Replacing injectors

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Mar 10, 2019
melbourne, Oz
I am not a mechanic but I have just changed my second set of injectors in my limited mechanical experience on my 2h. First time was years ago on a b engine in a bj40, rip. I must have fluked that one as I do not recall any issues and being very easy, but I am losing my mind slowly.

I thought a list of recommendations for guidance as there is certainly a leap between talking about paint colours, seats and working on engines especially high pressure fuel lines. There is gap on mud between very experienced, to folks who want to have a go and understand.

1. Prepare as if going to war.

2. A set of clean tools, almost separate from the ones used for dirty drive train work. Or clean them.

3. Air compressor is your best friend, to clean and find leaks.

4.Do not underestimate soft fuel line leakage. May as well replace the hoses along with good non mar soft hose clamps.

5. Good lighting.

6. Glasses if you need them.

7. Vacuum cleaner and little 4 and 6mm tube attachments, step down hoses to fit, use gaffer tape to join.

8. Tap and dies which fit your injectors and return hard line hold down nuts. Never force them on and strip your thread. You will not achieve enough torque otherwise. In case you stuff up. The more you fiddle, the greater the chance to strip threads using torque. The reason why injector conditioners want to check the housing before returning deposit. The more folks who strip the threads by over torquing, the less housings are available.

9. Spare washers. The crush washers, especially the one which sits below the nozzle are single use. It almost like calligraphy, one shot. The brass washers are very robust.

10. It is probably better to use the lower torque setting at first, then you have a bit more to go if you have leaks.

11. Don't even bother going for a test drive until you are absolutely certain there is zero leakage, after thorough bleeding of filters, pump, injector lines.

12. various sockets and crows foot which fit injectors and lines.

13. very easy to damage your engine, drop stuff in the cylinder, strip threads. Far more difficult than just changing spark plugs!

14. good reason why diesel mechanics charge a bomb. For a job only done every 100000km, it is worth considering for simple peace of mind..

15. Have plenty of juice in your tank, I recall some friends idling and revving for hours seeking leaks.

16. maybe the uv die and black light torch could be a really good thing if you can find exact location of leaks. Anyone got a good priced brand?

17. removing glows and pumping the injectors with the starter is an excellent technique. Thanks Rosco.

Please anyone, add more.
Very much liked the list....and I am still laughing at the "prepare for war". I have a bj70 with 420,000km and was going to do the injectors this month. This would be my first time so I don't have advice for you other than PSP (patience, swearing and patience). A request: if you are able to take a few pictures of your process/progress, it could be helpful for the newbies like me. Thanks and good luck.
Personally, I would learn some driveline stuff first such as brakes and wheel bearings plus more, before launching into injectors. Not sure of your experience.
For me , I feel like I kind of have to learn as the next step of intimate relationship with my cruiser.

Proper steer knuckle bearing preload, Clutch, diff, steer box, Transfer, transmission and engine are the next steps for me once I have nailed understanding of injectors and lines. Fairly long list!

I got an elcheapo pop tester, it is a piece of c@#p but has some potential to make it work proper with a better liquid filled gauge and pressure tap. There is a merc mechanic merchant who is rebuilding them to make work and then reselling them.

I would not touch an injector pump besides the diaphragm and out source the rebuild service of that one , due to the involved equipment necessary to test it..

I would love to know how many folks have taken diesels to the doctor after having a go themselves! Finding a leak and fixing it can take some time. Can't use, at least shouldn't use goop to seal high pressure fuel.
Of 4 x 2h's I am pulling, 2 sets of injectors and lines were trashed from lack of maintenance or over torquing which kills the thread.

However, plenty reconditioned injectors seem to sell on ebay, so lots of folks are having a go.

I refrain from posting pics of injector replacement process as folks rather look at the pics than read, I am not an expert. I generally have posted pics of my stuff ups with questions.
I have a bj70 with 420,000km and was going to do the injectors this month.
The FSM has it all. I find changing injectors only a little harder than doing spark plugs. Where you can run into problems is where other eager beavers have damaged some of the components.
Yeah, if I didn't stuff up, I wouldn't have had to fiddle, as fiddling increases the chance to stuff up more! Putting on, taking off the return line each time and re-torque. My stuff up post is 'dropping metal in cylinder'. I redid the job again to make the brass washer 2.2mm to compensate for the aluminium washer compressing down.
Very good lessons, so all good. I would be much better at it next time and look forward. Also very happy I was not 50kms walk to civilization.

