Lotus 5 speed gearbox-uprating-Victor Hollnagel

[john.p.clegg]

Dear All

After spending some time refurbishing my spare lotus 5 speed gearbox (and as it happens,first and second gear are now getting noisey) decided to uprate the box a little so dug out an article published in Club Lotus News a while ago and followed the instructions.....PLEASE NOTE....if you modify the selector shaft finger, as in the article,to take up any wear/play you will have great problems selecting reverse and fifth gears.
This is caused by the fact that 1st/2nd and 3rd/4th selector levers slide on bars wheras 5th/reverse PIVOTS around a fulcrum....the fact that the square headed selector finger fits snugly in the sliding selector cut-outs stops it doing its job in the third selector...

Hopes this saves other people money and time and effort trying to uprate the box only to find out that they are unable to select reverse and fifth....

John

[barrydoran]

Thanks for the tip John.

I am planning to follow those uprating instructions myself.

on a related note, did you manage to source all the bearings required?

Barry.

[john.p.clegg]

Barry

With three spare boxes I've managed to get one good set of bearings...

John

[barrydoran]

That is the strategy I am following, so far I only have the two. My original broken Elan box and an elite box.

What about special tools, did you make your own ?

Barry.

[gerrym]

Re Bearings for (Maxi) 5 speed, suggest you contact

Stephenson Transmissions
1 Waterloo Road, Ashton-On-Ribble, Preston, Lancashire, PR2 2YR
01772 723325

Their owner is a very helpful guy, well used to Lotus work. I originally was put onto him by Gordon Lund.

He has a design workaround for the bearings.

Regards

Gerry

[john.p.clegg]

Barry

What about special tools, did you make your own ?



Sad to say I am from the old school where a lump hammer is ideal,joking apart,slide hammer pullers can be made from your spare nuts but the rest you have to us ingenuu,injenut,ingennu,.....bugger it..... trial end error..

John

[elans4dhc]

John,

I have modified the selector shaft finger exactly as described in Victor Hollnagel's article and do not experience the problem you suggest in selecting 5th or reverse gear. The 5th/Reverse selector fork is in line with the other two forks when in neutral so Victor's "square" finger simply moves between the square gates in all three forks. Victor even provides a method for exactly aligning the 5th/Reverse fork gate with the other two should this prove to be necessary.

Selecting 5th or reverse is no more problematic than selecting any other gear. The angular movement of the 5th/Reverse selector fork is not large ( between 5 and ten degrees from memory) and causes no problem for the "square" finger.

The reason for the round finger originally fitted in the Lotus 5-speed box relates more to the Austin Maxi pushrod gearbox, where a different method of translating gearshift movement into selector fork movement required that a very much larger angular movement be accommodated, and I quess Lotus engineers left it unaltered on cost considerations and that it worked.

As far as parts for rebuilding are concerned, you will find very little available from Lotus sources but looking for the equivalent Austin Maxi parts can prove to be much more fruitful. The only parts that are well nigh impossible to find now are the castings, housings and rods that are peculiar to Lotus in the conversion to a longitudinal input/output gearbox.

Regards,
Andrew

[john.p.clegg]

Andrew


"Selecting 5th or reverse is no more problematic than selecting any other gear. The angular movement of the 5th/Reverse selector fork is not large ( between 5 and ten degrees from memory) and causes no problem for the "square" finger."


Agree with all...yes,between 5 and 10 degrees,except the selecting of 5th and reverse for me was nigh impossible...maybe you had larger fore and aft tolerances than me?

John

[elans4dhc]

John,

Agree with all...yes,between 5 and 10 degrees,except the selecting of 5th and reverse for me was nigh impossible...maybe you had larger fore and aft tolerances than me?

I had an extended correspondence with Victor about his gearbox upgrading and one piece of information not included in his article is the width of the "square" selector finger - 12.6mm - against the width of the cutout in the 5th/Reverse selector lever of 13.7mm in my case. This 1.1mm clearance is enough to allow selection of both gears, again in my case. Perhaps in your case this clearance wasn't enough to allow for the required rotation of the lever to allow selection of the gears.

Two ways to correct this would be to: a) increase the width of the selector lever cutout, or b) reduce the width of the square selector finger. The former requires a complete strip down of the gearbox to extract the lever as against the more straightforward removal of the selector shaft assembly of the latter.

In case your problem perhaps relate to the other dimensions of the selector finger, Victor's sizes are 12.5mm high and 6.2mm thick.

I hope this helps.

Regards,
Andrew

[john.p.clegg]

Andrew

That sounds good to me but I thought the reason for the square finger was to take up any play/sloppiness in the fore/aft movement,but,looking at the article again it seems that it is to take up any fore/aft play in 2nd/3rd selection (brass selector)...
So,to sum it up,selector finger should be a nice fit in 1st/2nd and 3rd/4th selector but needs more "play" in 5th/reverse to allow for "rotation"

"Two ways to correct this would be to: a) increase the width of the selector lever cutout, or b) reduce the width of the square selector finger. The former requires a complete strip down of the gearbox to extract the lever as against the more straightforward removal of the selector shaft assembly of the latter."................I suppose the four "corners" of the selector finger could be "cut" giving the same effect?

....as for stripping the box,I've just stripped the fourth box down to component parts hopefully being able to make two "good" boxes out of the proceeds.

John