 rods?

 

Sh*t man you got the wrong rods brotha.. Do u have custom pistons that move the wrist pin up?

 

Yeah they are the wrong rods. The part number said crs5531a3d which has a rod length of 5.5531" and the seller stated it will fit a b18b. The b18b rod length is 5.394" and the correct part number is crs5394a3d. I was so close too lol

 

Sry for u bro.. The only thing you were so close to was the head lol... Hope u didn't pay too much

 

Thanks man, im getting a refund except shipping.

 

Happy for ya. Always sucks getting the wrong parts even if you notice it before assembly. Just a pita. Good luck