Leaf over modification

[Gilmore]

I would like someone to shed some light on the suject of a leaf over modification. I have a 1973 seris 3 88 SWB. Of what i can gather on various articles on the net is that with this specific land rover that the angle of the prop shaft front and back becomes too large and it causes a vibration or ultamtely brakes the prob shaft. So what is the maximum angle the propshaft can opperate in relation between the axle and the transfer box? Have anybody done this before and have any thoughts on this especially in regard to stearing modifications exct?

Then the other way of getting some body and frame hight is an extention welded onto the body that the front end of the springs connect on to and then using longer shackles on the rear end. Is this a safer way of gaining some hight and is there any reason why this is not recommended?

Any info would be much appreciated!!!

[craig]

spring over axle is common on suzukis etc but not as common on series for some reason, saw one at sodbury a few years ago and it looked the mutts nuts,

[Gazzar]

Have a google for Timm Cooper, in the US, he has done this to a 109. Rubicon trail vehicles have many modifications to allow much greater extremes of articulation

SOA is a good idea, the Hi-lux by Toyota has done this to good effect.

Aside from Insurance concerns, it is technically doable on a series, the propshaft issue can be resolved by wide angle propshafts, double cardon versions and other fancy stuff. Bailey Morris and the propshaft clinic are good places to talk to.

What may be one option is to fit a hi-lux axle system complete. Or buy a Hi Lux

Playing with spring mounts is a major modification, but not beyond the experienced engineer. The vehicle is very different to drive, insure and maintain. You are on your own for advice and the like.

Still, I wouldn't do it. Not to my taste.

G.

[FridgeFreezer]

Been covered on here a fair few times, have a read/search back.

[plasticbadger]

I've read quite a few things on here, on Pirate and in the American mags on SOA, however I've never done it. From what I've read people have generally found that SOA has given more flex than spring-under (something to do with the distance of the axle from the main leaf and therfore the force exerted?), plus it obviously gives a cheap 6" lift if you can do all the fabrication yourself.

However the effects of axle wrap and the resulting tramp are well documented so you would have to add anti tramp bars or an anti-wrap device of some form. This can be difficult without restricting flex.

The steering drag link issue shouldn't be a problem, as if you are capable of safely fabricating a SOA suspension system, adjusting the diff angle and possibly rotating the diff nose up relative to the swivels then fabricating a custom drag link that clears the springs should be a doddle.

The other big problem you have touched upon, prop shafts. The landrover is pretty small (the 88 is anyway) and therefore the props are pretty short meaning the angles are high. I don't know what you can safely run angle wise on a normal or double carden prop, but I have run a Range Rover with a 5" lift and it was definately at the limit of standard props. The only way to tell if it will work is mock everything up and give the figures on the lengths and angles to a prop specialist and see what they say. You see some pretty huge short wheelbase Jeeps in the US, so it must be possible.

Finally, I would say if you are planning on a SOA then don't bother putting the Series axles back on. Something like Landcruiser 70 series axles will give you more strength, wider stance and factory locker options.

[Steve_M]

I don't think 70 series axles would be the best choice. They are not much, if any wider, than series axles and factory lockers aren't that common (LSDs in the rear are however fairly easy to find). If you want to go for Toyotas then 80 series would be better suited IMO.

Steve

[plasticbadger]

I bow to your greater knowledge Steve, I thought the 80 diffs fitted one of 70 cases, or the late model Hilux diff with e-locker?

[Snagger]

Plastic Badger is entirely right - axle wrap will be a problem, and you have already identified steering and prop shaft issues. You also need to consider how bad your side slope ability will become and how slow you will have to corner on road to avoid turning over.

It's a pointless mod in an 88" (and rarely worthwhile in a 109) as it's the diffs that limit ground clearance, not the chassis. You need bigger tyres and taller springs for the tyres to clear the wheel arches. 7.50s would be fine on standard suspension, but 9.00s will require either 1-ton style spring mounts and shackles (like you proposed) or you could just fit good quality parabolic springs which give a lift as well as better handling and ride (try to fit the 1-ton bump stop extenders to keep the 9.00s away from your wheel arch tops if you find they foul).

