It will be interesting to see what that car sells for. I was pondering it so I sent the link to a friend who's husband is very much into M cars (they have three). He pointed out a number of concerns about the car or info missing from the ad. The biggest is the miles since the swap was completed - only 2000. He wonders if something is wrong with it.
Considering it's about 3000 miles away and need another project like a hole in the head, I'll pass. Plus, I've never been a big fan of white cars.
In reply to Ian F: Yeah, there are a few red flags in the pics, but I'm not seeing anything that would scare me away from the car as a whole. I would want to know why it's being sold, though.
I didn't need this project either (I have three other cars and 4 bikes to attend to...) but I like these in white, especially with the later painted lowers like mine. And I was frustrated with one of the other cars when I bought it, hah.
Just put in a ~$500 order with Pelican, so should have all the parts on the way. Shipping ETA isn't until December 8th though, which kind of sucks. I still need to buy the cam locking tools and VANOS tools, but it looks like they're available on Ebay fairly readily. Since my other BMW has an M42, it probably wouldn't hurt to have the locking tools anyway.
There is one more update to the project - I spent most of yesterday working on the interior and getting the new carpet in.
How I got it:
New (dirty) carpet:
And proof that Resolve is magic. I sprayed the carpet with Resolve, scrubbed it in with a stiff brush, rinsed with a damp rag, blotted with paper towels to soak up as much of the stain as possible, dried with a clean towel, and then vacuumed with a shop vac. The results are incredible.
Before installing the new carpet, I rewired the shifter harness to disable the shift display on the dash and to get rid of the 'shift program' error on the dash. I also checked the cabin air filter, which looked like it had been replaced recently, and flattened/welded/painted this strange hole in the floor pan.
As of yesterday, this is what the interior looks like:
pic fail for me...?
No pics for me either
Ditto. Love the Wagon, though!
hmm. Pics should be fixed now. I've been trying some different host sites and have settled on Google Photos for now, but the downside is there is a specific order of operations I have to go through for it to work, and I don't always do it right.
Some of the pics work now but not all of them...
Same, some pics don't work for me. But wow that carpet sure cleaned up!
Pics should all be fixed (again)...I'll double check them better next time I post an update.
No pics to post right now, but interior is going back together now that I've verified that the heater core is ~6 years old, and cleaned out the little fan that blows air across the HVAC thermocouples. It was buzzing badly.
The wagon that Ian F posted a link to earlier just ended at $8600, and didn't hit reserve. 
I'm fairly happy with this purchase right now, haha.
pics all work. Great progress
Looking really good. What did you sort out for motor/head?
Love your GMT400, do you have a thread on it?
84FSP: I haven't totally sorted out the head yet. I went up to the north side of Indy to pick up a head. Upon inspection, it had recently been rebuilt, and had that crusty orange goop in the cylinder 3 exhaust port. You know, the crusty goop you get when coolant is burning in the exhaust port. Looking closer, that head had been welded and re-machined, and the repair was done rather poorly. The guy selling me the head felt really bad about it, and while he didn't have another M50 head, he did have an S50 head with a few bent valves, so he gave that to me. So now I have three heads. The best set of cams and a set of M50 valves and valve springs will go into the S50 casting and go onto the engine, and I may pursue repairing the other two heads and selling them to try to recoup some of my investment. This whole head thing is the next thing on the list for me to tackle, since the interior is basically done now.
Denton: Thanks! No build thread on the GMT400 at this point, since it's not really going to be built. It's just a solid truck for all my truck-related needs. 1998 K1500 with 175k miles. I'm the third owner, and there is essentially zero rust on it. The only mods are a dual exhaust (from the PO, soon to be replaced), different head unit, deleted DRLs, relays for the headlights so I don't burn out the switches again, 2010 GMC Yukon wheels, and a K&N filter. It is a fantastic truck so far. I've only had it a few months though.
Picture time!
I cleaned up the rear carpet as well, and put it in the car.
Left side clean:
Done!
