I just wanted to share the problems that I had using cp pistons 9.0 to 1 compression and 156 mm long rods in a stock 229mm deck evo 9 with 94 mm stroke, compresion distance of less than 26mm made the rings to close to the top valve relief, the first time I boosted 30 psi with a FP 3586 turbo the 4 pistons broke from that part , really disapointed I thought piston desingers didnt do pistons when they have a risk of breaking. Im switching to stock length rods and JE pistons. Hope somebody reads this and doesnt do the same mistake.
will post pics later

 

What did Carrillo say about the pistons? Any detonation or bad fuel quality?

 

was it a custom piston? 94mm stroke with 156mm rods in a 63 block is asking for trouble I'm suprised they even made it for you.

 

yeah that stuff just shouldn't randomly break off...
sounds like detonation?

 

On a stock 63 block a 94mm stroke should use a 153mm rod and a stroker piston with the pin moved up 6mm. The 156mm rods can only be used with stock stroke with a stroker style piston.

 

Yep sounds like he got the geometry wrong...

88mm Crank
156mm Rod
Stroker Style Piston with the pin moved up 6mm

Compression will drop by about 1point if off the shelf pistons meant for 100mm crank is used...


but 94mm Stroke and 156mm Rod thats sounds like the smoking gun to me too.

.

 

I ordered 156mm Carrillo Rods for a 94mm Crank. I asked CP to make me a custom piston to suit this scenario with a 10:1CR
Everything has been running fine

 

Do you have any pics of your pistons?
Was your pin up in the oil ring?

 

sorry don't have any pics
I think it may have been but am not 100% on the pin position

 

It would have to be WAY UP in the rings or tehe location of the rings is modified. I would love to see the pin location on these custom pistons.

 

No geometry problem it worked fine up to 22psi
when I used 30psi with q16 , the 4 pistons broke
fuel mixture was 11.4 to 1

I wouldnt recomend using 156mm rods with 94 mm stroke
because of my bad experience

 

From your pics, looks like you had some detonation going on. The #3 piston looks worse.

Aaron

 

Here is a photo of the piston

 

is the head toast also? What method were you using to check for detonation?
here's a pic of a Wiseco hd 9:1 94mm stroke 150mm rod for comparison, i dont know much about piston design but the top land looks to be alot bigger than your cp's.

 

This is just my two cents im no expert but OP was useing 156mm rods which is why there shorter. also it looks like detonation was the cause....also how does the head look were the valves bent or hit at all?