TD42 injector cleaning - can it be done at home?

[BrazilianY60]

G'day!

My TD42 was fully rebuilt some 5 years ago. I drove it for about 1500 km, no issues, sounded nice. I have stopped the car for 2~3 years for body work, during which I would heat cycle the engine maybe once a month. After that, the engine spent maybe 1 year without being cranked. Fast forward to Sept/2023 when I reassembled the radiator, did a full coolant flush and restarted to have the engine working regularly again, I noticed a knock on the last cylinders area. Engine internals are brand new, so piston or bearing should not be. I have opened the valve cover to check for valve adjustments to see if anything could have an excess play that could be responsible for the hammering noise I was hearing. Actually some of the valves were a bit tight, not loose. I have adjusted them all to spec but the hammering noise persisted.

I have asked some advice to the guy from the engine shop who rebuilt it, and he mentioned that he had seen engines that stay unused for a long time, since diesel collects water, to develop some corrosion on injectors. He advised me to take it to an injection pump/injectors specialist. I will eventually have the injector pump serviced when I install the turbo kit, but my plan is to put some 5000 km on it NA to get pretty familiar and used to its behaviour and then turbo it to feel the difference, so I am not really keen to doing it before that...

For illustration, the hammering noise is similar to the one on this video. This is a very boring video and I don't recommend watching, but the hammering noise is at 0:35 for a couple of seconds only. He replaced the injectors for brand new ones and it resolved the problem.




So, question is, do people know of any engine-running cleaning method that is worth trying? A few liters of kerosene on the diesel tank or something on those lines? Or if I take the injector of the head, is there any cleaning that can be done without disassembling it that you know to be effective, at least in some cases?

[mudski]

There is many fuel additives on thr market that claim to clean injectors. But there is really only one way and that is to remove them and get them professionally cleaned.

But if you are not in the position to get them done. Im not sure if you have ever pulled a TD injector apart. There is nothing in them. An injector nozzle, some spacer shims and a spring. You could attempt to clean them yourself. But testing the spray pattern you won't be able to do without the right equipment. But its certainly doable. I would only do this if my options were extremely limited and the injectors were really bad and I needed a quick fix.

If you have access to an ultrasonic cleaner that would be real handy.

[BrazilianY60]

Thanks mate. I've been reading the Nissan FSM and the injector seems pretty simple indeed. All the magic happens between the correct spring preload (say shims) and nozzle orifices being bare-metal-clean. I saw some videos where the guy was cleaning some (not TD42) injectors with small wire brushes and other rough tools and thinking it was too much of a shade tree repair, but then, the FSM shows the same tools (and the one with a manometer to build pressure and visualize spray pattern).

I don't have any friends with diesel shops but have some with petrol/ethanol shops. An ultrasonic cleaner is actually doable. Thanks for brainstorming here with me.

I have called a couple of pump/injector shops around here and they have everything for Bosh, Cat, MWM, Mercedes pumps and injectors but very few Zexel parts. They wouldn't even check the part-number, they unanimously said to bring'em the injectors and they would see what could be done. I don't personally like when things come to these terms, you know...

[mudnut]

Thanks mate. I've been reading the Nissan FSM and the injector seems pretty simple indeed. All the magic happens between the correct spring preload (say shims) and nozzle orifices being bare-metal-clean. I saw some videos where the guy was cleaning some (not TD42) injectors with small wire brushes and other rough tools and thinking it was too much of a shade tree repair, but then, the FSM shows the same tools (and the one with a manometer to build pressure and visualize spray pattern).

I don't have any friends with diesel shops but have some with petrol/ethanol shops. An ultrasonic cleaner is actually doable. Thanks for brainstorming here with me.

I have called a couple of pump/injector shops around here and they have everything for Bosh, Cat, MWM, Mercedes pumps and injectors but very few Zexel parts. They wouldn't even check the part-number, they unanimously said to bring'em the injectors and they would see what could be done. I don't personally like when things come to these terms, you know...

I've seen some of your work on your patrols. Maybe you could build your own injector pop tester. My quick search on google found a few interesting designs using small bottle jack to provide the required pressure.