Wild Fing gets a One Link front end ! maybe.

[bill van snorkle]

My 'Vapour Overdrive Project' thread drifted off topic a little ( my fault)So Dan has kindly invited me to start a separate thread on the subject of the One Link front suspension I am making up to replace the current 3 link arrangement on my slightly altered series 2 LandRover known affectionately by me, the local Kangaroos and Wombats as 'Wild Fing'.

The present 3 link arrangement works extremely well, and I'm probably a bit of a plonker for wanting to change it, but after recently analysing a set of Unimog front and rear axle assemblies I began to suspect that the Benz engineers got up to a bit of cleverness with their offcentre torque tubes, and the only reason I can think of why they offset them is to counteract a destabilising force known as driveline induced torque roll. This is a torque reaction force produced by the transmission and propshafts that tends to roll the vehicle sprung mass over to the R/H/side when the vehicle is pulling hard or climbing steep off camber gradients. I have found with my various 4wds that the vehicle is significantly more stable on off camber climbs when the cross slope puts the passenger side (left side) down, and less stable when the other way with drivers side down. It is my opinion, and possibly the opinion of the Mog designers that the torque reaction from the front and rear axle housings, through the torque tubes, could be used as a stabilising force to cancel out this torque roll if the torque tube or One Link chassis pivots could be positioned to either side of the chassis roll centre. For the front end my One link wishbone pivot will be either 50mm or 100mm left of centre, and If I do the rear end it will be right of centre.

Dan is moving the few One link specific posts from the overdrive thread over to this thread, and as I make a little more progress I will add posts, and/or reply to other interested members posts.

Bill.

Were you cutting welding and grinding something interesting?

Well nothing particularly original Jaime. For the past month or so I have had this bee in my bonnet about giving WildFing an offcentre One Link front end, in an effort to neutralise the effect of driveline torque, which tends to roll the sprung mass over to the R/H/side in more extreme terrain.

Building a One Link wishbone isn't all that difficult. In fact I had the original 'centred' one from my old 6x6 to start with. But because I am unsure how an offcentre one would affect on road handling, particularly during heavy braking, I decided to make it with a choice of 2 offsets, 4" and 2". That and together with a much more substantial 'clamp on' crossmember that is required, and that the assembly needed to be a fairly quick and reversible 'bolt on' arrangement that utilised existing bolt holes and brackets from the present 3 link setup, made the whole project a bit more complicated.

I will post up photos etc if the concept proves successful, but with my wheelybin and groundsheet outdoor workshop, I really need the bleedin weather man to give me a break on the few days I get to myself before I attempt to fit the assembly up.

[Jamie_grieve]

Is there some way you could have wildfing tilted to one side, maybe tethered from the top of the cage on a side slope and jag the clutch a couple of times to see how the effects of moving the offset relate to a real life situation? I'm really interested in what you're doing as I'm completely undecided on what I'm going to do to the front on my old stage one. One day it's a one link and Panhard, the next it's a three link with the A frame at the bottom guarding the prop from rocks and stumps and if it rains I think a four link with a Panhard would be the way. One of my considerations is getting the right roll centre to stop 52" tyres invading the engine bay too much and have enough room to steer. I was nearly thinking of going back to 40" tyres before I realised that would be just not in the spirit of things.

We digress, overdrives, that Spanish thing is really well thought out, shifts like a powershift without losing torque and was designed as a bolt in conversion. Would also have made a great underdrive if the gearbox could handle it. I wonder how the planetaries would get on bump starting an old high compression N/A diesel?

[bill van snorkle]

I think for maximum benefit, I will probably need to offset the rear One link as well, like on a Unimog Jaime. I found a bloke on Pirate that did the same to his solid axle M151 Jeep, and he reports no torque roll under power or under brakes. There is the little problem of the LandRover handbrake assembly that I will somehow have to work around in order to offset the rear link to the right hand side though. It's do able but the crossmember I am making for the front One Link that replaces the Series style arched crossmember will also need to pivot the rear link off, as well as project rearward at each side to support the transfercase mountings. It's actually turning out to be an intricate shape, and the twin offset front wishbone is an absolute cow to fabricate,with the legs starting off at the radius arm mountings on the axle, then tucking tightly inwards to miss the deeper part of the chassis rails during articulation, then meandering back towards the crossmember, whilst clearing all the other bits and bobs like winch pto shaft, exhaust pipe, propshaft, sump etc. All while attempting to keep it high so as not to affect ground clearance. It doesn't look anything like the wishbone shape I started with.

I guess we have strayed a long way from the overdrive topic, but I think we have just about flogged that horse to death anyway.

[dirtydiesel]

Hi Bill have you given any thought to raising the chassis mounting for the front 1 link so that angle of the link could closer converge with the CoG?

The front torque tube on the 404 is at quite an angle somewhere around 10-12 degrees, wheras the rear is closer to 5 degrees.

I realise that packaging constrains on an existing conventional car would kill this idea dead but i am wondering whether it could be usefull to design it in from the start in a scratch build?

[bill van snorkle]

Hi Bill have you given any thought to raising the chassis mounting for the front 1 link so that angle of the link could closer converge with the CoG?

The front torque tube on the 404 is at quite an angle somewhere around 10-12 degrees, wheras the rear is closer to 5 degrees.

