cooked it! What did I do wrong?

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MattP said:
Your compression isn't an issue with such low boost and 92 octane. I've found 15lbs boost on a 9.2 compression motor to be the safe limit on 93 octane.
It wouldn't hurt to be running a meth/water setup though since you could always get some questionable fuel. If you want more info on that PM me.

It sounds like your timing was too high and/or you got some lower octane fuel and detonation got the better of you. Lifted a head, blew a headgasket, and cooked a piston.


fwiw- Been there..it sucked 22lbs boost, 93 octane + water meth injection. Found out water/meth is best left to 18lbs. After that I only used race fuel for anything more than 18. The meth helps but it doesn't mix with the 93 to make all the fuel higher octane. It just makes a higher average.
7CC96AAA-8E43-44DD-B590-22792AFA9C60-4875-000006C56AFC82A9.jpg
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Yep that looks alot like mine. I'll take any info and tips you want to share. I do want to do a h2o set up on it. Just thought I would have been ok with where I was at.. guess not..
 
I plan to have it tore down tomorrow. Promised the girlfriend we would take the bikes out for a long ride today.
 
Need to look at the skirt real close, the bottom side of the piston, the rings, the pin, and the bearing. All need to be looked at very close, a good magnifying glass will help. This is caused by heat and way to much of it.

You need to look at all 8, not just the one that let go first.
 
I gave my opinion. Maybe MRL can elaborate. Did you check the turbine for damage to the blades. That debris had to go somewhere!
 
CUUDAK said:
I gave my opinion. Maybe MRL can elaborate. Did you check the turbine for damage to the blades. That debris had to go somewhere!
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I havent checked it yet but I honestly think the majority of this happened with the 88. Probably what bent the shaft.. Ill pull the dp after bit.. I hope the 114 is ok. :prayer:
 
Ok last pict for awhile.. Every piston looks like this.. They are all scuffed on the intake side. doesnt show any damage to the cylinders just the top edge of the piston. skirts all look normal no scuffing..
photo-37.jpg
 
Did you chase all of your head bolt holes in the block with a tap before assembling? Boogered up threads will cause the bolt to bind and reach torque before you reach proper clamp load.

Always chase your bolt holes with a tap and your bolts with a die before assembling to make sure that your threads don't bind and you get the proper clamp load.
 
krazykuda said:
Did you chase all of your head bolt holes in the block with a tap before assembling? Boogered up threads will cause the bolt to bind and reach torque before you reach proper clamp load.

Always chase your bolt holes with a tap and your bolts with a die before assembling to make sure that your threads don't bind and you get the proper clamp load.
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yes plus its studded..
 
I run a turbo 4cyl mopar spirit r/t i put meth injection on the day before i left and had very little tuneing time my first pass read 14afr i kept my foot in it and ran a 12.5 i asked around and the widebands can read off if your super rich. Just a lil info to keep in mind that widebands are not alway accurate iam running an aem also.
 
440dart123 said:
I run a turbo 4cyl mopar spirit r/t i put meth injection on the day before i left and had very little tuneing time my first pass read 14afr i kept my foot in it and ran a 12.5 i asked around and the widebands can read off if your super rich. Just a lil info to keep in mind that widebands are not alway accurate iam running an aem also.
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Location of the o2 is also critical for more accurate readings!
 
Need some good pics of the #2 rings on all the cylinders. The one from the blown piston does not look good. It should be 1/2 silver(bottom) and 1/2 dark color(top). If not the the taper on the ring is gone. This happens when you wash the cylinder down from a way rich condition.

It doesnt look like heavy detonation, the bearings look good and no scuffing on the skirts. It looks more like pre-ignition. Its getting the piston tops HOT, and they are all starting to melt. Plus with the high heat the rings could have butted and popped the piston top.

What do the undersides of the pistons look like? Right above the pin?
 
This the bottom side of the worst one. looks fine.

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Sorry it doesnt come out very good but the 7 other pistons show the half and half coloring..

photo1-9.jpg
 
im not a turbo engine expert infact i know almost nothing about turbo engines but just looking at the pics i have to agree that from the scuffing just on the intake side it looks like a to rich condition that washed the cyl. walls down but that alone wouldnt have caused the prob I'm thinking possibly when the head gasket failed the coolant had to go somewhere and tried to hydrolock that cyl. and that was just the weak spot .
 
Your piston looks quite reminiscent of a piston I fried in a supercharged engine I have. (Albeit not a mopar)
The engine was always very relaible, and took the beatings I used to give it like a trooper. It finally did what you see in the picture, after a prolonged high speed pull into a strong head wind on a hot day. My theory is that the charger heat soaked and lead to detonation that I couldn't hear till after the damage was done.


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You real think excessive fuel flow did that? I don't know just asking.

Did you save the oil that cam out of it.
If so send it in for a oil annihilation. sent two, on with new oil and one with oil from the crank case.

You could learn a lot.

This is the kind of stuff that scares me about forced induction.disgust
 
Pinging bad, saw it on a blower motor too. The one I worked on had too much timing advance. But it could be a number of things. But I agree other posts, it was detonating.
 
inkjunkie said:
Got this from the guy with the insanely fast Dart on the Turbo forums....

Matts turbo dart - YouTube
All that being said I would be guessing it was something in your tune.....
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I heard he broke a motor mount on that run, and probably pissed himself for almost tagging that concrete block at the end...That car is cartoon fast!
 
I have seen this exact effect before,.....numerous times.
 
D-E-T-O-N-A-T-I-O-N due to too much timing. Period!

That is the number one enemy of boosted engines! Can happen soooo fast you will never know it.
 
Lack of detonation resistance for a given altitude, and air density. Meaning / Octane.
 
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