Stripped injector base?

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
2,198
Reaction score
2,194
Location
OR
Here's a good diagram I found on the forums here. What I refer to as the retainer is listed as the nozzle cap here. It simply threads on to hold the injector tip to the injector body. If it becomes unthreaded, it can't simply fall into the combustion chamber, just the tip pokes through into the precombustion chamber.
On my dud engine the retainer broke and it just dumped a crazy amount of fuel and torched a hole.
You must be registered for see images attach
 

Brian VT

Full Access Member
Joined
Oct 25, 2021
Posts
974
Reaction score
557
Location
Maine, USA
Thank you for that. I was just looking at my old injectors to try to figure out what was being talked about.
So it seems that even if the retainer/nozzle cap was loose I still don't know why 1/2 a turn of the injector body didn't seat, or start to seat, the body on the head.
Where did yours torch a hole?
And if my retainer/nozzle cap is loose how to tighten it properly without doing damage?
 

ROCK HARVEY

Full Access Member
Joined
Oct 3, 2021
Posts
417
Reaction score
372
Location
Dayton OH
I’m betting they backed out. I would use a torque wrench on one of the easier to reach injectors, then grab it with a wrench to see how tight it feels. Basically “calibrating” your hand wrenching so you can get the harder to reach ones close to 35-40 ft lb.
 

gandalf

Senior Member
Joined
Jan 21, 2005
Posts
3,877
Reaction score
1,070
Location
CA &/or Maine
Good info.! Thanks.
So the bottom half of the injector might be ready to drop off into never-never land? (I'm not sure how they go together)

The bottom half won't drop into never-never land. It won't drop into the pre-chamber because of that copper washer. It will stay right where it is now. The trick is getting it out of that bore hole. If no one sends a picture and instructions I'll do so tomorrow evening when I'm home. All pictures are on my home desktop system. Extracting it isn't hard. You simply have to sacrifice an injector.
 

Brian VT

Full Access Member
Joined
Oct 25, 2021
Posts
974
Reaction score
557
Location
Maine, USA
Thank you for the offer.
We don't even know what I've got going on.
From my attempted fix on the road it felt like the injector threads, or the head threads, were stripped.
That's all we know until I dig into it further.
I just posted here hoping that someone would tell me that the injector threads were softer/sacrificial and I could sleep well knowing that I wasn't looking at possibly repairing the head threads.
 

Brian VT

Full Access Member
Joined
Oct 25, 2021
Posts
974
Reaction score
557
Location
Maine, USA
Before I dig into fixing this...what are the odds that the injector threads are stripped and not my head threads? Those injectors seem to be made of pretty stout metal. So I'm afraid of finding out the worst news. And then what?
I thought I was being to-the-point in my original post but got a lot more info. (and speculation ;-) than anticipated, but not much opinion on the screw threads. But lots of good, related, info. for future reference. I am grateful for that. The knowledge sharing here is fantastic.
Thankfully, there's PBR to help with getting to sleep and not worrying that my head threads are stripped.
 

Jesus Freak

Full Access Member
Joined
Apr 3, 2022
Posts
3,206
Reaction score
3,611
Location
Crestview, FL
I thought I was being to-the-point in my original post but got a lot more info. (and speculation ;-) than anticipated, but not much opinion on the screw threads. But lots of good, related, info. for future reference. I am grateful for that. The knowledge sharing here is fantastic.
Thankfully, there's PBR to help with getting to sleep and not worrying that my head threads are stripped.
I thought you were very "to the point", but when you get this many professional, shade tree, and armchair jockey mechanics in one place, boy howdy! The speculation! And not mention the PBR!
 

IDIBRONCO

IDIBRONCO
Joined
Feb 5, 2010
Posts
12,237
Reaction score
10,925
Location
edmond, ks
got a lot more info. (and speculation ;-) than anticipated, but not much opinion on the screw threads.
Well here you go. The threads on top of the injectors are softer than the threads inside the nuts on the ends of the injector lines. I see no reason at all why the injector threads that go in the heads would be harder than the ones in the head itself. You still won't know until you pull the injector out and look at it, speculation or no.
 

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
2,198
Reaction score
2,194
Location
OR
There's no real way to tell when one of those nozzle keepers will come loose. It's pretty darn uncommon.
Honestly I had no idea my engine had any issues until I pulled the head and saw the hone damage. I had pulled the head because it was seeping oil and combustion at the right rear most part of the passenger head gasket.

I still have that bad injector. If I find it I'll upload a photo of it. But when I originally had the engine before loading it into the truck, I had installed new sealing washers and a fuel return kit. When I pulled the injector after suspecting a failure, the bottom half of the injector stayed in the bore, and just the body came out.

I guess we're at a point where you should pull your injector and see what comes out.
 

Brian VT

Full Access Member
Joined
Oct 25, 2021
Posts
974
Reaction score
557
Location
Maine, USA
Well I dug into it tonight.
Nothing is stripped. I guess the injector had just backed out further than I would have thought so I guess I should have kept turning it in before driving it home like that and risking a fire and I dunno what else.
I'm not sure why the injector would have backed out.
One of the results were that one of the hose barbs on the return cap was partially melted off. Another was the base of the injector hole was pretty dirty. I tried to pick the copper washer out but got nothing. So I got a long bolt that would "thread" into the i.d. of a washer and tried pulling. It felt like I got it loose but nothing came out on the bolt. I looked down the hole again and saw what looked like a loose chunk of carbon. I put some grease on a Q-tip and taped that to a longer rod and fished the piece out. It turned out to be 1/2 of a washer.
I don't know where the other 1/2 went. I'd like to hope that it came out with the injector and fell off shortly after and I didn't notice it. Or maybe it's inside waiting to do damage. Or maybe it's soft enough that it got chewed up and spit out.
The base of the hole looked okay so I cleaned up my injector and put new grease and o-rings and a new return cap on it and stole a used copper washer off an old injector. I installed it and stated the engine.
It seems to be running fine. Of course, the new cap and o-rings are leaking, ugghh. But at least I'm not looking at trying to fix stripped head threads.
Thanks for all the replies.
I guess I'll plan on installing my new injector lines this weekend. If I can get new washers in time I guess I'll pull all my injectors and try to torque them to spec. in case that was why this one backed out?
And replace 36-43 o-rings in the process. lol
 
Last edited:

Nero

HD Diesel nut
Joined
Jan 3, 2022
Posts
2,198
Reaction score
2,194
Location
OR
Chances are with all the combustion sneaking out it may have melted the washer. Does it look melted or fractured?
A little carbon falling down won't hurt the engine. Try to get most of it, but don't stress it.

I also found that injector. Attached are photos for your viewing pleasure. Glad yours didn't do this.

You must be registered for see images attach
You must be registered for see images attach
 

Brian VT

Full Access Member
Joined
Oct 25, 2021
Posts
974
Reaction score
557
Location
Maine, USA
I had sent my old injectors to Accurate Diesel to have them test how bad (or good) they were and at least one the nozzles will now unscrew by hand like that one. I don't know if it was like that when I sent it to them.
 
Top