changing cylinder heads without family change..

[xABSOLUTIONx]

i think i already wrote on this, sorry if i did..

so as it stands - using the same block, but having a different head

for instance, Honda early D series SOHC heads are interchangable mostly, 1.5 block with a 1.6 SOHC VTEC head? no problem..

idea as it is - you've built a 2 valve SOHC setup, but as years pass, you want to update it with 4 valves, now you need to build a completely new engine, almost from scratch, why not just let update the head?

same goes for DOHC setups as well and of course VVL

[TrackpadUser]

It was done this way for balancing reasons.

Running a family long term, and using it will give some bonuses to things like reliability.

If you let people change the head of their engines, it will open the door to a few lame tactics like running just a few engine families from the start until the end since they can be used in all applications by just changing the head.

[xABSOLUTIONx]

it could be penalised by not allowing changing from carbs to injection and vice versa, that would make sense imho

also it could be giving a penalty in the finalised car - morally old engine (12 years+) or something like that

[TrackpadUser]

Not allowing to change the fuel system is IMHO, worse than changing the head.

And it doesn't really fix the issue, since I will still have some do everything engine famillies, until 1988 arrives and I have to create new do everything families.

As for the penality, while it could be interesting, is that actually a thing IRL? The americans especially have a few examples of engines that have been in production for a very long time, like the AMC 4L I6 and the Buick V6, and I don't think people really cared about the age of the engine.

[nialloftara]

To change heads involves new head castings, new camshafts, possibly pistons, valves, timing gear, and in the case of ohv to dohc a rework of the block. To change from carb to single point is just a computer chip and a few sensors, changing to multi point involves a new intake manifold, wiring harness, and a few more sensors. You can still keep like 90% of the heads the same for direct injection.

[xABSOLUTIONx]

To change heads involves new head castings, new camshafts, possibly pistons, valves, timing gear, and in the case of ohv to dohc a rework of the block. To change from carb to single point is just a computer chip and a few sensors, changing to multi point involves a new intake manifold, wiring harness, and a few more sensors. You can still keep like 90% of the heads the same for direct injection.

please read OP again, not talking about OHV to DOHC, but rather having a 2 valve DOHC and making a new head with 4 valves

[nialloftara]

Yes but while i was covering that head change I felt like including all the work needed for the other head types as well. You'll still need a new head mold, camshafts, pistons, valves, and timing gear to go from a 2v dohc to a 4v dohc, or 5v or any other combination of overhead cam valve trains.

[xABSOLUTIONx]

ok, fair enough, but still it's cheaper than making a whole block, intake/exhaust etc.

i would to hear Robs thoughts on this, because i still believe, that this is a workable idea to a degree

[nialloftara]

I remember this from daffy a few months ago
http://www.automationgame.com/phpBB3/viewtopic.php?f=15&t=5844&p=65933&hilit=changing+heads#p65933

[PMP1337]

3. The number of valves is locked to prevent you from basically designing two wildly different engines (for example the SOHC, 8 valve Toyota 4AC, and the DOHC 20V 4AGE Blacktop) and reaping the benefits of a shared engine family. Those engines should not be able to effectively share the same production line, nor should the 4AGE Blacktop get much of a techpool advantage because you've been building the 4AC for ages.

4. Techpool will most likely be gained by building the same engine for a long time. For example the Buick V6 got a lot better over the 40+ years it was in service, as the engineers learned more about it's design. A big part of that is that they made no major design changes, they didn't go DOHC 4v, they just refined the same basic engine over a very long period. That's your reward for keeping old designs in service and perfecting their engineering.

This mechanic, along with the fact that you'll gain production efficiency by having similar engines on the same line, are the reasons why there aren't wildly different choices within one engine family.

Since we have a techpool for each tab you could have the techpool of the part you modify reset to 0 if you changed something. Which is also fair right now for the injection tab.
As is you could build carb engines for decades and then use the techpool on a SFI... That doesn't make sense.

So I kind of agree about changing the Head.