M50 Worse than just a HG

[93 525 Paul]

Sooo, car was fine with 178k miles. Was driving it last fall up a long freeway climb, steady power, consistent RPMs, all was well. Felt engine kind of go off song. It started to lose RPMs, temp normal, power dropped off, saw smoke in the rear view, let off worked over from #1 lane to shoulder. Temp had begun climbing quickly. By the time I pulled over the engine wouldn't idle. Died.
Got it to the shop next day, they said HG, coolant in the #4 cylinder, $3k to repair. I said no thanks. Threw it on the side of the house and forgot it for awhile.
In the last month or so got motivated to replace it, seemed like a big, but not overwhelming task. I used to race karts, did my own engine work on those, and have built a handful of engines, set up differentials and even a couple of transmissions.
Via a poorly titled thread, I've used your help to yank the head, pull the cams, remove the valves, clean up the head, prep for reassembly and reinstallation.
I found the gasket remarkably intact, had expected a "blown" hg to be self evident. It was not. Expected the head to have problems, none. It's flat to within .002" in every direction, no cracks, valves and seats look good.
Today I went to clean up the block deck and my heart dropped. Partly because of the gravity of the situation and partly because I'm disappointed I didn't see the damage earlier.
Aaaaagh!!!
The cylinder walls of #3, #4 and #5 where the 3 cylinders adjoin look scorched from overheating and lightly scored. There appears to be some aluminum transfer from the pistons, but only at the very top of the cylinder above the ring level.
When racing a kart and letting the motor get too hot, many a karter "stuck" a piston. In those cases the piston would stick in the bore and the aluminum transfer would be in the middle of the stroke. We'd use acid to remove the aluminum, hone the bore, drop in a new piston and ring and be on our way.
This seems more mild than that and concentrated to the tops of the adjoining cylinders.
Any guesses on what transpired? How did just those areas get so hot?
What would you do in this situation?
Replacement engine time?
Hone and rings?
Other?
http://i123.photobucket.com/albums/o284/pmcdougal/IMG_08191.jpg

[bubba966]

If you could find a well cared for M50 I'd say throw a used engine in there if you plan to keep the car for a while.

Did you look at the oil pump? Not sure just a water cooling problem would do that. Seems like a lack of oil flow might've heated things up 'till they started binding causing problems which then caused coolant to enter your #4 cylinder. I'd be tempted to pull the crank & rod bearings and see it those got roasted while you've got it all apart.

But I think you need to figure out what you want to do with the car and how long do you want to keep it?

If you just want it to run for a bit then a hone & rings could get you by just fine. If you wanted to have it around for a few years a used engine might be worth looking into. If you wanted to keep it longer than a few years I might find a decent used engine and pull it apart and use the best parts from it & your blown engine to make one rather nice one.

Would also be a good time to change things up if that's your desire. Maybe add a third pedal. How 'bout an S50?

Point being this seems like a decision needs to be made based on your long term goals. And I wouldn't want to run that engine long term without knowing a little better what all got roasted and how bad was it cooked. I'd also want to give the pistons a good look at before I ran that engine.

Actually, the more I think about that the more inclined I am to say grab a used engine and at the very least give it a new HG before you slap it in...

[whiskychaser]

This guide gives pics of lots of piston problems and causes:
http://www.mlcmotorfactors.co.uk/Trouble%20Tracers/PistonTT.pdf
I think I'd be taking the crank and pistons out to see the total extent of the damage. I'd be concerned about using the same pistons because they seem to have gone oval, have been in contact with the bores but mainly because getting that hot may have damaged them and they may break apart if reused. Depending on the shape of the car and how much money I had to throw at it would decide the way forward. But if I decided to put a new motor in, I'd want to be damn certain the cause of the problem wasnt still in the car - like a partially blocked radiator or cat?

