Fuel Injector service

[Avenger]

Sounds right.

Good luck with all that. Most of the injectors we see from MANs are badly corroded. More often than not the nozzle retaining nuts have to be replaced because they split.

 

[Reefgeorge]

I do almost all of my own work on everything from HVAC to engine rebuilds and seldom have any trouble tackling something new, however I may need to rethink this subject since the impact (pun intended) of a mistake is big.

Thanks again.

George

 

[Avenger]

As long as you exercise some judgement I don't think it would hurt to at least try. They may surprise you and come out without too much trouble. If they don't then you can consider farming it out.

 

[Reefgeorge]

When the tools come in I'll go down there, take the fuel rails off of the most accessible bank and try one that's easy to get to.

One last thing. Is twisting the body in the bore while trying to get it out of the head/block after the castle nut comes out a good thing or a bad thing? IOW, is it a uniform press fit into the bore or are there pins, or flats, etc?

Thanks,

George

 

[krush]

As long as you exercise some judgement I don't think it would hurt to at least try. They may surprise you and come out without too much trouble. If they don't then you can consider farming it out.

Farm it out for somebody else to break it on his dime? Meh, better to just break it himself!

 

[Avenger]

George: No twisting. They'll have some kind of alignment pin or ball. You may be able to wiggle them a tiny bit which can help work penetrating oil in. BTW, these issues are not unique to MANs. We see it on Volvo's and other makes too. A lot of it has to do with the injector configuration and probably how long they've been in service and conditions in the engine space. I wouldn't assume they're one with the head, it's just something that can happen. Either way they have to be looked at sometime. Better sooner than later.

Krush: I'm with you 100% . I think the big concern is the fixing after the breaking. I don't want to think about what a head on one of those things costs. We both have a lot of experience with damage control on jobs like this. I don't know how much other people do and try not to make assumptions.

 

[Reefgeorge]

I think I have the whole picture now.

Iv'e done my share - alternators, charging system redesigns, coolers, water pumps, fuel delivery modifications, HVAC rebuilds ..... I'll decide after the first couple whether it's gonna be me or a mechanic on this one. The banks on the outboard side alone could break my spirit. 25 years old does pretzel better than 63 year old most times so we'll see. I am more stubborn than most which can compensate some.

Thanks again, I'll report back.

George

 

[Reefgeorge]

I finally received my special MAN/Mercedes fuel injector tools (one came from England). The set up is that a sleeve/socket fits over the injector body with a castle nut drive at the bottom and an attachment for the fuel line threads at the top (and the ability to draw them together). Do you know if the idea is to cinch everything up and exert upward pressure to remove the injector body while unscrewing the castle nut at the head (bearing on both sets of threads) or remove the castle nut, bear down on the head and then attach at the fuel line threads and pull the body up (bear down on the fuel line threads only)?

For the slide hammer approach that seems more obvious. You remove the castle retaining nut, attach at the fuel line threads and apply shock upwards. If I have that correct then in that case all of the force is exerted on the fuel line threads. Buggering those up would be bad but as you stated earlier, buggering up the head threads as could be possible in the first case above would be, well ...
Thanks,

George

 

[Avenger]

If the tool fits the castle nut you're not going to have anything to force against if you take the nut out.

You could try to find a compromise by putting the force on the injector line thread, but they're fairly short and you need enough engagement to prevent the threads from pulling off. You're probably going to end up using the castle nut to do the heavy lifting. It has bigger threads and can handle more force. Again, if it's an option I would pull the castle nut out first, clean the threads and use plenty of lubricant to prevent galling, then reinstall it and use it for forcing.

 

[Reefgeorge]

I got the first one out quite easily. I set the socket up on the castle nut, cinched the top threaded assembly down onto the fuel fitting threads and unscrewed the castle nut while I held the injector body in place with the Allen socket on top. The previous mechanic really lathered everything with a very thick anti seize compound. If I get any that are tougher to remove I'll do what you said and dress the castle nut threads first. That tool is the s;/$. BTW, the injectors are indexed with a pin so twisting would in fact be bad.

