Hey Guys.

Go here to see some pics of the rods/piston... Let me know what you think..

Thanks to Clint for taking these for me.

Gurgen

 

How did you blow your motor?

Chris

 

He describes what he thinks might've happened in that link

 

The broken top ring land on the piston was caused by likely detonation not a failure on the rod end. The rod end and piston could very well have happened at differant times. I have seen engines run normally with part of the ring land gone as long as the pieces exit the engine without damaging other parts.

 

You did that WITH a J&S Safeguard and an ECU flash?

 

remarkable...and at relatively low power levels. If I recall....Gurgen was running about 5.5psi and the motor let go at 5500rpm which is near 350whp.

 

Yes Sharif is on.... except that it was at 4500 rpm and about 340 whp. There are other issues that could have caused a totally rogue preignition..... I will keep you guys updates... I am finally in town and will be at TS first thing tomorrow morning....

Yes... as far as tuning is concerned.... TS reflash and J&S taking out just over 1 degree per psi... so I was taking out close to 6 degrees at 5.7 psi. It was a very good tune...

It is very possible that the piston was already damaged...and who knows maybe it was even the cause of the engine smoking ... However, there was NO detonation at the time (or any time withing the last couple of weeks) of the failure... The car very nice and smooth....

G

 

Wow such low boost to have those issues. I thought these Z motors would be the next Supra motors...Guess not

 

This is a long shot but that carbon buildup looks very strange. The mention of it smoking a little also makes me wonder if there was a head gasket leak, allowing coolant into the ignition chamber. Super heated water vapor could then have been the culprit. It would take a close chemical examination of that buildup on the heads to narrow the causes, though.
Just a SWAG here.

 

From my expierence, once the piston or ring landing is cracked, that cylinder is much more prone to detonation. All that smoke was probably from burnt oil. Oil mixed with fuel causes the resulting mixture to have a lower octane. Fouled spark plugs from oil and jagged edges on the piston surface could also lend that cylinder to detonation.

Can you tell us what happened to the middle of that rod where it looked like it snapped off? How much scaring was done at the bottom of that one cylinder wall. How long had you been driving when the motor popped?

 

Crunchy!!!! I love it total destruction!!!!!! Accually it doesn't look that bad(I am opptimist)...I have seen worse...keep us all updated!!

 

I love intelligent posts.

Detonation has nothing to do with the motor specifically vs. other motors. It can happen in ANY motor boosted or not and it can break even the strongest motor parts made.

 

Hey Guys

Several people took a look at the block... The condition of the pistons and the heads presents no evidence of detonation, as I know to be the case (at least so far as that which is detectable not only by the human ear but also the J&S Safeguard as well. Hence my belief that detonation it was not.

I do not know which rod came from which cylinder, sorry. I'll try to find out Monday when I go back to TS to check on the car. If you guys can deduce more from pictures than I can, then please check the original link for some new pics of the blocwn block.

IMO, the condition of the bottom half of the rod's big end lends more credence to the broken rod bolt theo. Everything else, including the piston, COULD have been damaged futher down the cascade of events.

Then again... what in the world was that smoke that was coming out of the tailpipe? I do not quite believe in coincidences. I am thus somewhat at a loss. What I tend to think is that immediate detonation did NOT bring down the engine, past detonation or a lean conditition, even if for only a moment, did cause damage that lead to the smoking issue (if in fact a piston was damaged - even though all the cylinders showed good compression), and, finally, a it a rod bolt that gave way, causing it's destruction and the subsequent twisting/destruction of the other rods.

Gurgen

 

I have the PE kit and I am getting ready to rebuild the motor as soon as my stud bolts get here. Is Technosquare going to create a flash set for higher boost levels than 8.5?

 

That's a good question for TS. I am sure that after Cheston's engine is done, there will be one. However, there are major issues with overvolting the MAF and hence not knowing how much air there is over about 6 PSI or so. There are ways around this such as other EM solutions (Unichip, emanage, etc.) as well as others.

G