Converting a Volumex Transmission to fit a Montecarlo

Non-engine, eg: aerodynamics, gearboxes, brakes, suspension
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Snakeman
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Converting a Volumex Transmission to fit a Montecarlo

Post by Snakeman »

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In 2005, after completing the restoration on my Monte, I made no effort to change or check the transmission, specifically ignoring issues about running a high output engine into a stock gearbox and subjecting it to the stresses of a race track. This was despite the car having uprated brakes, LEDA suspension and a Stage II race engine, so inevitably, by the end of the 2006 season it was becoming near on impossible to select 1st or 2nd gear - I knew the syncromesh on those two gears were almost certainly worn out.

For normal road driving the monte transmission is fine but on a race track it has it¢ž¢s downsides. Firstly the 1st gear has is very low ratio of 3.75:1. Also in top gear it rapidly runs out of revs at high speeds, meaning the final drive ratio is also a tad low. It also has a big difference in gear ratios between 2nd and 3rd which is very noticeable on fast track cornering

Now in the ideal world, where money is no object, I would have arranged for Quaife to manufacture a 6 speed close ratio race gearbox , with a top spec limited slip differential. I recently asked for a quote for such a bespoke gearbox - Circa ‚£6 to ‚£9k - Maybe not!

So what to do? After some enquires I established that Lancia Beta Volumex (VX) has the same core engine and transmission units as the Monte but, because the VX has more torque, it had changes in the transmission to accommodate the increased engine output. Specifically it had a higher 1st gear ratio of 3.50:1 and a higher final drive ratio. On discovering this I trawled the Internet to find VX box and, after a brief scan, I came across one from a Beta HPE that had only 39,000 miles on the clock ¢‚¬Å“ The seller conformed this by showing me the speedo which he fitted to a kit car he was building that had the VX engine from the same donor car. Perfect!

To make a VX trans fit a Monte requires the whole unit to be stripped down and rebuilt using certain parts from the monte trans, so after various ‹Å“web discussions¢ž¢ with people in the know, I borrowed the required special tools from Eric Weston and Wallace Brown and got to work stripping down the donor VX box. I already had a spare Monte trans so my garage soon became littered with gearbox parts.

After dismantling the VX box I examined the bearings and synchromesh, all of which were in good order, so then completely stripped down each alloy casing including removing all the studs and metal parts. The alloy casings where then blast cleaned and the steel items were cleaned and sent off to the electroplaters for making shiny.

Continues...
Attachments
Transmission removed
Transmission removed
trans_removed_674.jpg (94.57 KiB) Viewed 14490 times
Last edited by Snakeman on September 24th, 2007, 6:55 pm, edited 5 times in total.
Snakeman
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Differences between the VX transmission & the Montecarlo

Post by Snakeman »

On brief external examination they look very similar, but there are four major differences:

1 -The final drive output on the engine side is not the six-bolt mounting flange that is normal on a monte but a splined shaft (note the final drive on the other side is similar to the monte variant. To replace this wit the monte one requires the differential to be completely dismantled

2 - The breather vent on the VX is press fitted to the casing, smaller and made of plastic whereas the monte one is screwed into the casing, is larger and made of steel. No need to change, in fact the VX breather is lighter‚¦.

3 - The VX gear selector input rod, which is retained to the casing by a large 2.5' ring, nut, is taller that the monte variant (see photo x). The only way to replace this is by stripping down the gearbox.

4 - The clutch arm on the VX is completely different. It¢ž¢s just a straight swap with the monte one

Contunues...
Attachments
VX Transmission identifiers
VX Transmission identifiers
VX Box identifiers.jpg (132.69 KiB) Viewed 13184 times
Last edited by Snakeman on September 1st, 2008, 11:15 am, edited 2 times in total.
Snakeman
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Gear Selector

Post by Snakeman »

The VX box also has different gear selection rod attachments, and is externally a different length to a Monte/Scorp one.

