As few of you know, i had a 408 built not a month ago for my turbo setup. It ran for a week till i broke trans, then ran from wednesday to saturday when i raced the mustang i posted a video of. Well, after that run i heard my motor knocking so i went home. Pulled oil filter off and cut it open to find aluminum, or babbet material. Well long story short we finally pulled motor out yesterday and tore it down today to find this on number 2 and number 7 piston.





Before all the questions get asked.....I was on 14psi, afr was around 10.8-11.0, we have 16* of timing, have flowmatched 78lb fic injectors, vic jr intake, aeromotive a1000 pump with fuel cell and -8 feed line, 160 stat, coolant crossovers on front and rear.

 

I had the same type of scoring on my 410. I asked Bryan at LME about it and he said its likely material from my blown piston made its way around in the crankcase and got caught in there between the piston and bore. In your case since you heard knocking I would suspect rod bearings...

 

damn that sucks! I would be one pissed ****!!!

 

I never blew a piston though Atomic. the tops are flawless. Only the sides are like this on cylinder 2 and 7. Im thinking from piston wall clearance.

 

What do you suspect the cause of the knocking is?

 

My god how many engines have you blown now? Some are built and some were just pullouts? You should really consider the TUNING...

 

The knocking had to be the piston skirt slapping. It wasnt a loud knock but it was noticeable to me.

 

David, if you read what i posted i dunno know what else could be more conservative on the tune. We left sooo much power on the table with the way we had it tuned. When the plugs are clean but not chalky and the tops of pistons are fine it cant be in the tune.

 

I blew through number 8, but saw the same type of scoring on number 7. I only took those two out, but have a feeling I would have seen it on all of them had I taken them all out.
Have you pulled all of the rods out?

 

Yes sir, the motor is tore all the way apart and at the machine shop. All the others look fine.