S475 TCT single

[zf>allison]

And I always ran on tune 1 because the clutch wouldn't hold any more than that. I specifically remember it reving over 4200, but is there anything that would confuse your set limiter and let it rev higher? I remember thinking "oh it revs higher than duramax tuners tuning, that was at 4200.

 

[zf>allison]

Wow. Sucks to hear! That is some serious damage!

I totally called this. Post #168. Do i get a prize?

Yeah u get a chance to be my sponsor!

 

[zf>allison]

Each tune has the "Throttle Table" set to a different RPM, your three smallest tunes are limited to 4K rpms, the two bigger tunes go to 4200 rpms and that is the ecm REV LIMITER setting.

I would guess weak springs or incorrect spring height, revving it to 4200 would not be an issue IMHO.

I would probably bet that a valve dropped as others have suggested, the tuning you have I ran in my LB7 from 2005-2014 when I sold the truck.

It sucks when stuff breaks.........

I agree a valve dropped. But all pistons but one had a valve to piston contact mark. Making me think they floated. I have a pic I think they floated and this intake bridge fell off of one valve but not the other. And got stuck between the injector and valve keeper riding on the retainer. Maybe it pushed the retainer down and let the keeper pop off and drop the valve?

This was a pic before rocker assembly was removed

 

[Ne-max]

This is from spinning a crank gear. Bent all the push rods. The piston was 100% gone.

 

[zf>allison]

This is from spinning a crank gear. Bent all the push rods. The piston was 100% gone.

I have no bent pushrods, but I will pull the crank and cam gear and inspect the pins tonight. Will I need a special puller? I had one catastrophic cylinder all others just barely touched a valve. I would think all valves would be pretty equally demolished if the timing slipped.

 

[zf>allison]

And I don't think if timing "slipped" by shearing or stretching a pin, it would have hit the intake valve here and exhaust valves there, with some worse than others. And one piston has no visual valve hit mark I wouldn't think if timing slipped one piston would escape Scott free. Nor do I think it would have started to load it on a trailer but I wouldn't think it would how it is either.

 

[andy-stevenson]

I once bought a used lb7 engine. It was pulled because the engine over revved and bent a bunch of the pushrods. There was valve contact marks on quite a few of the pistons. The majority of the pushrods were bent. At least half the bridges had fallen off the valve ends. A bunch were actually all smashed up. But none of the valves dropped, no real damage to the pistons, cylinder walls or anything.

 

[zf>allison]

I once bought a used lb7 engine. It was pulled because the engine over revved and bent a bunch of the pushrods. There was valve contact marks on quite a few of the pistons. The majority of the pushrods were bent. At least half the bridges had fallen off the valve ends. A bunch were actually all smashed up. But none of the valves dropped, no real damage to the pistons, cylinder walls or anything.

Right but how that bridge landed it could have pushed the retainer down and let the keeper fall off. And that could of just floated worse. My valves hit but I don't think bad enough to bend pushrods. Some just barely hit. It's the only thing that makes total scents me as to what happend

 

[zf>allison]

I'll try to get some photos uploaded of the pistons

 

[GMC_2002_Dmax]

If it sucked in a small amount of oil, oil burns like fuel, it could have ran over the limiter.

Also the gauge uses a stepper motor, so there can be a variable between the gauge and actual rpm.

:thumb:

 

[zf>allison]

I don't think it hit a limiter one time other than in sixth gear it would fall on its face like it hit a speed limiter. It would not be full rpm and it would hit a limiter. And in the lower gears I swear it went over 4k plenty of times. Like I had had to be careful after I caught it close to 5k that first time.

 

[GMC_2002_Dmax]

All I can tell you is that is how the tune file is set-up, the Throttle Tables limit the rpm in the tunes and the hard limiter is in the ecm as a separate table.

Don't have anything else to add to it, but in all reality it let go, if a valve breaks or drops it causes that damage whether or not it revved to 3800 or 4200, it still is valve into pistons.

Your motor is one of very many that have been blown up and won't be the last, its the way it is when you push a stock motor with stock springs, rods, pistons etc.

I have plenty on guys that I know that have blown up fully built motors pushing and pushing with my tuning and with others tuning as well.

Wish I had more to offer you for a diagnosis, but I don't know anything more than you do as to the cause of failure.

Tony

 

[zf>allison]

All I can tell you is that is how the tune file is set-up, the Throttle Tables limit the rpm in the tunes and the hard limiter is in the ecm as a separate table.

Don't have anything else to add to it, but in all reality it let go, if a valve breaks or drops it causes that damage whether or not it revved to 3800 or 4200, it still is valve into pistons.

Your motor is one of very many that have been blown up and won't be the last, its the way it is when you push a stock motor with stock springs, rods, pistons etc.

I have plenty on guys that I know that have blown up fully built motors pushing and pushing with my tuning and with others tuning as well.

Wish I had more to offer you for a diagnosis, but I don't know anything more than you do as to the cause of failure.

Tony

I understand and am not blaming anyone just trying to figure it out. I don't feel it was being pushed on the first tune with a slipping clutch imho. Either way its blown up but to throw the engine aside without figuring out what caused it seems to be an expensive waste of knowledge.

 

[GMC_2002_Dmax]

I understand and am not blaming anyone just trying to figure it out. I don't feel it was being pushed on the first tune with a slipping clutch imho. Either way its blown up but to throw the engine aside without figuring out what caused it seems to be an expensive waste of knowledge.

Well obviously if it blew up on a small tune because the clutch did not hold the bigger tunes yet then it surely wasn't because you were making 600 RWHP and a rod decided to exit the side of the block.................

Since the heads were just off the truck and the failure is head related, or at least is appears to be head/valve related I would venture a guess that it is the reason.

Could the clutch have slipped and cause it to rev up a bit more so than anticipated, since the disk was only half in right and only half working per your other post then maybe that was part of it.

 

[PureHybrid]

Yea I wouldn't blame the tuning. I've ran mime up to 4400 doing a burnout, what can I say... It sounds sweet up there :spit: I should be nicer to this old girl.

BTW, I didn't read back through the thread, but had you recently removed the heads and had work done?

 

[Ne-max]

I could honestly see floating a valve being a issue. I know my 475 loves high rpms. Where with a manual you can keep in them longer.

 

[zf>allison]

I had just done head studs and grade c's. I never said it was the tuning I'm trying to understand what happend. My clutch did slip but when it reved higher than expected it was from traction breaking "same concept". whatever reason "what I'm trying to figure out" this thing blew up. Tony said it has a limiter so why would I not believe him. But something happend. And from what I can tell it experienced valve float. Crank and cam pins looked fine tonight. I'm open to any other opinions on what may have happend.

 

[PureHybrid]

If the valves/keepers had been apart while doing gaskets, turning a bunch of rpm right off the bat can kick keepers out. But I wouldn't think that much valve contact would take place when only one or two come loose.

Were the heads shaved? Maybe a tighter piston to valve clearance caused issues, especially if the valve wasn't recessed after the deck was shaved.

 

[zf>allison]

7 thousandths was shaved off the heads.

 

[pizza pig]

7 thousandths was shaved off the heads.

damn... were the valves done when they decked the heads? valve springs?