Das Beast: My E30 track / street build

[dvallis]

And .... we're back from Holidays. Have not touched a keyboard in two weeks. Lucky I can still spell E30. ;-) Made some progress tonight though. Ready to pull the trigger on the engine rebuild. We're setting up a friend's garage with an engine stand and building a metal frame lift. Should be ready to pull the engine and tranny in a week, then start tearing that thing down. Will be my first engine build but the guy who's helping has done several. Should be a good adventure.

[2mAn]

update?

[dvallis]

Hey Simon

Still getting friends garage ready. He's installing a permanent overhead I-beam to hang the chain hoist from. Might be another couple of weeks. Once we get that done, engine comes out.

[dvallis]

Das Beast Lives! Was regrouping resources. :-)

Here are the raw materials for our overhead hoist. It's being built into the garage structure and will have waaayyy more lift capacity than we need for the M20. Garage owner has future projects in mind. Steel I-beam and two 6x6 posts.


Beam ready to install. It's LARGE.


I beam getting sandwiched between two 2x6. Will be held together with compression bolts.


Posts in place


Mounting brackets for hoist


1,500 lb electric hoist, load leveler and engine stand


Engine stand ready to go


And the project stalls because we don't have the right damn BOLTS. Engine stand needs 4 x M12 x 80mm, T1.75mm for attachment to the M20 block. Hoist needs 4 x M10 x 180mm, T1.5 to mount on our beam. Neither of which were to be had anywhere in town.

Bolts on order. To be continued ........

[dvallis]

Great. Can a moderator please ban this troll?

[dvallis]

+1 for awesome moderators here! ;-)

[dvallis]

So, I decided Das Beast is going to be a turbo stroker. After reading 1,000 posts and making a spreadsheet until my eyes were blurry ... here's the plan:

Stock M20B25 engine
M52B28 forged crank
M20B27 ETA 130mm rods
140 mil head gasket
Assorted "refresh" bits and pieces (will know once we open the engine)

Specs:
Displacement: 2.8L
Crank stroke: 84 mm
Piston Bore: 84 mm
Rod Length: 130 mm
Rod/Stroke Ratio: 1.5 (I know, it's short. Oh well)
Piston height: 34.2 mm
TDC Height: 206.2 mm (Versus 206.7 stock)
Compression ratio: ~9.0:1 (includes 140 mil head gasket)

Got a fellow R3Vr selling me the crank. Might have the rods from CL.

The Adventure continues ...

[HennaE30]

Das Beast: My E30 track / street build

Eta cranks are forged? I thought the only forged M20 crank was the td cranks?

Also interested to see what the 3.1 stroker with 11.5:1 CR can do. Probably really limited by the 885 id imagine. Decided what turbo your going to run?


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[Reichart12]

What pistons are you going with? When I did my stroker I ended up getting +1 custom pistons and because of that was able to retain the 135mm rods. Your combo is definitely the more budget friendly version.

[stonea]

Eta cranks are forged? I thought the only forged M20 crank was the td cranks?

I'm pretty sure you're right. The eta was cast, but the Diesel was forged. Same dimensions, jut forged vs cast.

Great recipe though! I think its the best stroker combo out there! Just make sure to get an early model 2.8 crank, the later ones require machining.

[dvallis]

Lots of data over on e30tech about cranks, rods, pistons and such ....

So there was a cool development today. My favorite independent BMW shop is cleaning house and wanted some things gone, including a M52TUB28 E36 dual vanos aluminum block. I BRIEFLY thought "lightweight swap!" then recovered my sanity. We'll pull the 2.8L 84mm crank per the stroker plan.

Here's a shot of the engine. WTF is it?


Found this tag under the block. (Ugh) Translates to M52TUB28.


So some machining to do but what the heck. It's a free crank.

[dvallis]

Using stock pistons. Saving ~$1000. Need the short 130mm ETA rods to make it work. See the spreadsheet.

[HennaE30]

Das Beast: My E30 track / street build

I would keep the M52tu and boost it. You can make much more power, and it is lighter. Best of both worlds. Also it's a hell of a lot easier to do. Plus you don't have to cut anything up to do it (in terms of machining). Mate it to a ZF320 from the E46M and boom: high horsepower, lightweight, 6 speed E30. What more could you want?

Edit: if you want a little more info on the M52tu, check out 2mAn's build.


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[dvallis]

You would think aluminum M52TUB28 = lightest weight. Not so.

The aluminum block is 50 lbs lighter than the iron block, but dual vanos is 25 lbs heavier. Net result is the M52TUB28 and M20B25 weigh virtually the same. Since I can get a fully designed turbo kit from KaMotors (Canyon Crusher) I think the M20 2.8L stroker is still the better option.

Anyone have an actual picture of M52TUB28 fully dressed on a scale that says otherwise?

[stonea]

2mAn has an aluminum M52 not a M52tu. The M52 was actually an aluminum block motor in europe, but in the states it was iron (except in Z3 in 1997 and 1988). The M52tu then came out, and it is very closely related to the M54, but is drive by cable, smaller intake, and I think heavier internals. Those weights sound right, BTW