Carpet is in, steering column fixed (lower nut was too tight and would not allow it to telescope), all dash backlights replaced, and verified that the heater core isn't leaking. I also did some wiring to disable the shift display and error on the dash, so the ECM isn't looking for the transmission computer anymore.
The interior went together with more or less no issues. The heater core has been replaced before, and some of the tabs on the center console and HVAC stack were broken off. It doesn't seem to affect strength when it's all together, though. The E34 also has a large defrost vent on top of the center of the dashboard, and due to Texas/Kansas sun damage, it's a little warped. No cracks, but the vent doesn't sit flat anymore. I may try to make some kind of rubber gasket to make it look a little nicer, but I haven't come up with a good solution yet. The vent face isn't bolted down in the pics - it only protrudes about half that far when properly mounted.
Next step was putting the seats together. I bought an E32 passenger seat in good shape from the same guy I bought the cylinder heads from, so I had to convert this into a driver's seat. Along the way, I also found some very important differences between the E32 and E34 seats that aren't really documented well online. I set the seats side by side, upside down, with the backrest cover removed, to see as much as I could, and still missed a few things. I also discovered that the E32 seat is heated! I wasn't expecting that, so I am not going to try to wire it all up at this point.
Because I didn't find this documented well anywhere else, here's way too much information that I learned about it. This is a good post to just look at the pics if you aren't converting a seat.
These seats are basically 3 parts. The seatback, which is held onto two posts by sprung levers, and unplugs electrically and lifts off from the bottom. The only electrical components in the seatback are the headrest motor and the seat heater pad. The seat base, which contains the rear seat base height motor and seatback angle motor along with the base cushion. And the rails, which contains the front seat base height motor, the bulk of the wiring harness, and the fore-aft adjustment motor. The seat base attaches to the seat rails with four pivot pins.
First, compatibility between the driver and passenger seats.
Second, E32 and E34 seat differences.
E34 left, E32 on the right:
E34 sitting on top, E32 rail attached to the seat. Look at the tab with the ears and the weld nut - they are reversed.
So, there's all the words. Hopefully it helps someone someday, and saves all the steps backwards I had to take when I was converting the seats.
Here are the pics.
I took the nice passenger pocket off the seatback and put it on the driver's seatback - the pocket itself is the same.
Old and new seatbacks, armrests removed:
Old and new seat bases/rails:
All turned into a driver's seat:
Looks like a car again!!
I am way behind on uploading pictures, but the car is back together and is running. I'll post things in order with pictures soon, but here's my current issue.
Lifters took awhile to pump up and I had a little bit of a hard time bleeding the cooling system, but other than that it didn't have any issues. I drove around the neighborhood a few times, and when I got back, I had a small oil leak. Tracing it back led me to the dipstick oring (which I had already replaced), and then on to excessive crankcase pressure. There was a bunch of shmoo in the CCV tubes so I cleaned them out, and then went and got gas, which was a ~10 mile round trip.
When I got back, there was oil everywhere. The dipstick had popped out and sprayed oil all over everything. Also, the whole time I was driving, the car was kind of smoking, but with it being dark and about 10F outside, I couldn't tell if it was oil or what. No excessive pressure in the cooling system, and it stabilized a tick above the midpoint on the temp gauge. I'm confident that the head is good, and the engine doesn't have much blowby. It takes 15+ minutes of idling after venting the crankcase with the oil fill cap before it builds up enough pressure to start leaking again.
Anyone know if the M50 has any inherent ccv issues? I've seen a few comments scattered around the internet, but no one really has a solution or explains what they did to fix it. I have a feeling I'll be pulling the valve cover again to try to clean out the oil separator passages. I'm really not sure what else would cause this if that's not the problem.
Pic of the car on the ground, with snow tires on it. It does drive really, really well aside from the smoking and blowing oil all over everything.
Hey, built in rust-preventative undercoating, haha. Lots of people pay good money for that!
