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Thread: OEM piston grade sizes?

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Posts: 1-8 of 8
2008-02-25 00:21:25
#1
OEM piston grade sizes?
ok.......... i am in the middle of rebuilding an engine pretty much mod for mod with what rob is doing.

first block i had piston slap and made the cly's unusable without boring it out.

second block had a melted piston and again jacked up the cly wall.

third AND HOPEFULLY LAST block i currently have is old.............id say 200+k miles. that being said it has some ring groves. i am trying to keep my build costs as low as possible and i remember someone at work telling me "if you have ring grooves but the walls look ok you can cut the ring, ball hone the cyl, then get slightly over sizes pistons to take up the slop.

all 4 cyl are pretty uniform and clean save the ring at the top. im trying to figure out what the differance in size in on OEM pistons. they come in 5 grade sizes as well as over sized if i can find what the differance in size is i may be able to simply use a grade 5 sr16ve piston.
2008-02-25 00:37:53
#2
did you take a picture?
2008-02-25 00:45:55
#3
i would also say to give a direct answer would need pictures too, could be too bad and need a bore and hone to get the cylinder walls straight again.
2008-02-25 00:52:43
#4
Pete, they're only 3 grades of pistons. I believe you have grade 2 on all of yours

crop the pic, so it can fit better.



2008-02-25 00:57:14
#5
in other words, we need a bore gauge and if we're over 86.030 you need oversize pistons.

oversize piston means, boring with torque plate and that runs on a average $300. that's the price of a JDM DE lol.

edit: and if you go oversize, the piston you want only comes in .20 over IIRC. so I'm not sure if you need a torque plate for that or not.
2008-02-25 01:24:34
#6
im trying to find the tool i need..... imagine a T and the ends of the top spring out then lock into place you then measure that to find the width of your bore.

Originally Posted by Keo
in other words, we need a bore gauge and if we're over 86.030 you need oversize pistons.

oversize piston means, boring with torque plate and that runs on a average $300. that's the price of a JDM DE lol.

edit: and if you go oversize, the piston you want only comes in .20 over IIRC. so I'm not sure if you need a torque plate for that or not.


i can tell you now..........if i bore the clyenders out im not useing a TQ plate. i know "you are supposed to" but its to much and brian crower cams are supposed to suck. im not building a super high tolerance engine.
2008-02-25 01:28:07
#7
http://www.jegs.com/p/JEGS/957594/10002/-1/10783

yup
2008-02-25 02:55:04
#8
Originally Posted by classicaddict

i can tell you now..........if i bore the clyenders out im not useing a TQ plate. i know "you are supposed to" but its to much and brian crower cams are supposed to suck. im not building a super high tolerance engine.


I dunno, this whole Torque plate thing is new to me. but if anything your going over .2 and staying N/A, it shouldn't do much harm.

I would also like to add, with your luck with these blocks. I think I want to take my head off to check everything.
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