To physically remove the selector it is necessary to separate the main cases, but note it is not a direct swap as the Montecarlo selector has a larger diameter swivel base of 20mm not 16mm as on a VX, so the Monte selector will only fit a Monte casing unless the casing is reamed out from 16mm to 20mm
Attachments
VX selector Left - Monte selector Right
VX selector Left - Monte selector Right
selectors 4.jpg (75.19 KiB) Viewed 14487 times
Monte Selector casing with larger smaller 20mm diameter hole
Monte Selector casing with larger smaller 20mm diameter hole
monte_selector_hole_421.jpg (71.24 KiB) Viewed 14486 times
VX Selector casing with smaller 16mm diameter hole
VX Selector casing with smaller 16mm diameter hole
VX Selector hole.jpg (76.99 KiB) Viewed 14486 times
Last edited by Snakeman on September 24th, 2007, 5:28 am, edited 2 times in total.
Snakeman
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Other changes required to casing

Post by Snakeman »

If the VX casing is to be used it will also be necessary to tap the three M8 threads in the gear selector mounting

See Image
Attachments
These 3 holes will need to be tapped out to an M8 Thread
These 3 holes will need to be tapped out to an M8 Thread
VX Selector hole2.jpg (68.59 KiB) Viewed 14530 times
Snakeman
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Post by Snakeman »

The Monte Speedo gear drive has a different tooth pitch to the VX so both the Speedo crown-wheel gear, which is part of the final drive casing, and VX Speedo drive parts needed to be exchanged for the Monte parts.

Because I had no need to replace the synchromesh parts or the bearings, the reassembly of the transmission was straightforward, but an important observation was that the top layshaft bearing on the VX is different to the Monte bearing.

I used a new set of gaskets and all new seals. The gaskets were applied with a very thin layer of Hylomar to ensure against leaks. During reassembly one of the most difficult tasks was tightening the final drive flanges to the correct torque without causing damage. To do this I manufactured a special bracket that holds the final drive flange in place while the nut is undone

During this conversion the final drive assembly was disassembled and different parts fitted so it was also necessary to check the differential bearing preload. If it was out of specification then different size adjustment shims would be required. In this case I fitted the original shims and found the preload was still in specification (Mr Lucky!)

Special Sockets kindly loaned to me by Wallace Brown and Eric Western
‚¢ The 40mm OD castle ring retains the final drive flanges
‚¢ The 36mm OD castle ring retains the gearsets to the lay & main shafts
‚¢ The 46mm socket is to remove the gear selector assembly
‚¢ The 32mm Hex nut was from an Integrale trans but the threads seem different to the Monte/VX shafts

Once the car was fully reassembled I installed new oil* and went for a road test. The difference was immediately apparent, 1st gear had a significantly noticeable higher ratio. Before when accelerating from standstill the car would only travel a few yards before it being necessary to change up, but now the speedo is almost at 40 mph before needing second gear.

The top-end speed had also significantly changed for the better. With my tyres and the rev limiter set at 7200 rpm, the theoretical top speed is now 163 mph... Perhaps I need to have another look at those brakes!


Geoff Ward

Reference Books
For tolerances and specification:
Lancia HPE / Beta Coupe, Service Manual ¢‚¬Å“ Published by Fiat Auto

For transmission strip down and re-assembly:
Lancia Beta Manual. 1300, 1400, 1600, 1800, 2000 from 1973 to 1980 ¢‚¬Å“ Published by Haynes

Technical Notes & Explanations
A transmission with synchromesh is not ideal for track racing because the down shifting of gears is too quick for the synchros cope with so, inevitably, they suffer from premature wear.

Now the synchromesh mechanism in the VX transmission is almost certainly the same design as the Montecarlo, so it might be said that it will suffer the same fate as my original transmission. Possibly, but less likely because the ratios between 1st and 2nd gear on the VX are closer together than those on the Monte trans, so when changing down there is less ‹Å“synchronising work¢ž¢ going on therefore, hopefully, less wear!


*I use Red Line 75W 90NS gear oil

** A Synchromesh is also known as a Constant Synchromesh or Syncro Hub. Its purpose is to provide a smooth change between gear changes. It¢ž¢s operation is most obvious when changing down the gears.

Origionally gearboxes were just that, ‹Å“gears in a box¢ž¢, and in order to change down the gears the driver had to make sure the engine RPM matched the speed of the gear the driver was changing into. This was achieved by double de-clutching or speeding up the input (lay)shaft ¢‚¬Å“ revving the engine in neutral between the gear change. To eliminate the need to double de-clutch, the synchromesh gearbox was introduced. When a gear is initially selected the synchromesh is designed to create gradual friction between the differing shaft speeds to equalise them. The continued movement of the selector engages the gear.

