How to choose your engine for any vehicle

[philnewmerc]

Summary of number of cylinders acceptability:
1 pre 1959 motorbikes only
2 motorbikes only, or v small Italian car
3 inferior but characterful; any small vehicle
4 small soulless efficient diesels. Or, small to mid size zingy and fun Italian petrols (none Italian not acceptable unless a motorbike)
V4 no, unless Italian car or motorbike
Flat 4 good natural balance and character, maybe perfect combination of efficiency and character?
5 inferior to a straight 6 but tuneful
6 straight 6; perfection. Turbine smooth perfect balance and soulful characterful. King of the ice.
V6 as 3 cylinder above but for larger cars; characterful but inferior to the straight 6
(NB V6 has to be 60 degree banks or it is a cheap design of chopped down v8; ie 90 degree with balance shafts is a crude accounting job)
7 no
8 (vee) In cross plane form very characterful and smooth but inferior to a straight 6. In flat plane form it's just two straight 4 cylinder engines sharing a crank, hence see '4' above
9 just no
10 (vee) See straight 5 above; double the tunefulness
11 no no no
12 (vee) See straight 6 above and double the luxury (in a saloon) or character (in a supercar).
W5 An abomination, like Jeff Goldblum in The Fly
W6 Cheap, compact, inferior to straight or 60 degree vee 6, but has character so forgivable
W8 as w6
W16 Engineering marvel but still inferior to a v12

Opinions welcome...

 

[markjay]

No idea why the flat 4 isn't more popular. Lancia Fulvia, VW Beetle, Alfasud, Subaru, Toyota , Porsche, but that's about it (give or take). A light and balanced engine, lowering the centre of gravity, and lowering Cd due to sloping bonnet - why is it not more common?

 

[pioneercollector]

I agree with the Straight 6 being right up there and probably the best of the bunch. I do love the V8 though, and a V twin motorcycle is a wonderful unit that will probably outlive me.

 

[philnewmerc]

I agree with the Straight 6 being right up there and probably the best of the bunch. I do love the V8 though, and a V twin motorcycle is a wonderful unit that will probably outlive me.

Agree V twins are perfect motorbike engines and superior to parallel twins due to better balance (and tuneful noise)

 

[johncherokee]

I also like the straight six, but I prefer the power of the v8. I don’t think I have ever tried any of the other weird arrangement, apart from the straight 4.

 

[st13phil]

why is it not more common?

Probably a mixture of packaging compromises and cost - two cylinder heads vs one, etc.

 

[Bellow]

No idea why the flat 4 isn't more popular. Lancia Fulvia,

Narrow angle V4 in the Fulvia. Flavia IIRC had the flat four.

VW Beetle, Alfasud, Subaru, Toyota , Porsche, but that's about it (give or take). A light and balanced engine, lowering the centre of gravity, and lowering Cd due to sloping bonnet - why is it not more common?

The additional machining costs aren't welcomed, flat engines tend to end up oversquare (to constrain width) and tend towards being gutsy on fuel as a consequence. The main reason though (as alluded to in post # 6) the packaging just isn't suited to transverse layouts preferred by most.

 

[Bellow]

Nothing wrong with nine cylinder engines...

 

[BTB 500]

Nothing wrong with nine cylinder engines...

Or 7 cyls:

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[Bellow]

Or 7 cyls:

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Stop putting ideas in my head!




I know where this one is and it's only 50 miles away.

 

[ToeKnee]

Stop putting ideas in my head!

View attachment 151931


I know where this one is and it's only 50 miles away.

That looks like a lot of work!
I have a yearning to build a twin turbo big block ford V8. Problem is, I have nothing to put it in and I've stopped building engines for others now due to general dimfu**ery!

 

[pioneercollector]

That one might need a service!

 

[Bellow]

That one might need a service!

Oh, just a bit of accident damage. The kind you'd expect from crashing into the side of a mountain...
It's partner from the other wing is on display in either Braemar or Ballater (I always confuse the two).

 

[philnewmerc]

I'd completely forgotten about radial engines but I'm not convinced they're really suitable for a car let alone a Merc lol.

 

[Stratman]

No idea why the flat 4 isn't more popular. Lancia Fulvia, VW Beetle, Alfasud, Subaru, Toyota , Porsche, but that's about it (give or take). A light and balanced engine, lowering the centre of gravity, and lowering Cd due to sloping bonnet - why is it not more common?

Take a look at I Do Cars teardowns to see why

 

[Bobby Dazzler]

Summary of number of cylinders acceptability:
1 pre 1959 motorbikes only
2 motorbikes only, or v small Italian car
3 inferior but characterful; any small vehicle
4 small soulless efficient diesels. Or, small to mid size zingy and fun Italian petrols (none Italian not acceptable unless a motorbike)
V4 no, unless Italian car or motorbike
Flat 4 good natural balance and character, maybe perfect combination of efficiency and character?
5 inferior to a straight 6 but tuneful
6 straight 6; perfection. Turbine smooth perfect balance and soulful characterful. King of the ice.
V6 as 3 cylinder above but for larger cars; characterful but inferior to the straight 6
(NB V6 has to be 60 degree banks or it is a cheap design of chopped down v8; ie 90 degree with balance shafts is a crude accounting job)
7 no
8 (vee) In cross plane form very characterful and smooth but inferior to a straight 6. In flat plane form it's just two straight 4 cylinder engines sharing a crank, hence see '4' above
9 just no
10 (vee) See straight 5 above; double the tunefulness
11 no no no
12 (vee) See straight 6 above and double the luxury (in a saloon) or character (in a supercar).
W5 An abomination, like Jeff Goldblum in The Fly
W6 Cheap, compact, inferior to straight or 60 degree vee 6, but has character so forgivable
W8 as w6
W16 Engineering marvel but still inferior to a v12

Opinions welcome...

You forgot flat 12, they make a nice noise too.

 

[Bobby Dazzler]

I believe that an in-line naturally aspirated straight-six of around 3 litres displacement - in a RWD platform - makes the most sense for a road car, and is all the engine you’d ever need, and more besides.

I have a soft-spot for V8s though, better still with a transaxle. Bit of me that.

 

[SmartAmg]

W@nkel?

 

[Bellow]

Or, we could count the pistons. Why have only one piston per cylinder when we could have two?

 

[Bellow]

I have a soft-spot for V8s though, better still with a transaxle. Bit of me that.

Tatra are on the phone for you...