That removing the glows trick is almost worth doing just for the visual! V cool.
how's this?! I went to order some spare washers from dieselsystemsaustralia, and they have suddenly run out! is there silent lurkers out there
I would also add a concluding ramble.

Do not over tighten the return line aluminium crush washer. In my 1980 2h manual, it does not state how much the return line holding nut should be tightened, the injector line with the olive to injector is 27ftpounds, which is not much. Aluminium is very soft, so you only need a minimum tightness for these guys, if you over torque them believing they too, need to be 57ftpounds you can damage the little holes in the aluminium, even worse damage the injector thread or warp the injector return washer plate, over torquing also invites the nut to fuse to the return washer plate. The return line is going to leak. Thankfully it is not on the high pressure business side of the injector. I have learned just to snug them up progressively whilst searching for leaks.

I met an old school biodiesel friendly diesel mechanic. He mentioned the most important washer is the lower horse shoe washer, the fat 3mm brass washer is predominantly for height of the injector. If you get the height correct, your horse shoe washer should squish correctly and seal with the correct torque, as long as any hard packed carbon is removed from the port to the precups.

I have become a bit wary of ebay injector rebuilders. I cracked one open to have a look. He just used the fattest spring shim and ground the spring to get the correct pressure pop. I did not trust him , when I saw this. Is it even properly calibrated?. Whilst this maybe ok if you did not know, but, at the very least, a new spring will have to be sourced for the next rebuild. Just not good practice. If one is prepared to take short cuts or cheap out, where does it end?

I have experimented with el cheapo pop testers, they are not reliable. Straight from the unboxing I had to pull apart the gauge to put the needle on the correct side of the zero resting arm. C@#$!. why do they bother making rubbish besides a quick short term buck? ebay reviews do not give the time to use the thing first. At this stage it does get close to a calibrated injector, they kind of work for opening pressure, spray pattern and dribble.

There is a reasonably priced bosch pop tester from dieselsystemsaustralia, which comes with legible and comprehensive instructions upon servicing injectors. But even then, they require recalibrating at least every second year . They also have a tendency to gum up when not being used. There is expensive calibration fluid to buy to remedy this.
Also sourcing the 20 sizes of shims is not easy or cheap, unless you buy bulk. It is possible to cut up feeler gauges to tension injector springs, pending upon how 'howyagoin' casual you are.

But I have finally concluded after a full circle that paying for the service of a diesel mechanic with properly calibrated testers, who uses the instruments, fluids, cleaning apparatus frequently is actually worth it. Also, it is more pleasant for the mechanic to work over a bench rather than adopting 20 different prolonged yoga positions to work on parts in the engine bay of a vehicle which is not his own. They shall do a better job with better equipment, and you can do another job just as expensive in the mean time.

I tried ultrasound cleaning the injectors, bought special decarboniser for guns. It worked, but it all adds up with time and money. then one can also buy some special non rusting fluid to store the injectors, as they shall rust again once you have cleaned them.

The cheapest on ebay works out close to $70aud per injector with shipping, at least he used new denso nozzles.
More expensive is $700 for the set of 6, which in the grand scheme aint too bad. Wouldn't go looking to pay more.

The mechanic I choose, charges at worse, $80 per injector and is open to trades with parts. Blue mechanic overalls, scruffy hair, one car at a time, not too many cars, not too many staff, clean, quiet, modest and organized, no website, word of mouth, phone only contact, just honest, fair, old school, no flash bs. Showed me some bulldozer injectors!

The more expensive mechanic has uniforms for numerous staff, flash cars in the front, which makes me feel like I contribute financially to his vanity and aspirations. I can do without the stubby holder and sticker and fridge magnet. He is good at what he does, fully planning never to see you again, not scared of charging for it. Personally, found him a bit arrogant. But, this type of external confidence may appeal to some customers who see themselves reflected, believing that money buys integrity.

Hopefully, all my ramblings and mistakes helps someone, keen to give back to mud, learnt much from here.

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