1128 close ratio box

[e-type]

Has anybody any info on this gear kit, never seen a similar one. Note the output skaft is not straight cut, and the laygear has a big diameter on the 1 gear.

[rich@minispares.com]

its an old jack knight kit I think

the idea was you got the ease/cheapness of making the sc parts, but got the peace and quite of the helical top gear

[ianh1968]

Never seen one like that before... It's an idea that had crossed my mind before,
but I did not know that boxes had actually been done like this.

e-type, any chance of a "tooth-count"? Or do you just have the picture and not the box?

If we can identify it, it would be a good candidate for the "Ratios" spreadsheet,
See here:

http://mk1-performance-conversions.co.u ... anical.htm

Rich, would this be using a standard First Motion Shaft? Otherwise, I can't see
why it would be any cheaper to make than a full S/C Set... And it shouldn't make it
any quieter in top because the First Motion Shaft/Laygear meshing is not transmitting
any drive in this instance. It would make it slightly quieter in 1st to 3rd, however as
the drive would be only going through one straight meshing instead of two.

THE FIRST MOTION SHAFT IS NOT "TOP"!
(Do I sound like a worn out record, yet?)

Ian

[rich@minispares.com]

Rich, would this be using a standard First Motion Shaft?
Ian

I don't know tbh, though a tooth count will be handy

note how the 4th gear is 'pinned' to the rest of the laygear, as is the first - I bet it has a real weird spread of ratios....

[ianh1968]

Didn't notice the pins...

Maybe it's a "Cut-and-paste" job? I like to think that the pins are just for location
during manufacture purposes and are not taking any drive...

The tooth count would tell us the ratios - I'd be more than happy to post them
here if I can get the information to work them out.

Ian

[e-type]

Laygear 19-22-27-29
1=28
2=25
3=22
1st motion gear 18

1-2-3 gear has lost the special material where the synchro fit.

[ianh1968]

Thanks, e-type, that's great!
The helicals appear to be the standard S/GT First Motion and Laygear Driven pair...
1st might be a 2nd gear from a 3-Synchro ST set.
2nd and 3rd gears might be 4ST.

Looks like a right old "bitsa" to me!

These are the ratios:

Code: Select all

Unknown 4 Speed SCCR with Helical Drive Gears
Source: User "e-type" on Mk1-forum.net

18 29 19 28 (29/18x28/19) 2.374 (1)
18 29 22 25 (29/18x25/22) 1.831 (2)
18 29 27 22 (29/18x22/27) 1.313 (3)
Direct                    1.000 (4)

Rich's suspicion is correct, the ratios are strange.
For reference, the 4 speed ST drops are shown in brackets.

Code: Select all

1 to 2 : 77% (68%)
2 to 3 : 72% (73%)
3 to 4 : 76% (79%)

or, if you like, as per this sample...

Ratios.006.pdf

Normally, the gears get closer on each upward gearchange.
This one is closest from first to second, wider from second to third,
then third to fourth is about the same as first to second...

Still, if it was generally available and we can identify it,
it can be added to "Ratios.ods".

It looks like some kind of prototype, but I am sure that someone
here will have a definitive on this one.

Ian

[e-type]

Yes that is an odd one, drop gear is marked JKD an diff is Tranex Minispares type.

The FIA Mini race car came from southern Europe to Denmark some 12 years ago and has not been used. From the stickers on the rear window it seams the last race it was used in was 1995.

3 things i have newer seen before on this engine, the gear kit the 1295cc pistons in a thick flange S block and some very heavy brass dashpots in the H4 S.U carbs with out oil damper.