I have to question the engine in my 525i... skip down to the stars for the main question, but here is the history...

Got my '93 525i/A Oxford/Parch in February from a guy on Craigslist for $750. It sat for 2 years due to his prison term. Heres A link to some pics after I washed/vaccuum'ed it.
http://forums.bimmerforums.com/forum/showthread.php?t=715867

Well there were a few things that needed attending like control arms, sway links, missing ashtray and a few other weird things, Seats were all twisted and fu**ed, wipers didnt work, the engine would not exceed 3.5k rpm(learned after i found sport mode), and the previous owner said the tranny needed $400-600 worth of work to fix it. Few dents and misc and needs a new clearcoat.
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The good part, he said he put a new engine in it about 25k ago and showed me but I forgot to grab the paperwork for it in the excitement of the moment. Got the rest tho'.

Started thinking I may have got in over my head :mad Then...

Using my DIY skills, I started going through the engine bay. My god it was clean.... EXCEPT the valve cover... hmmmm. So I am changing the plugs to my favorite NGK's and remove the covers to reveal a beautiful engine that is clean enough to eat off of. I jack it up and so is the transmission, and drive shaft. WOW!!!:buttrock . Except the valve cover... weird...

So I finish doing the plugs, filters, etc... I flush the tranny to find it is about 2.5 qts low.... NO WAY.... Changed the tranny filter, gaskets, and filled it and it worked PERFECT!!! But now the engine was running just a little rough so I grab a can of MAF/AFM cleaner, and some good ol WD-40 and go to town. I cleaned the whole intake from the manifold to the box. During this I found a vacuum hose disconnected under the intake manifold. Oh did I mention the Vanos was stuck from sitting for so long... So I put berrymans in the oil and ran it for 15min and changed the oil again....

So I started the engine and it started making this sound... It was better than sex. I turned the throttle under the hood to hear the motor and wow it sounded awesome. Test drive time.... And now is when it gets weird... I take off and it drives nice and smooth around the neighborhood. I drive to the outskirts of town and I get to a stoplight. I drop the hammer and it accelerated like a rocket. POOF! The car accelerates above 3500RPM too!... Uh oh...:D:D:D:D:D:D:D:D I thought the amount of power before I fixed it was good....

I then fixed the whole front end which included upper controls, sways, new brembo rotors with ceramic pads. This thing now handles like a dream. not too expensive of a fix either...

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Now my old car was a nasty Supra Turbo so I know a bit about acceleration and speed...

Now since I fixed my '93 525i, things have been odd from what I read. Since I have gone through the motor and cleaned, maintained, and reseated everything and this thing is fast.... way to fast. I timed 0-60 averaging 6.3-6.6. I raced another E34 525i (had freeforms so M50?) and smoked the living shit out of him... The car severely feels like it wants to unleash HELL :evil2 but is being limited by the Automatic and diff. I have played with acceleration strategies and wow this thing scoots...

Now remembering the prev owners other cars, and the absolute newness of the replacement engine and tranny, what are the chances and how would I know if he was stupid (or smart for me..) enough to drop an S50 on an auto tranny? Will an M50 valve cover fit an S50 if they only got the long block?

If he did I will probably do a 5 speed and rear diff conversion immediately if you know what I mean... Dont want to burn the auto out as I enjoy a good drive:D...

It would also explain why the Indy BMW mechanic looked at my car so funny when he scanned it for codes for me.

Now to get new seats and body repair...

Thanks...

Jimmy

M50 and S50/S52 are nearly identical blocks and heads - the difference in power comes from a bore/stroke change and cams/timing. Yes - an M50 valve cover would bolt right on and is, in fact, required when doing the S50/52 conversion.

it sounds like the unwritten question is "how do I identify if my engine is an S50/S52?" right?

it sounds like the unwritten question is "how do I identify if my engine is an S50/S52?" right?

There are identification stickers with the original VIN on the engine, but they're usually on the backside of the head. Get a mirror and write down the information and look it up. Other than that - I haven't a clue.

There are identification stickers with the original VIN on the engine, but they're usually on the backside of the head. Get a mirror and write down the information and look it up. Other than that - I haven't a clue.

Yeah, if you can find a VIN anywhere, if it's a WBS instead of WBA, you got an ///M motor.

Or you could just get it dyno'd. $50 or so, and you'd know for sure... and get an idea how much power you're putting down. :)

the e36 m3 did come with a zf auto tranny, if that's what we're talking about.

Thanks, I couldn't find a block # anywhere. Now I know where to look and will sure do it when my gf gets home with it.

My tranny is ZF too.

I have a friend with a speedshop, I am going to ask if any of his friends would like to donate a dyno session to the cause...