Reversing engine direction

[Geoff in the Gully]

I've got a bit of an odd idea to put out there.
We know the 845cc engine rotates in the opposite direction to the 1100cc engine and we have to be careful to mate the right 4-speed box otherwise we end up with 4 reverse speeds and one forward.

A while back I looked into improving performance by using some parts including the camshaft from a Dauphine Gordini engine. The Dauphine is a rear-engine version of the 845cc Ventoux engine.
I eventually figured out I couldn't use the cam because the Dauphine Gordini engine rotates in the opposite direction and the cam would be opening the inlet and outlet valves in the wrong order.

But what if we want the engine to go the other way?
Can we use Dauphine bits to reverse the direction of our 845cc engine so we can use a later 354 gearbox?
I might be easier to do that than to find a gearbox that goes the right way.

The question is then just what does it take to reverse the direction, apart from the cam.
Is the crankshaft the same, or is it balanced differently?
Are the distributors rotating the same direction?

I can't think of what else would be different.

What do you think?

 

[mojobaby]

Bit above my pay grade, but what about the waterpump, I think the water would pump in the opposite direction. And the fan as well?

 

[malcolm]

I would investigate the timing chain tensioner and the water channels in the head too. If the distributor turns the wrong way then the oil pump will too. I don't have any experience of the rear engined cars but I suspect it would be easier to have an engine to examine (and perhaps use).

 

[JonathanT]

Oooh imagine finishing a perfect restoration ....jump in for trip to Mot station to discover one forward gear and four backwards!!


Interesting post but beyond my abilities

 

[Geoff in the Gully]

I would investigate the timing chain tensioner and the water channels in the head too. If the distributor turns the wrong way then the oil pump will too. I don't have any experience of the rear engined cars but I suspect it would be easier to have an engine to examine (and perhaps use).

Hadn't thought of the timing chain - most of our local engines have the timing gears.

 

[Geoff in the Gully]

Bit above my pay grade, but what about the waterpump, I think the water would pump in the opposite direction. And the fan as well?

Yep, water pump and fan would lose efficiency running backwards

Which makes me think of the starter motor - that's another thing to change.

 

[mr-reno-139]

I have used r4 head on dauphine gordini in an Alpine A108 out of necessity pump
Would be easier to get a camshaft ground with same duration and lift designed for standard rotation r4 845
Ports are bigger and manifold holes slight difference spacing I redrilled and had ports opened up skimmed head to match corroded original

 

[Piet]

Geoff, the early R5s with 850 engines had the same cam grind as the gordini. You can get your R4 engine cam reground to the gordini/R5 spec. Valves are the same as gordini and baseline R4.
Big problem with reversing crank direction is the direction of the labrynth seal on the crank- it will pump oil out of the engine when it goes too fast. There used to be a web page for a Rhodesian guy who inadvertantly put a dauph crank in an R4.

 

[Geoff in the Gully]

The subtle differences are starting to add up. I wouldn't have thought of all the things identified so far.
Some are an easy swap - starter motor for example - others like the labrynth seal are not so easy.

 

[Leonardo.IT]

If I'm remembering right in Italy the same problem is faced when you try to put an engine from a Fiat 127 or Autobianchi A112 on an older Fiat 850 (usually the spider and the coupes are considered not enough powerful ).
The engines are from the same familt, but they turn in opposite direction. So they don't change the engine, they "invert" the gearbox! I think reversing the differential.
I'm going to investigate!

 

[angel]

The major component in reversing engine rotation is the camshaft-mirror image of the opposite turning one.
The distributor is always clockwise rotating, what changes is the angle of its drive gear, and its meshing gear on the camshaft.
Oil pump is uni-directional. Some water pumps are, too, some others not, it depends on the design of the impeller. Water flow in the head has nothing to do with water pump direction of rotation, too. Cooling fan must be replaced with the correct one-otherwise it will push air through the radiator rather than pulling it!
Timing chain could be an issue-the tensioner is placed on the non-stressed side of the chain, with change in direction of rotation it will become stressed. The same goes for the earlier engines with the timing gears. Dauphine/4CV gears were not interchangeablewith 4L ones (different number of teeth) and I suspect the angle of teeth was such that axial forces tended to push the intermediate gear towards its thrust washer at engine block.
There is no screw type mechanical seal at the crankshaft, only at the camshaft end, so this may present no problems.
Alternators are not rotation sensitive, and dynamos can easily be converted for opposite operation, but in both cases their cooling fans must be changed with the correct ones. Starter motor can be electrically converted, but its drive gear will need to be replaced as it has an one-way clutch.
Don't forget the clutch cover, too.
Still wanting to convert your engine?!

 

[mojobaby]

I am beyond speechless

 

[Geoff in the Gully]

Nice summary Angel.
As for still wanting to convert my engine, the thread was all about exploring the possibility.
Which I think we've got a good sense of now.

It doesn't seem like its an easy alternative to finding a gearbox with the correct rotation direction.

But it doesn't seem impossible and I have to admit I'm tempted to give it a go, you know, just to see...

 

[mr-reno-139]

I've got a simpler solution
Find out how much to ship my R5 845 cc engine and box to Australia
As angel says this has got gordini cam and bigger carb
Even got dash change 354 gearbox with it

 

[Geoff in the Gully]

Already have an R5 cam from Angel and other bits I need.
Can't imagine the cost of shipping a whole engine and box is anywhere near within my budget.

 

[reidalpine]

Thinking lateral I would put in a reverse-turning motor and gearbox as is.Then just mount swivel-mounts for the seats.
I've heard rumours the 4L has even better CV if driven backwards,so you'd save on fuel going this way aswell....
In addition you'd also have the advantage of sitting the right round way when reversing.

I admit it would take some getting used to steering from behind your back,but it only takes a little determination-right?
Rest is minutae,not even sure you have road-regulations at all in Aussieland.so I'd give it a go..
Report back (or forward) will you.. All the bestest to you/-R.