[Ross]

"long freeway climb"
I'd be thinking detonation. Pull the pistons and have a good look at the top ring lands.
Quick bottle brush hone job and rings(pistons?) would be my solution. And maybe knock sensors.

[93 525 Paul]

I think you need to figure out what you want to do with the car and how long you want to keep it.


Great question. At this moment I simply don't know. I had intended to get it going and drive it daily while I get my POS Lincoln LS V8 squared away to get rid of without taking a bath on it. (Needs an H-pipe and a tranny rebuild.)

Now that it's more involved, I will probably go ahead and pull the motor and pull it down all the way and go from there. The S50 is an intriguing idea, particularly the manual (however it seems more than a bit complicated.)

Based on Bubba's response and the piston pdf, I believe the damage to be oil related. The car used to leak inconsistently. Sometimes not so much, other times it would leak like a sieve and I feel like and idiot because I can't say for a fact what the oil level was that day. Until now I didn't suspect oil but since we went out of town for a couple days it is possible that enough leaked in those days to create a problem at the back of the motor.

[BMW4LIFE]

Great question. At this moment I simply don't know. I had intended to get it going and drive it daily while I get my POS Lincoln LS V8 squared away to get rid of without taking a bath on it. (Needs an H-pipe and a tranny rebuild.)

Now that it's more involved, I will probably go ahead and pull the motor and pull it down all the way and go from there. The S50 is an intriguing idea, particularly the manual (however it seems more than a bit complicated.)

Based on Bubba's response and the piston pdf, I believe the damage to be oil related. The car used to leak inconsistently. Sometimes not so much, other times it would leak like a sieve and I feel like and idiot because I can't say for a fact what the oil level was that day. Until now I didn't suspect oil but since we went out of town for a couple days it is possible that enough leaked in those days to create a problem at the back of the motor.

stupid question but wouldnt the low oil warning come on?

[whiskychaser]

stupid question but wouldnt the low oil warning come on?
I never had this warning. But like the low coolant warning, I wouldnt expect it to come on with the engine running. The low oil pressure light might come on but probably after the damage has been done.
I'm not about to add insult to injury by asking the OP how much oil it has in it

[Mordan]

like a partially blocked radiator or cat?

off subject but are the consequences of a partially blocked cat?

[whiskychaser]

off subject but are the consequences of a partially blocked cat?
Engine gets hot as it has to work harder and cant get rid of the exhaust gases properly

[Tiger]

Mmm.. a mechanic who lied to you about HG problem and coolant in cylinder... wanted you to cough up $3000... even if he fixed it, you will still have problem with the car and he would just say he did the job to the 'best of his ability' and you will still be out of $3000. NEVER EVER GO BACK TO HIM!

I would find a donor E34 engine and put it in... the question is how cheap can you get the engine compared to buying a whole nother car and part out yours...

[93 525 Paul]

I'm not about to add insult to injury by asking the OP how much oil it has in it

I drained it early on in the process without checking the level or paying attention to volume (I wasn't thinking of oil related issues then.) Was surprised there was no coolant in the oil. Same thing with coolant. Drained it and was surprised it wasn't fouled.

[Ferret]

Mmm.. a mechanic who lied to you about HG problem and coolant in cylinder... wanted you to cough up $3000... even if he fixed it, you will still have problem with the car and he would just say he did the job to the 'best of his ability' and you will still be out of $3000. NEVER EVER GO BACK TO HIM!

Er, are we sure he lied? The headgasket if it's gone would show to be the only problem, how would a mechanic know about the bore issues if he's not torn the engine down yet?

OP, does the engine bind in the bores? I seem to remember my M50 motor looking like that in one of the early teardowns I did, cant remember though...

[Tiger]

You can examine the engine internal with scope just by taking out the spark plug.

[Ferret]

You can examine the engine internal with scope just by taking out the spark plug.

...and if the mechanic in question doesnt have a scope like that?

It's symptoms were so blatant it may not have warranted further inspection?

