Engine carnage
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 2,237
Likes: 9
From: Springhill FL
Engine carnage
When I break stuff, I go all out. I had a brain fart the other night fiddling with my tune. I did some cutting and pasting in my VE table and missed a section which left a nice low spot in exactly wrong area. Oh well, live and learn. Here is the result(pics with a borescope in the spark plug hole):
#6
#4
I already have another LS6 shortblock on the way as well as a set of 317 heads. I specifically did not go 5.3 because if I go back to NA down the road I dont want to be short of power. Still deciding which way to build the shortblock before I swap it. I still have no aspirations of huge power so I'm thinking just some forged rods and pistons if the stock crank checks out.
Still havent taken anything apart but its a good bet my turbine is detroyed as well.
#6
#4
I already have another LS6 shortblock on the way as well as a set of 317 heads. I specifically did not go 5.3 because if I go back to NA down the road I dont want to be short of power. Still deciding which way to build the shortblock before I swap it. I still have no aspirations of huge power so I'm thinking just some forged rods and pistons if the stock crank checks out.
Still havent taken anything apart but its a good bet my turbine is detroyed as well.
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 2,237
Likes: 9
From: Springhill FL
I was in 3rd gear doing steady state cruising at about 4k and gave it a bit too much throttle. It jumped right into boost and popped it pretty much instantly. Afr went from high 10s to 13.7 right at 5k rpm, timing was 15 degrees. It was a whole bunch of stupid on my part. I was way too tired and aggrivated to be tuning(4am sunday morning after working 12 hours). I was chasing down an issue with my map sensor scale and should have fattened up my VE across the board and gone back to conservative timing. Instead I just copy and pasted my rows in the ve table guestimating thier new spots on the map scale. It actually wasnt too far off except for the row I missed.....150kpa.... Absolute bonehead move on my part to even try it like that. As soon as I looked at the log and the tune I knew exactly what I did. Like i said, live and learn. I guarantee next time ill be a bit more conservative. 
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 2,237
Likes: 9
From: Springhill FL
The dead engine is a stock ls6 bottom with a 228r cam. I'm starting to lean towards a forged 383 rotating assembly in the replacement ls6 block. I'll go with barely dished pistons and let the 317s take care of compression. Down the road if i go back to n/a some high compression heads should still put down good numbers.
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ISIS SUCKS FAT CHOAD
Joined: Oct 2008
Posts: 8,124
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From: Earth, United States
The LS6 based 383 is a killer combo forsure. If I could give my advice though just some food for thought. If your not concerned with a few extra pounds you might want to consider doing a 390 iron block build. No need to worry about the possibility of cracking a sleeve. The iron block is definitely a more stout piece than the LS6. Very minimal modification to get everything to work together. 
Melting Slicks
Joined: Mar 2006
Posts: 2,749
Likes: 377
From: South Florida FL
I vote keep it simple personally. careful with those long strokes. piston skirt extending pass the bore and oil consumption If what i'll be concerned about. when it comes to longevity anyway. Find a proven builder.
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 2,237
Likes: 9
From: Springhill FL
Some good news. My turbo seems to be unscathed. 
I may have to toss my intake though. I flipped up the throttle body blade and there was shrapnel sitting right behind the blade. I will wash it and give it a thorough inspection with my borescope camera. 
I may have to toss my intake though. I flipped up the throttle body blade and there was shrapnel sitting right behind the blade.
I will wash it and give it a thorough inspection with my borescope camera.
Melting Slicks
Joined: Feb 2006
Posts: 2,163
Likes: 5
From: Houston
I usually use the vcm scanner to pull 4-5* out when I am unsure if the AFR is dialed in or not. Either way mistakes just happen. Sorry to hear.
Simple rods/piston motor build correctly should last a long while.
Simple rods/piston motor build correctly should last a long while.
Melting Slicks
Joined: Jul 2008
Posts: 3,002
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From: Houston Texas
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Also, don't waste your time at the house washing the intake. Take it down to the car wash and spend about $1.25 in quarters and stick the wand in each port and down the throat of the intake. This works way better than a water hose or the kitchen sink and takes way less time.
Burning Brakes
Joined: May 2011
Posts: 1,216
Likes: 56
From: Houston Texas
Damn, sorry to hear about the failure. Those stock pistons aren't going to take much abuse.
I agree with Turbo-Geist on the cleaning. A few quarters and it will be cleaner than you could do in the sink.
The displacement increase is tempting, but unless you change turbos then you're just going to have horrible backpressure issues. The factory 346ci is already pushing it for a single 68mm turbine wheel. Personally I would leave displacement alone, and put a decent set of 2618 pistons in to take some abuse when needed and a set of compstar rods or equivalent. Should last a long time that way for the power levels you want, and will absorb a little goof factor from time to time as well.
I agree with Turbo-Geist on the cleaning. A few quarters and it will be cleaner than you could do in the sink.
The displacement increase is tempting, but unless you change turbos then you're just going to have horrible backpressure issues. The factory 346ci is already pushing it for a single 68mm turbine wheel. Personally I would leave displacement alone, and put a decent set of 2618 pistons in to take some abuse when needed and a set of compstar rods or equivalent. Should last a long time that way for the power levels you want, and will absorb a little goof factor from time to time as well.
Thread Starter
Melting Slicks
Joined: Aug 2004
Posts: 2,237
Likes: 9
From: Springhill FL
