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Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

E28 technical advice asked and given! Troubleshooting, modifications and more.
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tig
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Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by tig »

Jan 8, 2018 Status:

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:
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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.
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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.
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Follow-along and enjoy the show...
Last edited by tig on May 21, 2018 1:44 AM, edited 3 times in total.
jodystevens
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by jodystevens »

In for another quality thread!
slack
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by slack »

Subscribed!

I am in the process of doing the same thing to an '88 325 that fell into my lap awhile back.
tig
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by tig »

Performed a light/quick cleaning of the bottom-end this morning so I can start to get a better picture of its condition.
  • Good: It rotates very smoothly and feels tight.
  • Ok: All pistons show impact marks from hitting valves. I don't think this ruins them based on what I've read. #2 is the worst.
  • Ok: Cylinder #1 is in the worst shape of all of them. There is a noticeable ridge at the top that can be felt with a fingernail.
  • Good: No cylinders show any significant ring scoring.
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#1 - There is a ridge that can be felt
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#2
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#3
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#4
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#5
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#6
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So-far, so-good, I think. Next, I'll pull the oil pan.
tig
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by tig »

Looks like it has a couple hundred thousand miles on it...
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After wiping down a bit.
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_marshall
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by _marshall »

Looking forward to seeing round two come together!
tig
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by tig »

What's the right technique for fixing this up?

Image

I'm thinking I'd rather not pull the rod caps off and take the pistons out. I want to just slap it together. If I take it apart, I know what's going to happen next...
Dub-Nub
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by Dub-Nub »

Smooth it out until no sharp edge is present, you should be fine after that. I've done some reading when i built my vw engine.
davintosh
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by davintosh »

Here's a little incentive that I saw on FB this morning;

https://www.youtube.com/watch?v=8ZAE3ynUmU0

189 HP, 197 ft. lbs. torque. Pretty respectable for an M20, albeit with a fair amount of work.
-I have an eta block. I combined it with a m52b28 crankshaft, m20b25 pistons and kept the stock eta 130mm. rods.
  • Ported, polished, m20b25/885 cylinder head.
  • Custom exhaust system without cats.
  • 280 degree camshaft.
  • 3.25i intake manifold.
  • Switched to 1.3 motronic for custom tuning.
Gotta wonder what kind of results one could get just assembling the parts, and not bothering with the porting & polishing. I'm sure it helps, but how much...
Mike W.
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by Mike W. »

Dub-Nub wrote:Smooth it out until no sharp edge is present, you should be fine after that. I've done some reading when i built my vw engine.
Agreed. Sandpaper, emery cloth, a file, whatever it takes. A small recess isn't a problem, don't worry about it, it will carbon up anyway. I've been inside lots of M30s but no M20s so the following is based on that. My guess is pistons and rings are ok, I'd probably do bearings and maybe an oil pump.
burmester
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by burmester »

Mike W. wrote:
Dub-Nub wrote:Smooth it out until no sharp edge is present, you should be fine after that. I've done some reading when i built my vw engine.
Agreed. Sandpaper, emery cloth, a file, whatever it takes. A small recess isn't a problem, don't worry about it, it will carbon up anyway. I've been inside lots of M30s but no M20s so the following is based on that. My guess is pistons and rings are ok, I'd probably do bearings and maybe an oil pump.
Yeah, I would do bearings too and check pump if it's still somewhat within specifications... it is probably worn out.
And I would use one of these Image
180/240 grits are fine just to deglaze the cylinder walls and freshen up the cross-hatch pattern. And then new rings.
Obviously you will need to re-seal the bottom-end while you are at it, crank seal etc.
It's time consuming but a good learning experience :alright:
tig
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by tig »

Yea, see, that's the kind of stuff I *don't* want to do. If the consensus is the bottom end is too worn to just slap back in as-is, then I'm going to part it out. I understand those Super-Eta pistons are worth some $$.
tn535i
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by tn535i »

Required reading "If you give a Mouse a Cookie" applies here. It would be more fun for us 'spectators' to offer up suggestions for what you should do and spend more time and money on though. :)