[whiskychaser]

Hmmm. £1900 for a head gasket is about 4 times going rate. But if you get a new engine fitted for that its not to be sniffed at :D

[bubba966]

If you like the car and plan on having an E34 for some time why not find another one that's got a good engine and make one good E34 out of the two?

In my area it seems to be easier to find an M50TU than it is to find a donor E34 with an M50TU in it. Plenty of E36's with M50TU's. Though you'd need to swap oil pans if you got an M50TU out of an E36. No biggie since you've already got the E34 specific oil pan.

Oh, and $3k for just a HG job? My friend had hers done on her '95 525iT for $2k and that included pulling the engine and honing the #6 cylinder and putting the engine back in. Still thought it was a little high even with the engine pull and machine work.

Anyways, you seriously need to figure out what you want to drop on the car first. Is it worth it to you to put any decent amount of $ into it? None of us can answer that for you because what you might deem acceptable to put into that car someone else might find it insane or vice-versa. I know what I spent on my M-Sport would be considered insane by most all but I don't mind. Virtually everyone thinks I'm insane to keep the EDC setup in it as well. But I'd not want to do anything else (even if the EDC's are ridiculously priced).


Anyways, I think it's definitely a good idea to at least tear this engine down further and look for oil starved heat failure. Of the pics of blown HG's in M50's I've seen so far I don't recall any of them having piston material embedded on the cylinder walls like that. Really the only reason I'm guessing an oil starved overheat rather than a cooling system overheat.

Sure, clogged cats could possible heat up things badly. But you'd know you had a serious problem way before it got as bad as it did. Had a clogged cat in something else once and it was very obvious that there was a severe problem. There was absolutely no power at all with a clogged cat.

[93 525 Paul]

OP, does the engine bind in the bores? I seem to remember my M50 motor looking like that in one of the early teardowns I did, cant remember though...

No bind. Turns over easily with a ratchet on the crank bolt. No diff in effort when those pistons are near TDC


Hmmm. £1900 for a head gasket is about 4 times going rate.

Yeah, it seemed mighty steep, immediately said no go. Checked here and found out it was in the stratosphere. Changed my opinion of the shop dramatically. If the car is only worth $2400...I'd like to keep my repair costs low.



In my area it seems to be easier to find an M50TU than it is to find a donor E34 with an M50TU in it. Plenty of E36's with M50TU's. Though you'd need to swap oil pans if you got an M50TU out of an E36. No biggie since you've already got the E34 specific oil pan.

Good thinking, kind of think that may be my best avenue, Craig'slist shows way more 3 series than 5 in this blue collar area. Need to luck into a good motor...


Anyways, I think it's definitely a good idea to at least tear this engine down further and look for oil starved heat failure. I'm guessing an oil starved overheat rather than a cooling system overheat. Sure, clogged cats could possible heat up things badly. But you'd know you had a serious problem way before it got as bad as it did.

Agree, I will tear it down. I think cats highly unlikely, all was peachy until she suddenly went off song

[93 525 Paul]

I would find a donor E34 engine and put it in... the question is how cheap can you get the engine compared to buying a whole nother car and part out yours...

Found an M50TU short block out of a 325 w 90k miles on it for $100. Guy took it out for a 2.8 upgrade. My head and cams seem fine so thinking I'll give it a shot...

[Tiger]

Wow! $100! Go for it!

[93 525 Paul]

Wow! $100! Go for it!

That was my reaction. The guy sounds solid, the story holds up. Here is the ad copy.

for sale, bmw engine Shortblock E-36, M50. engine has 90K miles and is guaranteed good, picture shows engine with cylinder head still on motor, i robbed head off of this engine some time back for another project. FOR SALE IS SHORTBLOCK ONLY (NO CYLINDER HEAD) i have some extras like exhaust manifolds ect. engine came out of 1995 325I.......Thanx!

Wish me luck.

