piston distruction

[chevyCowboy]

well i got the block tore down today and here is what i found.
3 pistons where cracked 3,7,4. #4 was completly destroyed the pics tell it best, the wrist pin did some damage to the cyl walls i think its going to have to be sleeved. the heads have some small cracks that i can see between the valves idk if they can be fixed or not.

 

[btfarm]

Good Job breakin' it!:thumbsup:



J/K

 

[DieselSlug]

Wow thats a nice little petrie dish you turned that piston into. What exactly is the story that happened here (sorry i have been away very busy with school and work). WHn i rebuilt my engine i had a burnt piston, about the size of a dime on the bottome in between the recessions.....

 

[chevyCowboy]

more pics

 

[chevyCowboy]

lost 4 quart of oil in a week and a half. started hard one day after work heard a slight knock it kinda went away and then came back bad and got worse i was in the middle of an intersection so i had to keep going till i got to the shoulder and i shut her down and had it towed home. might have caused more problems but i fired it back up to drive it in the garage i was cold as heck (think it was near 0 that night with a strong wind) and its kinda up hill.

 

[chevyCowboy]

Good Job breakin' it!:thumbsup:



J/K

ya i always say if you ganna do something do it right

i just hope the block is fixable

 

[bk95td]

Wow! Looks worse than any that I've taken apart. If you feel like driving to minnesota, I could fix you up with a block better than yours looks for pretty reasonable. Shoot me a pm if interested.

 

[bison]

wow,its amazing you did'nt break a rod

 

[3500GMC]

Mercy....I'd venture a guess the whole thing is scrap.

 

[chevyCowboy]

going to see what a mechine shop says this week its a 599 block so i would like to keep it if i can. A buddy of mine has had 3 cyl on his sleeved and it seems to be going ol for him. has any one had any experince with that?? didnt get a chance to check the bottom end not sure if there are any cracks down there.

 

[Turbine Doc]

Dare I say this but some have had success with sleeving a block if rest of it is sound.

 

[Crankme69]

Dam sure making me think about leaving my 200K mile motor STOCK that is for sure...:rolleyes5:

 

[chevyCowboy]

mine was stock other than cooling mods and advancing the timing a couple degrees. im not sure how the pistons got cracked but im almost positive thats where my oil went and then that one wrist pin froze in the piston and that was the end of the story. at lest thats what i think must have happened

 

[vail426]

Dam sure making me think about leaving my 200K mile motor STOCK that is for sure...:rolleyes5:

X2 on that. For my purposes, I have all the power I need. I've had my truck for 10 years and I want another 10. ( If I live that long )

 

[HighSierra86]

Dam sure making me think about leaving my 200K mile motor STOCK that is for sure...:rolleyes5:

Ive got 226K on my daily driver which has been chipped for a long time now, along with an exhaust, intake, and running 11psi max boost. Just thought id throw that out there

 

[Crankme69]

Ive got 226K on my daily driver which has been chipped for a long time now, along with an exhaust, intake, and running 11psi max boost. Just thought id throw that out there

Thanks for sharing that, I'm prolly gonna start another new post hoping for some pros & cons on this very subject. :thumbsup:

Cowboy I hope you get it back on the road real soon.

 

[SmithvilleD]

I'm not familiar with how/what cability the mech. inj pumps have to vary injection timing. Understand the cold temp advance mechanism.

Do they have some type of mechanical inj timing curve mechanism/linkage in the pump? Any PCM timing control mechanism?

As engine load/cyl pressures increase, combustion proceeds faster. So for a given timing advance, the cyl pressure peaks earlier in the cycle. So an inj timing advance that gives a little performance/efficiency bump over the stock timing curve at lower loads, might result in the peak cyl pressure happening too early at higher engine load/boost.

I've heard this described as "negative torque" if combustion starts/proceeds fast enough to build significant pressure while the piston is stilled headed up approaching TDC.

The PCM timing tables in the DS4 (electronically controlled inj pump) truck's will have compensation factors that pull timing advance back a bit, proportional to eng load.

 

[Matt Bachand]

A good tune should lower EGT's aiding to engine health, and optimizing shift points, also aiding to engine health.

Your right foot can kill any engine, chipped or not.

 

[Slim Shady]

That folks is fuel induced failure. That can be caused by turning up the pump to much or the cold start advance being on all the time or the return line check ball being stuck in the housing causing high IP internal case pressure.

High case pressure causes advanced timing. everything else is mechanical, rebuilt and played with more of these pumps than I care to talk about.

The fuel metering shaft could also be worn but that would cause an erratic idle, and uneven or elevated fuel levels through the whole range.

The extra fuel causes high heat temps and swells the tops of the pistons. The tops of the pistons separate at the ring lands when the piston expands in the bore enough to start sticking resulting in the top pulling off. Have saw it before, a few times.

 

[midniteplowboyy]

mine was stock other than cooling mods and advancing the timing a couple degrees. im not sure how the pistons got cracked but im almost positive thats where my oil went and then that one wrist pin froze in the piston and that was the end of the story. at lest thats what i think must have happened

Didn't you turn the fuel up also, that advances the timing even more.