Specs:
- M20B27 block bored "40 over" (86mm)
- Wisco custom pistons, based on C&D Performance's Pro3 design & tweaked for 9.5:1 compression
- Max-speeding 130mm h-beam rods
- 885 head with 3-sided valve grind
- Stock camshaft
- Cometic 0.086" Thick, 86mm bore MLS Head Gasket
- Arp studs
- 325i injectors
- 380 ECU (stock for now; planning D'syliva tune)
- Exhaust: TBD
Original post:
Time for me to start another project I don't need, and one that will be big enough for its own thread. The M20B27 in Maytag (87 528e) has three annoying issues. First, it leaks oil out of the headgasket like crazy. Second, the valvetrain is super noisy (and adjustments have not helped). Finally, I want moar power.
The car has gotten a lot nicer since I bought it. It's a $2000 car that I've put about $3000 into...and I could probably sell for $4000. It's now a 5-speed & 3.46LSD. Has a nice black/tan interior with black leather sport seats and rear seat. The mold in the trunk is gone. The windshield no longer leaks. The stereo sounds great. It's clean inside, outside, and underneath. It has big brakes. Given the futzing I do on Vlad (87 535is) I do need a 2nd car as a 'stand-in' daily driver every once and a while. Heck, even Julie likes driving it sometimes. So I'll keep it and keep tweaking it.
In my professional and hobby life, I am primarily motivated by earning what I call merit badges. You don't get a merit badge unless you've demonstrated, repeatedly, that you have learned the skill. With my M30B35 build for Vlad I am on my way to earning the "80s Vintage BMW Engine-Rebuilding" merit badge. But I haven't earned it yet, because I haven't done it repeatedly.
I have a bunch of other merit badges I'd like to earn. For example: Total/ground-up restoration of a car, Rebuilding an engine head, and Turbo-charging a car. I could list dozens I have ambition around.
My original plan for Maytag was to just sell it after Vlad got running. Then I fixed it up too much to do that. So my plan for addressing the engine became "Just replace the head-gasket". Then it became "find another head too". I actually bought a partially refurbished M20 200 head on Craigslist. I learned-up on e2i conversions too so I started thinking about 885 and 731 heads and all that crap.
Then I bought an 340k mile 88 528e "Super-Eta" parts car on Craigslist on a whim. As a result of that adventure I now have an 885 head with the 7 bearing journals already drilled out for the 325i camshaft and a Super-Eta bottom end with Super-Eta pistons. Simultaneously I found a 325i intake manifold and have two complete Motronic 1.3 harnesses and electrics. I have a line on a 325i camshaft too. In other-words, I have basically everything needed to build a complete "e2i" (the E30 guys call it a "stroker") M20B27.
This engine will give me a little more power, won't leak (assuming I've learned my lesson), and will run nice and smooth. As a bonus it will be a great platform for forced induction.
It's entirely possible this project will abort, or change course drastically, quickly. This is primarily because I don't really know the condition of the bottom-end. The bores look nice, with clear cross-hatching and no ridge near the top. But I'll need to take a much closer look given it has more than 340k miles on it. If I get the sense that I need to pull the bottom-end apart and replace pistons, rod bearings, etc... then I'll probably take a different tact.
I plan on doing this 'on the cheap'. Where the M30B35 build got out of hand quickly and was anything BUT cheap, I'm going to really try hard to stick to my guns and not let mission creep set in. I'm also going to take my time. There's no rush...assuming the engine in Maytag doesn't esplode soon (it's such a rough runner that I sometimes wonder if it's about to).
Off we go...
Here's the bottom end:









I've removed most of the accessories and have it sitting with some degreaser on it over-night.
Here's the head. One exhaust valve is clearly bent from the timing belt going. I'm assuming I will need all new valves. I am planning on rebuilding the head myself (but will, of course, use someone else to do the machining). I really want the experience of putting a head together, and an M20 seems like a reasonable playground to start on.


The 325i intake manifold, TB, and TPS will be cleaned and checked. I already know that the TB has a broken part, which you can see in this pic.

Follow-along and enjoy the show...