Diesels and autos for RTW

[gusgus]

Jeez Dougal your approach is becoming increasingly radical, I guess in response to the deepening hole in which I find myself.

I really like your lateral thinking but haven't even thought about that approach, and for the time being I'm refusing to do so.

The trouble with trying to plan that sort of thing is the language barrier ... the people with the answers
are Swedes, Norwegians, Finns etc ... makes it difficult.

Ashcrofts (who speak English) are professionally prompt with their replies, but are masters of the oblique answer. You ask the time and they tell you they wear Omegas. You ask what brand of watch they wear and they tell you the time!

I asked if the LT230 has the space to accommodate custom-made overdrive gears, if Ashcroft could make them if required, and if not did they know anyone who does.

The reply ... "The highest ratio you can get would be the 1.003 high range set. You can add an overdrive to this if you wanted to."

From that answer I don't know if there's space in the TC, know that Ashcrofts don't make the required gearset, and don't know if anyone else does.

As it is, I have a query into Gear Vendors to see what, if anything, they can offer in my situation.

Grafting in more common diff heads you say ...mmmm.

 

[Dougal]

I'd push Ashcrofts a bit further on their "You can add an overdrive to this" comment.

Sometimes, it's not what you ask, but how you ask it that gets the answer you seek.

And yeah, I'm a big fan of lateral thinking. It's a great business edge, keeps me ahead of the competition.

 

[gusgus]

Finally sourced the 'big picture' from Ashcrofts.

As I thought, there's insufficient space in the TL230 to accommodate overdrive high range gears.

On their idea of adding an overdrive, when I mentioned it would go behind a torquey 4 cylinder
diesel engine pushing 4.5 tonnes GVM the answer was, "I don't know if it would be strong enough".

So, the options just keep diminishing.

Waiting now for a reply from Gear Vendors.

 

[Gengis]

Marks 4x4adaptors do a 0.92 for the toyota split transfer case. May not be enough, but with a over drive 5th gear??? What is the diameter of your tyres??
G

 

[gusgus]

35" standard, up to 37" legally.

 

[Gengis]

OK I can see the problem: wow, Dougal may have a point.

On an h55F in 5th with Marks 4x4 0.92 overdrive at 100KPH
37tyres = 2509 revs
35 tyres =2625

Got any pics of the vehicle and diffs, just curious

 

[ToyRoverlander]

Perhaps an engine that doesn't mind a few more revs... mercedes om606 (3litre straight6 24valve) with turbo and mechanical fuelpump springs to mind... Bombproof and don't mind some revs..


OM606, see, it loves to rev
http://www.youtube.com/watch?v=KRhl182UAGY&feature=channel&list=UL

 

[cicak]

As they say, "an afterthought is better than no thought at all".

Just looking through my photo files before bed and spotted a Toyota 14BT.

Does anyone know if the 14BT or 15BT will bolt straight up to an A440F.

Then I'd just need one adapter ... transmission to Series transfer case.

Someone mentioned the B engines to me as a possibilty ages ago, and I'd forgotten all about them.

A 14B-T block and 13B-T is the same and A440F will fit but it will overheat in the hills been there and went H55F instead.

 

[gusgus]

O.K. for those still interested, after all the research here's where I've arrived.

With the highest available diff ratios for the Volvo being 5.99, I'm forced to adopt what I've learned is called 'double overdrive' to achieve around 2000rpm at 100kph cruising.

Around 0.7 can be achieved through the gearbox, with the remainder through a dedicated overdrive unit or an overdriven high range TC.

The only TC case I could find ( Ashcroft's Series HRTC) was ruled-out as too weak for the 4.5 ton GVM.

Gear Vendors overdrive can reduce revs by 22%, but they tell me their unit cannot be run behind a torquey four cylinder diesel as I'd planned. Apparently the four engine pulses per revolution, when overdriven by some 50% in total, are read by the GV unit as as a two cylinder and act like a jackhammer.

I'm now waiting to hear if the GV can be installed behind a six cylinder or V8 diesel.

However, even if it can, I believe the unit bolts to the TC. As I require a right drop case with aligned outputs like the Landcruiser, I doubt the GV unit can be adapted.

Dougal, could you please elaborate on your idea of swapping the diff heads. Which components would you envizage changing over apart from the C&P's?

The Volvo shares many parts with the Landrover ... 109 drums brakes, 101 parabolic springs etc.

It could be, although I doubt things could prove so easy, that the diff carriers contain some/many
LR components.

Looking up LR diff ratios I came across KAM Diffs in England, but their highest ratio is 2.83. I would require around 2.3/2.4 because the portal gears multiply everything by 2.06, which would give me a
total final drive around 4.7/4.9. Running those ratios, 35" tyres and a 0.7 top gear would only require
around 2000rpm at 100kph ...perfect.

Just out of interest, does anyone know if such a firm would run-off only three sets of special order C&P's
and if so, the likely cost?

 

[Dougal]

Dougal, could you please elaborate on your idea of swapping the diff heads. Which components would you envizage changing over apart from the C&P's?

The Volvo shares many parts with the Landrover ... 109 drums brakes, 101 parabolic springs etc.

It could be, although I doubt things could prove so easy, that the diff carriers contain some/many
LR components.

