mk1-forum.net

Just wondered if anyone had ever seen an engine gearbox without the idler, so the carbs face forward ?

As is pretty widely known, the prototype transverse engines faced forward but because of icing on the carbs, they were reversed

To reverse the engines they added the idler gear, but it apparently it cost about 4% power….designers were not bothered as they were trying to slow the prototypes down.

Just wondered if anyone had experimented by trying to remove the idler and having the carbs facing forward again?

In competition there could be some advantages here…….

Exminiman wrote: ↑Sat Jun 01, 2024 4:33 pm Just wondered if anyone had ever seen an engine gearbox without the idler, so the carbs face forward ?

As is pretty widely known, the prototype transverse engines faced forward but because of icing on the carbs, they were reversed

To reverse the engines they added the idler gear, but it apparently it cost about 4% power….designers were not bothered as they were trying to slow the prototypes down.

Just wondered if anyone had experimented by trying to remove the idler and having the carbs facing forward again?

In competition there could be some advantages here…….

There is some merit to this for sure however, it would mean a big redesign of the current gearbox and flywheel housing.
You would have a primary gear with a big circumference gear and an input gear with similar size.

There would not be enough room for the input gear in the current configuration.
It could be done.....comes down to $$ versus gain....

Attaching a picture of the early design......assume that is what they did with this unit.

Cheers for the response Dermot, take your point completely, but and that is where I started, but (another but) the prototype was the original design, space was at a premium, so, what did it look like before the idler was added ?

One issue with that design that is rarely mentioned is the inertia of the bigger gears used and how they wear the gearbox cones (or baulk rings) so much faster. That too was found in original testing.

I have seen such a set up, that is, without an idler gear, but that was a chain drive and retained the engine / gearbox in the conventional configuration.

Exminiman wrote: ↑Sat Jun 01, 2024 7:08 pm Cheers for the response Dermot, take your point completely, but and that is where I started, but (another but) the prototype was the original design, space was at a premium, so, what did it look like before the idler was added ?

Thanks....assume there would just TWO gears....that would also mean the gears inside would have to be turning opposite direction to the way it is now.
Be nice to get a look at the gearbox casing in that old prototype.
There may be some old pictures lying around....somewhere....maybe Mark Simon has a source!
Cheers
D

360gts wrote: ↑Sat Jun 01, 2024 7:47 pm

Exminiman wrote: ↑Sat Jun 01, 2024 7:08 pm Cheers for the response Dermot, take your point completely, but and that is where I started, but (another but) the prototype was the original design, space was at a premium, so, what did it look like before the idler was added ?

Thanks....assume there would just TWO gears....that would also mean the gears inside would have to be turning opposite direction to the way it is now.
Be nice to get a look at the gearbox casing in that old prototype.
There may be some old pictures lying around....somewhere....maybe Mark Simon has a source!
Cheers
D

Assume two gears, but maybe two gears and a chain ?

Exminiman wrote: ↑Sat Jun 01, 2024 8:01 pm

360gts wrote: ↑Sat Jun 01, 2024 7:47 pm

Exminiman wrote: ↑Sat Jun 01, 2024 7:08 pm Cheers for the response Dermot, take your point completely, but and that is where I started, but (another but) the prototype was the original design, space was at a premium, so, what did it look like before the idler was added ?

Thanks....assume there would just TWO gears....that would also mean the gears inside would have to be turning opposite direction to the way it is now.
Be nice to get a look at the gearbox casing in that old prototype.
There may be some old pictures lying around....somewhere....maybe Mark Simon has a source!
Cheers
D

Assume two gears, but maybe two gears and a chain ?

Most likely a chain....

It would be interesting to see the gearbox and diff drive layout on the early design.

Some photos below from the 1964 book 'The Mini Story' by Lawrence Pomeroy.







Mini Prototype - Orange Box:-
http://mk1-forum.net/viewtopic.php?t=7132

The two-cylinder A-Series also had the carb at the front...

Lots more detail on turning the engine around and (as mentioned by Spider's post above), the other reasons not often mentioned are in Jon Pressnell's book 'Mini: The Definitive History'.
Extract below...

Thanks for the info, nothing is ever as straight forward as you expect is it

So the 4% power gain if you have carbs at front sounds a bit iffy now as well…..

Makes me wonder if the noise claim is right though, three gears meshing being quieter than two ….

Could it be that it was safety driven, carbs at the front would not be good in a front end accident……even a small one

Exminiman wrote: ↑Sun Jun 02, 2024 4:05 pm Could it be that it was safety driven, carbs at the front would not be good in a front end accident……even a small one

I don't think accident safety was a high priority in any car design back in the late 1950's and was not an important selling point for buyers...as shown in this extract linked below from a TV documentary made several years ago about the early Minis and their safety issues. The early internal tank Mini Countryman/Traveller even had the petrol tank inside the load space covered with some cardboard trim, with no bulkhead to the passenger compartment! Kids in the rear seat were sat next to it....
Austin Mini and its accident safety:-
https://www.youtube.com/watch?v=TEbmPsukEHI

In later models small improvements made some difference, the saloon petrol tank neck was shortened and made less protruding, the door locks were changed to an anti-burst open design (Mk3), the tip up seats were fitted with lock down catches and the parcel shelf edges were padded (in most models from Mk2), the metal parcel shelf punched full of holes to make it less rigid to leg/knee impact, flush rocker switches (Mk3), plastic interior mirror, soft plastic choke/heater knobs, rear seat belts, etc...and towards the end of production, door impact bars, seat belt pretensioners and a steering wheel airbag.

mab01uk wrote: ↑Sun Jun 02, 2024 3:14 pm ,,,,, Jon Pressnell's book 'Mini: The Definitive History'.

One book - of many ! - I don't have !