as title. car is tune with less than 5k miles and last week i turn on my car to go somewhere and heard a clicking sound around #3 cylinder. i thought it was the bearings, but all bearings were check out ok. took off the head and found piston #3 chip on both side of intake valve relief side. you can see the top piston ring. anybody have this with cp piston before? these were the first batch of cp pistons before they change the design.

 

Yup had exact same problem with my 84mm CP pistons, #4 in my case. I think its the weakest part of the piston. It broke apart around the intake valve relief, rattled around and impacted the head rapidly. It was real pleasant.

Sent the pistons back to CP for "free analysis". And of course they blamed it on me - Detonation and signs of "fuel wash". I never logged any detonation. Plus you would think if it were serious enough to physicaly break a forged piston it would be pretty damn obvious that I was detonating.

I also log EGT and AFR full time. AFRs were never richer than 11.5:1 and you need to be alot richer than that to wash out rings. My EGTs where never above 1500*F

 

next time do yourself a favor and use some fine grit sand paper to sand down those thin edges. i could only imagine how glowing hot those edges get during full load making them much more vulnerable for failure. the smaller the bore the thinner the edges too

 

I saw a set of old ones and new ones......guess what they changed.

Yep, the very thin part of the intake valve relief is now gone. I guess too many people were detonating and "fuel washing" them so this obviously fixed it

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99B16Si &raquo;</TD></TR><TR><TD CLASS="quote">next time do yourself a favor and use some fine grit sand paper to sand down those thin edges. i could only imagine how glowing hot those edges get during full load making them much more vulnerable for failure. the smaller the bore the thinner the edges too</TD></TR></TABLE>

CP's don't need finishing unlike the majority of other pistons out there.

 

The chipping valve reliefs is a problem with CP pistons, it's WAY too common for it not to be.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by eg:R &raquo;</TD></TR><TR><TD CLASS="quote">as title. car is tune with less than 5k miles and last week i turn on my car to go somewhere and heard a clicking sound around #3 cylinder. i thought it was the bearings, but all bearings were check out ok. took off the head and found piston #3 chip on both side of intake valve relief side. you can see the top piston ring. anybody have this with cp piston before? these were the first batch of cp pistons before they change the design. </TD></TR></TABLE>

if you do a bit of searching you'll find this was a well known problem and a flaw in the design, CP has since redesigned there pistons to eliminate this problem. sorry to hear your **** busted.

 

Glad im not the only one.

CP can design my 495 back in my pocket.

 

when did they start re-designing the pistons? could i post a picture of my pistons and someone tell me whether mine are the newer series that dont have the problem?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Muckman &raquo;</TD></TR><TR><TD CLASS="quote">Yup had exact same problem with my 84mm CP pistons, #4 in my case. I think its the weakest part of the piston. It broke apart around the intake valve relief, rattled around and impacted the head rapidly. It was real pleasant.

Sent the pistons back to CP for "free analysis". And of course they blamed it on me - Detonation and signs of "fuel wash". I never logged any detonation. Plus you would think if it were serious enough to physicaly break a forged piston it would be pretty damn obvious that I was detonating.

I also log EGT and AFR full time. AFRs were never richer than 11.5:1 and you need to be alot richer than that to wash out rings. My EGTs where never above 1500*F</TD></TR></TABLE>

anyone know the address to sent it to? if they blamed it on me can i just buy the new style piston and drop it in??

 

I have a set of CP pistons, bought them last summer...when was the redesigned released into the public....

In my honest opinion, its a design flaw...they should compensate the customer. Although there must be thousands of the old designed sets circulating in peoples motors, it would be extremely impossible to give everyone a new set to replace....which they will probably go bankrupt if they do....

But, i don't know, something needs to be done though to reassure the customer...

Everyone knows now that it will fail...question is when!

This sucks....just tune very conservative is my advice...

 

CP pistons are like a hot supermodel. She can take as much sex as the next girl yet is 10x hotter. Unfortunately due to an inherant 'design flaw', IE decalcification of bones to the lack of food and general lack of muscle, chances are you'll literally break her if you're not careful.

CPs may be perfect, but the real world isn't. If honda designed everything for this perfect world, you've have paper-thin intakes supporting no more than 26"/hg of vacuum, sleeves almost as thin, no bracing on blocks, and crank conterwights as thin/light as a crappy T3 flange.

The real world has fantom detonation, slight lean mixtures due to voltage irregularities, and other things I pray I never have to need to know about, nor find out about from experience.

 

someone post the old design and new design piston, for future referance, when was the new design released?

 

Even if you knew the right address, your pistons can't just show up on their door step. You need to contact them about the matter first.

Im very upset they changed the design after I had this issue. I even bought ANOTHER $500 set of CP pistons bc eveyone swore they were the best. Any problems must have been my fault. I spent another $250 on top of that to get them coated by Swaintech to give the pistons additional protection.

Tony do you know which pistons have been updated?

 

The smaller bore pistons were the only ones affected. 81.0mm, 81.5mm and I believe 83mm have been redesigned.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PrecisionH23a &raquo;</TD></TR><TR><TD CLASS="quote">

CP's don't need finishing unlike the majority of other pistons out there.</TD></TR></TABLE>

im going to have to disagree with you on that...They may not NEED it but it is definitely a good practice

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tepid1 &raquo;</TD></TR><TR><TD CLASS="quote">The smaller bore pistons were the only ones affected. 81.0mm, 81.5mm and I believe 83mm have been redesigned.</TD></TR></TABLE>

I was under the impression only the 81.00 and 81.5 were redesigned? Didnt know about the 83mm. I have been running the old 81.50mm CP pistons in my block for 10,000 miles now. Luck. Ran the car at 6lbs, 9lbs, 13lbs, 17lbs and 22lbs. The exhaust manifold ended up cracking and the clutch went out. The new setup is almost done. I hope my luck keeps up, hah. -Alpha

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99B16Si &raquo;</TD></TR><TR><TD CLASS="quote">

im going to have to disagree with you on that...They may not NEED it but it is definitely a good practice</TD></TR></TABLE>

And I disagree with you. My pistons (the new design) were flawless. I inspected each one under a scope and I found no issues. Gas ports cut real clean too.

I also looked into their ring lands and the cuts that they made between the top and second compression rings. It appears that they changed the design a bit compared to the last model.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 99B16Si &raquo;</TD></TR><TR><TD CLASS="quote">next time do yourself a favor and use some fine grit sand paper to sand down those thin edges. i could only imagine how glowing hot those edges get during full load making them much more vulnerable for failure. the smaller the bore the thinner the edges too</TD></TR></TABLE>

They are aluminum, aluminum doesn't glow or change any colors when it gets hot, just turns to a puddle of liquid metal

-James

 

anyone know if this problem includes the H22 motor as well?

 

I was told ALL HONDA Applications have been redesigned by Darius at CP Pistons

I'll call them to verify again

 

someone post a pic of the old and new design

 

I havent seen the new design. I was basically saying that there is a benefit from sanding down the sharp edges that are exposed on the old style piston

anyone have a closeup pic of the new design?

 

It is tough to see in this picture, but this is the old design 81.5mm 9.0:1


Look at the valve reliefs on the intake side. You'll see that they are still there....

The new ones have removes the thin side of the relief cuts.

I will post pics of the new ones when I get home.

 

my CP's crumbled with very little abuse and its funny, it was mainly in the same areas. I'l Stick with Arias or JE.