TMH Montecarlo 5th gear ratio

[Nigel]

Hi all,
I'm aware that The Monte Hospital used to supply an alternative 5th gear ratio that was 0.780:1 as opposed to
the standard 0.925:1

I'd like to find out the teeth count on this pair of gears. A photo of same would
be a huge bonus.

Nigel

[WestonE]

Hi Nigel,

I have heard a lot of stories trouble installing this part from TMH. Not recommended. Sorry I do not have the tooth count.

Eric

[Nigel]

Thanks Eric.

I wonder what that issue was with the installation.

This exercise/research is merely exploratory right now. I'm quite pleased
with the performance of my VX box coupled to the standard 2000 engine,
but if there was a way of giving it even slightly longer legs this is something
I'd like to explore.

Edit: I've now read that US spec Betas had a 5th ratio of 0.865:1, something I'm going to explore.

Nigel

[squiglyzigly]

Watching this with interest
👌🏻

[WestonE]

To really change final drive ratio it would have helped a lot if the Pinion gear was removable to allow swapping final drives. With all fixed gears on 1 of the shafts it is not simple. Bacci  Romani make gear sets with interchangeable gear sets and final drives, but they cost a fortune. Remember standard Monte boxes are worse than Beta boxes because they have a stupidly low first gear as well.

I spent a lot of hours on this 10 years ago with no practical sensible cost solutions. Let's hope you find something I missed. BTW the TMH 5th gear was poorly made and had to have after sale keyway work done for example. It does not fit the VX multi spline 5th gear setup either.

Eric   

[SanRemo78]

Do you have a part number for the US 5th Gear Set?

https://www.ebay.com/itm/185377945272?_skw=lancia+beta+gearbox&itmmeta=01JGE9DAWKWTBYJH6CSF95VT57&hash=item2b2962f6b8:g:exAAAOSw6l1h1Ib8&itmprp=enc%3AAQAJAAAA0HoV3kP08IDx%2BKZ9MfhVJKkLBuxly1sago4xCMpz6PbJAmWUsq2kmYRZt%2BaLdlUE4CjsVArJVdIAtF2GA3TV7WGavTMW936FQTeUxEoZqvQE8ggDM5tH8e14dGEvYot5HUZ5s8QzRvdtLu7rycFmwFOsWqfcpW%2BYDGqGXsPwc8jH72tSkX9KqyrV6lwk498GN6%2B1%2FXDrw9qStZd5UhbuSv6o7pI7dYzkjzz%2FZyQ%2Fbydogf8iZ8td3LaNgBA2GyM0cJSQk6jQHGT2hAN80bgxUC0%3D%7Ctkp%3ABk9SR9autcmDZQ

Being in Italy this one is most likely European spec?

Guy

[HFStuart]

37 teeth on one, 40 teeth on the other = 0.925:1 Sorry!


Edit: Balls... I counted the teeth and only then scrolled down to the description where it tells you!

[Nigel]

I spent a lot of hours on this 10 years ago with no practical sensible cost solutions. Let's hope you find something I missed. BTW the TMH 5th gear was poorly made and had to have after sale keyway work done for example. It does not fit the VX multi spline 5th gear setup either.

Eric   

This could be an issue, I'd forgotten about those splines. That means my query to Midwest Bayless is void for now.
I have the parts so could build another gearbox with a VX final drive using the standard primary shaft though.

Alternatively, maybe my local engineering shop can cut internal splines during manufacture.

Guy, no I don't have part numbers [yet]. I wonder if Alan has a US spec parts list? Or someone stateside?

Thanks for the input chaps.

Nigel

[WestonE]

Hi Nigel

Remember Fiat Ducato and Integrale use versions of this Gearbox which was originally borrowed from Citroen. I used the Integrale 8V suppliers for the higher load base bearing and the VX double row outer bearing. I am not sure which way the Ducato went with higher load bearings 5th Gear and 1st and second. You need exploded parts diagrams to get into this. I suspect Ducato parts might be a route to replacement 1st and 2nd gear bits which are always the first to wear. Note VX Boxes run needle roller bearings on the gears and better tolerances. The multi spline 5th gear and double roller outer bearing 5th gear set up is all about handling torque. You could perhaps get an Integrale gear set into the casings, but you will need to make the Beta Selector work with it. Note Integrale boxes with big turbos add steel bracing plates to stop the gear shafts spreading under load and stripping gears. Many Thema 16V with upgraded turbos stripped gears back in the day. I get away with it so far because the Volumetric Supercharger does not land a huge smash of torque at 4k RPM like a big turbo. However I have swept the soot that used to be my Helix Clutch rated for 270ft lbs off the Garage floor.

