hello everyone.i have a 6 bolt 4g63 im building right now.its at the machine shop as we speak.the parts there installing are manley coated 8:5:1 forged pistons .20 over.eagle h beam rods arp studs/acl race main and rod bearings/stock polished crankshaft.the machine shop is boring it .20 over,decking the blocks surface and o ringing the block for better head gasket seal,checking all clearences and building the short block for me.im going to be runing 450 hp to 550 hp.my question is what kind of clearences should i have,ptw,ring gap,rod/main bearing clearences etc.and what should i do if im missing ang thing this is my first short block im having built.ill pass the info yall give me with the michinest.looking forward to everyones help thanks btw my name is wayne....

My set up consist of Ptw clearance is .0035
top ring gap is .021
second ring gap is .025
rod bearing clearance is .0025
main bearing clearance is .0025 to .003
The clearances i've listed are on my wiseco and eagle combo. before you use acl race bearings id have to ask if you are daily driving this setup. i remember reading somewhere that acl race bearings are primarily race only and are hard on the crankshaft for a daily driven car.

http://www.dsmtuners.com/forums/cylinder-head-short-block/416185-acl-bearings.ht


this may is some good reading.

link didnt work.yes i daily drive it.i ran acl race bearings before and my crank was fine when i took them out.crank rides on a film of oil im told that if there touching the crank your in trouble.how much power are you runing on your set up?and how much boost.i will be running about 30-32ish psi on meth about 450-550 hp.i dont want my clearences to tight or to loose just right for the power that im running thats why im asking for everyones imput.

from what im reach searching i need a ptw clearence of 0.35-.4 and my top ring 21 and my second ring at 25 and the bearings at .002-.003 is this right?like i said i dont want them to tight and i also dont want them over loose so i blow oil.

help needed

from what im reach searching i need a ptw clearence of 0.35-.4 and my top ring 21 and my second ring at 25 and the bearings at .002-.003 is this right?like i said i dont want them to tight and i also dont want them over loose so i blow oil.

help needed[/QUOTE]

I hope that .35-.4 really means .0035 to .004 . as long as it does mean that .0035 to .004 then yeah your numbers look pretty standard for your build. and the last time i dynoed my car i made 380 plus but i had a couple of broken valve springs and was only running 17 lbs. so yeah you should be able to hit your mark.

yea thats what i ment .0035 or .004 .thanks man for your imput.anyone else can also put there input in the more info i have the better.im very thinkfull for this forum its very helpfull..

I'd recommend .004 ptw since you're planning on being in the 500's. Otherwise everything looks good
Happy boosting

Wayne, you posted the EXACT same thing 3 times, and you have no apparent knowledge of sentence or paragraph structure. Come on man.

To answer your question(s): There should be paper work included with your pistons that will tell you how to set the ring gaps (to a point), as well as the piston to wall clearance (again, to a point). Running higher boost (as well as other factors) will change those things though. 35 thousandths PTW and .020/.022 top/bottom ring gap sounds reasonable to me though for a 450 - 500hp motor. As for rod and main bearing clearances. It also depends on how you plan to use the motor.

Make that 4 times . Talk about overkill.

i made it to 9th grade and just barly i know it my fault im sorry.typing the best i can..i posted in different fourms because i posted in the build part of the fourm and was getting no replays and i need this info.i do have the piston spec sheet just wanted yall input i mean this is the reason for this form.and i didnt know there was a rule about posting in diffrent forums.i did search and came back with a ton of different answers thats why im asking yall to help.thank you for replying man i really need this info its very important.

i thought a .004 sounded better but was told after my piston coating wears off the will go from .0035 to .004 is the true?im also running oil squirters so the piston shouldnt get as hot as it does w/o the squirters.

I was told to do as big as .005 for similar power levels.so .004 is the perfect compromise

How about we use the report post button if we have a problem with a post and not bring this stuff up in the tech forums. Thanks.

Cleaned up.

Thanks snowboarder. Im just tying to get info on my build. I know some people on here know a whole lot about forged pistons set up's. I want it to be done right and welcome anyones input..

Yes, depending on the Wiseco's, they do come with a break in coating on the sidewalls that applied ~.0005 thick. For your goals, I'd recommend .0040 as well for PTW, which should open up to ~.0045 if the coating wears off. This should be good for your goals (this is what I'm running as well).

For ring gap, some of your numbers posted seem abit on the loose side but better to be too big vs too small. Something like .017-.019 1st & .019-.023 2nd should be fine.

The rest of the build specs, I'd just go with what Mitsubishi recommends. Doesn't sound like you want an all out race motor (loose tolerance, make big power & wear out quicker), so the factory specs will be fine. Maybe go towards the looser end of the spec range, but thats it.

snowborder714 said:

How about we use the report post button if we have a problem with a post and not bring this stuff up in the tech forums. Thanks.

Cleaned up.

Click to expand...

Thank you.

Thanks man. I been getting so many different answers its hard to deside. im leaning toward .004 ptw and .0020 top and .0023 bottom. Would that we considered loose for a 500 crank hp motor maybe a lil more on the track hear and there? I have a 35r ill be pushing 30-32 psi on meth with 272 cams.

eclipse94turbo said:

Thanks man. I been getting so many different answers its hard to deside. im leaning toward .004 ptw and .0020 top and .0023 bottom. Would that we considered loose for a 500 crank hp motor maybe a lil more on the track hear and there? I have a 35r ill be pushing 30-32 psi on meth with 272 cams.

Click to expand...

No, I'd say those specs sound about right. I'm running the specs I've listed above & sounds like my power is around your goals.

Last year on my 3052 I was running ~28psi daily & flowing 50lb/min (so probably ball park 500 crank hp or so). This year I'll be running a DSM 82 HTA (or HTA version of 3582) & plan to run around 30psi daily. Should put me in the 550 crank hp range. At the track will probably up the boost abit more. My max goal would be around 600 crank hp as I don't like replacing trannies every other year

Ive never had coated pistons before thats whats throwing me off. Im scared that if i do a .004 ptw that the coating will wear off and put me a .0045 and ill be loose and have piston slap and have blow by. This will be a street driving car also, i dont a loose motor or piston slap.

eclipse94turbo said:

Ive never had coated pistons before thats whats throwing me off. Im scared that if i do a .004 ptw that the coating will wear off and put me a .0045 and ill be loose and have piston slap and have blow by. This will be a street driving car also, i dont a loose motor or piston slap.

Click to expand...

Piston slap seems to be more so from piston design itself, that is unless your running huge PTW clearances. Do not worry about it possibly opening up to .0045, thats not "loose". I have zero piston slap on cold start up, others run even larger gaps without piston slap. I'd have no problem recommending .0045 to start with as well (ending up with ~.0050) if you think you may want to go "bigger" in the future.

You are more likely to get blow by from too small of ring gaps, not too large. The gaps I recommended should be good for you.

Well i called the machine shop and told them to do a .004 ptw, and a .020 top/.023 second ring.