Production line change observations

[Kthree]

Thought it may be an interesting topic to discuss production line changes, specifically small/undocumented items of note rather than intentional model updates

S50B32 / E36 Evo

02/96 - Machined Conrods
??/97 - Fractured Conrods

02/96 - Engine/Main harness has direct ignition coil feed from IGN branch in fusebox (via X20 pin 21 - roughly 6mm2/10AWG
??/97 - Ignition coil B+ feed supplied via relay in DME fusebox, Relay/IGN remains via X20 pin 21 - roughly 0.75mm2/18AWG
*Available OE wiring data/diagrams are incorrect on both accounts

02/96 - Small charcoal canister in engine bay, below ABS pump, nothing in spare wheel well
??/?? - Charcoal canister in spare wheel well/under spare wheel

02/96 being my car, other dates are observed on other seperate cars/parts/spares

[MParallel]

Evo's never had machined rods, but the cracked ones.

[Kthree]

Evo's never had machined rods, but the cracked ones.

As i've just pulled mine down post failure, i can confirm that they did indeed have machined rods until some point in time 😄

[J!m]

Just like every other major manufacturer, often the documentation does not align with reality...

[Steage]

This is fascinating. When I did my head gasket a couple of years ago I found this sticker on the back of the head. Still (mostly) there after 20+ years and 120k miles. The date is a little hard to see, but it's 19/09/98. I've always wondered if that is when the engine was assembled, or specific to the head...

[J!m]

I'd guess build/assembly date of the engine.

[Kthree]

As i've just pulled mine down post failure, i can confirm that they did indeed have machined rods until some point in time 😄

After a brief look, it turns out that the conrod PN changed from 11241405263 to 11241406582 on 02/10/1997

[MParallel]

This is fascinating. When I did my head gasket a couple of years ago I found this sticker on the back of the head. Still (mostly) there after 20+ years and 120k miles. The date is a little hard to see, but it's 19/09/98. I've always wondered if that is when the engine was assembled, or specific to the head...

Cool. I only noticed this label when I was retiming the vanos last summer and had the scuttle out. I was cleaning out the space where the interior fan motor is located and when I leaned all the way over, I noticed this label. I wanted to pull it off, but also not. Anyways, it was too deep to reach anyways, but could make out the numbers with the help of an inspection mirror.

That's definitely the engine order/built.

When was th ecar produced? Should be later than the engine.

[MParallel]

After a brief look, it turns out that the conrod PN changed from 11241405263 to 11241406582 on 02/10/1997

The thing is that these numbers have overlapping production dates. This would imply that both machined (do you mean forged, as machined would mean machined out of a piece of billet in my book) and fractured (they are refered to as sintered) existed at the same time during that overlapping period.

I need to look further into this. BMW TIS wasn't helpful as no mention at all about manufacturing of conrods.

[Braymond141]

They can be forged with machined cap joints (this just means cut and machined to tolerance) or fractured caps.

BMW isn’t machining billet rods on a production car. I also doubt any S50 ever came with a non forged rod.

[Kthree]

Context was in respect to forged-machined vs forged-fractured joints

edit; photo would have highlighted the context but couldn't be arsed setting up a hosting service vs IG 😁

[MParallel]

Found some more info. Not much in BMW tech docs or anything, but multiple referenced to early Evo's having forged rods and from 2/97 having the sintered ('cracked') ones. (I knew about the latter)

I don't have a copy of the BMW Technical Training manual. They might have some info about it.



The E36 M3 one only has a old version that only talks about the S50B30

[Kthree]

Sintering and powder forging are a bit different, however often lumped together as powder is the base form. Powder forging pours the powdered material into a shaped preform mould (compacted with pressure/heat etc), heated to forging temp and transferred to the forging press for final hot press.

Still forged but without the higher level of machining required, win win

I'd love to have a go at the 3d printer here (at Airbus) and make up some fancy HR Giger looking conrods. Love to see what the FEA spits out, as even engine mounts/cowl brackets etc are markedly stronger and lighter as it is also a 'powder' base.

Found a video of it, old stuff but same principle https://www.youtube.com/watch?v=Cy3V3KR1LWc