'94 E34 Touring slicktop, forged M50B30 powered, S362SX-E boosted, daily driven

[greyis89]

Glad to see this back up and going forward. Keep after it! The last we read on this thread made me sad :(

[varg]

My wagon is finally back on the road, I've put about 45mi on it now and it seems to be running well. In July, I had the engine re-honed, the rings inspected, and the bottom end assembled while I was on vacation. This saved me some time. Luckily the scores weren't too deep and the rings were ok, my leading theory at this point is that there was some debris in the intake manifold or spark plug wells that caused it, either that or my ring deburring was inadequate but I don't see how. Here are some highlights.

3D printed front main seal driver.


The engine going back in the car


Take 3 of new AC lines. And they're still too close for comfort with the downpipe.


The intermediate line that goes through the firewall, stock vs modified


Freshly surfaced head.


Hoodless for the first break in drive.


Heat shield I made so I don't cook my hood and strut tower paint.


I have some troubleshooting to do. There's a power steering leak and either my new heater valve is already leaking or the firewall partition in front of the blower and/or the ECU box partition is getting hot enough that the HVAC (AC not charged yet) is pulling hot air out of it as if the heat is on low. Fingers crossed that the AC lines are ok with the aluminum heat sleeve and relocation, and that the lines getting too hot and pressures rising past the cutout switch point was actually the problem that was causing the AC to work for a while then kick off and refuse to work again until I unplugged the AC control module to reset it. If not, I have an AC control module to replace or fix, and I hate that stuff. I might try to bypass it and put it on a manual setup like the E30.

[Dj Buttchug]

Damn... :( If it catches your nail the old school rule I learned was its about .002 which is pretty decent unfortunately. I feel this pain. So many setbacks when building something. It can really take the wind out of your sails. On my build I ran into several transmission issues one after the other. Transmission in/ out count on my car is now at 6... Stuff like this sucks but makes the final product when done and working as designed that much sweeter.


Keep on hammering dude!

[varg]

Since last posting I ran it until hot after putting it in the garage for head removal and did a hot compression test, seeing more consistent numbers across the board when hot. I purchased a borescope with side camera and checked the cylinders again, and decided to pull the head based on what I saw, which looked to me to be pretty bad scoring on 1, 4 and 6. I reached out with those images to an old classmate who I trust, older student like myself but a real smart and hard working guy in engineering school who built engines and did machine work for years, mostly on 2JZs IIRC. He said there's definitely skirt scuffing and asked what the cylinder wall clearance is; unfortunately I don't have the answer to that I can only assume machine shop used the specified clearance on the piston sheet when the job was handed off to them, 0.0035". I had no direct communication with the machine shop though, it was outsourced to them.

I've pulled the head now, the news is not great. The piston tops were very oily and covered in carbon grit but there is no damage visible. Bores of 1, 4 and 6 each have a scratch that catches my nail, as I suspected from the higher res borescope images. The scuffing seems cosmetic, I can't feel it, but the pistons rock a lot more than I would expect. This comes with a big caveat that my experience with disassembling and checking such a thing with forged pistons is zero, so I don't know how much is normal. This is after all the first time I've built an engine with forged pistons.

Last time I'll see this for a while:


Hot test results:


Borescope image of the cylinder 4 scratch (the one highlighted by the glare about 1/3rd of the way up)


Borescope image of the cylinder 1 scratch:


Current status:


To be continued.

[econti]

In my uneducated opinion:
I wouldn't worry just yet. Concerns about being too harsh on break-in are unfounded. Boroscopes often make scratches look worse than they are, just the way the light works on them. Could be as simple as a little carbon on the valve on that hole, and it not quite sealing correctly, which if you're running rich is certainly an option.
That hp/L is high but isn't insane.
Drive it a little more.
Can always have the block bored then sleeved and re-use the same pistons.
Also, rings rotate on the piston, staggering the gaps doesn't really matter past first start.

[hasa]

Okay, you've done careful considerations. Time to pull the head and specially the pistons to see if there are problems with ring clearances etc.

But... just to adjust expectations. Running 230hp/litre BMW is dancing on the razor's edge all the time no matter how careful you are. Bad fuel one day. Small mistake with mapping. Slightly over abusing the engine. Many scenarios where evil things can happen. I would not rely my daily driving on that, even it is fun!

[varg]

I appreciate the hopeful input but I'm sorry guys, I just am not comfortable trying to make 230+ hp/L on an engine that is all scuffed and has scoring of unknown depth, and DDing it. I have tuned a couple of cars making these kinds of numbers, and they were not the kinds of builds where you would wonder if stuff looked like this inside. I don't know what's causing it and it isn't supposed to happen regardless of who else it may have happened to. I also found those 4 metal slivers on the magnet which has me worried about a broken ring and noticed a loud tapping in the video of me pulling out of the driveway for the first drive which I could not hear in the car with the exhaust booming in the cabin which may indicate a more serious issue or just a lifter that wasn't pumped up. Can't tell.