If you really want good ground clearance, then portal axles is the way to go. They lift the diffs as well as the chassis, but SOA is just a street posing option which greatly reduces your stability and handling without any significant increase in off road ability.

[plasticbadger]

If you really want good ground clearance, then portal axles is the way to go. They lift the diffs as well as the chassis, but SOA is just a street posing option which greatly reduces your stability and handling without any significant increase in off road ability.

I don't think I'd go that far, as for all these mods SOA should be seen as part of a modification package. If you are going to go to the work of a SOA set up then fitting stronger, wider axles should be part of the plan, offsetting the negative effect of the lift. Likewise those stronger, wider axles can carry larger tyres without breakage or steering lock worries thus improving under diff clearance.

A lot of US built Jeeps, Toyotas and 70's full size pick ups run SOA setups to great effect with excellent articulation. It's just a matter of selecting the right components and doing the engineering right. If you can do that at home then it can work out to be mighty cost effective.

Also, now that you've swapped axles, built steering, had custom props made etc. a set of disconnectable antiroll bars should be easy! To be honest though the progressive nature of leaf springs is far better at reducing roll than coils.

[Snagger]

I don't think I'd go that far, as for all these mods SOA should be seen as part of a modification package. If you are going to go to the work of a SOA set up then fitting stronger, wider axles should be part of the plan, offsetting the negative effect of the lift. Likewise those stronger, wider axles can carry larger tyres without breakage or steering lock worries thus improving under diff clearance.

Using Defender or RRC axles would be the way to go, if you do it - fitting wider wheels and spacers to the existing axles will make the steering incredibly heavy and will also put tangential loads on the hubs, causing bearing and stub axle wear.

[plasticbadger]

Using Defender or RRC axles would be the way to go, if you do it

You've abviously lost your mind? I certainly would go to all that effort and work to fit S#$%t land rover axles that are made from chocolate, barely live with 33s, are higher geared than the standard axles and cost a fortune to upgrade.

If you're going to do it use some good axles like Landcruiser 80 series or Nissan GQ.

[Snagger]

You've abviously lost your mind? I certainly would go to all that effort and work to fit S#$%t land rover axles that are made from chocolate, barely live with 33s, are higher geared than the standard axles and cost a fortune to upgrade.

If you're going to do it use some good axles like Landcruiser 80 series or Nissan GQ.

I was just recommending not using Series axles because their track is insufficient for a seriously lifted vehicle and adding spacers or wide wheels has other repercussions. Whether to fit later LR axles or something completely different comes down to a lot of specific factors for the user.

[plasticbadger]

Fair enough, we agree that series axles would not be the best option. I just have a low opinion of LR axles in general.

[Snagger]

Fair enough, we agree that series axles would not be the best option. I just have a low opinion of LR axles in general.

That seems a widely held view amongst the Americans, too, who find them too weak for use on rock crawlers. I suppose a lot of issues are tied into what you use the vehicle for - mine is a daily family vehicle and expedition vehicle, so keeping it all LR is the easier option for maintenance, and expedition use is unlikely to overstress the axles or transmission. Serious off-road competition vehicles will need something tougher, though, and can also use components from more varied sources because maintenance problems will merely result in a missed event, not being stranded in the middle of nowhere... Still, Bowlers seem to do alright with RRC/Defender axles

[Gremlin]

Sure they are ok but you really do not know how much money is invested in those axle internals . You can run rover axles but its what you are willing to spend to make them durable seems to be the problem.

G

[FridgeFreezer]

There's also the small point that racing is not the same as rock crawling is not the same as challenge driving is not the same as is not expedition driving and is not the same as the average daily use most LR's get from the factory which LR design the axles to cope with.

There's no right answer for anything, it's all a compromise and is largely down to personal preference.

[Snagger]

There's also the small point that racing is not the same as rock crawling is not the same as challenge driving is not the same as is not expedition driving and is not the same as the average daily use most LR's get from the factory which LR design the axles to cope with.