Parts from later boxes adapted is the safer option IMHO.

Eric       

[HFStuart]

Fiat Coupe 16V also used what is essentially the same gearbox as the Beta. Somewhere I've a collection of roadtests. I'll see if I can dig one out and whether it gives the ratios. I've got a gearbox from one somewhere too - or at lease the diff & viscodrive driveshaft.

[rossocorsa]

I spent a lot of hours on this 10 years ago with no practical sensible cost solutions. Let's hope you find something I missed. BTW the TMH 5th gear was poorly made and had to have after sale keyway work done for example. It does not fit the VX multi spline 5th gear setup either.

Eric  

This could be an issue, I'd forgotten about those splines. That means my query to Midwest Bayless is void for now.
I have the parts so could build another gearbox with a VX final drive using the standard primary shaft though.

Alternatively, maybe my local engineering shop can cut internal splines during manufacture.

Guy, no I don't have part numbers [yet]. I wonder if Alan has a US spec parts list? Or someone stateside?

Thanks for the input chaps.

Nigel

What US part numbers do you need? I have a scorpion parts manual plus some fiche for north American Betas but not everything and they appear to be a bit of a law to themselves! Parts could even differ from year to year due to the emissions regs. and Lancia trying to circumvent them.

[rossocorsa]

Fiat Coupe 16V also used what is essentially the same gearbox as the Beta. Somewhere I've a collection of roadtests. I'll see if I can dig one out and whether it gives the ratios. I've got a gearbox from one somewhere too - or at lease the diff & viscodrive driveshaft.

I had a Delta HPE HF new which is basically a more racy set up of the same running gear, if I remember it correctly the gearbox on that had different closer ratio gears 1 to 4 than the fiat might be another option depending on 5th? Also aren't the 1.4 fiats using a similar box? Such as Abarth

[Nigel]

Alan,
Thanks for responding. Eric has reminded me that the VX box has a splined primary 5th gear
so anything from a 79 US spec gearbox wouldn't actually fit.

I don't really want to go backwards with respect to strength or reliability so that
idea is now paused.

Thanks again,

Nigel

[rossocorsa]

Fiat Coupe 16V also used what is essentially the same gearbox as the Beta. Somewhere I've a collection of roadtests. I'll see if I can dig one out and whether it gives the ratios. I've got a gearbox from one somewhere too - or at lease the diff & viscodrive driveshaft.

I had a Delta HPE HF new which is basically a more racy set up of the same running gear, if I remember it correctly the gearbox on that had different closer ratio gears 1 to 4 than the fiat might be another option depending on 5th? Also aren't the 1.4 fiats using a similar box? Such as Abarth

Abarth is a C510 fiat coupe and similar a C503 I don't know the differences I'm not that technical! I thought they may all be derived from the Citroen/Beta original. My Abarth has a proper LSD as standard (performance pack) which is handy when pushing on.

[mangocrazy]

I ventured down this rabbit hole a few years back, and couldn't understand for the life of me why the guy who initiated this project (it wasn't TMH, they just sold the gear sets) chose the ratios he did. As Eric says, they were problematic in multiple ways, not least the fact that the gearbox housing had to be 'eased' (i.e. filed away) to accommodate the primary gear. I got as far as speaking to my local engineering firm who were happy to point me to either of two local (Sheffield) gear manufacturers, but I never followed it up.

What I did do was to compile a spreadsheet listing Pri/Sec gear teeth combinations and projected RPM/MPH figures, which I've converted to a JPG and posted below. If anyone wants a copy of the spreadsheet, please let me know. I'd be grateful if you see any glaring errors/omissions that I need to correct.

My take on this was to use readily available Primary gears and only get the required secondary gear sets made up. I mean, why reinvent the wheel? This is why my two preferred gear sets use readily available Lancia Primary gears.

Hope this adds to the sum of human knowledge...

<edit> Having looked at this again, could one use an i.e. secondary gear (32 teeth) with a carb primary gear (40 teeth) and create the 'higher' of my preferred gear sets?