I've been looking at some options for a little newer engine for my 1993 OBD1 325i. I guess the M52 is bolt on identical to the M50. Even further, the Z3 2.8 (M52B28) is aluminum block. A little searching has led me to deduce that the Z3 engine would be about 25 pounds lighter than my M50. Is the M52B28 also bolt on identical to the M50? Could I get a Z3 long block and bolt it in, in place of my M50?
In reply to Canute:
Oh wait, you're not kidding.....
Yes, the M52 is a bolt in affair for you. Just swap all your OBD-1 stuff from your 2.5L and you should be fine. While you're at it, you could do a custom chip, and s50/52 cams and intake. 
You have two options. One swap all the OBD1 sensors and harness from your M50 to the M52, and run the OBD1 ecu. Two get a complete M52 with all of the sensors, harness, and ECU; have the OBD2 ECU flashed to delete the EWS and while you're at it have it performance tuned. Either way run the M50 intake on the M52.
I vote OBD2 just because that's the route I went with my e30 swap. But since you have all of the OBD1 stuff already that makes a difference.
In reply to nokincy:
OBD2 conversion is a great idea...........SAID NO ONE EVER.
yamaha wrote: In reply to nokincy: OBD2 conversion is a great idea...........SAID NO ONE EVER.
Why? It's literally plug and play except for having the ECU flashed. If you don't already have every OBD1 sensor sitting around it's cheaper too. Not to mention you get the benefit of diagnostic and running the engine on the computer it was meant to be run with from the factory.
In reply to nokincy:
Ehhh, still not worth the effort....he could get a bare long block and be golden with a little time. There is a reason they convert to obd1 though, simplicity.
To each their own. If you're pulling the engine its no more effort to pull the electrics with it.
OP here is a OBD2 to OBD1 conversion so you can see what it would take to convert the m52 properly as well as what parts you would need. You should have some of this stuff to swap over from your m50.
yamaha wrote: In reply to nokincy: Ehhh, still not worth the effort....he could get a bare long block and be golden with a little time. There is a reason they convert to obd1 though, simplicity.
A lot more of the 24v swaps going into e30s these days are sticking with obd2 rather than converting. It seems to be the simpler route now that EWS is easily defeated.
there are also less OBD1 E36s on the road than OBD2 cars...
What would make the decision easy for me is that I have a running M50 in the car. If it's all just swapping parts over then it's a no brainer. The only issue I'm thinking about is the DME tune. Hmmmm... 25 pounds off the nose and a bunch more torque.
yamaha wrote: While you're at it, you could do a custom chip, and s50/52 cams and intake.
The cool thing here is that the S52/M52 guys are swapping in M50 intake manifolds anyway. I've been looking at swapping in an S52, but they're more than I want to spend and low mile ones are getting rarer.
Here's a company that can sell me a chip for the OBD1 M52: http://www.trmtuning.com/product/trm-obd1-performance-software-2/. I'm stunned at how expensive cams are for BMWs. As much as I can buy the whole engine for.
I was wondering, which injectors do M52s come with?
nokincy wrote: To each their own. If you're pulling the engine its no more effort to pull the electrics with it. OP here is a OBD2 to OBD1 conversion so you can see what it would take to convert the m52 properly as well as what parts you would need. You should have some of this stuff to swap over from your m50.
Thanks for that link. I wouldn't have known I needed to swap timing chain covers too.
The upgrade to a 540 MAF looks like a no brainer too. TRM wants another $25 for the software and I see them under $50 on EBay.
Just for giggles, this is how the car was doing at my last track day: https://www.youtube.com/watch?v=g1AOZa2SqK4 The suspension still needs some tuning.
I just kicked down for an 80k mile 1997 Z3 2.8. $1,200 sans accessories, no core. I go pick it up tomorrow.
You can get an S52 for that much, and almost everything will bolt to it. I'd really, truly, just get the S52 if you're going through all the trouble. A short block can be had for $1200 for sure
Canute wrote: Here's a company that can sell me a chip for the OBD1 M52: http://www.trmtuning.com/product/trm-obd1-performance-software-2/. I'm stunned at how expensive cams are for BMWs. As much as I can buy the whole engine for.
I have a TRM chip in my E30 with OBD1 M52,S50 cams,headers,M50 intake etc and it runs really nicely for an off the shelf tune.
Yeah, I was seeing S52s on http://car-part.com/ for a while, but they were in the $2,000-$2,500 range. Now they're getting rarer and higher miles.
If you're planning to stay OBD2 check out http://www.markertmotorworks.com/ for the ecu tuning. I'd recommend them over TRM. Just send Dave an email and he'll take care of you.
I'm going OBD1, the car's current M50 for the M52B28. Long block for long block. Kind of thinking what I want to do for an exhaust manifold. On the subject of 540i MAFs, I'm not sure what I want to do. The lowest price I've seen on new replacement Bosch parts is $185-$200, from RM European. While on EBay there are sellers doing repro units under $30.
I think for the moment, a large MAF is out of the budget. So are S52 cams. Anyway, I picked up the engine from the wrecking yard and took it to my racecar mechanic. We were both a bit excited as everything looks a generation newer than the M50.
We're debating about how much lighter the aluminum block Z3's M52B28 will be than the M50. I'm planning on taking my heavy duty digital hanging scale with me when I take the car with me.
I like the Z3's stock exhaust manifolds. They look nice and light. I'm planning on keeping them. I also like the look of the Z3's phenolic composite valve cover. We're going to try to keep that too. I guess I want to use the M50's timing cover.
I'm going to have some parts left over. I think I want to use the 325's oil pan. I'm also planning on using the M50's fuel rail but with the M52's injectors. I'm guessing I also need to use the stock 325 throttle body?
Anyone know of the top of their head what the rating is for the M52B28's stock injectors?
I think the M52B28 should have the pink top injectors, which I'm pretty sure are 21# injectors.
Yeah, I was seeing S52s on http://car-part.com/ for a while, but they were in the $2,000-$2,500 range. Now they're getting rarer and higher miles.
I bought an S52 for $1600 with 138k on it back to drop in my race car in the spring. A friend just got one for $1000 that needs a head gasket (and some freshening) to use for next season in his car. They are out there.
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