My son has read and studied the M20 stuff a bunch as we have a slightly modified 2.7 in our e30. We did not pull the head on our project but did a few things. Some of what I hear sounds opposite of what I may have thought but you should look into. One example is that the e intake manifold with an i (or maybe it was an an M30) throttle body works better than the i intake, obviously with some work, for all around power delivery. True or not IDK? There are maybe three exhaust manifolds on the other hand and the last i are most open and maybe the same as seta but again can't remember. If you have one of everything you have options to think about. On the e30 you can use a full i exhaust so on an e28 either exhaust manifold should work with seta exhaust. The e30 crowd may give you more to go on in a lot of areas. I do know a 2.7 in an e30 with a 3.64 rear end and 5 speed is very quick and fun to drive. Maybe not a whole lot of top end but with run away from my 535i at 'normal' speeds.

IF I pulled the bottom end apart at all I would get a proper tool to hone the cylinders or even pay to have it done. Did you do a compression check before it came apart? Our M20 bores looked just like yours, some discoloration and slightest of what looked like pitting and barely an edge at the TRR. It had nearly 300k when we did the head and compression was OK before hand, but after the head work it was nearly perfect with NO work on the bottom. 150 +/- 5 on all 6.
Mike W.
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by Mike W. »

Bearings last a very long time but not forever, but as odd as it seems, rings and cylinder bores don't seem to wear any significant amount. Looking at things it appears the pump might be moot point, looks like they are currently unavilable. I'd still at least do rod bearings on a 340K engine.
oldskool
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by oldskool »

cek wrote:What's the right technique for fixing this up?

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JB weld that son-ofA-bitch!
Stevo12
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by Stevo12 »

One thing that's bothered me from the Maytag thread, is where Joel mentioned that the Super Eta pistons are dome shaped, and regular Eta pistons are dished. The shortblock off the '88 looks to have dished pistons.

I'm not an M20 expert by any means - but did he have it wrong (i.e. should SuperE pistons be dished), or do you in fact have a regular Eta that was transplanted into an '88 and run off of M1.1?
slammin_e28
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by slammin_e28 »

Those are super E pistons.

This is regular E pistons:

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Stevo12
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by Stevo12 »

slammin_e28 wrote:Those are super E pistons.

This is regular E pistons:

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Consider me learned. Thanks :cool:
slammin_e28
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by slammin_e28 »

Stevo12 wrote:
slammin_e28 wrote:Those are super E pistons.

This is regular E pistons:

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Consider me learned. Thanks :cool:
:up:

The dome refers to the portion protruding above the block deck. If you look in some of cek's pics you cans see the tops of the pistons doing that. The regular E pistons don't protrude above the deck.

IIRC the super ETA pistons are the same as late M20B25 (they were the same in my friend's 89 325is)....what's special is the rotating assembly as a whole. It's just a stroked M20B25. Head --> throttle swap with I stuff and you're gold.
JohnH
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by JohnH »

Just for completeness, this is a euro 276EB 10.3 piston as used in the 525e. The piston above is a 206E?, 9.8 piston from a 520i for comparison.

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Using the 731 head from the 520i together with its inlet and exhaust manifolds with Motonic 1.3 (173 non kat) and a M20B25 throttle body produces an engine which revs well to 5500rpm and on the road testing confirms that it provides similar level of performance as a 528i in the all important 20-80mph region.
slack
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by slack »

slammin_e28 wrote:IIRC the super ETA pistons are the same as late M20B25 (they were the same in my friend's 89 325is)....what's special is the rotating assembly as a whole. It's just a stroked M20B25. Head --> throttle swap with I stuff and you're gold.
Correct me if i am wrong, but the B25 Pistons differ slightly from the Super Eta pistons. The cut-out for the exhaust valve is smaller on the Super Eta ones. Hard to tell unless you have them both right in front of you. Allow me to illustrate this with my wonderful photography and professional use of Microsoft Paint:

Here is a piston from an '89 B25 block

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And here is an '88 Super Eta (ignore valve damage next to cut-out)

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stoney
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by stoney »

Having read through this post too now, Its hard to say what to do with the bottom end. Not sure where you are now seeing as this is 6months old.

Sounds like a compression test would have been useless due to bent valves, which is a shame, but these BMW bottom ends are pretty hardy things.

