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Make an engine turn the opposite way around?
Alez - 8/11/16 at 08:13 AM

Hey guys,

I'm wondering: is there a fundamental reason why you can't make an engine turn the opposite way around by changing its cam shaft to a custom one? (and adjusting ignition). I'm thinking that would allow one to turn a rear engined car into a mid engined car by putting its drive train reversed.

Cheers,

Alex

Schrodinger - 8/11/16 at 08:23 AM

I'm not too sure about the cams but you would need to rebuild the engine with the pistons turned as the gudgeon pin is not central. Which engine are you thinking of? Iirc in the 60's/70's it was popular with the beetle engine to turn the gearbox over so that it could be used as mid engine.

r1_pete - 8/11/16 at 08:26 AM

In the 50s some Panther single motorcycle owners had their ignition advance lever adjusted so in one extreme position they could make their engines kick back and run in reverse it was useful when hauling a sidecar, I wasn't there so haven't seen it done, just read about it.

Alez - 8/11/16 at 08:30 AM

Thanks, Keith.

I don't have anything in particular in mind, just wondering if it makes sense to do that and/or it's been done, but your reply makes it clear that it involves major work which makes it pointless given other options like using a front engined car drivetrain or the one you mention.

These days I'm liking the Simca 1000 Rally small saloon and sometimes I find myself thinking random things related to rear engine configuration

Cheers,

Alex

Alez - 8/11/16 at 08:32 AM

quote:
Originally posted by r1_pete
In the 50s some Panther single motorcycle owners had their ignition advance lever adjusted so in one extreme position they could make their engines kick back and run in reverse it was useful when hauling a sidecar, I wasn't there so haven't seen it done, just read about it.

Wow, just ignition. I thought cam timing would need reversing.

britishtrident - 8/11/16 at 08:59 AM

Simca 1000 and the later fwd Chrysler engines were anti-clockwise rotation anyway.
They were very prone to camshaft wear problems.

britishtrident - 8/11/16 at 09:03 AM

quote:
Originally posted by Alez
quote:
Originally posted by r1_pete
In the 50s some Panther single motorcycle owners had their ignition advance lever adjusted so in one extreme position they could make their engines kick back and run in reverse it was useful when hauling a sidecar, I wasn't there so haven't seen it done, just read about it.

Wow, just ignition. I thought cam timing would need reversing.


Only valveless 2 strokes can run backwards without major changes.

Alez - 8/11/16 at 09:09 AM

quote:
Originally posted by britishtrident
Simca 1000 and the later fwd Chrysler engines were anti-clockwise rotation anyway.
They were very prone to camshaft wear problems.

Hmm why do you mention this, does it make any difference which way it rotates? Just curious.

quote:
Originally posted by britishtrident
Only valveless 2 strokes can run backwards without major changes.

Oh, of course 2-stroke don't have valves, that explains it

nick205 - 8/11/16 at 09:11 AM

quote:
Originally posted by Schrodinger
I'm not too sure about the cams but you would need to rebuild the engine with the pistons turned as the gudgeon pin is not central. Which engine are you thinking of? Iirc in the 60's/70's it was popular with the beetle engine to turn the gearbox over so that it could be used as mid engine.


As above I understood IC engines were designed with rods and associated pivot points off centre to handle the explosion forces. With that in mind I'd have thought running them backwards would run mechanical risks and increase wear on cylinders and pistons.

Whilst not a transmisson man I'd imagine transmissons are designed and tested to work with certain oil capacities and movements. Running them upside down would change this dramatically and no doubt raise issues with fill/drain plugs and breathers.

What sort of project are you thinking about?

Some more guidance on what you're looking to achieve may help us suggest some transmissions for you.

Alez - 8/11/16 at 09:16 AM

Thanks, Nick

It's just curiosity. I'm not even a builder. I thought I had seen other solutions before, but not the one I was thinking, and I was wondering if that was because it can't be done easily (which I've now confirmed) or maybe it had been done but I wasn't aware.