On a serious note, that sucks. I'm not really aware of any ccv smoking guns on the motor. Is yours OBD1 or 2?
I know that the CCV valve (it wasn't called exactly that but I can't remember the real name) on my E36 with an M44 failed, and that caused excessive pressure and oil leaks. May be worth looking into.
golfduke - yeah, nothing in the engine bay will be rusting anytime soon, for sure. This is an M50, so it's OBD1. The ccv system is very, very simple on these with only the old-style baffle in the valve cover really doing any separating. There is no check valve or anything liek that.
Entropyman - I think the M44 had the cyclone kind of separator that the M52 got (both OBD2). The M50 doesn't have any of that.
I guess the plan now is clean things up, disconnect the ccv and plug the vacuum leak, remove all the ccv hoses, and see if it still builds pressure. If so, the valve cover will come off and I'll clean out the oil separator baffle.
I disconnected the ccv line and drove around some last night, and I am no longer blowing the dipstick out. The ccv line was full of water, which absolutely does not bode well. I might be burning residual moisture out of the engine....hopefully. I guess all I can do is keep an eye on it. The water was sitting in what is basically a U bend in the line, preventing pressure from escaping.
Meanwhile, there is still a pretty solid drip of oil off the bottom of the engine. No idea where it's coming from, but it's severe. Every seal is new, so I'm guessing I blew something out with the extreme crankcase pressure. It's leaking off the back of the oil pan, which is front sump on the E34, so basically off the middle of the engine. There just isn't that much that can leak oil back there, so for now I'm feeling pretty bamboozled.
Okay, so my last update, in order, was getting the interior back in the car.
The next step was getting the engine back together. I had stripped down all three of the heads, and figured out what I wanted to use for the head to go back on the car.
The first interesting find was this chunk of cam thrust bearing, off of the intake cam:
This is what the cam looked like:
And here's what the good intake cam looks like:
I'm not sure how that damage occurred; the only thing that puts thrust load on that cam is the variable valve timing actuator, but the helical splines would have had to have bound up somehow for that to be the case. On top of that, for that thrust surface to fail, the cam would have to be pulled forward. The VANOS actuator is only capable of pushing on the helical splines - friction load against the cam drive is what pulls the cam back to its base position. The actuator can only apply load in the opposite direction. the head showed signs of being apart before though, so maybe there was some installation error that caused this. I really have no idea.
Sludged up original head:
And this is what 2.5 M50B25TU/S50B30 heads looks like, all disassembled. There's a lot going on in there.
I did check all of the S50 valves for bends, and only one of them was slightly tweaked. It must have been an incredibly mild overrev and some misdiagnosis for the engine to get stripped down. That, or some of the valves may have mild bends that I wasn't capable of measuring. For sure, cylinders 1 and 2 would not hold denatured alcohol in the chamber, but I don't know if it was just from dirt or not. I wasn't planning on using those valves anyway.
This post will just be some interesting finds when I had everything apart; not really any progress here.
This is the head that was removed from the car, cylinder number three. You can see the crack, which runs from the water jacket, through the combustion chamber, behind the valve seat, and up into the exhaust port. The car was not really pressurizing the cooling system, but it was dumping coolant out into the exhaust, and would eventually fill the cylinder after sitting and cooling down.
This is one of the heads that I bought, and that I ended up using the cams, trays, lifters, and valves out of. It had been repaired and ran fine, but lost coolant over time. Note the undercuts from welding cracks behind one exhaust seat. Those deposits are what happens when you burn coolant in the exhaust port.
Another shot, into the port. The wall should be smooth - that divot is part of the (poorly done) repair.
To better understand what I was looking at, I cleaned the port out. I'm pretty sure this head is junk, with how poorly this was repaired. I wouldn't trust trying to fill all this without creating new stress concentrations in the process.
Another of the undercuts behind the seat:
Somewhere between 1993 and 1995, the M50 got some updated parts. Updated lifter is on the right, which has more internal volume:
Again, 1995 on the right. The angle of the pressure feed hole changed.