There's no right answer for anything, it's all a compromise and is largely down to personal preference.

My point more clearly made!

The Yank rock crawlers put massive amounts of torque through their axles with big engines and a lot of low 1st and under-drive use on big tyres. Not many of us put anywhere near that amount of torque into an axle, though racers and mud pluggers have to consider shock loadings from spinning wheels finding grip, which may need more strength than standard but less than the rock crawlers.

[FridgeFreezer]

...and of course you can't sink on rocks, so weight is less important than many of the other disciplines.

[ToyRoverlander]

Right.. My first post here on this forum. Better make it an informative one then..

Some of you might already know me (snagger, plasticbadger) from other forums. For the others, my name is Koos, I'm 27y/o and live in the netherlands. Oh, and I drive a '65 109" stationwagon.

Right, tech talk.

Doing a SOA conversion is a great idea! If you like it to perform well offroad that is, don't expect it to be a weight carrier or a heavily packed expedition vehicle any more.

Like with many other mods, there's compromises.

A SOA conversion is awesome, if done right! Here's my idea of it being done right. I'll break it down into the individual components.

Axles

It would be silly to keep the Series axles. They're narrow and weak. Some will argue that drum brakes perform well, I hate them. I like GOOD brakes.

Coiler axles are wider, have disc brakes but I still wouldn't choose them because they're still fairly weak. Plus I don't like the trackrod sitting ridiculously low behind the axle. There's no high-steer arms available for coiler axles. They can be made for Series axles though, at least that's a good thing...

I would use something else than LR axles. Keep in mind width, locker and ratio options and whether you can get high-steer arms for them.

Steering

I've already mentioned the high-steer arms. They replace factory steering arms on the swivelhousings so the track rod and draglink are moved up and over the leafsprings. That way they're less vulnerable. And it reduces bumpsteer. The higher the angle between the drop-arm and the steerin arm on the swivelhousing, the more it will suffer from bumpsteer.

Springs

Whether you use parabolics or standard springs with leafs removed doesn't matter much. It's all possible. I like parabolics as they're more supple, are a thinner spring pack (especially with all those spacer plates removed and in a 3leaf setup for instance) and they're still 'tuneable'. You can remove or add individual leaves to raise or lower spring ratio. Reducing spring rate will lessen the arch in the spring, and so lower ride height. Depending on how soft you go, it will also make it more unstable on side slopes and it won't ride nice on the street.

It would be wise too to get rid of the short front springs and use rear springs up front. They're 12" longer, and the longer the spring is the more flex it has. And having more flex up front increases overall articulation and also more balanced articulation front to rear which is also very important.

Shocks

Ditch those original, and those pro-comp, shocks and go looking into aftermarket long-travel shocks. Those long soft springs are capable of some pretty amazing articulation, if they're not being restricted by short shocks.

You want decent high quality shocks that are valved (or are adjustable) to be much 'stiffer'. That will make it ride a lot nicer on the street and controls the supsension way better. Look for around 12-14 inches of shock travel (measure to see what fits before buying obviously!!!). That's a lot of travel, and you DO need to fab up some shock mounts for them.

Tyres

Don't put 7.50's on a SOA'd Series. It looks stupid! You need some bigger rubber to fill up those arches, you got the clearance now anyway. Anything less than 33" will look funny. And there's another reason for going to non LR axles, stronger stock and, depending on what you get, better brakes. Bigger tyres need more stopping power too!

Bigger tyres add under axle clearance, and ofcourse overal under chassis clearance. The SOA gives very good underchassis clearance and approach angles.

Driveshafts

These will need to be custom made. Depending on axles (low or high-pinion) your options are high-angle yokes, longer slip joints, custom lenghts and DC shafts.

When doing the conversion keep an eye on u-joint angles! unless you like vibrations.....

Ofcourse you need to look at other things too. Will the tyres stick outside the body, are brakelines long enough.... stuff like that.

Enough with the tech talk for now....

I've converted mine to SOA and am currently converting a mate's 109" too.