Now it's off to find the funky fuel line wrenches that I need to get all 8 of them out. Thanks,

George

 

[Avenger]

You should send the mechanic a Christmas card every year for that.

 

[Reefgeorge]

You should send the mechanic a Christmas card every year for that.

That's for sure. BTW, the last injector on the fwd right bank was too cramped for the longer removal tool that I started with and so I wound up using the lower right item in post 10 which is much more compact and a better choice overall if anyone ever tries to tackle this on their own. It's also the one shown in the MAN repair manual photo that I showed in an earlier post. Also, that injector was partially corroded and tougher to remove. It's right under a bunch of coolant hoses and fittings so I bet there has been some leaking. Fortunately it came out but it was a lot tighter. Once again these tools are fantastic, I can't imagine this job without them.

George

 

[Reefgeorge]

All the injectors are out. This is what the set up looks like for the removal tool. The center nut for the fuel line thread attachment is 7/8" or 22mm drive. The outer socket with the castle nut drive is 1 1/4" or 32mm drive. You fit the socket onto the castle nut, screw the center piece into the fuel line threads. Then you immobilize the center nut and back the castle nut out which forces the injector up as the castle sleeve backs out and up.

George

 

[Reefgeorge]

I decided on Diesel Injection of Martin County (John) as suggested here as apposed to the shop that Ace Marine uses because they are closer, less expensive and seemed to know what they are doing.

Thanks,

George

 

[Reefgeorge]

When you guys reinstall the injectors do you do anything to flush the fuel system to the point of injector attachment? The whole time that you are removing the fuel line attachments at the fuel pump, pieces of paint are breaking off of the nuts. I kept wiping everything and then capped the upright threaded fuel pump attachment points but i can't be sure that nothing dropped down into the standing fuel in the tubes. It would suck to do all this work and wind up with a piece of crap being pushed through the line and plugging the injector.

Thanks,

George

 

[captpl]

I would suggest when you re-install your injectors use copper (high heat) never seize... makes for
an easy removal next service. Whoever you have rebuilding your Bosch injectors make sure to spend
the extra money for bosch tips, the cheaper Monarch tips will not last as long, and will potentially
make your wallet scream when one becomes embedded in a cylinder crown.


Other things to look for on older Man diesels (they have no engine zincs) is to pay attention to your
heat exchanger - periodically remove and clean the "bundle" and inspect the tank for pitting. If you
have ANY leak at all on your oil cooler, don't over look it, that will be the most expensive 30 second
of your life, when this element fails it is catastrophic. I take a lot of "heat" for Man engines from
the crowd, but I still think they are far superior in all aspects to the GM 8v-92's they replaced.

Paul
MAN 2842 12cyl.

 

[Reefgeorge]

I already had an external raw water leak on my port transmission cooler and replaced it. I will probably do the stb next to avoid problems. 10-4 on the heat exchangers. The old injectors were coated in the aluminum based (silver) anti seize compound. I have now been advised to use that one again, the copper based one and also the nickle based (black) one. Reading the company literature does not help straighten that out so I will probably call the company on Monday to see what they recommend. The default is probably to repeat the silver colored aluminum based compound so that something new does mix with the considerable amount of the aluminum compound left behind.

Do you guys attempt to clean out the gunk in the injector bore and the castle nut threads at the top of the bore before re-installing the injectors?

Thanks,

George

 

[Reefgeorge]

I did have the rebuild service use Bosch tips.

Do you guys go to the trouble of trying to clean up those holes and threads so that you dont wind up with a piece of crud under the copper sealing washer, interfering with the threads, or fouling the tiny injector openings? Does it matter that some of that crud would be falling through the opening into the cylinder bore?

 

[Avenger]

Can't see it from here, but cleaning isn't usually a bad idea as long as you don't drop anything hard in the cylinder.

 

[Reefgeorge]

The supplier of the engines to Cabo just confirmed that I need to wipe all of that stuff out, clean up the threads and make sure that the flat surface that the copper sealing washer bears on is dead clean.

Thanks,

George