[whiskychaser]

If the head is off you get to see the bores no problem. I would be cheeky and bid it down for cash. Including the bits of course. Its still a risk. I might be able to buy a '99 engine and manual tranny for £100 but if its at the end of the world its no good to me

[bubba966]

Since you've got to pull the pan anyways to throw an E36 M50 in an E34 I'd be tempted to change out crank and rod bearings while the pan is off and the engine isn't in a car.

Though you could just check them to make sure all is well when you pull the pan.

VAC Motorsports has nice bearing sets with what they're referring to as a "performance coating" which sounds to me like powder coated dry-lube. If so that's quite nice. They've also got MLS headgaskets.

MLS gaskets and dry-lube coated bearings would make that engine last a really, really long time.

[bubba966]

Oh, you are going to have your head checked out for cracks and if it's flat & true before you re-use it, right?

If might be perfectly good, but it's a long head and something got really hot in there...

[632 Regal]

pop a different engine in it and run synthetic oil and move on. Could be 50+ different things. using non synthetic oil will leave scars that can leave you guessing your entire lifetime. With synthetic this will not happen unless you feed sand down the intake.

[Tiger]

Mmm... I think his head is fine... he is making sane choices and I am pretty sure he need his head to function so there is no reuse factor... he just needs it.

[93 525 Paul]

If the head is off you get to see the bores no problem. I would be cheeky and bid it down for cash. Including the bits of course. Its still a risk. I might be able to buy a '99 engine and manual tranny for £100 but if its at the end of the world its no good to me

So far so good.
Head is off, bores look great. Piston tops much lighter carbon than ours.
Great guy, looked to be of modest means. I couldn't bring myself to be cheeky, I gave him the $100 thinking it a great deal, he did throw in the bits although I didn't really want 'em.
Dude didn't have a lift so the two of us chucked it in the back of the pickup. It wasn't as heavy as I expected but it is full of coolant and oil plus it has a fair bit of stuff still on it. Not light.
I guess any used part is a risk, but it's pretty transparent with the head and pan off. I did have to go 180 miles for it, Fresno to Sacramento CA but took off Fri night at 4 and was back at home by 9:40 or so. Truck had satellite radio so time went quickly.


Oh, you are going to have your head checked out for cracks and if it's flat & true before you re-use it, right? It might be perfectly good, but it's a long head and something got really hot in there...

Yeah I took it to a machine shop and it's flat. The .002" feeler gauge wouldn't pass under the straight edge anywhere. I did not have it magnafluxed but no apparent cracks from the ex valves to the coolant passages.
I could take it back now that the head is fully disassembled for cleaning and magging if you think it's a good idea...

[BMW4LIFE]

pop a different engine in it and run synthetic oil and move on. Could be 50+ different things. Using non synthetic oil will leave scars that can leave you guessing your entire lifetime. With synthetic this will not happen unless you feed sand down the intake.

+1

[Mordan]

about oil starving

didn't you get a light on your dashboard to say oil level was critical?

[93 525 Paul]

about oil starving

didn't you get a light on your dashboard to say oil level was critical?

No I didn't. On other occasions I have had an oil level message via the dash lcd message area when the level was low. IIRC that was a startup deal, never during engine operation...

[93 525 Paul]

So I tonight I ran across an S50 '99 M3 engine and transmission in the local Craigslist. 107k miles, $2000.
A) What would you pay for similar?
B) How hard is the swap? What's the worst part of same?

[bubba966]

'99 should be an S52 and is OBD II rather than OBD I. $2k actually sounds cheap.

Hardest part on that is converting it over from OBD II to OBD I. I don't know all of what's involved but I know it's been done many times and shouldn't be hard for you to find that info.

If you want easy you want to find an S50 from a '95 M3. OBD I for that engine so is pretty plug and play as far as the engine goes.

[93 525 Paul]

'99 should be an S52 and is OBD II rather than OBD I. $2k actually sounds cheap.

