LB7: Lb7 injector stuck, bent push rod maybe more?

[Dukchunter]

Hello guys (and gals)
So had the weekend from hell last weekend. Towed the 5'er about 200 miles for a fishing/car show weekend... blew a heater hose fitting on the way but the bad news comes on the return trip. Pulling up a slight grade at about 40 mph I notice an engine vibration and loss of power look back to see thuck black/grey smoke pouring from the exhaust started to pull off the rd and the truck died rolling at about 25mph... was luckily able to get stopped off the road without smashing anything... got the truck towed and some good ole boys from a local campground offered to pull the camper there and store it till I could get the truck up and running... (thank god because the $600 tow charged for the camper was hard to swallow.)
Anyway I figured I had a stuck injector. So last night I pulled the glow plugs to figure out what was going on. Glow plug on cylinder 8 snapped off about the las inch or so... so now im thinking thats the cylinder i need to focus on and begin to be more irritated as now i will have to pull the head to get the glow plug out... i then continued to Turn the motor over with the ecm and ficm unplugged and and found out that injector on cylinder 6 is spraying fuel so now I have 2 cylinders to focus on... anyway pulled valve covers and got to injectors pulled injector #6, moved to #8 and tight as can be... long story short 30 min later finally get it out and now we are to the horror story... looked over at the rods and noticed the front rod on cylinder #8 is bent... check the rest and all are good look around a lil more and see that a retainer is gone on a valve spring and valve spring is un compressed. I then examined the injector and notice the tip came in contact with something as it is peened flat....

I'm scared of what I'll find when I pull the head. What am I getting into? How did I only bend one rod?

More info- injectors replaced 2 years ago with bosh remans from LDS currently have just over 21k on them. Head gaskets replaced last year with arp studs. About 8k miles since the head gaskets.
Oil is clean changed before our trip no diesel smell at all
Did not lift heads as far as I can tell



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[Dukchunter]

Here are some pics

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[ZeroGravity58]

Sounds like you dropped a valve. Pull the head and see but the Piston is probably trashed along with the head. Block maybe salvageable

 

[Bdsankey]

I've never seen that before. I can tell you it isn't going to be pretty as that tip probably did some damage to the piston and head. I'm betting the root cause is the keeper on the spring broke/came unseated somehow and dropped the valve into the cylinder enough to get hit by the piston. Again, all speculation, but I am guessing then the valve is what broke the glow plug.




I've got a set of 160k mile lifters, pushrods, and springs I can send you pretty cheap if you need them. they are off of a LLY.

 

[Dukchunter]

Thanks, I will get the head pulled as soon as I can and go from there... it's drivers side so it's a pain... hopefully get to it tomorrow. Praying for the best expecting the worse don't really have budgeted a rebuild right now.
I failed to mention that the truck did fire back up but it sounded like someone was beating on the engine with a wooden baseball bat

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[Bdsankey]

Thanks, I will get the head pulled as soon as I can and go from there... it's drivers side so it's a pain... hopefully get to it tomorrow. Praying for the best expecting the worse don't really have budgeted a rebuild right now.
I failed to mention that the truck did fire back up but it sounded like someone was beating on the engine with a wooden baseball bat

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Might as well just pull the motor out of the truck. It will save you so much pain trying to pull the head and to be honest, you are going to need to pull it anyway.


I've got 3 good used LLY pistons (same as LB7) that I'll give you (bent rods). The head is the only thing I don't have but I can probably source one from a scrap yard.

 

[Dukchunter]

It's not in a good spot to pull the motor atm sitting outside in a gravel lot... I might get a bore scope and stick it in through the injector cup to see what is going on and what I need to do next. Quite frankly I'm a lil aprehensive on pulling the motor as I've never don that before.

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[Bdsankey]

It's not in a good spot to pull the motor atm sitting outside in a gravel lot... I might get a bore scope and stick it in through the injector cup to see what is going on and what I need to do next. Quite frankly I'm a lil aprehensive on pulling the motor as I've never don that before.

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Honestly pulling the motor on a Duramax is easy as hell. If you've gotten it to the point of pulling injectors out you can easily handle pulling the engine.

Bellhousing bolts (9), torque converter bolts (6), motor mounts (3 bolts per side), 2 wiring harnesses, cooling stack, and boom its out lol.

 

[Chevy1925]

It's not in a good spot to pull the motor atm sitting outside in a gravel lot... I might get a bore scope and stick it in through the injector cup to see what is going on and what I need to do next. Quite frankly I'm a lil aprehensive on pulling the motor as I've never don that before.

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borescope it first. thats easy enough to do. then you can decide on if just the head needs to come off or if the whole engine needs to come out.

 

[DAVe3283]

If you dropped a valve, that piston is going to be hamburger. If you are feeling lucky (and it isn't cracked and has no holes), you can try and clean it up from the top, then put a different head on and see how long it lasts. But it will be weaker than before. The right answer is to pull the motor and put a different piston in.

If you aren't in a position where you can pull the motor yourself, you might just have to save up and pay a shop to do it. Though you might as well pull the head and see what you are dealing with while you save up. But with the valve hitting the piston, I don't imagine you will like what you find.

 

[Dukchunter]

I can pull the motor that's not the issue just have to move the truck inside somewhere.

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[valleyduramax]

My lly just did that last fall and motor is getting rebuilt now. Valve broke and dropped into piston and got slammed around. Block is salvageable but needed a new piston and head. I pulled both heads while motor was still in the truck and was not a fun time. But engine was easy to get out once I figured out what was wrong with it.

 

[WVRigrat05]

Why does it have to go inside? I did a top end job and swapped motors in my yard with minimal tools, did the heads in the dead of summer and the motor in January, bought a 10x10 canopy and put the hood in service mode, I did use a track hoe to pull the motor though lol.

 

[Dukchunter]

Who wants to roll around on 2b stone working on a truck?
Anyway scoped the cylinder and confirmed everyone's thoughts motor has to come out. Guess I'll be reading up on the how to's till I get to pull it. Now if I could find a way to get my camper the last 60 miles home since the truck is going to be down awhile I would be set

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[six5creed]

What part of the world are you in? Someone may be willing to get your camper home for fuel money.

 

[Dukchunter]

Central pa
I can't find anyone I know that has a 5th wheel

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[Dukchunter]

A local campground towed it to their campground for me and is allowing me to store it there for 3 bucks a day... not a bad deal but I prefer it not be there since I thought it was only an injector not a rebuild

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[zakkb787]

I had something similar happen but not as catastrophic. Did head gaskets and injectors and had no compression on #2. Wound up being a bent pushrod holding the valve open. Had two valves stamped in the piston. But lucked out cause the valves weren’t bent and the piston wasn’t cracked. Still don’t know what caused it

 

[Dukchunter]

Update, motor is out hopefully can pull head tomorrow after I get it on a stand and see what I'm getting into

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[Dukchunter]

Update is not good, pulled the head and we have some major issues. Basically cylinder 8 is pretty screwed. Stripping block down and seeing where I'm going from there. Sending a fuel sample out as myself as well as 6 others have said it smells like it's mixed with gas. If so it will be handled by the insurance. cylinders 2 and 6 also have metal it them I'm assuming they worked in there threw the exhaust valves as my exhaust brake was engaged as I let off the throttle to pull over.... I will keep updated

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