Stuck Injector Rail, 6-71 DD

Good morning gents, I have spent hours searching with no answer to be found. I have a stuck rail on a 6-71. The funny thing was it wasn't stuck yesterday. I prep'ed the engine for a run and made sure everything was working, rail movement and all. Today I hooked the battery up and checked the rail one more time and the damn thing is stuck open. I tried to pry it shut and it won't move. Any idea would be great. I will be working on it again hopefully this evening. Thanks Paul (oh yea, I've narrowed it down to one particular injector)

So what you're saying is 'one injector is binding up the rail'?
Do you have the tools (guages) to run the rack and reset all the injectors on that rail?
Check the governor linkage.

Yes, one injector is binding the rail. I don't have the tools to run the rack so I was hoping for a trick to unstick the stuck injector. The governor linkage seams to be fine. It's just that one injector. Everything worked fine yesterday. That's the strange part.

Man...I hate giving advice over the internet w/o seeing it....and it's been a long time since I've been into a 6-71....so caveat imptor.
First check for broken springs or bent linkage on the rack. Then,
I'd back off the adjusting screw on that injector until I could free the rack. If it is indeed a stuck injector then you may be able to free it up by tapping on the piston and using some penetrating oil. Detroit injectors are robust and all mechanical. If you get it free, you'll then have to reset that injector and you can use a feeler gauge for one injector.
...or call a mechanic with some DD savvy.

turns out its a stuck injector. I am going to try to pull it!

A while back one of the guys at my diesel-pump and injector shop to me to soak them in penetrating oil and they'd free up fine. This was for DD injectors that had been sitting. That might get you running and then you can replace the entire set when the time is right. You'll know more when you get it out.

update on the rail and injector. Turns out after I took off the fuel lines, took the bolts holding the rocker arms and took the retaining piece off of the injector it was still stuck. I was able to tap the other end of the "shut off" piece. The part that turns the injector off. I tapped it until it was in the off position. Than I used a pry bar to push it the other way and back and forth and back and forth. Finally it popped out. I took the injector out and worked the shut off for about 3 minutes. I put everything back together and turned it over a while and checked again. I did this several times and seem to have an operational rack. To bad my battery didn't have enough to make her start after all that. I'll try to crank it up tomorrow and post an update. By the way I have a large CO2 fire extinguisher just incase.

Clamp a pair of vice-grips to the rail for a "throttle" so you can shut her down if she runs away with herself.

If you removed the rocker arms you must check every valve clearance and re adjust ALL the injectors.

This requires a "pin" that measures the height of the injector setting.

The pin comes from DD and is engine specific , there is more than 1.

And then "run the rack" ,,adjust all the injectors to start to feed and reach full at the same time.

The complete drill should take 4-8 hours .

A book will be a great help.

FF

should I not crank the engine until I run the rack?

The DD will run even if the ejector is considerably out of adjustment. Make sure you left some clearance between the rocker arm and injector and the rack closes to full off. Have an emergency plan in place to smother the intake if the engine runs away with itself. The fire extinguisher won't help when the piston comes through the block. Crank her over.
or
Call an experienced DD mechanic as you will need to run the rack at some point. The fuel line jumpers should be properly torqued at some point too.
It's your call and your money.
I would be comfortable firing it up if it was mine just to see what I had going on. You do need to eventually pull the injectors and replace and run the rack for any long term use. Good time to compression check.

It will run , but the exhaust valves may be at the wrong clearence, and some cylinders will be firing harder or softer than they should.

I would quick check each valve that there is still clearance (so it wont be held open and burn).

Running it to warm it up a bit , so the work can be done should do no harm.

The bigger question is why an injector decided to hang up.

Spray them all with PB Blaster , Krolls or your favorite,,
then douche with 3in 1 or sewing machine oil.

Sewing machine oil , unlike engine oil , is designed to stay in place

A frequent trick if you are stuck with Ultra Low government required crap diesel is to add 1 gallon of 2 stroke outboard (K mart or cheapest) to every 100g of diesel.



FF

Update?

well for some reason the battery was dead. I hooked the cables to the 8d battery while it was hooked to the other motor and then the next day the battery was dead as a door nail. I unhooked the battery completely and it has been on the charger all night and most of yesterday. I will give her a try about mid morning. I've got a little work to do this morning.

Anode, it runs great. Turned the injector rail off and turned it over twice (about 30 seconds at a time). Turned it on and she came alive. This one runs better than the other one did. Sounds better too, this one has the new muffler and it has more bass to it. Tomorrow I am going to run them both up to temps and and try to figure out why the little genset overheats too. Everything runs though. Happy day!!

Outstanding! Gotta love those old Detroits! Get somebody to due a proper tune up before you load them up too much and they'll last you a long time.

Anode said:

Outstanding! Gotta love those old Detroits! Get somebody to due a proper tune up before you load them up too much and they'll last you a long time.

Click to expand...

Already in the works my friend. When I get the temp issue worked out I'm going to run the controls, get the alt. reworked and call the dd man with his bag of trick. Great days ahead. Can't wait to actually untie from the dock.