HELP reinstalling diesel injectors

[vanderd]

I have a trawler with two Yanmar 4LHA-STP engines. I removed the injectors and sent them out to get cleaned and rebuilt. I’ve never done this before and I’m confused about the reinstallation process. at the nozzle end there is a metal collar slid over the nozzle but not firmly attached. I also have a bag of little copper washers. I have eight injectors and 16 copper washers. I’m guessing that the copper washers go at the tip of the nozzle but I don’t want to screw anything up. I’m also guessing that I only need eight washers and they gave me spares, but that’s just a guess at this point. It cost $200 to get each injector rebuilt and I certainly don’t want to mess it up at this point. I’m enclosing two pictures of the injector tip. I would greatly appreciate any thoughts on reinstallation. Thanks in advance.

[tkeithlu]

Disclaimer - I've got zero experience with your engine.

A technique I've found useful in this sort of situation (when I didn't take photographs as I did the disassembly) is to refer to the parts catalog exploded view. Here's (I think) the right catalog. I also think the parts assembly you need is on page 17. If I'm completely wrong, perhaps you can still pursue the strategy.

https://dieselpartseurope.com/media/...-M47803_en.pdf

[more]

https://www.youtube.com/watch?v=Bg1-WtqjpW8

[vanderd]

Thank you. I did actually look at the exploded view in the manual but it wasn’t an exact match so I hesitated. I’m pretty confident at this point but I’m still questioning why they sent me exactly double the number of copper washers. Unless someone can tell me with complete certainty I’m inclined to delay installation until after the holidays in order to confirm with the rebuilder. I very much appreciate your response and link to the video

[captstu]

The injector rebuilder will be right, but my 3gm engines took one at the injector and 1 below the cone. Put a small amount of grease on them so they stay in place during the install. The washers crush slightly on install and can be used only once.

[sailcrazy]

Following. We had a mechanic remove and rebuild our 4 (Yanmar 4JH-TE), and I watched closely as he reinstalled them...but I was much more concerned about the bleeding process once they were reinstalled.

[vanderd]

This is all new to me and I’ve never had to bleed them in all my years of owning them. I’m under the impression that all I need to do is crank the engine with the high pressure lines loosened until they all leak fuel. Is it that simple ?

[sailcrazy]

A mechanic I'm not...but from what I've read/observed.....no, it's not that simple. As I understand it, a diesel will not run if there is air in the fuel lines! So after opening up the system, that air needs to be purged. If you opened at the primary filters, then that's where you need to start; the fuel goes from the primary filter, to the eng-mounted secondary filter, to the inj pump, to each injector...and that's the route you need to take. Using an electric fuel pump (if installed), or a squeeze bulb on the fuel line, or the "lift" pump mounted on the eng, whichever you have, open the first item, pump until no air bubbles show and only fuel flows, then close that up. Move to the next, etc, etc. The injectors are done one at a time, starting with the first in line. After tightening the fuel line, back the nut off just a little, pump until only fuel comes out, then retighten. And so on until all the lines and air are full of fuel only. THEN try to start...it will likely run a little rough initially, but as all the air is worked out, it will/should get smoother. And you're done! Maybe a more knowledgeable owner can confirm/correct my understanding??

[vanderd]

I’ve not disturbed any of the fuel lines other than the high-pressure lines that to each injector. Therefore, do I only need to bleed the injectors by loosening the lines that go to them?

[sailcrazy]

Try it and see if she starts??? If it does, you're good to go.....if not, I'd guess you have some air in a line. BUT...if you're in the water, and your seawater pump is working, and you crank and crank....you may very well get hydrolock in 1 or more cylinders(not good!). Crank it some, if she goes, you're good....but don't crank and crank.

[arcticmonkey]

merry Christmas to all
If I remember correctly my little 4-108 came with primary pump which made bleeding simple
don't let it know

[sinnerman]

About the use of the copper washers: ask the injector shop. They will know.

My guess is that you install one at the top of the removable heat shield and one at the tip of the injector.

Also, use a Torque Wrench to install as over torquing can distort the nozzle.

Cheers

[oleman]

I would go back to the people who took your money for rebuilding the injectors and use their technical support people for assistance in reassembly.

AND always remember the only "dumb question" is the one that you failed to ask when you needed advice.
My advice is to obtain a service manual for your engines!!
Banjo fittings have a sealing washer at the top and bottom of the fitting that is normally changed every time the fitting is removed and replaced. Tapered fittings are self sealing and normally have no washers.
Good luck with your project.

[GWilly]

On my old Volvo diesel, copper washers were used for the fuel lines. Anything rubber would deteriorate, and copper is soft enough that they worked to seal the fuel line joint at the injector. Actually, one washer for the fuel line going in, and one for the unused fuel going back.

[iabmatos]

I don't know much about Yanmar engines, but on my Mercedes diesel engine, the copper washers have one flat face and a slightly convex face, with a very specific thickness. One specific face goes against the injector and the other against the engine block. They are not "just copper washers". Ensure that the injector is properly seated when reinstalled.