tim01customs Posted December 1, 2007 Posted December 1, 2007 are npr or ypc pistons beter and are they up to specs i baught a set of ypc pistons an they are suposed to be 75mm but they are only 74.956 are they supose to be a little smaller or what?
cranny Posted December 2, 2007 Posted December 2, 2007 yes , otherwise they wouldnt be able to go up and down would they , lol.
tim01customs Posted December 2, 2007 Author Posted December 2, 2007 yes , otherwise they wouldnt be able to go up and down would they , lol. im not dumb thats to much play i have piston slap they should have .001 to .002 thousands piston to cylendr bore fore clearence these are like .006 thats um about 4 thousands to much play.
Kegger Posted December 2, 2007 Posted December 2, 2007 Are they a high silicon piston? If they are then they expand a lot and it'll take up the rest of the room.
tim01customs Posted December 2, 2007 Author Posted December 2, 2007 Are they a high silicon piston? If they are then they expand a lot and it'll take up the rest of the room. im not shure if they are or not but i do know they are a cast piston heat treated and have some kind of coating on them fore sealing and heat resistence they are the ebay special pistons ther cheap and say they can hold up to over 450Hp im hoping i can find some one that has ran these pistons to see if they worked half deasent or not. if u wont to see these pistons just go to ebay youll find them thers lots of them there the ycp and nippon racing pistons
Kegger Posted December 2, 2007 Posted December 2, 2007 There's your problem, lol. Should'a saved your money a bought some good forged pistons. Cast pistons suck for high HP applications.
Hatch92 Posted December 2, 2007 Posted December 2, 2007 ok 1) don't buy ebay motor parts, you get what you pay for 2) how many miles are on the block. there is a big chance that the extra clearance you are refering to is worn cylinder walls.
tim01customs Posted December 2, 2007 Author Posted December 2, 2007 ok 1) don't buy ebay motor parts, you get what you pay for 2) how many miles are on the block. there is a big chance that the extra clearance you are refering to is worn cylinder walls. there are 250,000 mil on the block but the block is withen specs its the pistons that i baught are the wrong size.
Hatch92 Posted December 3, 2007 Posted December 3, 2007 i'm gonna say it's because the block has 250+k Edit: yea the block is within specs for oversized pistons.
Kastigir Posted December 3, 2007 Posted December 3, 2007 I don't know how much metal expands, but .044 mm seems like a good figure for both the block and pistons expansion.
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