Here's mine:

Good articulation for a Series:http://www.expeditionportal.com/forum/newreply.php?do=newreply&noquote=1&p=392422

Compared to my mate's 109" that's getting converted too and is almost done:

What I've done.....

First of all, the engine and gearbox have been swapped in favor of a 3.4 4cyl diesel from a BJ42 Cruiser. Axles are from a HDJ80 LandCruiser.

On the front:

- rear parabolic springs, 2leaf with a 3rd 'helper' leaf made from the second leaf of an old 2leaf parabolic front spring (thus a bit shorter).

To fit the longer springs the chassis has been extended and the rear shackle bush in the chassis has been moved back.

- Bilstein 5125Series shocks with 14" travel with a 270/55 valving.

- Driveshaft with high-angle yokes and 180mm slip (don't need that long, but is from my old setup).

- steering is just a bend trackrod from a 60Series cruiser with a bit of the old LR trackrod welded in. No PAS here and I doubt I have the strenght to bend it, and if the wheel gives it a kick it will rip the steering wheel out of my hands (been there done that). High-steer arms for 80series axles are available from Slee offroad in the US. However, there's someone currently developing new swivel housings and highsteer arms that fit on top of the housing with 4(or 6?) bolts. There's only 2 bolts now holding in the top swivel pin, not enough.... The Slee arms use the ABS sensor hole for a 3rd bolt hole.

On the rear (keep in mind my rear suspension mounting points were NOT stock to begin with)

- 3leaf parabolic springs.

- mounting points of the leaf springs have been moved up, about 1.5" at the front and about 4" at the rear. This moves the spring up and lowers ride-height. This was needed on mine because of the modded rear spring mounts.

- Bilstein 5125Series 14" travel shocks with a 270/55 valving

- Custom length high-angle 110mm slider driveshaft. (on my mate's 109" we've used a DC shaft with high-angle yokes, 110mm slider and Series pattern flanges)

Tyres are 255/85 KM2's

Offroad this thing is a beast. It crawls through everything. Offroad I haven't had it lift a wheel off the ground yet! It has that much articulation!

Onroad it handles really well! There's less bodyroll than my mate's 109" when it still had parabolic springs and pro-comp shocks. It corners good! There's no need to slow down to a crawl to go through the corner!

High-speed stability is good. I can take my hands of the wheel when doing 60mph and it tracks straight as an arrow.

The one thing it doesn't like is crosswinds, you get blown around a fair bit. And it suffers from bumpsteer as I havent got the high-steer arms yet. And as a result, on bad bitumen roads it tends to steer left and right a bit because of the bumpsteer.

That's it. Hopefully it helped out a bit and if you have questions, feel free to ask.

regards

Koos

[western]

Great post Koos, good to see what owners have done, you certainly have lots of flex in your trucks suspension.

[FridgeFreezer]

Oooo, good tech AND a lovely couple of 109's too, this surely deserves some sort of medal for a first post of unsurpassed quality!

[Retroanaconda]

That flex is immense! Far more than most 'coilers' I've seen, nicely done!

[FridgeFreezer]

Just noticed the Bilstein 14" shocks, how are you finding these and how much did they cost? I've been trying to find a set of 14" shocks to replace my shagged out procomps, I fancied OME ones but they don't make any long enough (or they wouldn't tell me if they did )

[ToyRoverlander]

Thanks all for the kind words!

Fridge, I love the Bilsteins. They're nice and firm. As you've seen, mine is a heavy station wagon sitting on 3leaf rear springs. That's very soft for suft a heavy vehicle. I used to have 4leafs with original armstrong shocks and that was just cr*p. It bounced coming of speedbumps. Now it doesn't bounce at all. The suspension compresses, comes back up again and that's it.

I got mine from the US, shockwarehouse.com. Mate of mine just ordered the same ones. I believe it was €400 for 4 shocks including shipping and import duties and tax. I beleive they're 70odd dollars each.

[plasticbadger]

Great tech there Koos, I've always loved your build and it looks like it works really well too. Just remember that it was I who started the Toyrover thing