Hardest part on that is converting it over from OBD II to OBD I. I don't know all of what's involved but I know it's been done many times and shouldn't be hard for you to find that info.

If you want easy you want to find an S50 from a '95 M3. OBD I for that engine so is pretty plug and play as far as the engine goes.

And the tranny?

[93 525 Paul]

'99 should be an S52 and is OBD II rather than OBD I. $2k actually sounds cheap.

Hardest part on that is converting it over from OBD II to OBD I. I don't know all of what's involved but I know it's been done many times and shouldn't be hard for you to find that info.

If you want easy you want to find an S50 from a '95 M3. OBD I for that engine so is pretty plug and play as far as the engine goes.

Found this thread...great writeup and even though it's an OBDII owner moving down to OBDI, it gives an idea of the specific differences. Love to find a thread of an OBDI owner who dropped in an S52...
http://www.dtmpower.net/forum/showroom/164835-just-finished-m52-obd1-conversion.html

[93 525 Paul]

Alright, so back on page 2 of this thread someone asked to see the carnage. Well, with replacement shortblock in hand (well on the stand actually) I've yanked the crippled motor along with the tranny, separated them, dropped the pan and pulled a piston.
If you recall, the back bores look like this...
http://i123.photobucket.com/albums/o284/pmcdougal/IMG_08191.jpg
So, what do the bearings, pistons and rings look like?
On first glance, they look fine.
http://i123.photobucket.com/albums/o284/pmcdougal/DSCN0218.jpg
The rod journal on the crank is mirror finish, no scoring and the bearing inserts are smooth as can be. No scoring, no heat issues.
http://i123.photobucket.com/albums/o284/pmcdougal/DSCN0219.jpg
But on this, the #6, rearmost piston, the damage is on the front side above the pin. The top 2 rings are seized in the lands and you can see the source of the transfered aluminum in the cylinder. Ouch.
http://i123.photobucket.com/albums/o284/pmcdougal/DSCN0220.jpg
So, there you have it. All done. I screwed up, I murdered a perfectly happy 2.5l shortblock for no good reason. Clearly it was oil starvation and I have to say I must have unknowingly let the level drop on that trip to LA.
I'm paying the piper in cash and with my time. I feel stupid and embarassed but let's move on.
Now it's time to swap everything to the substitute shortblock. Should I pull a bearing cap or two for inspection? If the bolts are one time use only, is that worthwhile? If it makes any difference, I used a telescoping mike on the two engines and my reportedly 94k mile sub sb has slightly smaller bores than the 187k mile original.
My only concerns are that my cams look mirror and the cams that came out of this motor are scored on the bearing journals, not on the lobes. That and the mild sludge in the sub sb and I'm a wondering.
What should I do to the short block before jamming it in?
Since I have the 187,000 mile original tranny out, should I go through it? I've done a domestic 3 speed so I think I could refresh it without effing things up. Is there an ATSG manual for the tranny?
So many questions.

[whiskychaser]

If it makes any difference, I used a telescoping mike on the two engines and my reportedly 94k mile sub sb has slightly smaller bores than the 187k mile original.
For a minute there I thought OMG he's bought a 2.0 litre block - the bore on those is 80mm and its 84mm on the 2.5. But you dont get the 2.0 in the US do you?

[Tiger]

So what is the replacement engine you got?

[bsell]

My only concerns are that my cams look mirror and the cams that came out of this motor are scored on the bearing journals, not on the lobes. That and the mild sludge in the sub sb and I'm a wondering.
What should I do to the short block before jamming it in?
Since I have the 187,000 mile original tranny out, should I go through it? I've done a domestic 3 speed so I think I could refresh it without effing things up. Is there an ATSG manual for the tranny?
So many questions.

Yes to the 'should I dig deeper?' questions. You will never have it so easy to do the refresh than now. I know I'd sleep better at night knowing I took advantage of the R&R time for the engine and tranny...

