S38 to M21 - My first diesel

Finally, a home for all you 524td oil burners out there.
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Burnze
Posts: 502
Joined: Jul 17, 2014 5:00 PM
Location: Los Angeles

S38 to M21 - My first diesel

Post by Burnze »

With the value of M5s at an all time high I decided to cash in. We’re trying to buy a house in a market that feels impossible so selling the car made the most sense.
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I decided to use part of the cash to find another e28 and this is what I settled on. It’s a 1986 Euro 524td.
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I’ve owned and serviced many e28s but this is my first diesel. Is there a considerable difference between the euro M21 and what we got in the states? I assume the timing belt and other maintenance is similar to the M20. Are there other euro diesel owners here?

EDIT: Fixed pictures.
Last edited by Burnze on Feb 24, 2022 3:54 PM, edited 1 time in total.
gadget73
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Re: S38 to M21 - My first diesel

Post by gadget73 »

so far as I know, the major difference in the Euro vs US M21 is the injection pump. The Euro one is purely mechanical, the US one had a computer controlled timing solenoid. Exactly how much that affects performance I have no idea. Lincolns got the Euro pump except California models.

how similar the belt is to an M20 I don't know, but its not real difficult. Does use different tools to lock the cam, crank, and injection pump. Details are on here elsewhere on exactly how to do it but I got mine done easily in a day having never worked on a diesel or a BMW engine in my life and that included making the lock pin for the crank and the injection pump timing tool. You also need a tool to time the injection pump properly. Same one is used on early 12V Cummins and VW engines so its a pretty available thing. Its a dial indicator threaded into the back end of the injection pump, and you set it to an amount of travel at TDC. Not real hard, most difficult part is getting the inner injection pump lock nut loose. Not a lot of room in there. The Ford manuals in the sticky up top are arguably better than the BMW models, if only because they were written for non-diesel mechanics who probably had no idea how to deal with a German engine.

One problem thats come up recently is the lack of available timing belt tensioners. I have an old one that I picked up with the idea of figuring out how to rebuild it, but I haven't really done it yet. Its going to involve machining some parts to allow an available idler wheel to be used so its not going to be a fully DIY solution unless you have a lathe in your garage. If you do though, you're smart enough to figure out your own solution.
Burnze
Posts: 502
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Location: Los Angeles

Re: S38 to M21 - My first diesel

Post by Burnze »

Thanks! This helps a lot. I got the car registered yesterday and I was elated at how smooth the process was. I was nervous for a bit because they asked for my smog papers. But once we got past that, I cut a check and was on my way. No more smog stress!

I'm still working my way through all the posts in this section. Right now, I found rust inside the gas tank's filler neck so I need to address that. The PO said that it's isolated to the neck but I'm wondering what I'll find once I'm in there. Would a US tank swap in? or do I need to source a Euro gas tank?
gadget73
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Re: S38 to M21 - My first diesel

Post by gadget73 »

BMW-specific stuff I have no idea about. Mine is a Lincoln, frankly I'm mostly just here for the driveline info since nobody else knows anything about these things.

https://www.realoem.com/

may have an answer for you about the fuel tank.

I believe that was another difference on the Euro vs US diesels. US ones got an in-tank lift pump, Euro models did not. I don't know if that means the tank itself is different or not.
Burnze
Posts: 502
Joined: Jul 17, 2014 5:00 PM
Location: Los Angeles

Re: S38 to M21 - My first diesel

Post by Burnze »

So, I tried loving the td but in the end I caved. I have an S38B36 on the way and it will be swapped in.

I will have my engine and TD-specific parts up for sale soon. Please let me know if anyone is interested, I am taking offers on the complete engine.

The car is running and driving so it's a good time to take a look.
Galahad
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Re: S38 to M21 - My first diesel

Post by Galahad »

Anyone else notice the chrome grille surround? Haven't seen that on an e28 before
gadget73
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Re: S38 to M21 - My first diesel

Post by gadget73 »

as rare as these are, maybe the better path is to find a gas engine model. I think only around 1500 524td's were brought to the US.

If you want go power, the M21 definitely is not the way to get there, at least not in anything resembling stock form. With a little injection pump tuning they go better, but you're still on the "this sucks" scale of performance. It just creeps towards the "sucks less" end of it.
Burnze
Posts: 502
Joined: Jul 17, 2014 5:00 PM
Location: Los Angeles

Re: S38 to M21 - My first diesel

Post by Burnze »

This car is a great platform for my project because it is a diesel. I wouldn’t need to go through smog here in CA. If I get a US car I would need to do the euro conversion as well.
Burnze
Posts: 502
Joined: Jul 17, 2014 5:00 PM
Location: Los Angeles

Re: S38 to M21 - My first diesel

Post by Burnze »

Galahad wrote: May 30, 2022 6:21 PM Anyone else notice the chrome grille surround? Haven't seen that on an e28 before
It is just some autozone trim. It’s on there pretty good so I haven’t tried removing again.
RobertRO
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Re: S38 to M21 - My first diesel

Post by RobertRO »

I believe that the factory manual at the link below may be of some use:
https://82.78.8.129/mye28/files/524tdIndexedManual.pdf

The quality is rather poor, but that's what I have.
Burnze
Posts: 502
Joined: Jul 17, 2014 5:00 PM
Location: Los Angeles

Re: S38 to M21 - My first diesel

Post by Burnze »

RobertRO wrote: Jun 02, 2022 2:21 AM I believe that the factory manual at the link below may be of some use:
https://82.78.8.129/mye28/files/524tdIndexedManual.pdf

The quality is rather poor, but that's what I have.
Thanks but this will be sold soon.
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