I just recently took my motor apart this winter to hopefully just find leaking piston rings and replace my valves, springs, and ret. I was surprised to find that my cp 9.1 84mm pistons had a a piece of each corner of the top of the piston missing. These pistons have under 5000 miles on them and the car was tuned with hondata s200 as soon as they were broken in. I was lucky and no damage was done to my sleeves and no damage to my head. I havnt even looked at the exhaust side of my turbo but i was planning on upgading any ways. I deff dont want to go back with cp pistons, my car was tuned very conservitive and dont really understand waht casued this any imput would be great. I know though that the part of the piston that broke of is obviously the weakest part where the dish meets the side of the piston. What would be some better suggestions for pistons this go around, and should i stay at 9.1 or go to 9.5.1 to try to get more torque out of the motor. I will be using the gt35 this go around for turbo.

 

pics?

 

You probably detonated from a bad tune on 9:1 compression, so you want to potentially compound the problem by throwing more compression into the mix? You arn't going to notice a difference from 9:1 and 9.5:1, just stick with the lower compression.

 

I deff will not put this persons name out there but it was tuned by a very reputable tuner in NOVA (norther virginia). So its tough for me to think it was the tuner. I could believe I got bad gas before i ever thought it was a bad tune. The car spent some serious time on the dyno.

I will deff post pics, thanks for the quick reply ill have them up tonight..

 

I have heard nothing but great things about ARIAS pistons. I would stick with the 9:1 CR

 

pics?

 

People are often too quick to blame the tuner. Has anything maybe changed with your setup recently?

 

... this would be the 5th time ive heard of this problem.... ive seen it 2 times out of a customers motor.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jared &raquo;</TD></TR><TR><TD CLASS="quote">pics?</TD></TR></TABLE>

 

wow, this is like the 3rd time i read that about cp pistons in a week. mine ended up the same way but that was because of too much timing

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B18 CYA &raquo;</TD></TR><TR><TD CLASS="quote">wow, this is like the 3rd time i read that about cp pistons in a week. mine ended up the same way but that was because of too much timing</TD></TR></TABLE>
yeah there have been a lot of these threads lately. I wonder if they had a flaw is some of there product or its just chance.

 

Does it looks like mine?

CP 84mm 9:1


This seems all too common. I know everyone wants to blame the tune but when you have 50 sets of pistons all breaking in the same manner at the same location, its obviously a weak point.

 

How there are the four dishes on the piston it is in the top right dish of all four , right where the dish and the sidewall of the piston are the thinest. All four pistons in the exact same spot.../

 

I dont understand this, I have a brand new set of CP pistons... 9 to 1 comp. for 81.5 mm, Maybe its because of the oversize... 84mm is pretty big, the design looks different for the 84mm than for the 81.5, my pistons dont have the dish, they have the valve reliefs but there seems to be more material at the top???

Strange, I'll post some pics up for you to see. I haven't put mine in yet but the more I read the more nervous I get. I assume cuz you are in NOVA it was tuned by Inline, I am currently running a tune on my hatch by Stan and it is great, car hauls ***.

 

read this thread.. this guy had the same problem you did.

https://honda-tech.com/zerothread?id=1438331

he thinks it was oil leaking into the combustion chamber from poorly fitted valve guide seals that created hotspots. i was just casually reading and cant reall comment on that.. but his pictures on the second page are identical to yours.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by project dc2 &raquo;</TD></TR><TR><TD CLASS="quote"> ... this would be the 5th time ive heard of this problem.... ive seen it 2 times out of a customers motor. </TD></TR></TABLE>

happened on my motor , pistons 2 3 and 4 had the corners of the valve reliefs missing .the 4th was so bad you could see the piston ring , but the car ran fine.

 

His incident doesnt really compare because he had severe mechanical issues that led to oil getting into the cylinders.

 

are cp pistons poorly designed? im getting ready to assemble my engine with them

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by imola-red dc2 &raquo;</TD></TR><TR><TD CLASS="quote">are cp pistons poorly designed? im getting ready to assemble my engine with them </TD></TR></TABLE>

I'm wanting to know this also, because I was about 12 hours away from buying a set...

 

too many people are using them without problems for them to be flawed . but like i said it happened to me as well . only reason i found out was because i blew a headgasket. it looked real thin where the valve relief met the skirt maybe certian designs are flawed.

 

which piston did you have? 83-84mm?

 

75mm it was a build d16y8

 

you weird *** SOHC bastards...

 

ahahaahhaa

im 84.5 now tho

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by KooK &raquo;</TD></TR><TR><TD CLASS="quote">which piston did you have? 83-84mm?</TD></TR></TABLE>

im gonna be running 83mm. im contemplating about getting rid of them for a different set of pistons.

is this common to all piston?