[bubba966]

yes to the 'should i dig deeper?' questions. You will never have it so easy to do the refresh than now. I know i'd sleep better at night knowing i took advantage of the r&r time for the engine and tranny...

+1

[93 525 Paul]

So what is the replacement engine you got?

I got a M50TU short block out of a 325. The owner said he upgraded the car to a 2.8 reportedly at less than 100k mi.

On the bore, I telescope miked both bores and the replacement is the same bore, just a smidgen, like a ten thousandth of an inch "tighter"

[Tiger]

Ahh... the $200 short block. No scoring like your old engine right?

[93 525 Paul]

Ahh... the $200 short block. No scoring like your old engine right?

Man, you guys are relentless. (Just kiddin') Ah, correct. No scoring, definitely. I see my judgement and credibility are completely shot around here so I will shoot some photos to upload.
Irrespective of your reaction to the bores, should I yank the caps and are the capscrews one time only units or are they reusable?

[93 525 Paul]

Ahh... the $200 short block. No scoring like your old engine right?

(Sigh) Can't get any love for a bargain price eh? Ok, the cheapo short block looks better than the high mileage old one in general, consistent with a lower mileage unit. To me the biggest negative versus my original is the sludge in the pan and unknown rod and main bearing condition. Replacement had fewer oil leaks, is far far less grubby externally, way less carbon on the piston crowns.
http://i123.photobucket.com/albums/o284/pmcdougal/BeemerEnginePull006.jpg
the bores aren't perfect, there are some minor scratches, nothing I would judge to be significant. Some staining, presumably from sitting around. Virtually no ridge at all.
http://i123.photobucket.com/albums/o284/pmcdougal/BeemerEnginePull005.jpg
The key question though is what would you do? Rod bolts are $128 for 16, the rings are $22 a hole and rod bearings are $45 a set so for $300 more you could hone it and freshen up the whole deal. $400 if you did main bearings.
http://i123.photobucket.com/albums/o284/pmcdougal/BeemerEnginePull001.jpg

[Tiger]

I would lube up everything, install head, fill crank with oil... hook up a starter and do a compression test and leakdown test.

[whiskychaser]

Its all very subjective. I'd check the crank end float. Pistons out and check big/small ends are ok. If so, a couple of runs with a honer to take the glaze off the cylinder walls and fit new rings and new bolts. I'd be really p....d off if I rebuilt a motor to find the compressions were sh1te

[ryan roopnarine]

email me at rr08!g!@!fsu!.edu
(remove exclamation marks)
for aye tee sss gee manual in pdf

ps...that is, if you'd like it.

[bubba966]

The key question though is what would you do? Rod bolts are $128 for 16, the rings are $22 a hole and rod bearings are $45 a set so for $300 more you could hone it and freshen up the whole deal. $400 if you did main bearings.

For $400 to hone the bores and install new bearings in the bottom end I'd do it. Makes it a $600 short block that you know the exact condition of (and it should be in good condition after that). Seems like a no-brainer to me. $400 isn't that big a sum IMO to know that you'll not possibly be stranded somewhere or know that you won't be pulling it out again any time soon.

After all, how much time will you have put into pulling the M50, fixing it all, and putting it all back together? I'd not want to do all of that for $400...

[bubba966]

Hell, if it was me I'd do all new bearings and send them off here to have them dry film coated. Look under internal coatings to see what I'm talking about.

http://performancecoatings.com/index2.html

And I'd also be getting the VAC oil pump upgrade kit to ensure you don't melt pistons again.

http://store.nexternal.com/vacmotors/vac---m50-m52--s50-s52-us-oil-pump-upgrade-kit-p1041.aspx

Granted, dry lubing the bearings and upgrading the oil pump would add a bit to the price. But it should still be a sub $1k block after you add up the HG, block, hone, bearings, dry lube, oil pump upgrade, and possibly pump upgrade install & recondition by VAC. But it'd be a damn nice short block then.

