Just curious, as to who built your engine in the first place? It might be best to do a thurough failure analysis to find out what actually went wrong.You should at least disassemble the rod caps from the rods and check for signs of cap walking or chafing, as well as measure all rod bolts with a stretch gauge. I don't think that you should rule out improper assembly as a contributing factor.

It sounds like you may have been running too lean or that you could have experienced a momentary failure with your alky delivery. Are there any signs of destructive detonation in the combustion chambers, on the piston domes or on the ring lands?

If you are going to go out and spend big money on expensive engine parts, it may be advisable to have an experienced Evo engine builder put your short block together next time. Someone like J.A.M., A.M.S., or Buschur Racing.

 

engine havn't been disassembled yet, but of course i'll check everything to investigate for any other failure sings. I just leave the assembly problem theory cause it had been running for a year with not a single problem, but maybe as someone said, it may be a rod bolt failure.
I really discard the lean theory, there wasn't any knock event present.

PD: once again, i'm not blaming crower, i've always thought that there are no indestructible engine parts, anything can be broken, what matters is to check why it broke.
PD2: anyway i'm going to buy more resistant rods like que oliver ones. (AMS use them )
Thanks everyone.

 

12.5 -13:1 is indeed too lean for peace of mind, and is why everyone has made the same comment. You are free to believe and do whatever you like and put as much faith in the knock alert as you wish, but there is nothing theoretical about the fact that approaching 13:1 with a 550whp turbo motor isn't doing anything for power, reliability, or longevity. Just keep in mind that even stock blocks (with stock rods) at that power level have had next-to-zero rod failures. Think about it, and try not to rule out anything until/unless disassembly proves otherwise.

FYI

 

Ok ted, i'll take your advise, so a safe afr would be 11-11.5:1, or richer??

 

I strongly suggest richening the AFR to around 11.7 - 12.0:1 across the board. That shouldn't be rich enough to reduce power, but it will cool the mixture sufficiently to give you a decent cushion of error between the onset of preignition and destruction.

Are you dyno tuning or road tuning? If you are dyno tuning, what type of dyno?

 

was alky spraying when it popped?

 

Yup.
Road tuning for now, on the first days of december it will be ready and operative an AWD dyno, i'm pretty sure it's a dynojet.
Is there any difference between dyno tuning and road tuning?
Thanks.

 

Is there a difference between dyno tuning and road tuning? Yes, and especially with a Dynojet or any other inertia type dyno. Just be careful tuning to the ragged edge while on the dyno, as the loads from actual road use will be different, and will be greater.

 

I ran crower and pauyer rods at 900 whp power levels and they have held up with no problems

in fact when I rebuild my motor i send the rods back to Pauter and or Crower - (they are in same area) and they chekc them magnaflux them and send them back for more

Overrev and detonation is what kills a rod

 

This is good advice - and can be verified on the track and dyno

 

12.5- 13.0 is the problem. On alky and pump , I am 11.5 down low 10.9-11.1 up top.

 

I bet the EGT's were way high!

 

i have pauter rods the hold up very good

 

well guys, first of all, thanks everyone for your replyes, all of the info is usefull.
Let me tell you that yesterday engine was disassembled, and surprise, the rod is in one piece, the problem was a broken valve due to a problem with the valve springs. Due to low tension, a valve crashed with the piston, broke it and and ended breaking the piston. Rod is bent, but still in one piece, so crower and all their users, relax.
BTW, not a single sing of knocking on the other 3 pistons, so i discard the lean theory in this case.
I'll post some pics soon for you guys, and once again, thanks a lot for all the info.
Cheers.
And have a (as long as your not gonna drive)

Thanks.

 

What type of valves springs and retainers were you using ?