Cylinder 4 in particular has me worried with a particularly bad looking mark. I won't have access to the scope for another week or so to take a second look, so I'm planning to pull the head this weekend and inspect the bores, then I will pull the engine if I feel anything in these scuff or score marks. Unfortunately I didn't take the best borescope pics: you can't tell which way the camera is facing and some seem to be inverted but maybe not all. But here they are including the newer ones like # 4. I don't want to continue run with a serious problem it and trash the bores and/or pistons if I can avoid it. These pistons are now $200 more than when I bought this set, and if I have to get another block machined and o-ringed because the bores can't hone out and stay in a reasonable piston clearance range with the ones I have I'm out a significant sum of money. I have built a few but I am not an engine builder, nor do I know any who would look at these pictures and give me an experienced response. I am extremely bummed but I'm unwilling to just wing it and possibly make a $2500 mistake; trashing my pistons and block in addition to what are likely already trashed rings. If I don't feel anything in the scuff or score marks, we'll see how I feel about running it.

1:


2:


3:




4:


5:




6:






Completely bummed out to see it languishing again, but I also need this car on the road ASAP because my E30's clutch is beginning to fail, the engine has been producing metallic oil for the better part of a few years now, tracked closely by oil analysis, and the rust is accelerating being outside all of the time. I did get a new phone though to replace my iphone 8 with its failed camera, so at least the continuation will be easy to document. I don't like having my DSLR around in the garage.

[Dj Buttchug]

I too have seen brand new engines do this. Even when all tolerances are correct the rings can cause some very very small markings. Just enough to be seen through the hone exactly as pictured. Varg, I would put a few thousand miles on that engine and the re check just for measure.

[AWDBOB]

I once built a 4g64 and had almost this same thing happen (compression, and vertical scoring), and freaked out. I was told by some meticulous engine builders (english racing) that there was something slightly askew. But was told by everyone else to send it. I sent it. The compression evened out once I got to the 500mi break in oil change, and was fine at 500whp for another 5+ years.

[varg]

I would not care. Ensure that injectors are good and send it.Those are quite minor scratches and compression is good.

You aren't the only person to say something like that, but it's not happening. The goal here is a daily driver that will occasionally go fast but will be relied on for years with as little excess maintenance as is possible with such a highly modified car, not a pile of junk or a weekend car. I didn't spend all this money on new parts to run an engine that is scuffed up and outside of any OEM or aftermarket compression test spec just so it can fail at an inopportune time, these results are worse than my E30 engine which has completely unknown mileage, pitted cylinder walls and glittery oil. I would have turbocharged a used M52B28 with cams and a cut ring head gasket if I were going to cut corners like that.

[hasa]

I would not care. Ensure that injectors are good and send it.Those are quite minor scratches and compression is good.

[varg]

A lot has happened since the last update. I installed the condenser fan and got a break-in drive per the Metric Mechanic protocol done, discovered an ac control issue and a heating issue, fixed the heat issue by wiring the fans to the ECU to switch them on when I want instead of when the thermoswitch on the cold side of the radiator decided it was 178° or 190°F, discovered it resonates in the cabin at idle and probably needs a longer tailpipe and maybe an exhaust butterfly, got another break-in cycle run, found that the flex joint scrapes a little on one of the speed bumps in my neighborhood, took the car on one 10mi drive... noticed something a little off. My tuner's ear told me that the idle, despite holding 13.3-13.5afr, was a little bit unsteady and maybe a little weak on one cylinder. I got worried so I parked it, did an oil change, saw more ferrous metal than I expected including 4 very thin 3-5mm slivers and decided to test compression. Bad news. A picture is worth a thousand words.



The subsequent borescope images:

Cylinder 6:




Cylinder 1:


They all have some scuffing and scoring. I don't know what I did wrong. What I do know is that:

• I oriented the rings per instructions
• I staggered the ring gaps
• I didn't put them in dirty bores
• I didn't put them in dry, and I even dropped 5cc of oil down the bores before cranking to build oil pressure (4x 10 second cranks, longer than I would like)
• I didn't over rev it (I had a limiter set for 5,000rpm)
• They weren't scratching the bores when I installed them and turned the engine over by hand with the head off so I doubt my deburring wasn't thorough enough

