Pistons

[SC2NR]

Going to order pistons this week. and need to know the piston specs... what are the stock piston specs? and I want to get a little bit of a overbore but not to much whats a safe bore size? Oh and also i'm going to be buying the forged rods from SDA is that going to make a difference on the Pistonss?

[therealm0rh0us]

i got a set from sda for 150 stock size
has your block been bored?

[Anonymous]

Re: Pistons

Going to order pistons this week. and need to know the piston specs... what are the stock piston specs?

[insert year/model] pistons = "pistons specs" as much as you need. what kind of pistons are you ordering?

and I want to get a little bit of a overbore but not to much whats a safe bore size?

Well this really all depends on the setup of your build. N/a = 40 thousands is about as large as you're gonna want to be safe unless you sleeve your block.

Oh and also i'm going to be buying the forged rods from SDA is that going to make a difference on the Pistonss?

No. just make sure the pin sizes match. If you are getting forged rods, I really hope that you are getting forged pistons as well.

[SC2NR]

No my block has not been bored yet.

[SC2NR]

Re: Pistons

Going to order pistons this week. and need to know the piston specs... what are the stock piston specs?

[insert year/model] pistons = "pistons specs" as much as you need. what kind of pistons are you ordering?

and I want to get a little bit of a overbore but not to much whats a safe bore size?

Well this really all depends on the setup of your build. N/a = 40 thousands is about as large as you're gonna want to be safe unless you sleeve your block.

Oh and also i'm going to be buying the forged rods from SDA is that going to make a difference on the Pistonss?

No. just make sure the pin sizes match. If you are getting forged rods, I really hope that you are getting forged pistons as well.

Ok It's a 98 SC2, it's going to be a turbo build. I'm ordering the pistons from JE...

[sl2wycked]

you should really bore your block first and then get the pistons done to match the block. its easy to make pistons to a spec but hard to bore and hone a block and end up at an exact spec.

[Anonymous]

you should really bore your block first and then get the pistons done to match the block. its easy to make pistons to a spec but hard to bore and hone a block and end up at an exact spec.

eh, I would suggest getting the pistons he wants, then take them and the block to a machine shop and have them do everything at once.

and I didn't want to know your year or model. That part is for you to tell whomever you are buying the pistons from. Honestly, I would not overbore the block if you are going turbo and the fact that your pistons are coming from JE tells me nothing other than that they "might" be forged.

But now that we know you are going turbo, I would suggest a 8.5:1 compression piston to take advantage of the turbo, forged of course, paired with a set of forged rods with pin size match to the piston. Obviously, order the pistons as stock "dimensions" but as 8.5:1 and then once you get them take them to a machine shop with your block and let them do their magic. I would suggest clevite 77 bearings as well as molly chrome rings (I'm not sure about JE's or if they even supply rings as my only piston experiance is with stockie replacements and CP). Have "edges" of your crank shaved to a point as well as the front rotational side, and then take it to the same machine shop and have it balanaced for 10K rpm as well as micropolished. Hell, if you can, try and get ahold of a 3rd gen block to go with the forged beauty and balanced crizank. The only thing I could think else to do to the block would be to find some way to add oil squirters lol. Oh, thread lock everything that has threads (for the most part, not like the oil inlet screw, but the main cap shiz)

So there is your bottom end. You'll want to include a copper headgasket as well just for the hell of it. If you're going forged, more than likely, you're gonna get boost greedy and wanna up the power... and you'll have one weak point covered with the copper hg.

What do you have planed for whats going to be setting on this expensive paperweight?

[sl2wycked]

unless je tells him how much his pistons would swell with heat, the machine shop cant do anything but open up excess clearance between the piston and cylinder wall if he has them done in stock size.
the only options there would be putting the pistons in there with the cylinder walls in the condition they are, or resleeving the block/buying a brand new block from saturn to have the pistons installed in good condition cylinder bores.
when reconditioning your cylinders, you fix out of round and taper and all in each cylinder and end up with equal cylinder specs across all four. unless you have little to no miles on your block, this will require some overbore and honing. you wont know how much until its all done. so then you get your pretty beautiful block back from the machine shop and sliding the pistons and rings in is like throwing a hotdog down a hallway. or jaysons penis down vinny's ass. either way. theres really no point in buying stock size pistons unless your block is flawless and not having anythign done. you can tell your machine shop to end at a certain bore if you want and order pistons for that size. just be sure you're using a good shop that isnt skimping on good work cuz they know you wont chack behind them.

[sl2wycked]

also jayson he's asking us what the specs are for our cars. which i dont know. you're welcome to bore out whatever you want because not enough examples of a turboed overbored block have been done to tell us where the limit is. most will tell you not to overbore any more than you have to(reconditioning the block) just to have plenty of thickness in your sleeves. some will say no more than .040 or .020 or so. there are na cars with somethign like .080 which appearantly make them a 2 liter.

[Plastic Fury]

It's so hard to get a good straight answer lol. I am going through the same thing right now. I orderd the forged rods from SDA and just got my block back from the machine shop. I had them deck it and just glaze hone the cylinders. I figured it made sense to do the blockwork first and then get the pistons. I too am looking at JE forged pistons and although I am spraying it now, I am thinking of going turbo in the fall, so 8.5:1 is the compression I want. I have been told to get the moly rings but now I have to figure out what size pistons. I am assuming stock since the shop only broke the glaze in the cylinders.

I had the crank polished but am thinking of having the rotating assembly balanced once the pistons/rods are here, we'll see. Clevite 77's seem to be the common choice as well.

I also pulled a '99 block (with the extra material) and then pulled the better bottom end brace from a 2000 SL2 from the junkyard w/corresponding bolts ( or whatever you call it, that sits under the crank for support.

Just gotta figure out the damn pistons. And then see if JE has a part number so my local speed shop (as a JE dealer) might be able to get a better deal on them.

[sl2wycked]

yeah if you just had them do that, stock size should be what you want.

[Anonymous]

okay, either way I still disagree with having to make two trips to a machine shop. Order the pistons the size that you want, oh say 20 over. Order the pistons 20 over, when you get them, take them and your block to the machine shop, and have your block bored/ honed to match. Whether they make it 20 over first and then match it, still no point in making two trips

[TheMU47]

stock piston bore = 3.227
forty over - add .040 (3.267)

pistons first - then the block honing/boring. The machine shop can get the bore dead on balls.
Each piston may be slightly different in exact tolerances, so you get those and bore match the cylinders. Know what I mean?

[Anonymous]

stock piston bore = 3.227
forty over - add .040 (3.267)

pistons first - then the block honing/boring. The machine shop can get the bore dead on balls.
Each piston may be slightly different in exact tolerances, so you get those and bore match the cylinders. Know what I mean?

and the skies open up...

[SC2NR]

Thanks for all the Info ! i'll Keep you updated....