I have a question…
in the sr’s there listed as 86mm oem pistons, now most of the upgraded pistons from like greddy or hks can be 86, 86.5 or 87. now if you get say 87 do you just need smaller rings and if its an 86 bigger ones, or if your gonna go past 86 do you need to bore it out? thanks
Correct. As far as engine tolerances every 0.5mm increment (or 0.020") is a lot. You would have to bore it out.
for any oversized pistons u need to bore out your block! sr20 has steel sleeves so u cant bore over a whole lot as cuz the OEM sleeves are pretty small! dont go to big! the pistons should come with rigns ETC if its a kit so all u need to do is take ur blocka nd pistons and rings and shit into the machine shop and they will make it all right! but still make sure all tolereances and clearences are within spec 
yes^^^^^
Cheak if berrings are standard too. I think there is a std stamped on them and I cant remember the number but ya look it up!
for your berrings there is a CODE stamped onto the crank it will tell u what grade it is, u need a FSM for this or u can take the code into nissan!
If you go with the 87mm you will need to re-sleeve your block. HKS and a whole bunch of companies make them.
lots of other companys can sleeve your block! it dont need to be HKS or any jdm company! just get a company here to do it DARTON sleeves i have herd good things!
I never said he just had to go with HKS or JDM. Darton are great sleeves as well.
i just dont see the the point in having to bore the block out for just another mm, plus wouldnt this kinda defeat the purpose. i mean if your building the block, you probly want power, and thinner sleeves could weeken the block. If your just gonna go with the stock size internals then should you still have the block machined? or can you do it yourself by just honing out the cylinders and using a fine grit paper like i’ve heard other people do, then just clean it with like brake cleaner and be careful to get it all. if not what kinda price am i looking at to have the deck machined and the honed to fac specs?
If your looking into 87mm pistons and all the aftermarket stuff, don’t cheap out and screw around, do it right the first time. For 1, crosshatch on a cylinder wall is VERY important. If the crosshatch is too wide, the rings won’t seal. If the crosshatch is too narrow, it will burn oil like mad. 1mm is BIG when dealing with engines. If you ever look at clearences in an engine, you’ll know how tight everything is and how something can EASILY cause a chain reaction. If you go with 87mm, you will have to re-sleeve the block. Besides, upgrading to 87mm pistons seems like nothing to you, but you WILL feel the difference. You need to do some research to find out some stuff so you can build it the way you want it and build it right.
DO NOT do it urself! take it to a professinal shop where they have the REAL tools to do the stuff even on just a hone! like apexi240 said the crosshatches have to be good
fair enough, i just ment honing it for stock size 86 pistons, but i get what your saying. so who does it and what kinda price is on it?
Honing and boring are 2 different things. Anything bigger then 86mm will need to be BORED, if you keeping the 86mm it will need to be HONED (And no not with sandpaper at home). EC Automotive Machining does it all. I have my stuff done by then as well as half this board. Give them a call, their located on 118th street.
is there any sort of discount for n-e-c-c members?
No, discount.
why would u bore?>> just go oem . if u want displacement u better of building up ka-t or dropping in rb25. etc machine shop work aint cheap…
Umm when putting in new pistons and rings it is best to bore to make sure you get a good seal.
Going .20 over on a SR, you will not notice a difference. MAYBE .025 of a litre.
For example, if you blew the rings, and the cylinder walls have been scratched, they need to bore it out to get rid of the scratches. Usually the scratch is around the 20 over as Rob said.
The point in boring it out isn’t to get more displacement. There isn’t even know room to bother doing it to make a difference; otherwise you need to sleeve it. It’s like Rob said, to make sure the seal is perfect with the new pistons you put in.