Thoughts on Injector Cleaning

[tangofox007]

I am attempting to evaluate the benefits of periodically cleaning diesel injectors. By "cleaning," I mean disassembling and brushing/scraping as specified in the MB 617.95 Engine Manual. I notice that one vendor sells a small tool kit for the job.

Can anyone provide any insight? I am more than happy to put forth the effort to do the job is the benefits outweigh the risks by a reasonable margin. I just don't wnat to open a can of worms if it is not justifiable.

[dieseldan44]

I asked the Bosch shop I go to about this when I had my injectors rebuilt for the 82. They mentioned that if an injector is working properly and has been in operation for under 100k, do not touch it and that 'only bad things can happen'.

They were of the opinion that a preventative pop and spray test every 25k would be ok to do, but probably overkill, and if any showed issues to then clean them.

They thought the best preventative maintenance was to use a good injector cleaner additive (they carry Stanadyne stuff) or to use biodiesel at least occasionally.

dd

They are right, taking them apart 'only bad things can happen'.

Even the acids on your fingers can etch the unprotected nozzle metal and ruin them.

[aklim]

I had mine taken apart at 100K. Actually only 1 was taken apart. The other 5 passed pop pressure and spray pattern test. At 200K, they passed the test but I wanted to go with Bosio nozzles since they were getting long in the tooth.

[Diesel911]

The stock Nozzles have a Tiny central hole drilled thought the center of the Pintel. If these get plugged up (as happened on my car) in effects your idle. Ounce they are plugged the holes have to be cleaned by hand with the correct size music wire (what size to use is in the Factory CD Repair manual). If you do not use the right size and strength of wire you can enlarge the hole or break the wire off inside.
Probably if you do that Diesel Purge on a regular basis you can keep the holes cleaned out so they do not plug to begin with.
Any time the Injectors are taken apart the parts for the individual Injector should be kept with that Injector and the flat surfaces in side of the Injectors should be Lapped flat again before they are assembled again.
Pic of the holes

I have seen the kit sold by M-source and doubt if it is of much use. We had no such kit when I worked in a Fuel Injection Shop for any Injectors except the skinny Caterpillar Pencil type Nozzles.
The Pencil type Nozzle kit had a scraper that goes inside of the Injector and was supposed to clean out the internal seat in side of the Nozzle. It would only help maybe 1 out of 100 nozzles.
The reason is that when the Nozzle Pintel is opening and closing (up and down) bits of carbon and even bits of metal get trapped between the Pintel seating area and the seating area of the Nozzle and hammer themselves into the seat pitting and eroding the seating area.
No manual cleaner or scraper can fix that.
My Boss even bought some equipment to regrind and Lapp in the Nozzle and Pintel seats on Detroit Diesel Injector Nozzles. Even with this equipment only about 1 out of 4 nozzles could be reused.

[tangofox007]

Thanks to all who responded. It looks like the risks exceed the benefits, so I will let those sleeping dogs lie.

[aklim]

Originally Posted by tangofox007

Thanks to all who responded. It looks like the risks exceed the benefits, so I will let those sleeping dogs lie.

Question is how many miles you have. Nothing wrong with taking it out and having it tested. In my case, with 1 out of 6 bad injectors, I think I gained about 1 mpg after it was cleaned at 100K. So it might be worth it. This is why I don't like additives and other snake oils. They will never tell you how your injector is. I compare them to sweeping the room in the dark. You might think you got it all but you will never be sure. Turn on the light and you will know for sure. In this case, the test will show a good or bad pattern. No ifs, ands or buts about it.

[Caduceus]

I just cleaned my injectors today and i was very disappointed to see that all the pintle holes were open and clear. My injectors are original and my car is very high mileage. I thought for sure that I could get some improvement from the cleaning but alas they were in pretty good shape.

But I did tweak the "cam phasing" on cyl 1 after I put it all back together and was able to stop the pinging noise I always heard at idle and now the engine doesn't rock at all anymore! super smooth!

[brainlair]

This seems like as good a time as any to stop lurking and post....

I obtained a beautiful 1984 300SD with 351K on it from JohnHef a few months ago, and he's been good enough to help me get some DIY maintenence experience. Anyhow there's a decent diesel shake at idle, and since it as far as we know it has the original injectors, I'm going to check all the pop pressures and spray patterns. To that end I just built a diesel injector pop tester out of a bottle jack as per the instructions here (but I tapped the jack nut for 3/4" NPTF instead of welding) and just pulled the injectors from a dead 617 John had on the floor of his garage last weekend. My plan is to check all 10 and put the best 5 in the SD (possibly grinding down/ shuffling shims if the pop pressures are too far off from one another).

