cp piston wrist pin
 

hi i was wondering whats the max power made on a standard cp piston wrist pin.

im building a fully built h22 but i forgot to upgrade the wrist pin. i would hate for that to be my down fall on my build.

if this question is in the wrong location i apologize.

Re: cp piston wrist pin
 

Nobody is going to have an answer that's worth a damn. Your best bet would be to call CP and ask what they're designed to handle.

Re: cp piston wrist pin
 

a close friend of mine made 700whp on off the shelf CP pistons

Re: cp piston wrist pin
 

when I called CP and asked them they said between 5 and 600, but there are people on this forum making 1000ish on stock wrist pins...I personally have the upgraded ones just for peace of mind.

Re: cp piston wrist pin
 

thanks guys.

my budget is on its final string so i think im just gonna run the standard wrist pin and get the car dialed in. then upgrade when my money back to par. gonna enjoy what i have for now. thanks again.

Re: cp piston wrist pin
 

for those who have upgraded pins (primarily CP), did you have to hone out the small end of the rod and/or wristpin opening in the piston to add clearance? or did you just run the upgrade .180 wall pin in the standard piston and rod? Thanks!

Lou

Re: cp piston wrist pin
 

On all of our engines, we have them Pin fit at the machine shop. Wiesco/JE/CP all of em. You'd be surprised how off some of them are.

Re: cp piston wrist pin
 

Its usually just a thicker wall pin same outer diameter, inner diameter is smaller and the material is of course stronger. Why not just upgrade pins, its like 75 bucks more to upgrade wrist pins. I ran my standard pins to 650+whp without problems but im not chancing it with the new power goals of 800+, not much money for peace of mind.

Re: cp piston wrist pin
 

yea you always need rods hone at machine shop...they come tight....

Re: cp piston wrist pin
 

Thanks guys. I was told by some popular vendors on here to just slide them in and run them without pin fitting. Anyone have a spec of what kind of clearance they should have? I'm running CP Pistons with their 9210 upgraded pins. Same outer diameter etc, just a slightly smaller hole in the middle. Thanks.

Lou

Re: cp piston wrist pin
 

My h2b made last year on 9.1 comp cp piston with stock wrist pin that they came with 831hp at 33psi never had any problem with it I will said that u will have to worry when u start making over 900hp plus just my opinion

Re: cp piston wrist pin
 

i'd just save up the extra 150 and get the upgraded wrist pins

It's just a little piece of mind

Re: cp piston wrist pin
 

Hey, I think I know that guy your talking about... Oh wait, that guy was me haha!

I made 700/500 on stock wrist pins revving to 10200-10400 and beat the living hell out of the car, never had any problems. Wrist pins and pistons themselves looked great after 5k miles. Spun a bearing so got a chance to check them!

Re: cp piston wrist pin
 

The wrist pins will outlast the off-the-shelf CP pistons at that RPM and power level. You'll eventually finds cracks at the base of the skirt. The non-strut design just can't deal with the abuse. The off-the-shelf pistons will last about a full season though... but when you're ready for a piston that really can deal with the abuse, we have these:
http://i680.photobucket.com/albums/v...stonswlogo.jpg

The underside looks like this... it's just an iphone pic but if you look closely you'll see the cracks in the corners of the skirt. Our HD piston has a strutted skirt to keep the skirt from flexing, cracking and collapsing.
http://i680.photobucket.com/albums/v...d/IMG_2046.jpg

Re: cp piston wrist pin
 

Those are some strong looking pistons Reid!

Re: cp piston wrist pin
 

doesnt really make sense to me why they wouldn't manufacture the shelf version like that. People will still destroy it, but from melting rather than collapse.

Re: cp piston wrist pin
 

Those pistons look sick. Much beefier.

For those who are wondering about pin fitting, I am sending my pistons, rods, and upgraded CP pins to my machine shop today. I'll let you know the results. I am thinking no change will be necessary as the upgraded pins slide smoothly (if not even looser) into the piston and through the rod than the shelf pins do.

Lou

Re: cp piston wrist pin
 

Reid are those piston the hd wiseco ??? One 10.1 comp ????

Re: cp piston wrist pin
 

FWIW, and for future searches that bring this thread up... I DID need to pin fit the upgraded CP pins. CP's tech told me that the upgraded pin is more ductile and needs a little "flex" or "give" compared to the standard pin. He suggested .001 to .0012 clearance in the piston hole, and .001 in the small end of the rods bushing (which is what my machine shop did for me.)

Lou

Re: cp piston wrist pin
 

That must have been in the motor I bought from you but you never sent me right? The one you scammed me on. Man it either takes stupidity or balls to come on here and still post about the parts that you scammed me on. Im still waiting for my $1500 refund and dont worry I wont forget about it either.

Re: cp piston wrist pin
 

dude the upgraded wrist pins for 1000hp+ from ipgparts.com are only $99.

Re: cp piston wrist pin
 

you DO NOT!!!! need to machine anything to run upgraded Wrist pins. the inside diameter of the upgraded pin is smaller therefore a thicker side wall, outer diameter remains the same as the standard pin. as stated earlier... I can associate it like this say you are running 24.5 slicks on 15" rims, an uprgade would be to run 24.5" slicks on 13" rims would give you bigger side walls without increasing the diameter of the tires. hope this helps.

Re: cp piston wrist pin
 

I went 760ish whp(dynojet) at 30psi for about 20-25 hits(including track+street passes). Then we we went 33 psi at the track once it ripped the wristpin right our of the piston and kabaaaam'd everything. It was CP's 11.5:1 shelf piston.......that was a bad idea.

Re: cp piston wrist pin
 

This is why I'm running diamonds this year.