Possible Detonation

[Deathseeker31]

hello Everyone
I need your opinion on what could have possibly gone wrong with this motor. A little history on the motor it was rebuilt 6k miles ago. Machining work performed to it was balance the rotating assembly, deck the block and head, bored .020 over, and polished the crank and rods. Motor has ARP bolts all around, Cometic 2mm hg, JE pistons and piston rings, with clevite standard size bearings. When the motor was running it had code 52 for about a month with mild driving not much until it was fixed. I believe the motor spun a bearing based of user error i belive ;[
Please look at the pictures and let me know what you guys think or if there's anymore information you would need to help me determine what needs to be done to the motor.
Once again thank you for all the help ahead of time.

Ricky

 

[jdub]

Looks like it went lean and tried to torch the pistons. #6 looks like it never set the rings and the oil kept it cool enough to stop what was happening to the rest of the pistons.

What was used to tune this motor? What injectors?

 

[Deathseeker31]

stock injectors, nothing really in the sence of tuning. It was all stock except for the exhaust, intercooler, and piping which is how i purchased the vehicle. Motor was timed at 10* properly.
spark plugs were autolite plugs and they were gapped to .032, i believe have to double check when i get home on the gap.

 

[jdub]

Were the injectors cleaned/flow tested?

Is there a Lex AFM on the intake hose? (might want to confirm...they look a lot alike)

 

[Deathseeker31]

Thank you Jdub for the help. The Injectors were not cleaned, they came of the original original motor and at that time were working properly. In regards to the Lexus AFM there's no adjustment bolton mine and the person i bought it from said that he hadn't upgraded it. do some of the lexus AFM come without the adjustment bolt?

 

[jdub]

Both AFM's have the bolt/screw...it's covered with a pressed in aluminum cap on both.

Those injectors should have been cleaned. Has the CT26 waste gate been shimmed (washers) for more boost?

 

[Deathseeker31]

yup turbo wastegate was shimmed 2 washers.
I should also say I had a DDP to a 2 1/2 inch exhaust no cat.
I was seeing 10 lbs of boost the max i ever saw was 12 and that was once AFTER the knock sensor issue was fixed.
I do agree with you they should have been cleaned, One mistake I will not make again.

 

[jdub]

The combination of crap spray injectors + almost double the boost is not a good one

 

[Deathseeker31]

very true :[ would you say there is a high chance that the head could be crap because it ran so lean?
Are those pistons reusable?
Thank you for all your help i really appeciate it.

 

[jdub]

You're welcome

Hard to tell from the pics, but if there is a depression melted out where the spots are...you need to get new ones. The head "should" be fine unless there's damage...even minor damage to the seats can be fixed with 0.5mm OS valves. I would have it hardness tested before I spent a penny on rebuilding it.

BTW - the white ash deposits on the intake valves are a lean indication as well.

 

[Deathseeker31]

When u say depression do you mean exactly?

 

[jdub]

Those donut shaped burn marks on 5 of the pistons between the valve cut-outs...the surface should be flat. Compare to the other side...if it's not identical, the piston is FUBAR.

 

[Deathseeker31]

Thank u once again. Ill check those out and see what I find out.