.120 over pistons

[needmydatsun]

i heard that you can bore the l28 .120 over and i was wondering if knows where to get forged piston that size and what rods and crank should i use to get 9.5:1 compression for a turbo setup.

also does anybody know the combustion chamber size on a stock l28 with the p79 headthanks
Modified by needmydatsun at 6:39 PM 7/2/2007

[evildky]

yes you can bore the L28 .120 over, you shgould have this done at a good machine shop, as for rods, and pistons it just depends, if you're going .120 over then you likely want the 72-73 133mm 240Z L24 rods wiht the 9mm rod bolts, as for pistons, you can sue stock KA24 pistons but they are still cast and if you plan to turbo then you're gonna want forged, unfortunately no-one makes these stock but you can have custom forged pistons make by ross or wiesco for less than most off the shelf aftermarket forged piston sets, and your machine shop can halp you order the pistons and they'll want them before final bore anyhow

the P79 has a 53.6cc head but has restrictive sleaved exhaust runners, the P90 is a better choice, same volume but no sleeves

and the basic L31 stroker setup yileds about a 9.0:1 CR, you'll want to machine the head or dome the pistons to raise compression further but the 9.0 is probably a better place to be

[needmydatsun]

would i use the sohc pistons or dohc pistons?and what pieces do i use for the 3.1L stroker?

[evildky]

as far as I know the KA pistons are the same wether they come form the single or dual cam, and again, they are cast and not recomended for a high compression turbo build

the basic recipe for a 3.1 stroker is:LD28 crank (this comes form the 81-83 diesel maxima)133 mm rods (the 72-73 240z wih the 9mm rod bolts are stronger and recomended)KA24 pistons or custom forged (custom forged wiesco's can be bought through summit for about $600 a set and that includes pins and rings)L28 block (there is a great deal of debate over which block casting block is best, some say the F54 which has every other cylinder siameased, others say the N42 block with all 6 cylinders siameased, a god machine shop to do the .120 overbore is the most omportant part

[needmydatsun]

i just went to thezstore.com and i found a 3.1L stroker kit with 89mm pistons. with crank and rods with the 9mm bolts and bolt kits good up to 190,000 psi, so i will probably get that, oh and it comes with rings and pins, and do you know what i could use to get primer off of carbon-fiber?thankls alot for all your help with advice, i apreciate it.

[evildky]

MSA's kit uses cast pistons, I hihgly recomend custom forged but it's your dollar! as for getting primer off carbon fiber....sandpaper? I assume you mean real conbonfiber, so you can sand off whatever is on it and you're still gonna have a carbon fiber surface, just choose your grit wisely, if we're talking very fine overspray 1000-3000 grit might do it, if it's got a bit more build to it 300-600 might be more in line, and ofcourse sanding blocks will help you keep and even surface

[needmydatsun]

i was looking at the hood and hatch from betamotorsports.com and it says they come primered but i like bare carbon fiber, i was thinking paint thinner but i dont want to mess anything up, and how much power could the cast pistons hold up to

[evildky]

bata's CF parts come primered? are you sure you weren't looking at the fiberglass parts? as for the cast pistons, I'd be afraid to run them on a turbo setup, the problem is one slight ping and you melt a hole in a cast piston, if you must use them spend a few bucks on have them coated

[needmydatsun]

http://betamotorsports.com/products/index.html

read the bottom sentance

the reason im intrested in the msa kit is because i really like the fact that the crank and rods are new but if wiesco can make forged rods for me then i will definitly do that and then see if they could make forged main caps then that would be awesome

[evildky]

why do you want forged maincaps? the stockers are not known to fail, it helps that there are 7 of them, but I believe they are block specific, once you trash a cap the block is garbage

[needmydatsun]

nevermind the forged maincaps, i didnt know there were seven of them.thanks for all your help