I hope it makes sense. GW


I will continue to upload relevant images at a later date
Attachments
Checking the turning toruque on the final drive
Checking the turning toruque on the final drive
turning torque gauge.jpg (76.86 KiB) Viewed 14487 times
The top layshaft bearing on the VX is different to the Monte bearing.
The top layshaft bearing on the VX is different to the Monte bearing.
ready for assembly.jpg (66.6 KiB) Viewed 14481 times
Speedo drives.  Metal = Monte.<br />White Plastic = VX. <br /><br />Note the different tooth pitch
Speedo drives. Metal = Monte.
White Plastic = VX.

Note the different tooth pitch
speedo drives 4.jpg (79.59 KiB) Viewed 14481 times
This image provides further clarification on the layout of the VX Trans final drive
This image provides further clarification on the layout of the VX Trans final drive
VX final drive.jpg (81.32 KiB) Viewed 13294 times
Last edited by Snakeman on May 23rd, 2008, 8:33 am, edited 4 times in total.
Snakeman
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Post by Snakeman »

And of course I had to test it out at the Nurburgring!

G
Attachments
T7W_0094.jpg
T7W_0094.jpg (81.48 KiB) Viewed 14474 times
T7W_0090.jpg
T7W_0090.jpg (69.28 KiB) Viewed 14473 times
Guy Croft
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Post by Guy Croft »

EXEMPLARY POST!

Quite exceptional Geoff, thanks very much indeed for compiling it for the benefit of site readers. And I would point out that at my request, Geoff took time to write it so that it might be uploaded directly rather than as a pdf attachment, a thing that takes a terrific amount of effort.

I don't do gearboxes but it's so well set out I had to read every word!

GC

*Nurburgring eh? Piston and rod killer that circuit....hint
sumplug
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Post by sumplug »

Fantastic thread!!
Well written, and well executed. Oh and what a cracking car!!

Andy.
Snakeman
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Post by Snakeman »

Thanks for the kind words,

Rather the using a trailer I drove the car to the Nurburgring completing over 1000 trouble-free miles. The VX conversion gives a greatly improved (Higher) cruising speed for the engine RPM. It is also a beast to be reckoned with on the tracks - Goodwood, Mallory Park & the Nordschleife.

If only I had just a bit more power.....
Guy I will be in touch...

Geoff
Guy Croft
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Post by Guy Croft »

My spies tell me Geoff, (rightly or wrongly) that you and your well-known car had a class win at Goodwoood quite recently. I should be most interested to hear about that and what you were up against.

GC
Snakeman
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Post by Snakeman »

Hi Guy,

It's all detailed in the readers cars section with Pics of the Chequered flag!

viewtopic.php?t=165

I was up against a Motley Bunch in Class 10 which included two Lotus Exige's. See link for the results

http://www.amoc.org/images/stories/docu ... esults.pdf


Geoff
Guy Croft
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Post by Guy Croft »

Aha! Thanks Geoff, I did not know that,

GC
Geoff T
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Montecarlo Gearbox Swap.

Post by Geoff T »

Hello Guy,
I too have just carried out a volumex gearbox transplant into my S2 Montecarlo. I now have the ratios it should have had from the start!
My Monte has a standard motor with the exception of twin 40 DCNF carbs on an Alquati manifold.
I essentially stripped both gearboxes and transferred the gearshafts across into the Montecarlo casings. The diff was easy as all you need to do is unbolt the ring gear and install the Volumex item. If you are careful you won't even split the diff! This solves all the problems of swapping drive flanges / speedo drive gears / bearing preloads etc, as the same unit will be refitted to the original casings. The difference with the VX layshaft is that the 5th gear is splined on and uses a taller rear bearing, wheras the Monte one uses a keyway. You need to swap the gearsets as a pair.
On the road, as Geoff said, the difference is very noticeable, and the taller final drive ratio makes for much quieter cruising. The is enough torque available to pull away from 30 mph in 5th with ease. Top speed has remained the same, but of course achieved at lower revs. Now I need more horsepower to go faster! Fuel economy should improve too. Haven't checked it yet. Even at 30 mph in 4th the rpm is only 2000, and 60 mph in 5th is 2800 against the standard 3250!
If you don't mind a very small trade off in outright acceleration, for less noise and improved economy, I recommend it!

Geoff T.
1982 S2 Montecarlo
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