I realise that packaging constrains on an existing conventional car would kill this idea dead but i am wondering whether it could be usefull to design it in from the start in a scratch build?

Hi Dan. I think you are correct that for a scratch built vehicle it would be worth trying to emulate the Unimog geometry,but on my truck packaging is really tight.For the chassis end of the wishbone I am using the original 4"x 2 1/2" metalastic bushing from my old 6x6 Landy front wishbone, which will sit snugly under the gearbox bellhousing at just over 2 ft above ground level. A smaller bushing may have gained an extra inch of height, but this one lasts forever. I don't really know the position of the centre of gravity, so much of the original Landy has been rearranged, but it's possible that 2ft may be getting close, seeing as how a standard Defender is apparently at around 2'3". My other concern with a steep wishbone angle is of course that of the portals, in that the line from the tyres contact patch up through the pivot axis of the wishbone bushing is already very steep and any more may produce excessive antidive under brakes. I have tried to keep the instant centre and effective distance from the front axle centreline to the bushing axis the same as for the existing 3 link. I would have preferred to have made the wishbone longer, but the transmission gets in the way, and I'm not keen on lifting the truck any higher than how it stands now.

[landroversforever]

Subscribing to this .

[o_teunico]

Will be great seeing pictures of current setup for comparing them with the one link, once made.

[bill van snorkle]

Will be great seeing pictures of current setup for comparing them with the one link, once made.

I will take photos of both systems before I install the One Link, but I will only post them up if the One Link works at least as well as the present 3 link, otherwise there will be no point to posting up a failed project.

[muddy]

I will only post them up if the One Link works at least as well as the present 3 link, otherwise there will be no point to posting up a failed project.

Pictures either way surely bill? It's always nice to see why and how a project does not work. Going the ill not share it if it doesn't actually work mentality I can only elude to the hundreds of projects I have built

Will.

[bill van snorkle]

Pictures either way surely bill? It's always nice to see why and how a project does not work. Going the ill not share it if it doesn't actually work mentality I can only elude to the hundreds of projects I have built

Will.

I guess you are right Will. If it doesn't work, at least I would have replaced the rusting, fatigued number 2 crossmember and bulkhead outriggers with fresh stronger units, and gained maybe an extra inch of ground clearance under the belly.

[Michele]

produced by the transmission and propshafts that tends to roll the vehicle sprung mass over to the R/H/side

Subscribed of course...

I had one thing to ask you about DITR but I forgot...

[Daan]

What advanteges do the 1 link actually give you if I may ask? If you look at the mainstream off road scene, about 99% is going for a 3 or 4-link. Is this a case of people just going with the herd or are there more advantages to a 4 link?

You can modify a 3 link to cancel out roll torque as well: if the toplink sits on an angle pointing to right (seen from behind of the rr axle) it will cancel out torque roll, depending on rotation direction obviously.

I did this on an oval racer with a live rr axle once were the torque roll would unload the rh front wheel, causing understeer. angling the rr toplink as much as I could did make matters much better.

Daan

[bill van snorkle]

What advanteges do the 1 link actually give you if I may ask? If you look at the mainstream off road scene, about 99% is going for a 3 or 4-link. Is this a case of people just going with the herd or are there more advantages to a 4 link?

You can modify a 3 link to cancel out roll torque as well: if the toplink sits on an angle pointing to right (seen from behind of the rr axle) it will cancel out torque roll, depending on rotation direction obviously.

I did this on an oval racer with a live rr axle once were the torque roll would unload the rh front wheel, causing understeer. angling the rr toplink as much as I could did make matters much better.

Daan

It's a question of packaging !

Angling the top link of my present 3 link front end is not really an option. Due to my portal axles and lowered suspension, the top link angles down from the top of the diff to the mounting on the crossmember. There simply isn't enough vertical room to raise the crossmember mounting higher up.

With the engine in its normal offset to the left location, plus the PTO shaft for my winch, plus exhaust system, there is insufficient space beside the engine to swap the 3rd link to the left with the vertical separation necessary to cope with the added leverage of portals.

There are 2 perpendicular forces contributing to Torque roll in this case, and I could reduce it somewhat by making the top link longer, although it would still angle down to the crossmember, but at a reduced angle. I won't be burning bridges behind me with the One Link. All the present 3 link brackets will remain, and I have made provision on the new bolt on crossmember to fit a longer top link if I am not satisfied with the One links performance. I am a bit anal about ground clearance and snag points and although I have made the wishbone to be the same height from the ground as the 3 link lower arms, the fact that the wishbone basically fills up the space between the chassis rails means it will probably plough more earth on steep hummocks. I'll wait and see if that disadvantage outweighs the advantage of reduced or negated torque roll.

[bill van snorkle]

The One Link wishbone is proving to be virtually impossible to make as a 'bolt on' unit that picks up the original radius arm mountings on the axle. The reason is that my actual suspension height is significantly lower than standard, so the ends of the wishbone legs strike the chassis rails at around 20 degrees of articulation.Wild Fings front axle articulates to 30 degrees presently. Also, due to the springs being mounted behind the axle housing and level with the bottom of the axle tubes, I can't tuck the legs inwards more tightly from their outboard mountings to clear the downward sweep of the chassis rails behind the axle, unless I lift the suspension 2 inches, which I'm not prepared to do. So, it's back to the drawing board for now.