My leading theories

• bore wash - during the first few minutes of idling and revving to troubleshoot the misfire, the wideband didn't work because of a loose pin in the connector
• #6 injector sticking open or leaking since injector 1 stuck closed, I can't test them until I pull the intake because they don't clip in
• breaking it in too hard - it saw 4psi boost a few times because the throttle pedal was not moving smoothly, but was tuned conservatively and under 12.5:1 AFR
• taking too long to prime the for the oil I put in the bores during assembly and before cranking
• stalling too many times once hot during the break in cycles (I was interrupted by traffic and rain and the idle settings were too aggressive when hot)

Hugely bummed. 44mi is all it took. All I can do now is hope the damage is minor enough to hone out without exceeding the piston clearance spec so that I don't need either a replacement block or an overbore and replacement set of pistons, both of which would be painfully expensive. This weekend begins a scramble to get the engine out, strip it down, and get it re-honed and re-assembled the latter I don't think I am going to do myself this time because I don't know what went wrong.

[varg]

Big news! I got it running on all cylinders today. I called FIC and got a particularly helpful employee who recommended that I pulse the injector for a couple of minutes and tap on it with a mallet, that it's basically what they do with a stuck injector that sat in the box for too long. I wanted to do this in the rail so I tapped on it while using output test mode to give it 2ms pulses, around the tenth tap on the rail the injector started ticking. I let it cycle a few more times then promptly grabbed my cameras and started the car. It runs on all six cylinders now, what a relief. Who knows, it may have cleared up on its own with more running but I didn't want to take the chance and only ran the car for 3-4min total yesterday.

It's easier to tell what it sounds like now, it's a little raspy, and not as deep and burbly as my M20, but I'm also not idling at 875rpm here; 1100-1200rpm cold idle. I didn't rev above about 2,800rpm in this video, it may sound better under load at higher RPM. It's not too loud, which is nice. That was a concern of mine with a 3.5" turbo back exhaust. It's pretty responsive for a base tune, that lightweight flywheel is making itself known.

The radiator leak, which drips about once per 15s with the car off, I didn't get the cooling system pressurized today so I don't know what it's like at full temp. Same with the freeze plug, which barely dripped during the 3min or so it ran today.


And my simple and adjustable fix for the broken clip on the dashboard vent, a common E34 problem. Yeah, clear epoxy and AL filler wire. Not the most high tech or professional but it makes a good adjustable clip that does the job nicely and can be bent to fit nice and tight. Totally invisible with it installed. If BMW had glued a piece of filler wire to the vent from the factory, E34s wouldn't have had dash vents that pop up and bounce around.


Once I get the leaks fixed and install the brushless condenser fan, it'll be ready for engine break-in and tuning.

[varg]

It runs!
But only on 5/6 cylinders. These were not cheap injectors at $800 for a set and not only do they not fit without extra parts but my cyl 1 injector isn't firing. The injector has the appropriate resistance but it just won't click when tested independent of the ECU, I tried reversing polarity to unstick it because sometimes that works to unstick an old injector and got nothing. I also have a dripping freeze plug which has me pretty steamed, and a leaking radiator. The radiator is a brand new Nissens 540i radiator, I'll be testing FCP euro's replacement policy on this one I guess. I was tempted to try and re-crimp the area that leaks, but I didn't because I don't want it to hurt my chances of an exchange. You can't even pay for quality these days it seems. I have a couple of videos but there's no point in posting videos of it running on 5cyl, I'll post up when I have 6. I'm glad these problems didn't stop me from taking this car on my road trip in November because I would be way more angry at these issues than I am now.

Post run engine bay shot. The turbo is a big pain to install with the short S-pipe coming off of it and going to the intercooler. I am going to have to re-work that. It took way too much time cramming silicone couplers onto the turbo and intercooler, but space is very tight there, it's up against the wheel well and the AC lines. There's not even enough space for a tight cast aluminum 90° coming off of the turbo if I wanted to do that. I may modify my S pipe and intercooler to take one of those expensive aluminum clamped flanges that are so trendy right now but pointless for most applications. We'll see. I'm just hoping I don't have to take the turbo off for the freeze plug fix, the wastegate pipe is in the way and I don't think it can be removed without getting at the flange from the top.



Wastegate blanket. I thought this was pretty neat, I bought it to help keep the radiant heat off of the valve cover gasket area and oil return line (which has a sleeve, but still). It's kind of a pain to install and I hope I don't have to remove the wastegate any time soon.



Priming the oiling system. It still took about 40 seconds of cranking cumulatively, 10s at a time, to get the dummy light to go off. Pouring fresh oil into the galleries directly through the center tube gave me a little bit of peace of mind though.


Looking forward to driving it, but that can't happen until I get a new radiator and replacement fuel injector.

