FYI - Aluminum e36 Block

[rwh11385]

alright. Bore/Stroke numbers :P

I got all this in a simple program, plug and chug: put in the #'s, spits out the CC's:

Bore Stroke Displacement Liters
84 75 2494 2.5L stock i
84 81 2693 2.7L stock e
84 84 2793 2.8L stock 328
85 75 2554 2.6L bored i
85 81 2758 2.8L bored stroker
85 84 2860 2.9L bored 328

86.35 86.6 3042 3.0L stock 95 M3 (not sure on bore/stroke #'s, different sources=diff #)
86.35 91 3197 3.2L stock 96+ M3

84 86.6 2880 2.9L 328 w/ 3.0 crank
84 91 3025 3.0L 328 w/ 3.2 crank
85 86.6 2948 2.9L bored 328, 3.0L crank
85 91 3098 3.1L bored 328, 3.0L crank

86.4 75 2638 2.6L M3 pistons, 2.5L stroke
86.4 84 2955 3.0L m3 pistons, 328 crank

haha that's as many combos i can think of right now! Hope you enjoy..... I was really bored at work today 8)

EDIT: when comparing say..... 85bore/84 stroke and 85bore and 86stroke:
85 84 2860 2.9L bored 328
84 86.6 2880 2.9L 328 w/ 3.0 crank
they are within 20cc's of each other. But compare the cost of a 3.0L crank with the cost of custom pistons, and then the benefit of being able to high-compression..... i'd go for overbore than a longer stroke.

[rwh11385]

theyre not as rare as you think. all 96+ (or maybe 98+) E36's (2.5 and 2.8L's) had alluminum blocks, its not just for z3's

Hey, sorry i'm post-whoring this thread, but i love Engines!!! It must be the engineer in me..

anyway, could one find a M50 head ala Vanos and OBDI, and swap in onto a 328 block (which would be aluminium, giving him a 2.8L aluminim OBDI motor?) And also, one could swap in 85mm pistons and 3.0L crank if desired, right?

- - Wingnut

[Stu]

MattM20--

Incorrect. The aluminum block that's M50/M52 is only in the 2.8L Z3. Newer motors (M54 or S54 or whatever) have aluminum blocks, but those are out of the question for E30 swaps.

We did an aluminum block E30 swap 4 years ago.

[lukasbmw]

When did they switch to the M54's in th Z3's? 2000? Just something to remember. If you see a BMW Z3 block on ebay make sure you get the year as 2000+ blocks are aluminum but they are M54 blocks and will not work. You need a 96-99 2.8 block from a Z3.

[Inspar8r]

I would have raised the red flag when there was RUST in the ALUMINUM block. Caked on from the pistons? Can't be good. Even if....

I know Aluminum oxidizes, but damn, under what kind of circumstances have you seen aluminum rust?

[trent]

I would have raised the red flag when there was RUST in the ALUMINUM block. Caked on from the pistons? Can't be good. Even if....

I know Aluminum oxidizes, but damn, under what kind of circumstances have you seen aluminum rust?

If I am not mistaken, the bores are sleaved.

[JRowe]

Sleeved block. Stock bore is 84mm can be bored to 85mm for new pistons. Rust wouldn't have been a problem.

[lukasbmw]

Gotta bring this thread back from the dead as I just found an aluminum block in a local yard. Similar situation, total price is $400. Block comes complete. Owner of the yard says the block is in working order but it has some rust.

I guess now I have to decide what do do. Do I want a 2.9 high reving machine, (85mm high comp pistons and 3.0 crank), a 3.1 torque monster (85mm high comp pistons, 3.2 crank) or a boosted 2.9 (85mm low comp pistons, 3.0 crank)?

Stu would you recomend a 2.9 or 3.1? HP/TQ estimates for each one? I think I'll go N/A for now as it will be cheaper, and lighter (A turbo system will add 40 pounds to the front and I want 50/50 balance).

[Rob]

if you're going NA, there's no replacement for displacement.


To me, coming from two low torque cars, the 2.9 would feel like a V8, however, since you already have a m50, the 3.1 may feel better to you if its an option

[MattM20]

MattM20--

Incorrect. The aluminum block that's M50/M52 is only in the 2.8L Z3. Newer motors (M54 or S54 or whatever) have aluminum blocks, but those are out of the question for E30 swaps.

We did an aluminum block E30 swap 4 years ago.

i'm positive the 2.5L and 2.8L M52 blocks found in the E46 are alluminum, so i was just assuming it was that way with the E36's since they were fairly unchanged except for double vanos

[FredK]

lukas, weren't you planning on selling your E30? I guess you just don't want to sell it!

Anyway, I like this thread, because it is pretty informative.

[edit] I just read Stu's earlier post about sourcing 85mm pistons--they'd have to be custom.

If you wanted to replace the steel sleeves, where would you get them?

FredK

[lukasbmw]

I'm always selling my car if I get a good enough offer. In the meantime I'll buy parts if the price is right. Afterall, I could always flip it for a profit.

But things are also looking up for me money wise. I just started a new business venture that should bring in some nice extra income.

[Addissimo]

Square means the bore diameter is same as stroke length. It is the balance between long stroke -> low-revving torque machine and big bore -> high rev, high horsepower engine. This was much talked about when i was in the Honda camp years ago. When building a motor, too much stroke can ruin revability....etc.


from http://bimmer.roadfly.org/e30m3/mess...w18/25552.html

basically, high specific output from a motor requires a proper balance of bore/stroke and other factors. Many engines seek the perfect combo, like the 95 M3 was square, 86.4/86.4 i believe..... and the famous SR20DET from Nissan was 86/86. And the new Acura RSX is 86/86. See a pattern?

Look at the "I" and "e" engines, the I has shorter strokes, and rev like made....the e's have long strokes and are torquey.....

I'd say 84/84 is good, but well, that's stock 2.8L..... I'd go for 85 aftermarket, high-compression pistons and the 84mm crank..... for a high horse, high rev NA machine!

Or go for a long stroke, low comp, high boost monster....... just think about what applications your looking for and have a motor-builder help you...... or their sons. **cough** Stu **cough** anything he says will probably be accurate and helpful

i need to take a break, but i'll be back with calculations of all the stroke/bore combos.

What do you think the limitations of a 3.1 would be redline wise? Would 7300rpm be safe with this setup?

[Budget Beater]

S50 and S52 crank both have 91mm stroke. one has slightly larger bore. you can make E36 325 engine into M3 engine (almost same displacement) merely by swaping to M3 crank and rods. both the rods on the 3.0 and 3.2 are 135mm.

325 is 84mmx74mm stroke
328 is 84mmx84mm (square)
3.0 is 86mm-91mm
3.2 is 86.5-91mm

i think those are accurate as i remember from bently manual, only one im unsure about is the 3.0 but others should be right.

7200rpm is the max SAFE RPM you can push b/c of the hydraulic lifters, the hydraulic lifters max out at 7500-7800rpm. another reason is valve float, with high RPM valvetrain you can solve that problem. thats why you can't push the E36 motors any further. 7200rpm is honestly all the rpm you'd ever need though, S50/52 motors at 7200rpm sound heaven-like. If you do get the high RPM valvetrain for the E36 motors you CAN push it all the way to 7500rpm they safely they say.

[Beej '86 325es]

I'm not Jim Rowe. I'm Jeff Rowe and I'm not related in anyway that I know of. I just happen to have the same first initial and last name.

That threw me off. I already sold Jim Rowe an aluminum block with 8k miles and he already knows how to build them up. ...plus I can't see Jim saying "score!"