This is the intake cam lifter tray, #1 bearing surface. New on the right. Note longer oil feed gallery and 'V' in the thrust bearing to provide improved oiling. The 1993 part is the one that suffered the thrust bearing failure, which is probably responsible for the bearing scoring.
Another shot of the thrust bearing surface:
At this point, everything is pretty much ready to go back together, or so I thought. As I was rearranging the timing chain to allow me to slide the gasket and head on, I discovered that the timing chain tensioner guide was chipped and missing a clip. That means that the front cover has to come off, so at this point I decide to just re-seal everything. Remove the crank bolt with a big breaker bar, pull the front cover, pull the oil pump pickup and pan, etc.
Head anxiously awaiting installation:
Oil pan, with the pickup in it, full of sludge and other assorted detritus. The pickup was all sludged up too, so in the end it was good that I removed it.
Oil pumps on these are fairly notorious for unscrewing themselves over time, especially with high rpm use. Not wanting to risk it, I loctited and safety wired mine.
New guides and oil pan gasket:
While I was in there, I also replaced all of the coolant hoses and some of the fuel lines. Regardless of what happens (keeping the M50, swapping in an S52, etc) I'll probably be glad it has new hoses. One less thing to think about, even if they bump the budget up some.
Head reinstalled, waiting for the valve cover:
No pictures after that, but it does run and drive now. There was so much coolant in the exhaust from the cracked head that it didn't want to run smoothly, and it smoked like crazy. The last 50 miles of driving has cleaned it out pretty well, and it is running much better.
Downside is that it keeps building crankcase pressure as a result of filling the CCV breather with water/emulsified gunk. I don't know if the HG is still leaking or what, but when I get back from vacation, I'll pull the drain plug. It has been sitting for 2 weeks. If any real amount of coolant comes out before the oil, then I definitely still have a leak somewhere. Signs are pointing this way anyway - the cooling system doesn't build as much pressure as I expect it to, and the coolant level has dropped somewhat. It's hard to say for sure if the latter is caused by air in the system slowly purging, but it seems slightly excessive to me. I have a cooling system pressure test kit coming in the mail, which may be able to shed more light on that situation.
It's a little discouraging to have not fixed the issue, but I guess that's the nature of projects. Hopefully I'll know more next week, and figure out where to go from there. On the plus side, the car drives very well, there are no thunks, no rattles, and it goes down the road straight. There are a few surprise electrical issues (maybe not so much of a surprise, actually). The aux input on the Alpine head unit doesn't seem to work, the driver's side door tweeter doesn't work, power locks are intermittent (alarm chirps but nothing happens. Opening the door sets the alarm off), the rear hatch window likes to open itself while driving down the road, and the main hatch latch switch only works about 5% of the time. As a result, as soon as the engine thing is figured out, this is going to become a '90s electromechanical troubleshooting thread!
Were you able to clean out the CCV? I've got a pretty specific coolant system bleed procedure for my E36 M3, works like a charm.
I jack the front end up, bleed screw out, cap off.
Heat on high, blower speed in the middle.
Start the car. Fill the overflow tank and keep the level higher than the crossover tube to the bleed screw. This forces air out the bleeder.
I slowly keep the level up and periodically squeeze both upper and lower hoses.
When I get hot air out of the vents and no more bubbles I turn the car off and let it get stone cold.
Drop the car level, fill to the "Kalt" line and that's it.
I cleaned out the external part of the CCV and have verified that I have decent flow. It seems to temporarily clog after the car is shut off, and then it will flow a bit again after some driving. Didn't get a chance to check for coolant in the oil (Settlers of Catan distracted me last night) but will look tonight. Unfortunately, the pressure tester won't show up until the end of the week, so if there is no obvious coolant in the oil pan, I will likely drive it, pull the valve cover to see how everything looks and to clean out the ccv passages, and if I'm not staring at a milkshake, I'll change the oil and see what happens.
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