Juiced

iTrader: (2)

I'm Trying to Decide What pistons to go with for my 388 build.

I want about 13.5:1 compression, Currently the heads have a 64cc chamber running a .040 gasket.

I can't decided between the regular JE 13cc Domed piston or the JE Nitrous dome piston. The nitrous dome piston is only a 7cc done. i know i can kill the heads but seeing as to not knowing what cam i'm going to run i don't know what my PTV clearance is going to be.

Can anyone she some insight into my issue?

BTW i do plan on spraying a dual stage 300 shot.

rocket22

iTrader: (2)

Nitrous pistions.

mrdragster1970

Make a mold, lower the rings and tell them to beef up the meat, you plan to spray the hell out of it.

Juiced

iTrader: (2)

thanks, now if i could only figure out what that means in laymans tems, lol

mrdragster1970

I was trying, sorry. For a few extra dollars, we have a mold made of the chambers,
a good company will make you a piston that match's. We always lower the rings to help keep the extra heat off them. We have extra meat in the domes for the obvious.
We also coat the domes for heat and skirts for friction. Good luck.

PS We always buy extra pistons.

Juiced

iTrader: (2)

now that, i understand!

What company do you usually use for pistons? and what do you use to make a mold of the chamber?

johnjzjz

Its not a good thing to have one off parts unless you have a complete shop or endless money -- BRC pistons will get you their as well as many of the others -- you will need to have some kind of idea what parts fit what -- otherwise you will end up with a big box of e bay stuff you can get your money back on -- call a head company you want to use and ask them for their opinions on all of it - and dont sway away or you will spen thousands to fit stuff you thought would fit and now dont -- put it all on paper price it and do your homework it will pay for you in the end -- jz

Juiced

iTrader: (2)

thats why i was going to go with off the shelf JE pistons and i couldn't decide between a 13cc domes piston to get the compression i wanted or a 7cc domed piston ment for nitrous but lower compression.

is there a formula for me to figure out my PTV clearance with a 7cc dome and 64cc chamber running 2.1 intake 1.6 exhaust valve and 1.6 rocker?

Could i mill it .060 to get 54cc chamber?

johnjzjz

no their isent it all depends on the cam and the cams timing as it relates to your combo you must invest in a degree wheel -- everything in every motor must be considered IE: deck height - length of the conecting rod and the stroke - the location of all the valve components are only adjustable to your block location -- they wont just fit into any block once fitted correctly -- dont know if you know what i mean -- to answer your original question the 13cc pistons are lighter and will net more compression than the NOS ones unless you intend on spraying it all the time ( and want to redo the motor all the time ) dont get them - they are heavy and require more clearence to run corectly - stick with a usable combo that parts are off the shelf and avail --jz

mrdragster1970

Why would a piston with perfect chamber, perfect ring location, perfect pin placement, perfect dome thickness end up in a box for E-bay???

Obviously you can't buy any part of the rotating assembly until you know all the specs, deck, bore, stroke, cam, head ect ect.
A 300 HP shot will make a lot of heat, ~$40 per piston is cheap insurance & extra compression adds HP. Reliable professionally built pistons will more than make up for trying to use something that is half & half. I recommended a custom piston for max strength, max power, max life. Obviously there are cheaper ways to do anything.
Quick ???, would you use K-Mart torque wrench?? dial indicator?? ect ect.
Good luck, be safe.

Juiced

iTrader: (2)

they aren't ebay pieces they are pre-engineered from the JE SBC catalog, i would never run someone elses piston in my motor.

I would rather run a $800 off the shelf piston than a 1200 set of custom pistons, being that this is just a weekend track car, i don't plan on competing in a indexed class, just the local PSCA trophy class and possible the summit 1/8 mile series.