A 24-valve M20

[Alex Mc]

I want a 12v head for an M50 now.

HA! That made my morning!

Bending valves depends whether the engine is "intereference" or "non-interference" and this is a fuction of lift, duration, piston design, CR... not as simple as how many valves are in each hole.

[dougie30]

I live right down the road from where he blew up the quatros engine ahaha

My dream is to find one of these in some old woman's garage somewhere in the back woods of ct

[Vin-barrett]

Eh ludicrous is a strong word. But it's not out of the ordinary for companies to buy out the technology of other companies, or even buying up entire companies for that purpose.

While it may sound reasonable you have to understand Germans are not.
From experience I will tell you there is no way in hell that in those days BMW would adopt Callaways design.

Never mind a cylinder head, If the Germans gave a $hit your E30 would have come with a cupholder....

[fporro]

It's my understanding that 24v m20 heads went from Callaway's shop to Racing Dynamics, once there Federico's team took a shot at them as a few critical issues remained, project ran out of time due to m50 engines.

As far as bringing them back from the grave ... RD would do it, but whom's pledging 250k's to get project started ?

Group buy ? $ 2,500 each x 100 heads = much happiness :)

[TobyB]

There was a BMW production prototype for a 4v head for the M10 in the early 70's.
BMW decided that it would be too expensive and too hard to maintain (i.e. warranty).

The M12 4v M10 racing head's not all that uncommon in a Chevron, March, etc sports
racer from the early 70's.

Alpina did a 4 valve head for the M10, too, and Alpina and BMW got along pretty well.

Well, then there's the S14, too. Oh, and the first M42's showed up in ROW in the late '80's.

So BMW was no stranger to DOHC, they just didn't see a place for it in a production
car until the 'gas crisis' blew over.

So really, while it would be cooler than shit to bolt a 24v head (and pistons) onto an
M20, it certainly can't be cost- effective, seeing as an M5x can be had (with a whole
donor car wrapped around it) for a couple grand. AND the M20 bottom end's not really
that different than an M5x anyway.

Historically cool, sure!

t

[LJ851]

Alpina did a 4 valve head for the M10, too, and Alpina and BMW got along pretty well.

I have never seen an Alpina 4 valve M10 head, You aren't referring to the Schnitzer 4 valve M10 heads are you? I have seen a few of those in person.

[lukeADE335i]

There was a BMW production prototype for a 4v head for the M10 in the early 70's.
BMW decided that it would be too expensive and too hard to maintain (i.e. warranty).

Rumour has it that BMW also originally wanted to stick with a single cam for the M50, but went over to 24 valves for marketing purposes to avoid being seen as technically inferior to Mercedes (and by then the Japanese were also getting into twin cam engines in their mainstream vehicles in a big way).

[nando]

BMW made a 24v M20. Its called the M50.

[TobyB]

You aren't referring to the Schnitzer 4 valve M10 heads are you?

oh, yeah. probably am, now that you say it.

t

[Julien]

back from the dead...


It's always been my understanding that the release of the e30 m3 killed off the 24v m20 heads

[ELVA164]

back from the dead...


It's always been my understanding that the release of the e30 m3 killed off the 24v m20 heads

That seems like a reasonable conclusion, since the 2.5 with a 3.73 was already torquey enough to beat an M3 to 60 unless it had a 4.10 rear.

[whodwho]

back from the dead...


It's always been my understanding that the release of the e30 m3 killed off the 24v m20 heads

From Frank's discussions with Federico @ RD

"It is the same head that Johnson made, it was sold to Callaway in CT then it passed on to RD., by then BMW had their new engine, so project was dropped."

Not sure when RD got it/gave up on it

Reeves Callaway developed and marketed a 4-valve M20 head back in the E21 323 days
Discussions started - November of 1983.
Initial blueprints made spring of 84
Hans Hermann would perform the initial design.
Six months later,the initial design was finished.
On October 1, 1984,at 2:27 am, the first Quadros 2.3L prototype on the dyno at Callaway Turbosystems
By the end of 1984, the people at Callaway had customized a special intake design, coupled with the Hartge exhaust, and achieved 200 HP.
In car testing - winter of 1984

On looking for timelines I stumbled across this, lots of people talk about doing it but hadn't seen or heard on this one

3.0 Liter Stroker M20 with s50b32 Head


Published on Feb 25, 2014

M20b25 engine block with S50b32 (E36M3) cylinder head .. Protest Safe DMSB group H15 engine
Nearly 1,000 hours of working time for planning and implementation .. Over 2 years.
But for now I've got a unique engine ...
It was supported by a forged crankshaft with 86mm stroke and connecting rods H ...
Schmiekolben according to my specifications ..
dry sump pump ...
Freiprogramirbarem KMS controller ....
airbox ...
2Scheiben AP sintered metal clutch Nought Nothing was left out.
What can I say about the performance ....
SUFFICIENT .:-))))
Comments about this is, please save any M20 block and look closely!

[fporro]

I'll like to add that during passed conversations Federico said that "250K for further development before 100% completion was needed".

That's a 100 of us at $2500 ea.

Perhaps value assessed from original expected sales figures.

In any event, the meltdown was real, from heads casting molds to valve covers and rigs for headers, everything.
RD's unequal passion and love for motoring can bring them back, all they need is a commitment from the community and maybe ...
a good 3d printer ;)

Mahalo.

Aloha.

[digger]

From Frank's discussions with Federico @ RD

"It is the same head that Johnson made, it was sold to Callaway in CT then it passed on to RD., by then BMW had their new engine, so project was dropped."

Not sure when RD got it/gave up on it

Reeves Callaway developed and marketed a 4-valve M20 head back in the E21 323 days
Discussions started - November of 1983.
Initial blueprints made spring of 84
Hans Hermann would perform the initial design.
Six months later,the initial design was finished.
On October 1, 1984,at 2:27 am, the first Quadros 2.3L prototype on the dyno at Callaway Turbosystems
By the end of 1984, the people at Callaway had customized a special intake design, coupled with the Hartge exhaust, and achieved 200 HP.
In car testing - winter of 1984

On looking for timelines I stumbled across this, lots of people talk about doing it but hadn't seen or heard on this one

3.0 Liter Stroker M20 with s50b32 Head


Published on Feb 25, 2014

iirc there is also a m54b30 head on an m20 block.

TBH i cant figure out why you would build a 3L m20 and put a 24V S50B32 head on it. it seems like a complicated and potentially unreliable way to achieve something that basically exists already. at least use a 75mm stroke if youre going to do it

[fporro]

and oem dual valve pistons, instead of e36 units ?