Cheers,

Alex

Alez - 8/11/16 at 09:22 AM

quote:
Originally posted by nick205
Whilst not a transmisson man I'd imagine transmissons are designed and tested to work with certain oil capacities and movements. Running them upside down would change this dramatically and no doubt raise issues with fill/drain plugs and breathers.

Hmm I thought it's a typical thing to do... the G50 transaxle for example is used that way on GM V8 (small block) Ultimas and similar cars with same configuration (Lambo replicas, etc.), I seem to remember.

[Edited on 8/11/16 by Alez]

red22 - 8/11/16 at 09:30 AM

VW Beetle gearboxes just get the diff flipped to the other side of the pinion. No inverting of gearboxes needed.

Ivan - 8/11/16 at 10:50 AM

It has been done to Honda engines a number of times for racing engines. No serious complications - they cut new camshafts. It's also done on American V8s for marine use where twin engines are installed.

Google it.

nick205 - 8/11/16 at 11:08 AM

quote:
Originally posted by Alez
quote:
Originally posted by nick205
Whilst not a transmisson man I'd imagine transmissons are designed and tested to work with certain oil capacities and movements. Running them upside down would change this dramatically and no doubt raise issues with fill/drain plugs and breathers.

Hmm I thought it's a typical thing to do... the G50 transaxle for example is used that way on GM V8 (small block) Ultimas and similar cars with same configuration (Lambo replicas, etc.), I seem to remember.

[Edited on 8/11/16 by Alez]


Yes I think Ultima do use an inverted Porsche G50 transmission. Porsche being Porsche I suspect their transmissions are rather well engineered and in that instance proven to work OK inverted.

There was a recent thread on using VAG transaxles for RWD cars - http://www.locostbuilders.co.uk/viewthread.php?tid=205354

VAG cars using them have the engine and transmission mounted longitudinally. My concern would be the length of the engine and transmission in this configuration for a mid-engine car. I'd have thought using a FWD engine and transmission layout in a mid-engine position would be more effective and give a shorter car overall. It would also give you more choice of donor engine and transmission too.

redturner - 8/11/16 at 11:23 AM

quote:
Originally posted by Alez
quote:
Originally posted by r1_pete
In the 50s some Panther single motorcycle owners had their ignition advance lever adjusted so in one extreme position they could make their engines kick back and run in reverse it was useful when hauling a sidecar, I wasn't there so haven't seen it done, just read about it.

Wow, just ignition. I thought cam timing would need reversing.

Lots of Villiers engines were fitted with the Cibie dynastart system which allowed the engine to start in reverse, lots of large marine engines can run either way by simply moving a lever to move the camshaft to a different set of lobes and as far as the Simca Rallyes are concerned you should check out the French hill climb (course de cote) scene and see what kind of speeds they are doing, scarely quick.....

coozer - 8/11/16 at 01:20 PM

You would have to rearrange the can chain tensioner to the opposite way and re engineer the oil pump to make it pump properly... Then a host of other mechanical things.

Why not just use any fwd engine and box in the back of a midi????

r1_pete - 8/11/16 at 01:26 PM

quote:
Originally posted by britishtrident
quote:
Originally posted by Alez
quote:
Originally posted by r1_pete
In the 50s some Panther single motorcycle owners had their ignition advance lever adjusted so in one extreme position they could make their engines kick back and run in reverse it was useful when hauling a sidecar, I wasn't there so haven't seen it done, just read about it.

Wow, just ignition. I thought cam timing would need reversing.


Only valveless 2 strokes can run backwards without major changes.


Probably some urban myth I've mis remembered.....

mcerd1 - 8/11/16 at 01:38 PM

quote:
Originally posted by nick205
VAG cars using them have the engine and transmission mounted longitudinally. My concern would be the length of the engine and transmission in this configuration for a mid-engine car.


but the driveshafts come out quite close to the front:



so if you can afford the overhang to the rear its not so bad (thats the audi 4.2 V8 in the pic so hardly a compact engine)


always thought it looked quite neat in this build: linky

trialsman - 8/11/16 at 02:10 PM

Didn't some of the older Honda car motors run opposite rotation. I don't know the series designation but they were in older Civics. Russ

Dingz - 8/11/16 at 02:54 PM

quote:

Lots of Villiers engines were fitted with the Cibie dynastart system.

