Time for Timing Chains

The Al Rilma update is upon us, and there’s one particular change about Engine Family Cylinder Head Materials being reworked into Head Architecture instead. Now the way I think the options will look like, according to how they were proposed in the dev updates, is probably about like this:
Iron Eco
Iron Cast
Iron Performance
Alu Eco
Alu Performance

However, I see a missed opportunity to add one particular nuance to those options between efficiency and performance: What if those were heads optimised for reliability/reduced service costs instead? By hypothetically using a timing chain in place of a timing belt for overhead cam designs.
It would yield an option which, at a cost of reduced smoothness and higher friction, give the benefit of a more robust utilitarian engine. Opening up that alternative so one wouldn’t have to rely on pushrod valvetrains for that archetype.

The options could be even increased if one would use a 2x5 selection field like it’s already used for fuel systems:
Discrete VVL
Continuous VVL

Doing so, one can propose returning VVL to the Engine family options again, as, by logic, the sytems and mechanics of those are complicated enough that they rather have the head get designed around it instead if being added in with a variant. Discrete would here correspond to having two different switcheable cam profiles like it’s implemented already (akin Honda VTEC), and Continuous VVL would correspond to infinitely variable lift (Fiat MultiAir, BMW Valvetronic).

I’d dare say that’s even better than implementing Flat 1 engines!

Given that chain-driven cams have not been implemented, the next major update could provide an ideal opportunity to introduce them to the game. Looking further ahead, gear-driven cams may well be considered for inclusion in a future build as well.

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I created a mockup of how the options could look like in the UI, not quite sure on that naming convention, but “Heavy Duty” would be the “Simple” but sturdy option.
On the flipside, Pushrods are already a sturdy design, but there are things like Hydraulic vs Solid vs Rolling Lifters, which can be thought to lend their role into the build-plan of those various Head Architectures. Maybe the Heavy Duty option is actually adding Smoothness to that valvetrain type, thought to utilise Hydraulic Lifters!

Oh and as to how it could be relevant to discern Discrete vs Continuous VVL, the discrete would already be the option lending to performance, as you can freely add a high RPM focused profile while still keeping a strong midrange, and it’d be easier and earlier to develop than continuous. That one however would be strong for emissions and efficiency alongside throttle response, as it can functionally replace throttle bodies and even engage in atkinson-cycle mode.

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The issue with VVL is that it’s incredibly hard to place. On one hand, there’s some modifications that need to be made to the head design in order to allow for VVL. On the other hand, some real engines like the Honda D15 B ere offered with multiple states of VVL - in the case of the D15B, it could be found with conventional valves, 2-stage VVL and even 3-stage VVL, with only relatively minor differences between them. There’s other cases of this as well, but the D15B is literally the same engine. The argument can be made both ways, and I personally feel that it’s a little less family defining than the other characteristics in there in the current version. It’s probably hard to find a consensus on this, though.