I've been thinking about injector cleaning since i'm going to have them out anyways and can experiment on the spare injectors before I pull the ones from the SD... I saw the cleaning instructions Diesel911 referred to in the manual but i'm a little leery about marring the lapped surfaces where the needle and nozzle body meet.

Have any of you guys tried/ heard of someone trying to clean the disassembled nozzle components using acetone in an ultrasonic cleaner? I've got one in the lab that I work in, and was thinking I'd give that a shot unless one of you can come up with good reason not to. It seems like an ideal solution for getting carbon deposits out of the nooks and crannies without messing up the lapped surfaces any more than they already may be.

Also, do any of you know where to find ISO 4113 test oil? I'd rather not use diesel in my pop tester if i can avoid it.

Thanks in advance, i'll post some before/ after pictures of spray patterns once the whole process is done.

[aklim]

I don't know about that model of engine but it cost me $70 to get mine done. That was including testing 6 injectors and finding one bad, disassembly and cleaning, reassembly and retesting. The prices were the same or about the same from 2 yrs ago. This time, I decided to just have them tested and they were ok. I did it just for fun then I told them to go ahead with installation of the Bosio nozzles.

[badgator]

I bought a new Bosch Nozzle cleaning kit on Ebay about a week ago for $20 shipped, Late last week I bought a Harbor Freight 1 1/2 qt Ultrasonic cleaner on ebay for $55 shipped, I rec'd this yesterday and this has FAR exceeded my expectations. After cleaning with both my "new" 83 300d runs very smooth and quiet. I bought it not running, switched the IP as 1 port was not pumping, and then switched injectors as the car would still not start. (I have 2 spare motors) With WD-40 in intake it tried to run but I until I really cleaned the injectors it never started . Finally the 300 springs back to life, runs super smooth, has much more power than my 85 300sd as PO tweeked the ALDA!

******** AZ finally has the Bosch afterglow kit back in stock for $97 shipped so I will wait to clean the inj and change GP on my 300 sd

Along with $18 tie rod assemblies, $22 steering stabilizer, 2 window track kits $15, bunch of small parts.

[badgator]

Anyone have any ideas on plating after cleaning? Something easy - chromate, black oxide to prevent rust? I will try to document the cleaning process with before and after pix as they will be pretty dramatic!

[brainlair]

Awesome, I hope that cleaning my injectors leads to a similar improvement.

What surfaces do you want to plate, and why? I can understand possibly wanting to plate the exterior of the injector body that would normally be exposed when you pop the hood for cosmetic reasons, but it seems like plating the surfaces that would normally be exposed to high pressure diesel would be asking for trouble, since it could wear off and clog the pintle.

What were the injector parts immersed in when you used the ultrasonic cleaner? I was thinking I'd use corn oil if I wanted to be gentle, and acetone or some other solvent if I wanted to be more aggressive.

When you cleaned your injectors, did you try the two cleaning methods (manual and ultrasonic) independently so that you could disentangle what the most important part of the process was? Did you check the spray patterns and pop pressures before and after cleaning? I'm just really curious what made your engine run more smoothly and why.

[badgator]

I want to plate the outside to prevent rust
I used water first and it worked great. DO NOT use a flammable liquid!

I disassembled ONE at a time, DO NOT mix parts as the are calibrated! but had all injectors in to clean initially. To speed up the process I did gently scrapped off heavy carbon after cleaning for 15-30 min. 2 nozzles were carboned? into the inj - cleaned 1 hr + gentley tapped out on outside edge of nozzle, DO NOT damage the pintle / tip of the nozzle! 1 nozzle pintle was totally siezed in nozzle , 1 hr clean = pulled out. Then I use WD40 to reassemble.

[brainlair]

Yeah, I know the ultrasonic cleaner manual says not to use flammable liquids, but we've found that suspending a beaker with ~100mL of acetone in water such that the beaker does not touch the walls is safe enough (or at least it has been for the last few years). We do that to prep metal parts for vacuum and it strips everything, including anodized coatings from aluminum.

I think it would be more of a problem if ours had a heater. It all depends on what the flash point of the liquid you're dealing with is....