I had a scooter with this set up, it gave me a bit of a shock when it had started backwards and I tried to pull away!

jollygreengiant - 8/11/16 at 03:04 PM

From the purist technical side, not a good idea to run an engine the wrong rotation.
Gudgeon pin off-set would be wrong.
Little end lubrication would be aligned wrong for the piston loading.
The crankshaft would need a re-grind to allow for rotational difference (crank rotation is important for re-grind operatives, or that is what I was told in the engineering workshop).
Timing chain and timing belt tensioners would be incorrectly sited and loaded.

Just my 2p's worth at a reply after 30 seconds of viewing the question.

Alez - 8/11/16 at 03:14 PM

quote:
Originally posted by nick205
There was a recent thread on using VAG transaxles for RWD cars - http://www.locostbuilders.co.uk/viewthread.php?tid=205354

VAG cars using them have the engine and transmission mounted longitudinally. My concern would be the length of the engine and transmission in this configuration for a mid-engine car. I'd have thought using a FWD engine and transmission layout in a mid-engine position would be more effective and give a shorter car overall. It would also give you more choice of donor engine and transmission too.


quote:
Originally posted by mcerd1
but the driveshafts come out quite close to the front:

so if you can afford the overhang to the rear its not so bad (thats the audi 4.2 V8 in the pic so hardly a compact engine)

always thought it looked quite neat in this build: linky


I'm most familiar with that configuration because I've been the owner of an Audi 4.2 V8 engined Ultima for a few years and it used a VAG 6-speed. Here's a pic of the engine bay:



It's a very compact installation in Ultima engine bay size terms, there was significantly more space than the average GM V8 gives. The whole thing worked really well.

quote:
Originally posted by r1_pete
Lots of Villiers engines were fitted with the Cibie dynastart system which allowed the engine to start in reverse, lots of large marine engines can run either way by simply moving a lever to move the camshaft to a different set of lobes and as far as the Simca Rallyes are concerned you should check out the French hill climb (course de cote) scene and see what kind of speeds they are doing, scarely quick.....


I got interested in the Simca 1000 because a guy here in Madrid does hillclimbs with a 1000 Rallye 3


[Edited on 8/11/16 by Alez]

Alez - 8/11/16 at 03:19 PM

quote:
Originally posted by jollygreengiant
From the purist technical side, not a good idea to run an engine the wrong rotation.
Gudgeon pin off-set would be wrong.
Little end lubrication would be aligned wrong for the piston loading.
The crankshaft would need a re-grind to allow for rotational difference (crank rotation is important for re-grind operatives, or that is what I was told in the engineering workshop).
Timing chain and timing belt tensioners would be incorrectly sited and loaded.

Just my 2p's worth at a reply after 30 seconds of viewing the question.

Well, definitely it seems there's PLENTY wrong with it, after all

Thanks

r1_pete - 8/11/16 at 03:22 PM

Thinking that one through, the oil pump would run the wrong way, any white metal forced lubed bearings wouldn't last long either.

coozer - 8/11/16 at 03:34 PM

Thinking about the original op question I think flipping the diff would be the best way...

Ugg10 - 8/11/16 at 05:22 PM

Just use a Honda b series engine as they run the opposite way to most others.

snapper - 8/11/16 at 07:04 PM

Cam belt or cam chain tensioner would effectively intensional itself

Adamirish - 8/11/16 at 07:55 PM

quote:
Originally posted by Ugg10
Just use a Honda b series engine as they run the opposite way to most others.


These can be made to run the right(opposite) way too. Someone in America does the parts to convert it. I looked briefly as a B16 would make a cracking engine for a kit.

IIRC it was just cams and an oil pump. It was a while ago I looked mind.

LBMEFM - 8/11/16 at 08:51 PM

When I was at tech collage many, many years ago we advanced the timing on the caretakers two stroke moped, when he started the engine he put it in gear and shot off backwards, cruel but funny.