How to choose your engine for any vehicle

[Londonscottish]

A friend of mine used to run a Mini in Rallycross back in the late 70's / early 80's and also a Mini as a road car. Most years at the end of the Rallycross season he would build a new, higher spec, motor for the competition car and put the end-of-season competition motor in his road Mini.

The Rallycross car had a box let into the bulkhead to provide room for the intake side of the split Weber (45 DCOE, from memory), but for a few months after installing a similarly equipped motor in his road car he simply moved the central speedo and removed the panel in the bulkhead thus allowing the engine to breath its inlet air from the car interior. You had to drive it with the windows open

Ah yes, I remember now; to complete my install I would have had to box it in. But I didn't have the time/patience/skills. So I just removed the removable panel to make it fit and that was that. Thinking about it, I think the panel was to give access to the back of the dash where they had the central speedo - presumably to change the cable.

Mine used to spit back unburnt petrol something rotten when cold and, even when it was hot, it ran like a bastard below 2-2.5k. The amount of spit back was huge and it used to make your eyes water/your clothes stink. And, as I found one day on the slip road to the M90, it would also soak the sound deadening padding behind the dash which could catch fire. And, which, on this occasion, actually did.

My mates, following behind, saw me suddenly veer into the verge, stop the car and jump out. Luckily, the car used to overheat so I had a large bottle of water with me at all times. I opened the bonnet and started pouring into the hole behind the carb. Meanwhile all the smoke and steam was being pumped into the cabin by the heater fan.

My mates offered no help at all - they just stood on and watched, crying with laughter

 

[Bellow]

Mine used to spit back unburnt petrol something rotten when cold and, even when it was hot, it ran like a bastard below 2-2.5k. The amount of spit back was huge and it used to make your eyes water/your clothes stink.

Fuel stand-off the technical term I think!
As a kid messing about with a race kart with a highly tuned Villiers 9E 2T running at low/mid rpm I'd look over and there'd be a cloud of fuel hanging just outside the carb's mouth. Then it would disappear and I'd have to shift my gaze to forwards - pronto.

 

[st13phil]

My mates offered no help at all - they just stood on and watched, crying with laughter

That's what mates a for

 

[ALFAitalia]

Another single cylinder car....bit more practical than the Peel....if colder! A Rover 6 from 1905. 780 or 812 cc with only one pot must have been quite a thumper.

 

[st13phil]

Another single cylinder car....bit more practical than the Peel....if colder! A Rover 6 from 1905. 780 or 812 cc with only one pot must have been quite a thumper.

The evolution of the i/c engine for motor vehicles has basically gone full circle when it comes to number of cylinders.

They started with single cylinders because they were cheaper and easier to manufacture, but had poor driveability and refinement.

Then the number of cylinders increased so as to provide better refinement and driveability, but increased the cost of manufacture, increased internal losses due to friction and reduced thermal efficiency.

More recently, the focus has been on increasing thermal efficiency and reducing frictional losses, hence the shift to less cylinders. Refinement and driveability has been (largely) retained through better understanding of vibration management and isolation - dual-mass flywheels, sophisticated engine mounts, etc. - and forced induction / precise fuel metering.

 

[Fastcar155]

Anyone mentioned the Rover JET 1

 

[pioneercollector]

One of the best things in the Science Museum - Rover Jet 1 ..... Marvellous

 

[philnewmerc]

Jets are not allowed.
Neither are ****el.
It's just a list of acceptable engines that are slightly better or slightly worse than the straight 6 piston engine really.
Sorry, I don't make the rules, but rules iz rules

 

[philnewmerc]

lol, the algorithm is not happy with W a n k e l engine

 

[Wolfie1]

And why arent w a n k e l engines allowed?

 

[BTB 500]

And why arent w a n k e l engines allowed?

Could just call them rotary engines

No, not this sort ...

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[Wolfie1]

Could just call them rotary engines

No, not this sort ...

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What about the ones in a car for example in an RX7? Is that not a radial engine in a plane?

 

[Fastcar155]

Jets are not allowed.
Neither are ****el.
It's just a list of acceptable engines that are slightly better or slightly worse than the straight 6 piston engine really.
Sorry, I don't make the rules, but rules iz rules

Or to be broken !

 

[Bellow]

Jets are not allowed.
Neither are ****el.
It's just a list of acceptable engines that are slightly better or slightly worse than the straight 6 piston engine really.
Sorry, I don't make the rules, but rules iz rules

'Turbine smooth', yeah, not a patch on a six.

 

[BTB 500]

What about the ones in a car for example in an RX7? Is that not a radial engine in a plane?

Different types of rotaries. On a rotary aero engine the propeller was attached to the front of the crankcase, and the crankshaft fixed to the firewall. So the crankcase, cylinders and prop all spun together when running . A radial engine looks similar but that's fixed to the firewall, with the prop driven by the crankshaft in a conventional way.

Rotaries were widely used up to the end of WW1 but became impractical as engine sizes and power outputs rose - for one thing the amount of rotating mass caused all sorts of gyroscopic issues in flight. The famous Sopwith Camel fighter would have been considered unflyable by today's standards - left/right rudder inputs caused the plane to pitch nose up or down, and elevator inputs caused it to yaw left or right. So for example if you applied down elevator to dive the plane also yawed to the left. Correcting this with right rudder then caused the nose to pitch further down. Many pilots only ever turned right in combat as it was quicker to turn 270 degrees to the right than make a 90 degree turn to the left! This was considered acceptable at the time as if you knew about these tendencies and exploited them correctly it was exceptionally manoeuvrable, making it a great fighter. But lots of pilots were killed in accidents, even though it was forbidden to fly aerobatics in the Camel.

 

[Flyinspanner]

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?

You forgot small Citroens (flat 2s)

 

[Bellow]

You forgot small Citroens (flat 2s)

And you forgot Citroen's flat fours (GS series).
Lancia's Fulvia had a narrow angle V4. The Flavia had the flat four.

 

[DaveE320CDI]

Talking about induction noise brings back memories of my old mk1 Ford escort twin cam which i dropped Cosworth L1 cams into and chrome trumpets on the webbers, would always try to find a long tunnel to go through and boot it! reminded me of the great Rodger Clark on the Rac rallys before the BDA engine was used glorious sound, dont think a Tesla will ever sound as good.

 

[Flyinspanner]

Nothing wrong with nine cylinder engines...

View attachment 151926

As part of my apprenticeship we used to take apart a double row, 14 cylinder radial engine, (one cylinder) and rebuild and gap valves. (Bristol Hercules) bloomin huge pistons compared to the FS1E I was riding at the time