Diesel runaway carnage

eric28miller

Newbie
Aug 12, 2016
24
0
0
Iowa
Like the title says, I had a terrible day.. So I bought a rolled lbz duramax, was working on getting it running so I could pull it into the shop to start body work. Was running perfect, letting it warm up, been sitting a long time so I was easing into the throttle to clean things out when all of a sudden the rpm's sky rocketted to what sounded like 10k rpms. I quickly tried to shut it off which obviously did nothing. By the time I ran around and pulled the intake off to shove in my shirt it died on it's own. So it only over revved for 12-15 seconds, although it felt like minutes. I right away knew oil must have ran into the intercooler while it sat upside down. I've had this happen with turbos going out on equipment once the oil was hot enough, but I never would have guessed it would runaway on cold oil, I was very very wrong. :violent: I keep beating myself up over this costly mistake..but I gotta quit looking back and move on towards getting this motor fixed.

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So far I have the passenger side injectors pulled and valve cover off. Nozzles are toast and multiple bent pushrods. I'm picking my buddies borescope up later to inspect the pistons which I suspect are cooked. I'm praying that the head is ok..
 

Burn Down

Hotrodder
Sep 14, 2008
7,092
28
48
Boise Idaho
Ouch... Not sure many of us would have thought of that either. I wouldn't beat yourself up to bad. Be a great time to throw those 2 piece pistons in the trash and run some LLY/LB7 or Fingers Oval's:thumb:
 

JoshH

Daggum farm truck
Staff member
Vendor/Sponsor
Feb 14, 2007
13,711
772
113
Texas!!!
That sucks. If it makes you feel any better, a friend of mine that owns a body shop and is constantly buying and selling wrecked trucks did the same exact thing once. Now he always pulls the intercooler pipes loose and checks for oil before he fires up a rollover.
 

eric28miller

Newbie
Aug 12, 2016
24
0
0
Iowa
Thanks for the condolences, think everybody hurts to see the death of a perfectly good duramax:violin:
I just got done peeking inside with the borescope. It was hard to see much but I could definitely tell the valves kissed the pistons. Though I didn't see any signs of melting on the pistons so hopefully the cylinders are ok. Now i'm very worried about the heads being ok.. Think the valves could have bent or do the pushrods have enough give to bend before damaging a valve?..
 

clrussell

pro-procrastinator
Sep 23, 2013
5,928
399
83
Thanks for the condolences, think everybody hurts to see the death of a perfectly good duramax:violin:
I just got done peeking inside with the borescope. It was hard to see much but I could definitely tell the valves kissed the pistons. Though I didn't see any signs of melting on the pistons so hopefully the cylinders are ok. Now i'm very worried about the heads being ok.. Think the valves could have bent or do the pushrods have enough give to bend before damaging a valve?..

Valves that touched pistons = scrap metal
 

ALLY Fox

Old Man Truck
Dec 14, 2010
434
0
0
Oregon 7S5
I know it's a little too late but you can make a cheap temporary air shutoff using a manual RV black tank dump valve, just get some heavy Fernco fittings or whatever to adapt it into the intake tube if you have a diesel that might have some oil trapped in the intake.
 
Oct 16, 2008
948
12
18
Idaho
Thanks for the condolences, think everybody hurts to see the death of a perfectly good duramax:violin:
I just got done peeking inside with the borescope. It was hard to see much but I could definitely tell the valves kissed the pistons. Though I didn't see any signs of melting on the pistons so hopefully the cylinders are ok. Now i'm very worried about the heads being ok.. Think the valves could have bent or do the pushrods have enough give to bend before damaging a valve?..

Valves that touched pistons = scrap metal

Depends. I've had several engines apart that were fine but had valve "witness marks" in the carbon on top of the pistons. If it didn't take a beating, I'd say there's still a chance they aren't toast.
 

N2BRK

Well-known member
Dec 31, 2009
2,054
371
83
For what little it's worth, you have my respect for coming in here and owning up to the mistake. The egg on your face is washed off by knowing that you may have prevented others from making the same mistake. Thank you, Sir.

Wally
 

Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,661
5,808
113
Phoenix Az
As long as the valves didn't drop into the cyl, you will be fine on the heads. A severely bent valve will show in the piston as a heck of a hit/indent. Then I'd worry about the head

9/10 times the heads need full rebuilds anyhow cause the valve guides wear out quick in these trucks. So really, besides the normal decking, cut valve seats, guides, check spring pressure, check for leaks, ect, your just adding some valves to the list
 

Max Attitude

11SIX
Mar 7, 2012
814
0
16
Caledonia, MI
Same thing happened to a guy I know who bought a '13 rollover to rebuild. He had been driving it around earlier that day but the second time it took off. Lucky for him he only bent push rods.
 

eric28miller

Newbie
Aug 12, 2016
24
0
0
Iowa
Thanks for the help guys! I definitely need it with the very little experience I have with these engines, whole different ball game than a cummins. I just joined a few days ago and have already learned a large handful. Sounds like it's a good time to swap out the pistons for lb7's. Now i'm wondering what else I should have done while the motor is pulled out. It's is completely stock, never touched, which I was very happy to see. With 173K miles I knew it would have a lot of life left. Problem is I have every man's addiction to seeking more horsepower :driving: But I gotta do this on a tight budget.. There's some overhaul kits and used pistons on eBay, but ebay kits make me nervous. Do you guys have some vendors you recommend contacting?
 

tmartin000

Member
Feb 2, 2009
30
0
6
Thanks for the help guys! I definitely need it with the very little experience I have with these engines, whole different ball game than a cummins. I just joined a few days ago and have already learned a large handful. Sounds like it's a good time to swap out the pistons for lb7's. Now i'm wondering what else I should have done while the motor is pulled out. It's is completely stock, never touched, which I was very happy to see. With 173K miles I knew it would have a lot of life left. Problem is I have every man's addiction to seeking more horsepower :driving: But I gotta do this on a tight budget.. There's some overhaul kits and used pistons on eBay, but ebay kits make me nervous. Do you guys have some vendors you recommend contacting?

Whatever you ultimately choose, I, for one, would love to see you through the process!

Please let us watch through pics along the way. :thumb:

Thanks for sharing your experience thus far. :hug:
 

Bustedknuckles

Honey Badger
Sep 25, 2010
1,308
2
38
33
Hagerstown MD
Swap the pistons for cut lb7 ones. Key the cam and crank, put upgraded valve springs and a pinned water pump on and you will have engine that will hold 600 hp for a long time!

Sent from my SM-G930P using Tapatalk
 

eric28miller

Newbie
Aug 12, 2016
24
0
0
Iowa
Its just another cummins swap that i got way too carried away with.
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Heres how far i got on saturday morning
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Oil jus kept poring out the intercooler..

Ill probably key the crank and cam but whats this "pinning the water pump"?


Sent from my iPhone using Tapatalk
 

Burn Down

Hotrodder
Sep 14, 2008
7,092
28
48
Boise Idaho
Cummins or not that truck is sweet:thumb: Mind posting more of the build pics? I have a little white 84' Short Bed that will be getting a LLY stuffed in it at some point.