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poorboy44 said:
so was this problem only with the 12.5:1 pistons or was it all 87mm cp's. Because I have a set of 87mm 11.5:1 pistons and I wanna make sure evrything is cool

dude read ! its the blocks and your bore size,its any std size piston!A std size piston is meant for a perfect/new block.If you have to hone the shit out of it it wont work,if you have a motor with high miles it wont work.You should never order a std size piston until you measure your bore first! If you want to be safe and order pistons before you open your motor go over sized and have it bored.You shouldnt be building motors if you dont have the correct measuring equipment!! And i dont care what machine shop you go to alway check over there work!!!
 

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2k2_nbp_egg said:
Will a good hone and some oversized rings work?

NO !!!! youll have piston slap its where the piston rocks back and forth hitting the top side of the piston and the bottom of the skirt, it almost sounds like a really bad lifter or rod knock. After time depending on how bad it is it will eat up your skirt. The main reason you will hear piston slap with after market pistons is they make the skirts shorter then factory to save wieght. Also i can tell you right now that 70% of the machine shops out there cant even bore a straight,round hole so if people think that just by having their blocks bored they will be safe good luck!!! Most machine shops that have a name for them selfs are old school they dont give a f*ck about your 4 cyl jap sh*t they build american v8's cause the pieces of sh*t only last 50k miles. American's have sh*tty quality control and sh*tty standards.75% of people take cheap over quality.what ever its not this tread its just dealing with people all day that want 10 sec cars for like 5 grand and want it next week or the guy that thinks that cause he has a built motor its going to last forever making 4 x stock hp, i could go on bitchin for days
-donnie
 

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speedsex said:
dude read ! its the blocks and your bore size,its any std size piston!A std size piston is meant for a perfect/new block.If you have to hone the shit out of it it wont work,if you have a motor with high miles it wont work.You should never order a std size piston until you measure your bore first! If you want to be safe and order pistons before you open your motor go over sized and have it bored.You shouldnt be building motors if you dont have the correct measuring equipment!! And i dont care what machine shop you go to alway check over there work!!!
Thanx, I did read!!! And everytime this problem was mentioned, the cp 12.5:1 were always mentioned as well!!!!
 

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speedsex said:
NO !!!! youll have piston slap its where the piston rocks back and forth hitting the top side of the piston and the bottom of the skirt, it almost sounds like a really bad lifter or rod knock. After time depending on how bad it is it will eat up your skirt. The main reason you will hear piston slap with after market pistons is they make the skirts shorter then factory to save wieght. Also i can tell you right now that 70% of the machine shops out there cant even bore a straight,round hole so if people think that just by having their blocks bored they will be safe good luck!!! Most machine shops that have a name for them selfs are old school they dont give a f*ck about your 4 cyl jap sh*t they build american v8's cause the pieces of sh*t only last 50k miles. American's have sh*tty quality control and sh*tty standards.75% of people take cheap over quality.what ever its not this tread its just dealing with people all day that want 10 sec cars for like 5 grand and want it next week or the guy that thinks that cause he has a built motor its going to last forever making 4 x stock hp, i could go on bitchin for days
-donnie
Wow....I just find it really hard to believe that I just bought a brand new piston from a reputable company such as CP that isn't going to work. I'm going to resolve this w/o spending money on new pistons or sleeves, fuck that.
 

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CP didnt do anything wrong. They just designed the piston for a new unbored/unhoned stock-sleeved k24block. These pistons do work fine in a k24block as long as it isnt bored or honed too much. i kinda wished they made em a lil bigger since my block is gonna need a lil boring cuz of some scratches in one wall but too bad. Im just gonna buy a new block and throw these pistons in.
 

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Needless to say, this thread pretty much crushed my plans for a build this summer.

I bought 87mm CP units almost a year ago thinking theyd work fine in the stock bore...:down:
 

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nikos said:
I don't know. I think they did it do that they can sell custom pistons for more. I see no logic in people using brand new blocks to use only 87mm pistons.. why?
Nikos any idea if those TSX motors (that have just been sitting around not being used) would be able to get away with the 87's. Just thinking since mine is still sitting there with the same amount of miles I bought it with... :rolleyes:
 

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Well, my only option now is to either get a fresh block and take a punch in the face for the money I spent having it machined after my turbo fun last summer, or to take a punch in the face and get new pistons. I hear their .2 oversized pistons are coming soon though? Maybe I can work something out...
 

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siknezzallmotor said:
why not got 88mm is it safe ???is there any other piston company that make em 88mm besides cp
heres a pic of my current k24 block 88mm bore CP pistons...no problems yet....my old b20 was 13.9:1 c/r 85mm on stock sleeves no block guard nothing...never cracked and had over 100 passes...i also have a friend with 87.5 on a stock sleeve k20 with no problems....if you cant afford sleeves you just need some tuning skills:silly: lean is mean just dont get to greedy with stock sleeves




 
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