Yep, another M5x question

[Jean]

Searched to see what I could find on aluminum engines and just wanted to confirm a few things.

1. how much lighter is it really ? (52lbs?!)
2. did they only come on z3s?
3. if staying na, what combination of crank/pistons would you go with before seeing insignificant gains?
4. cooling, are they prone to warping easy under racing conditions?

----- notes----
A 2.8 aluminum block from a Z3, with a knife edged 3.2 crank, .50 oversized pistons, M3 cams and
an OBDI conversion m
stu-
aluminum Z3 block
84mm bore 11:1 pistons
E30 turbo-diesel crank
Solid lifters, Schrick race cams
Oversized intakes
OBD-1 manifold with custom dual-throttle bodies
Euro HFM
Custom software (8500 redline)
17# injectors with bumped fuel pressure
E30 doghouse gearbox
8 pound fly
Motorsport 228 clutch
3.64 rear end.

mattm20-
you know the all the later (not sure about the earlier ones) M52's and M54's have alluminum
blocks. which includes 2.5L, 2.8L, and 3.0L
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

stu-
Side note,
I'd recommend using the 3.0 or 3.2 crank, but I'd probably retain the 2.8L 84mm bore pistons.
They are graphite coated and work very well. 3.0L 86mm or 3.2L 86.4 pistons won't fit in the
aluminum block because you can't stretch the bore far enough though.
You can fit aftermarket forged 85mm sluggers though!
Aluminum blocks rock!!! 52 pounds lighter and cross-bolt mains.!!!
crap, another side note...
2.8 crank is 84mm and forged, so if you retain the stock pistons you'll have a square bottomend,
which rocks.
Go whatever route you please though.
My dad is running 84mm bore in his aluminum block, with a 3.0 crank. It's about 2840-2850cc.
3.0 crank is 86.6mm
3.2 crank is 89.6
so you make almost anything out of it, just not quite a 3.2.

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
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.

stu-
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.

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.

jarvis-
M50B25 = 84 x 75mm
S50B30 = 86 x 85.8mm
S52B32 = 86.4 x 89.6mm
S50B30 crank + rods in an M50 block (stock 84mm pistons) = 2.9L
The S54 has a 91mm crank, which is what you might have been thinking of.

[FredK]

Hahaha JEAN, M5x time huh!? :mrgreen:

You might as well delete what Budget Beater said. The bore x stroke info is only half right, and his info about increasing displacement with just a crank and rod change is DEAD wrong.

The M52 with ferrous cylinder liners came ONLY on the 1997-1998 Z3 2.8.

I am not sure what your intentions are with this car, but there's certainly nothing wrong with the 2.8L engine as-is. With S5x cams, you are already over 200 whp! My humble opinion is, BMW assembled these engine pretty well. If you get a nice 2.8L engine, just run it!

[Jean]

Lol, yeah I'm getting closer to decision time. I sometime tend to overanylize things but I would hate to do a swap twice .

Intention is to make it into a solid and competitive autox car that will also see some track days. I've gotten my feet wet in HPDE, would love to try TimeTrials next but don't want to risk running in close groups at events like Nasa etc...

[PiercedE30]

Here's what I would suggest. Get the S50 crank, same rods as the 2.8L and they are forged, get some custom pistons (from the math I have done you need a piston that is flush with the deck of the block and has a 3.3cc dish) and do the 2.9L, which is 11.5:1 with the custom pistons.

[static]

I agree with Piercede30, run s50 crank, 11.5:1 comp, custom tuning and maybe even meth/water injection (or just race gas).
-50lb at the nose = sweet.

also i hear 7500rpm+s52 crank = teh destruction. You can beef up the head all you want, the bottom will vibrate itself apart with the s52's stroke above that rpm (esp with 8lb fly).

[PiercedE30]

Yea, my rev limiter is set at 7500 and normally shift around 7000, when getting on it. But I have my bottom end balanced and ARP main studs.

[Jean]

I am taking notes

[Jean]

Would a non z3 2.8l m52 head bolt onto the z3 2.8l m52 block ? Are the heads and blocks interchangable between the M50/M52 engines of different models/years ?

This MIGHT make it easier for me to find a good deal and get the right parts for a swap.

[PiercedE30]

As long as the head isn't from an M52TU, you're golden. The M52TU is a dual vanos motor that is a completely different casting from the normal M5x motors and are non-interchangeable.

[btec116]

Back to weights, with all accessories Drew325is weighed the engines back-to-back (the only guy I know who has) coming straight out of the bay (not just the stripped engine);
M20B25: 180kg,
M52B25: 150kg.
That puts front-end weight closer to a 318 than anything else.
I like the idea of that!
Otherwise, the change to M52 (in the E36) was in '96. Mine is out of a build date Feb '96 (AUS). Although you US boys got some wierd cast-iron concoctions for a while, I think. Not sure what the go was with that. Come to think of it, maybe it was the sulfur problems???
FredK, what are ferrous liners? Just wet sleeves? What were they used for? Fuel (erosion) problems? I have never heard of that used on a BMW block. How interesting...

[PiercedE30]

Shit, I weighed my car last week at one of the CAT scales here in town. Total car weight with spare = 2675. No A/C compressor, condenser, or lines and no PS.

[Jean]

Back to weights, with all accessories Drew325is weighed the engines back-to-back (the only guy I know who has) coming straight out of the bay (not just the stripped engine);
M20B25: 180kg,
M52B25: 150kg.
That puts front-end weight closer to a 318 than anything else.
I like the idea of that!
Otherwise, the change to M52 (in the E36) was in '96. Mine is out of a build date Feb '96 (AUS). Although you US boys got some wierd cast-iron concoctions for a while, I think. Not sure what the go was with that. Come to think of it, maybe it was the sulfur problems???
FredK, what are ferrous liners? Just wet sleeves? What were they used for? Fuel (erosion) problems? I have never heard of that used on a BMW block. How interesting...

This is for aluminum M52, correct ?