[varg]

There's going to be a huge inconsistency in photo quality here and I apologize. My iphone's camera has been messed up for a little over a month now, the focal plane is rotated and the image stabilization just twitches like mad so it can't take a good photo. As a result some of these are taken with my DSLR, which is very inconvenient to have in the garage while working, and others are iffy phone images. The E34 is getting close to being on the road now. There have been some delays, like damaging the O2 sensor bung and having to cut a patch out and weld it on my downpipe with a new fitting. The downpipe slip joint also got ovalled out from all of the clearancing and welding, so I had to weld a new one on. I could not find a single shop around here with a pipe expander that can do 3.5" pipe. Then while welding the new one on it started to oval a bit too, so I bought a pipe expander kit from harbor freight anyway making the rework feel like a waste of time it wound up fitting in the end, I haven't even opened the HF expander yet and may return it if I don't need it for the final assembly. This welding also altered the wastegate pipe fit, so I had to re-work that as well. No pictures of any of it.

This week I finished off the interior, the gauge pod next to the A-pillar is the CAD I was working on before, it's a weird looking pod but it was necessary to retain all functionality. It has a defroster vent, and it holds both gauges far enough away from the windshield that I can use a reflector. A pillar pods aren't available for the E34 and I didn't want to attach anything to the dash through adhesive of any other means, so this was the solution. Also, in place of the OBC, there's an oil pressure gauge. Just like my E30. The other printed parts aren't visible here, plugs for the holes the auto shifter was bolted into, and the ring that holds the shift boot in the surround. I also epoxied a piece of bent aluminum filler wire to the bottom of the big dashboard center vent to replace one of its broken clips. Seems to be a common problem in E34s that the clips break and that big vent sticks up from the dash. While we're at it in the interior, the twin disc clutch is super heavy and will take some getting used to.


Here's the current state of the engine bay. The downpipe and turbo need to be installed, fluids added, EBC solenoid wired, and it's ready to run. The radiator straps are the other type of CAD from before, I decided to change the way they attached. The intercooler has mounts welded to it that drop into the stock radiator mount cups, they were very ugly, I didn't take any pictures. the radiator and intercooler need to be securely mounted so they don't slide back and hit the pulleys, clearance is very tight. Also not pictured; a duct that fills the gap between the condenser and the radiator below the intercooler, so cooling air doesn't go around the radiator. It's just made out of corrugated plastic from signs. It's buried so it doesn't have to be pretty, just functional.


The radiator fans are an interference fit. The passenger side fan touches its hose clamps and the driver's side fan comes close to everything.




The radiator fans are controlled by a relay I added to the E34's convenient relay box, which contains the condenser fan relays. I like to scavenge BMW relay holders from junkyard cars that are ready to be crushed or not likely to be a harness donor for someone. The stock condenser fans relays will be needed for my big brushless delta pag condenser fan.


Getting a little out of sequence here, but I had to torque the crank bolt down to the M50's ridiculous 300lbft figure and that required a counterhold tool. They're ridiculously expensive, so I drew one up in CAD and had it cut, for something like $35 shipped. A block of wood against the AC compressor mount served as the brace point. Easy.



I probably would have had this thing running last weekend if it weren't for the fuel injector issue. Turns out the plastic manifolds don't butt up against the injectors, they just have a smooth bore, so Fuel Injector Clinic's direct fit application injector for an E36 M3? Not direct fit at all since it has no clips and doesn't bottom out. The injectors will pop out of the rail and spray fuel everywhere, which I found out when I tested the system for leaks after installing the new fuel pump and lines.


I was going to make some spacers but I was too busy this week so I wound up just fitting the nice spacers I ordered for just this problem from RallyRoad. Silver ring, visible at the bottom of the injector. A friendly PSA to anyone searching in the future, Fuel Injector Clinic's E36 M3 1200cc High Z injectors will not fit your M50 or S52 without spacers and a modified injector harness box (it hits the valve cover because the connectors are lower). Just like everyone else, their service seems to have gone down the tubes since COVID too. They didn't have spacer rings and didn't have upper spacers with clip grooves and a ridge for the necessary dual clips.


The fuel pump fit is pretty easy, luckily. you just slide the stock pump out of its plastic case, slice the case open to fit the much thicker DW400 pump, and slice most of the bottom of the case off so the pump can rest on the remaining portion and fit its sock. Wiring harness connector needs changing as well, of course.


Finally, a rear view showing the rear muffler and single tip. I may fabricate a dual 2.5" tip for this later, I would really like to since it would look better. I just need to figure out how I'll go about that. The brown paper taped to the hatch is to keep it from hitting the garage door when the car is lifted higher, which already happened once and left a scratch.


Fingers crossed, I should be able to install the condenser fan, fill up the fluids, and have it on the road tomorrow.