Hmmm, what to do now?

[z31maniac]

My plan was to try to just find a good condition M50TU to swap into my car.

A local club member has now offered me a non-vanos M50 from an E34 for $150. It has some pitting in one cylinder, obviously needs a rebuild. So now the thoughts of a stroker M50 build are running through my head.

I know that this would end up being more expensive than buying a used M50 with accessories, and would probably fall closer to the cost of an OBD-I S52.

Would the extra effort, time and money be worth it? I've been searching on bfc, but there seems to be a ton of conflicting information on what parts achieve what displacement and what compression ratio.

I would really be interested in the most displacement I could get out of the engine, so S52 pistons...........?

[Farbin Kaiber]

Please, don't do it. Just get a drop in m/s50/2 and reseal the whole thing. Worst case, you'll see 100k out of it. Then overhaul that.

You go through all this work w/ a $150 block, put it all together, and in the end, only end up getting 100k out of it, was it worth the extra work?

[flyboyx]

i agree with farbin. if you want that engine for parts thats fine, but don't waste your time and money rebuilding that one. look at it this way, an e34 oil pan, pick up tube, and dip stick is probably worth what your friend is asking for the entire engine. kinda like meeting women in bars. they are good for what they are, but don't loose sight of this and try to have a long term relationship with one. it will cost you more money and pain than its worth. you should be able to find an good running engine for 5 or 600 bucks. the kind of rebuild you are talking about will cost you so much more than that.

better yet, try to get your hands on a 93 or 94 e34 525i that is wrecked. the second choice would be a 95. you will wind up with just about everything you need except the engine mount arms. don't worry if it is an auto, you can just cut that part of the harness off. try running a wanted ad on craigslist in your area.

good luck

[matt]

I'm with them.

Get a whole motor,throw it in. I would get an M52, they rock.

[z31maniac]

Alright, decision made. I knew it would be a bigger PITA and more expensive just needed someone else to give the proverbial bitch slap.

I think an M52 is in my future, I wanted to try to keep it cheaper, but I think I'm just going to take the extra time to drop in an OBD-I M52.

matt, do you still recommend just S52 cams and chip for the M52, like you do S50 cams and chip for the M50, or are there any other things you would add?

[Farbin Kaiber]

z31, keep in contact with me, we can work something out on the OBD1 stuff.

[z31maniac]

z31, keep in contact with me, we can work something out on the OBD1 stuff.

Will do. Over my lunch break I was just doing some research on everything needed for the OBD-I swap.

I'd have to go back and check but I think yours is pretty close to complete.

Just don't sell the good harness!

[Farbin Kaiber]

it's set aside with your letter, numbers, and mental issue on it.

[matt]

matt, do you still recommend just S52 cams and chip for the M52, like you do S50 cams and chip for the M50, or are there any other things you would add?

Yes. That's really the way to go...

[rThor432]

Matt, you just prefer the M52 over the S52 because of cost and availibility, correct? I've just noticed that most of your posts in the 24v section support buying an M52 and adding the hot-rod bits from the S motor. Just wanted to know.

[matt]

Yes. And because you can rev it out to 7300 without having harmonic issues with the crank. And because it's has a lot of cool features that the M50 doesn't.

I mostly prefer the M52 over the M50. I would still rather have an S52 if money isn't a problem and the motor won't be FI.

[rThor432]

I mostly prefer the M52 over the M50. I would still rather have an S52 if money isn't a problem and the motor won't be FI.

Gotcha. That's exactly what I figured. Thanks for replying to my post.

[MIKe30]

I would go rebuilt bottom end on the m50 with s52 internals and s52 head. voila, new motor at s52 specs at cheaper than used s52 cost.

m50 motor your buddy offered, $150
completely rebuilt bottom end $1500
pistons, rods, crank $500 max
s52 head, $600 max

you're at 2750 with completely new bottom end. have someone redo your top end for an extra $1000.

3750 brand new s52.


If i were to do it all over again, I would either go the way I just mentioned OR I would buy a crate motor completely done from someone like a metric mechanic.


Keep in mind, when you buy a used motor - there's no garauntee it's good. Ask me how i know.


Good luck whatever you decide.