Hi, Here are some suggestions for the engine designer.
Keep up the good work!
hard to make them disappear, but maybe just grey them out/lock them?
Well, the family bore/stroke is setting the Max bore/stroke and then you can reduce from there (so you still have a block designed for the biggest capacity you need), though I guess there is no reason they couldn’t default to half way between max and min.
Yeah, we do need that in a tutorial, we noticed that today.
Re 2; When you start with an engine family, you need to begin with the biggest engine.
And downsize from there. Ok.
Cheers!
[quote=“ThomasD1962”]Re 2; When you start with an engine family, you need to begin with the biggest engine.
And downsize from there. Ok.
Cheers![/quote]
Yep, you have to make a block BIG enough to fit the biggest bore and stroke you might need. Then you can always sleeve the bores smaller, or run a shorter stroke crank (but it won’t make the external dimensions or weight lower)
That last bit of explanation is quite important for people to be aware of. I can see there being a lot of questions like: “why can’t I fit my 1,4 engine in this body like before” when the engine is actually physically as big as say a 2,0 engine.
But then again, the size arrows should make that pretty clear? 
Can you make the variant capacity become even larger? Since this is already allowing more under bore and over bore designs, I would like to take it further to make a 2-1 b/s ratio if possible, so far its 4" - 2.55" b/s and 2.7" - 4" b/s. I would like to make a very underbore to build a car suitable for Britain’s rules, and a very overbore engine to make a very high performance N/A engine.
Making a 2.8L V8 engine with a 4" bore would be a monster and sound like none other.
So… which production car engines use such bore and stroke ratios?
the wartsilla engine has a ratio of 0.384:1, and I’d really like to see the engine car sized. with 120 mm stroke and 46 mm bore a 4 cylinder would be a 1.8L. This engine would be great for England, very small bore tax, good power, and this ratio has proven to work.
You didn’t answer my question. I don’t care what you want until you can show where in the automotive market that thing was used and to what extent.
Wärtsilä produces two-stroke diesel engines for SHIPS (your example has a bore of 960mm and a stroke of 2500mm, how is THAT going to fit in a car?) not cars, the lowest ratio I can find is for an old Dodge flathead with a bore of 83mm and a stroke of 117mm (0.709:1), FAR more than your example, I dont even think that your engine would be feasible, the stress on the components alone would be so high you would need to keep the RPMs below 2k just to keep it from flying apart. And even IF you can provide an example within your limits most of these types of engines were pre-1950 flatheads, there are very few engines these days that use such a ratio, most of the modern ones are above the 0.8 mark, nowhere NEAR your 0.4 mark and still not close to the historical flatheads that ran in the 0.7s.
The original wartsilla is on a cargo ship. The old willy engine has a crazy undersquare design but its able to thanks to the current version. Even though you didn’t want to make as many engine sizes as possible, this is the only realistic software that works. It shouldn’t take that long to finish the possibilities and dyno graphs of all sizes of engines. Rollercoaster tycoon had a similar idea with limits and all but that grows old within hours of playtime. There’s many that love to go over the limits to see how high and fast they can go before it breaks. This game could meet a similar fate. The only reason we don’t have every design possible available in the real world to this date is we’re limited by money and storage.
The Willys 134 was still not as over-stroked as the Dodge in my example, it was close though at 0.714.
the willies go devil (such a awesome name BTW) is re creatable in game currently, 79.4mm x 111.1mm is easy. The largest capacity possible at maximum undersquare is 81mm bore x 120mm stroke, and largest at max oversquare is 120mm bore x 76.5mm stroke.
Except that it is only creative size wise and not technology wise, the Go Devil was a Flathead design, the Hurricane was a F-Head design, neither are reproducible to exact specs, you can get close with a really crappy (-5 tech or so) OHV and no compression though.
The question for over/underbore though so valve placement doesn’t apply, and as for compression it only had 6.48:1 anyway.
Back to the core question, perhaps? 
As I witnessed myself: it is possible to widen a bore, if the block allows it, to a certain amount. We did widen a 1800 gti mk1 engine to 1900cc in one of our RX-cars. And you can elongate the stroke by using longer conrods and thinner (but better) pistons.
This techniques to secretly raise the capycity just a little bit are considered a bit shady in motorsports but not uncommon.
So to raise and/or lower both bore and stroke is technically possible in the real world (alas lowering the stroke should reduce reliability, since the sleeves react to heat differently as the block itself)