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Discussion Starter #1
So i am replacing two pistons cause well they melted...

anyway i ordered (2) 75.5 cp pistons. I received them and i was wondering before i start tearing them apart that they are right. They came in a box but no markings too assure me they are the right size. It came wiht a spec sheet but nothing i could understand on it to tell me they are 75.5mm pistons

I meassured them really quick and from side to side it meassures around 74.83mm does this sound right?
 

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98 Civic CX-T on E85
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are your other 2 good pistons 75mm or 75.5mm if it was me i would keep all the pistons the same bore so if i had oem 75mm and i had to go to 75.5 i would do it to all 4 cylinders and replace all 4 pistons...
 

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Poop Sock
wrx & slut rex
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are your other 2 good pistons 75mm or 75.5mm if it was me i would keep all the pistons the same bore so if i had oem 75mm and i had to go to 75.5 i would do it to all 4 cylinders and replace all 4 pistons...
haha omg, can you imagen mud pistions, all different sizes, oh god.


stock bore is 75mm on the D's. BUT make sure your cylinder walls are ok before you install them. if the pistons melted chances are the walls are scared to hell. measure the other pistons and see what they read. can you see the crosshatching still? how many miles are on that block?
 

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'91 CRX Si
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Discussion Starter #6 (Edited)
my bore is 75.5mm on my block. Cross hatching is still there. The block has about 3k miles maybe a bit more. I had head lift for a prolonged period of time and piston 3 and 4 4 getting it th eworst as the piston is shiny from the coolant washing it. I dont have pics but my valve reliefs are some what gone. No damage to the walls when i had the head off.

anyway i ordered two 75.5 mm pistons to replace those two. I finally got them in. I may have meassured it wrong ill double check. This is the the spec sheet that i got with it.

according to the number on the sheet SC7026 it is indeed a 75.5 mm piston? or for a 75.5 mm bore.

 

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2.9695 is the size of the piston.. it says it right on the paper they sent you lol

which measure out to be about 75.48888888888

you buy the piston, and then bore your block accordinly.. so your bore will have to be .0035 bigger then 75.48888888888
 

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'91 CRX Si
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2.9695 is the size of the piston.. it says it right on the paper they sent you lol

which measure out to be about 75.48888888888

you buy the piston, and then bore your block accordinly.. so your bore will have to be .0035 bigger then 75.48888888888
yeah, thats what it says on the paper.

but he says he measured them and they are only 74.83
 

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measure 1/2inch above the bottom of the skirt. also, if you install 75mm pistons inside a 75.5mm bore, even though theres not too much difference but a half a mm, you will still notice the clearance issue.
 

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10 second daily driver :)
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check this out, i ordered a new cp piston and 4 sets of rings to rebuild my civic, well my buddy broke a secondary ring on number 2 piston so we had to pause and wait for a new set to be over nighted, well all the rings needed filed to set end gap to what i wanted, however the new set of rings that came needed no filing at all!! exact same part number on the bag and all. i think they bagged a 81 mm ring in a 81.5 mm bag, i mean its no big deal i simply didnt have to file it but just seemed odd that it would happen.
 

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Discussion Starter #12
Where on the piston did he measure?????

Tapered for comfort.
measure 1/2inch above the bottom of the skirt. also, if you install 75mm pistons inside a 75.5mm bore, even though theres not too much difference but a half a mm, you will still notice the clearance issue.
ya i just found this out. I meassured at the top of the piston.

so tomorrow i will go out and meassure 1/2" above the skirt to make sure.

oops newbie mistake:)
 
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