[93 525 Paul]

email me
for aye tee sss gee manual in pdf

ps...that is, if you'd like it.

Thanks Roop, I appreciate it. Message sent.

[ryan roopnarine]

Thanks Roop, I appreciate it. Message sent.

email sent. ross might be able to recall the brand of kit he used. the precision international one i tried wasn't very good. there's an integral circlip in there that won't fit in the bmw application (i guess it is for isuzu or cadillac iterations???). I wouldn't put it past the kit i bought to be functional only in the academic sense.

[Dave M]

(Sigh) Can't get any love for a bargain price eh? Ok, the cheapo short block looks better than the high mileage old one in general, consistent with a lower mileage unit. To me the biggest negative versus my original is the sludge in the pan and unknown rod and main bearing condition. Replacement had fewer oil leaks, is far far less grubby externally, way less carbon on the piston crowns.

the bores aren't perfect, there are some minor scratches, nothing I would judge to be significant. Some staining, presumably from sitting around. Virtually no ridge at all.

The key question though is what would you do? Rod bolts are $128 for 16, the rings are $22 a hole and rod bearings are $45 a set so for $300 more you could hone it and freshen up the whole deal. $400 if you did main bearings.



This is similar to my block relacement (low comp. from bottom end of #5, 450K). I found a good block for $400 and did rod and main bearings, honed cylinders and did the rings. I had the shop I bought it from do the job to save some time.

I'm very glad I did it all.

Dave

[93 525 Paul]

This is similar to my block relacement (low comp. from bottom end of #5, 450K). I found a good block for $400 and did rod and main bearings, honed cylinders and did the rings. I had the shop I bought it from do the job to save some time.
I'm very glad I did it all.
Dave

So baseball season has killed my progress. 2 kids on teams and helping coach has become a time suck. I am still not enamored with my cheapo replacement shortblock and I came across this locally. Please translate for me if possible...
---
Rebuilt Engine
E46 330 Crank & pistons with a E36 OBD1 Block...
comes with new and old parts
It is a very fast motor
---
I know I need an OBD1 M50 or similar so that sounds good, but what is an E36 block? E36 is the 3 series chassis right? So...It must be a stroked I6 like I have or is it something else???

[shadowpuck]

an e36 block should be from an m50/s50....can't recall all the combinations right now off the top of my head....

based on some quick reading, that sounds like a stroker motor....M50/3.0L - interesting....

[Dave M]

You can fit the M50 block from an E36, but need to transfer the E34's oil pan and clean out some (likely) rusty threaded holes to relocate the engine mount brackets.

I took an E36 M50 block and swapped it into my E34.

Dave

[93 525 Paul]

an e36 block should be from an m50/s50....can't recall all the combinations right now off the top of my head....
based on some quick reading, that sounds like a stroker motor....M50/3.0L - interesting....

Haven't heard back yet, hoping to hear from seller. In the meantime-
E36 3 series '91 - '99. Used the 2.5 L M50B25 in the 325 which was replaced in 1996 with the 2.8 L M52B28, creating the 328i line. Another 2.5 L engine, the M52B25, was reintroduced in 1998 but the cars were sold as 323 rather than 325.
In 2000, the E46 lineup received an engine boost when the new M54 engines appeared for Model Year 2001 cars; with the new 3.0 L 330 replacing the 328.

[93 525 Paul]

Seller advertised a rebuilt engine but didn't know what she had. Hmm. So I went over there to look see. Not really what I expected. It wasn't an engine, just less than a short block of bits and pieces. Used block, old 2.5L crank, used 3.0L crank with polished bearing journals sitting in the bearing saddles of the block. Bores had been lightly honed with a brake cylinder hone (in the box with the bits.) Unknown source used rods and pistons.
I was hoping for more of an engine.
What's a 3.0L crank worth?