Thread: The Ultimate FC

Ron, have you met the Stolly owner from Geelong who fitted higher gearing to the transfercase (60mph) axle disconnects and LPG?
Just noticed said vehicle mentioned on a historic MV forum.
Bill.

There are previous posts on this thread about a Stalwart going to Corowa.
I was going to go and have a look but my house was broken into the day before I was going to leave, so I stayed put to sort things out.
A spy of mine did take some pics of the internals for me.

I have spoken to the owner afew times over the phone.
LPG is easy except for the gas tanks and the disconnects are straight forward to do........access is a problem.
Regearing on that 60 mph stalwart cost over 10 K and the lowest gear according to my caluations would limit off road work and may be climbing out of the drink and up a steep river bank.
The gearing was raised by 40 percent and that 60mph is done at comfortable engine RPMs
My idea is dog clutches on either side of the transfercase
with one side standard or slightly lower ratios and high ratios gears on the other side.
The problem is if it can be done this way and retain enough strenght in the transfercase and the cost too.

That high speed stalwart is a lighter MK 1 which is almost 2 tonnes lighter than mine.
One over seas stalwart owner pointed out the cost of a regearing conversion with its problems would be money better spent on a truck to carry the thing around with less wear and tear to the stalwarts drive system.

The 60 mph stalwart (in fact it is slightly faster)has shown me two things.
Drive on the centre wheels only is no problem with the disconnects and the bevel boxes are out of the equasion driving though the centre wheels.
That stalwart I heard had a drive shaft come loose on the way home due to the way most people do the disconnects, and to do it properly the shafts must be supported with a extra bearing and not the original cupplings converted into a sliding dog still supporting a very heavy shaft.
The higher rotational speeds would not have helped
The owner told me the higher speeds would not have been possible
with out the reduction in drag the disconnects gave
I have noted the LPG system he had fitted was not ideal and more power is possible .

Yes my main concern with raising the gearing was the reduced tractive effort offroad with only around 65:1 low gear. Maybe ok for a vehicle that just travels to shows.
Do you know what the hub reduction ratio is? Could you use the trick that Foden used with their hubs that could be changed from direct drive to 2:1 by changing their halfshafts? A little more complicated with steering stubshafts on the Stolly I guess, but you'd only need to do 2.
Bill.

Hub reduction ratio is the same though the Alvis series of FV 600 vehicles , the ratio beening 4.125.
The hubs are double epicyclic and the gears are timed to one another and at the factory gears were machined as sets and cannot be swapped around in any form, or the hub, wheel bearings and outer tracta are scrap metal in short order.
I beleive the problems with bevel boxes, tracta joints etc on the stalwart are from water ingress and the need to maintain seals to stop oil leaks/water ingress and the need to top up these items and a real lack of know how on how work on these machines and how to drive/ treat them
A special tool has to be fabricated just assemble the hub reduction gears.
Any ratio change must come from the gearbox or transfercase and both are specialised ,but it can be done with a different gearbox if you do not want hydraulic crane, winch or water jet drive.
The standard gearbox cannot take more than 4000rpm input speed as there are stories of the syncros spreading with rpm.
The bevel boxes must be 1 to 1 ratio due to straight though drive on centre bevel box for centre wheels.
Another trap for highway use on the stalwart is a lack of lubrication of the tracta joints at speed and constant load as the oil will squeeze away from the faces of the tracta joint forks and they start to weld themselves together.
Therefore the idea behind driving the stalwart up the gutter, side of road or over speed hump etc........to so call unwind the transmission is not that, but to get abit slack between the tracta joint forks so oil will lubricate them.
With drive disconnects , just backing off on the throttle every now and then would be enough.(most likely enough with standard set up too )
The British army came up with a fix called oil dag which is a graphite compound added to gear oil which remains on the metal surface at extreme temp and pressure.
Oil dag is mainly designed for use with hot metal dies and presses.
It should be noted that tracta joints are used in many famous 4x4 and trucks without trouble,,,ie Dodge weapons carriers and power wagons, WW2 jeeps (some production runs) ect.
One interesting story I learnt when I was ARES in RAEME was why the Australian army was a big user of Molybond products.
The Aussie Saracens were chewing though hub reductions every 50 hrs road time when they first issused..........so the story goes.
Molybond was used in the hubs the overhaul time increased to hundreds of hours

The Myth about stalwarts giving the drive train a hard time appears to have started in Germany where the Stalwarts were deployed in NATO
The stalwart was designed for Germanys rivers and steep river banks etc.
A unloaded Stalwart has a tracta joint angle of about 40 degrees and when they were driven along the autobarns unloaded, flat out and as normal transport hacks, problems occurred.
Orders were issused to drive them loaded with tank tracks etc to load down the suspension and reduce tracta angles and drive them over wooden sleepers after a set distance on hard roads.
The drivers under stood this to be to unwind the drive train.
In civie hands, lack of information and throw in age it is easy to see why the stalwart is seems to be weak in the tracta joints and bevel boxes

The suspension on the stalwart is easily lowered and the weight can be adjusted to be more on the centre wheels to help the outers to scrub out during use.

[ame=http://www.youtube.com/watch?v=mfzZ_d3JpAA]Stalwart Playing in Mud Shobdon Sept 1993 - YouTube[/ame]

Originally Posted by 101 Ron

It should be noted that tracta joints are used in many famous 4x4 and trucks without trouble,,,ie Dodge weapons carriers and power wagons, WW2 jeeps (some production runs) ect.

And 80" Land-Rovers

Cheers Charlie