I say go ahead with your initial plans of refreshing the head and sorting out the conversion side of things, and if the bottom end then is suspect, at least everything else is finished and its just a bottom end refresh then, and wont be as daunting as a complete rebuild and wiring conversion.
tig
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by tig »

I forgot I had created this thread.

Since the engine re-build may or may not ever really happen, I'll keep it separate. He's an update I posted last week in Maytag's main thread:
cek wrote:I found my head! I've had a search going on CL for a while for a good 885 head and I finally hit the jackpot.

Just a few thousand on it (supposedly) since rebuild. E30 guy who met me in his jacked up Tacoma with big 'murican flag in the back. Really nice kid who works at Boeing. Had built his ultimate E30 325i and then got it crunched. My gain.

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He included the intake and valve cover, which I don't need.
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I noticed this on the head. Any idea what it means? It looks like it's glued on.
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For a little extra $ he threw these in:
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I have no idea if these 130mm rods are any good. Thoughts?

I'd like to get the exterior of the head, and the combustion chambers cleaned up. Any tips/techniques for doing so. I'm assuming it's be a bad idea to use soap and water...don't wan the camshaft etc... to start rusting.

Now I'm either going to find a nice donor bottom end or rebuild the Seta bottom end I have sitting on the stand from the parts car.
I've found a low mileage block that has already been honed (it's actually from the same guy who sold me the rods). He also has a 524td crank and a Gates Blue timing belt. I'm probably going to buy those off of him and ditch my 360k mile block and crank. The only thing I'll be keeping from the donor motor then will be accessories and the pistons.
KrautnotRice
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by KrautnotRice »

Rock on! Glad to see Maytag getting some love again.
I'm going down the same e2i road (aka the dark path) so will be following along :rockon:
tig
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by tig »

Team: I have been doing a lot of studying (and watching of Youtube videos) on engine rebuilding. I'm more motivated than ever to do the bottom end rebuild on this myself.

Step one is to take the current bottom end I have, which is presumed 'bad' due to the 360k miles on it, and carefully tear it apart, 'blueprinting' it as I go. It will be super interesting to determine just how far out of spec it is. I'll, of course, post my progress here.

This will give me practice (and I've read that practice is important in doing some of the kinds of measuring required). Two, it won't hurt anything because I've already made the commitment to buy a different block, so this one is assumed to be trash anyway. Three, I get to buy more tools. My birthday is next week and as I watch Jafromobile's Blueprint 10x videos I'm noting all the tools he uses :laugh:.

My question is: Do any of you know of a good Excel spreadsheet for tracking all of the blueprint numbers for an M20? I've looked around the r3v and other E30 forums and found some sheets (and dead links), but nothing that actually had the right format & data. I'm hoping to find something where someone's already put in the factory specs/tolerances. I want something that I can use WHILE taking measurements. I imagine something with a separate tab for each of:

-Overview
-Crank/Main bearings
-Rod bearings
-Pistons/Cylinders
-Deck

It would have all the factory tolerances built-in and would do the math (I hate math, even addition/subtraction) to show deltas.

Of course, this has to turn into a software project for me. ;-). I could just use pen & paper like the olden days, but then again, I can't.

I can't be the first one to have thought of this. But I've been surprised to not have found anything good yet.

While I'm at it, I'm not even sure where to go to get the truth of factory specs on an M20B27 other than Bentley's, and I'm not sure I should trust that, and I also am not sure it's comprehensive enough.
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by wkohler »

I have no idea where you would find any of those specifications.
tig
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by tig »

wkohler wrote:I have no idea where you would find any of those specifications.
Perfect. Thanks.
burmester
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by burmester »

I noticed this on the head. Any idea what it means? It looks like it's glued on.
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Old Stasi surveillance - pretty rare on the later 885 head...
VW+bimmer=bliss
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by VW+bimmer=bliss »

Saw that the cam belt gear was of the early stamped version, replace that with the solid sintered version. Would be a shame to put it all back together and have that fail.
ldsbeaker
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Re: Maytag's M20B27 'e2i' Engine Build Thread (87 528e)

Post by ldsbeaker »

I'm glad that Jafro motivated you. I knew he would.
I don't imagine such a spreadsheet exists, YET.

Sending you an email.
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