MyE28.com

Hi all,

In preparing to install new nozzles in my injectors, everything I have read so far about best practices indicates that one must always replace the heat shields for diesel injectors whenever they are removed. The problem is that I can't find any mention whatever for that part on an M21 engine. Neither realoem, nor the online repair manual mention them and Google searches have come up empty. There is one mention of the size of the heat shields for the M21 in this thread here: http://www.mye28.com/viewtopic.php?f=12&t=90556 (middle of page 1), but no part number is provided.

If you have serviced your injectors, what have you done in this regard? Did you find separate heat shields? If so, did you replace them? If you did, with what?

Any help would be greatly appreciated.

I guess I will respond to my own thread in case it might be helpful to someone later...

It turns out that injectors for the M21 do not have heat shields of the kind many other injectors have (those on Mercedes, for example). The nozzle end of the injector is part of the injector assembly and is not replaced when removing and then replacing the injectors. There is a copper washer a bit further up on the injector (from the nozzle end) that, having no special contour or shape, can be replaced by any standard copper washer of the same size. The local diesel shop that pop-tested my injectors after installing new nozzles had washers on hand that worked fine.

When you posted this up I couldn't remember where I got my cooper injector washers from. I just spent 30 minutes trying to find where the part number was for them since i recently bought another 524td that needs nozzles, and I finally found it. When in realoem.com you must look up a euro 524td and you will find the diagram of the exploded injector. You probably found a better solution since its quite painful paying $4 for 6 copper washers, but hey that's the M21 life for you.

http://www.realoem.com/bmw/enUS/showpar ... Id=13_1055

Part# 13532242754

Actually, the injectors *do* have heat shields, but they are installed internally between the nozzles and the nozzle holder body. These are crushed into place when the injector is reassembled.

*As best as I can tell*, the part # is BMW 13532242711, or Bosch 2430190002. O.D. 13.9mm, ID 7mm, Thickness 1.15mm

See Part #5 in this image from http://www.realoem.com/bmw/enUS/showpar ... 3532242711 :



I just need to verify this is correct (you never really know until you actually have them in hand). Note this is different than the 21x17.5mm copper washer that sits between the injector and cylinder head.

Problem is I can't find any here in the U.S. I've sourced some in France, and plan to place an order for a large batch of them to get reasonable per-item shipping. Once I get them in, I can post them up for sale here on mye28.com in sets of 6 for reasonable cost.

The heat shields I got in work perfectly.

I installed a couple to test, and after going through a full tank of diesel I pulled the injectors to inspect. The heat shields did their job.

So, for anyone who needs to rebuild their injectors, you MUST replace the old heat shields with new ones (re-using the old ones will NOT work, trust me).

I have the correct heat shields and can provide a set of 6 for $7 shipped in the U.S. I also have the proper copper sealing washers, which I can provide properly annealed and ready to install for additional $5 for set of 6. No matter how long it's been since I made this post, assume I still have them available and just PM me.

-Jason

Here's what they look like. The heat shield is on the right. The copper washer is on the left

Just sent out a PM for some.

Next question is which directions the shield go. Does the bowl need to be a "mountain", or a "valley" when dropping into the cylinder head?

Also, somewhat unrelated, how reliable are these pre-combustion chambers? Obviously dieselboost has done some gnarly stuff but doesn't mention pre-chambers going, only headgaskets. It seems like there's no documentation on those. Where as on om606 and om617 (don't quote me, you get the idea) MB diesel have ways of removing those chambers via giant nut and then a slide-hammer etc.

Here's a cutaway illustration with what I think the orientation of the heat shield is (pardon the drawing, I'm not an artist)

AWESOME that's perfect.

Interesting that the placement of the nozzles when comparing to the MB injectors are quite different, despite having very similar bodies.

Bumping this for new folks.. I don't think it's a sticky (though it should be).

I received my order of heat shields and copper washers from Jason and they were shipped quickly and look great. Thanks a lot for doing the research and legwork to make these available. I won't have them installed for a while but I am happy to add them to the growing stack of parts for my rebuild.

Annual bump to let you know these are still available. Just send me a pm (which notifies me by email) since I don't check here often. My 524td is still running great!

-Jason

Jason I sent a pm on how to order hear shields. please respond my project needs them! Thanks! -Paul

noddaduma wrote: Aug 02, 2020 3:40 PM Annual bump to let you know these are still available. Just send me a pm (which notifies me by email) since I don't check here often. My 524td is still running great!

-Jason

Hey Jason, I'm looking for some washers too. I'm a newbie and can't PM you just yet. But I'm guessing you can PM me? Let me know if you still have the washers...

Thanks, Flash