NPR Piston ring gap

[RadDsm]

So I'm going to pick up a set of NPR pistons and throw them on my 7 bolt rods to get my motor back together.

What PTW, top, and bottom ring clearance should I have them at?

This is a daily driven 2g 7 bolt with no balance shafts, probably for the mid to upper 300whp range.

Should I keep my oil squirters for the stock rods and npr pistons?

 

[RadDsm]

Can anyone give me some advice on this, or maybe a point in the right direction on where to look?

 

[JacksonAuto]

The piston set should include a sheet from the manufacturer which states how much PTW they should have. It will also tell you specifically where to measure the piston (bottom of skirt, middle, top, etc.). Give the pistons, sheet and block to your machinist and have him give them the proper clearance. Your machinist should be able to advise you on the end gaps. You may even want to have him file the rings since he should have the proper tools to do so.

YES keep the oilers and I would put the pistons on 6 bolt rods.

 

[RadDsm]

I would put the pistons on 6 bolt rods.

I have a set with the wrist pin already made out to 22mm, but they wont fit on a 7 bolt crank as is, right? The big end seems to be too wide to fit on there.

 

[JacksonAuto]

Right.

 

[DSMified92]

yea you cant put 6 bolt rods on a 7bolt crank. as for ring gap i set mine at factory cause mine is a daily driver to kinda and also i am running npr pistons and rings and it didnt come with a sheet.

 

[RadDsm]

yea you cant put 6 bolt rods on a 7bolt crank. as for ring gap i set mine at factory cause mine is a daily driver to kinda and also i am running npr pistons and rings and it didnt come with a sheet.

I know you can use the 6 bolt rods, but I don't want to pay to have the machine work done to the journal end to make them fit. I already have a set of forged internals, but I need to sell my standard sized Wisecos to get .020" and I haven't been able to yet. I need to have the car running again asap because I don't have a way to get to work any longer without it, thats the only reason for using stock pistons and rods.

 

[ziggo0]

My 0.030 NPR 2g Pistons came with rings but no sheet. Then again, research into the subject will yield your answers. I had my machinist bore out the block with the pistons in hand and he included PTW in his boring. 1st ring came out to exactly 0.019 for all bores, 2nd ring came out to exactly 0.024 for all bores. This in my eyes was damn near perfect seeing as I didn't have to file any of them, glad I went with a difference machinist this time.

 

[dsm-onster]

Considering NPR manufactured the original rings and pistons for your Mitsubishi motor, spec everything to factory.