I would first look at swapping over crown wheels and pinions, if that wasn't looking good, then I'd look at cutting and welding in a complete centre section from a more suitable diff. It all depends on the physical size of the opening and also what splines you have on the axle shafts.

Ashcrofts have a range of ratios available for landrover, but if you had to graft the centre across to something else, you'd lose your lockers.

Are your C306 axles similar to these C303? https://forum.ih8mud.com/70-series-tech/393623-volvo-portal-axles-under-my-hzj78-troopy.html

Is the 5.99 reduction the combination of diff and drop-box? What is the gear ratio in the drop-box?

 

[gusgus]

Yes Dougal, the axles are the same as in the photos on your link.

I believe all the Volvo C-series axles are the same, except for the location of the diff on the third axle of the 6x6s.

The first and second axles have right-side offset diffs (as in the 4x4) but the third axle diff is centred ... taking its drive from a PTO outlet above the pinion housing of the centre axle. The PTO housing goes back over the middle axle, to drive a tailshaft to the rear axle.

Ratios are apparently interchangeable. Everyone refers to the overall drive ratios of either 5.99, 7.1 or
7.6, depending on the model. Those figures are rounded-out and include the portal gear multiplication of 2.06.

The model I want comes with 7.1, but my discussions have revolved around fitting 5.99 C&P's which
are available through an outlet in Europe. But as you're witnessing, it's proving impossible even with that gearing and double overdriving to achieve the required engine cruising speed.

From my point of view, losing the lockers in any diff change would make the project unviable.

Anyone have any experience re the cost of making C&Ps?

I hadn't examined that path before, because initially when I asked people here in Australia they just shook their heads and muttered something about mortgaging the house!

 

[Dougal]

Yeah that multiplier of 2.06 is the real problem. It means a 5.99 axle already has a 2.9:1 diff ratio inside.

Is it possible to get new portal gears cut to drop the ratio from 2.06 to something like 1.6? Development and prototyping costs would be up there, but I suspect there would be a huge market for them.
First question is what can actually fit in the casings?

 

[gusgus]

I don't know about space in the drop box, but the gears themselves are straight cut. Major problem would be the internal splines on the larger gear.

I'm not sure I agree about a ready market for higher gearing. I don't think enough C-series were produced and it's only a few diehards like myself pursuing the issue.

If you have a spare chunk of your life available you might want to visit www.c303.de. An incredible German site on these vehicles.

You choose the English version at the top, go to Documents (pdf files), Service Manuals, and Transmission File 16 if you'd like to see an exploded schematic of the drop box.

Just waiting now to hear from Gear Vendors and KAM Differentials ,who'll largely decide the next move.

 

[Dougal]

Excellent reference site. Very little of anything on the internet is so well organised.

It looks like the show-stopper will be space around the top gear. To reduce the reduction the top gear needs to get bigger and the lower one smaller. The housing looks too close to the top.

Other than that, straight cut gears are no problem to make and splines are easily cut via EDM.

It looks like your only real easy option is the Isuzu MXA-6R manual 6 speed box.
1st 4.987:1
2nd 2.870:1
3rd 1.684:1
4th 1.000:1
5th 0.728:1
6th 0.626:1
rev 4.774:1

Overall gear ratio in 6th of 3.75:1.

 

[gusgus]

Picture this.

Foreign driver, foreign truck, steering on the wrong side (LHD), driving on the wrong side of the road (RHS), surrounded by traffic density you wouldn't believe, lost, well-meaning handbrake shouting instructions (late), and grabbing for the appropriate gear with the unnatural hand!

Been there, done that ...six lanes (loosely speaking) of evening peak hour traffic in Naples last year, keeping-up with a local who was 'guiding' us to our destination ... oh how glad I was the hired campervan was an auto.

No Dougal, I'm planning to give-up gear shuffling for the relaxation that comes from tootling along.

If this project finally goes pear shaped there's always Plan B. Still refusing to consider that though.

 

[Dougal]

In the current trucks Isuzu have automated 6 speed manual boxes. Basically their manuals but with computer actuated clutch and gearchange. Apparently with manual over-ride.

Unfortunately, they are only running a single overdrive in those 6 speeds. It's good to have a solid plan B though.

But crunching numbers on 0.7 overdrive, 6:1 diff ratio and 35" tyres (stock in the 303 brochure I just read) is 2,500rpm at 100km/h.
This isn't that bad. My rangie ran that rpm for 14 years until I found one of the rare high ratio LT230's to bring it down to ~2000rpm.
I figure in a vehicle like that you'd be cruising at closer to 90km/h most of the time anyway. That's 2250rpm.

With 37" tyres those become ~2400 and ~2100rpm.

BTW, I have experienced that on a minor scale. I picked up a rental car in Prague and had to find my own way out. I don't speak or read the language. Worst thing was following another driver through an intersection who led me onto the tram tracks, then took and blocked the only clear way out.

 

[serenity]

A mate I mine has worked out that you can bolt a 4bd1 to a torque flight auto then onto an atlas transfer case. He is planning on running that in a defender. He doesn't often visit this forum, but I can send him the link and he can give you details on the setup he was planning if you are interested.

 

[Dougal]

A mate I mine has worked out that you can bolt a 4bd1 to a torque flight auto then onto an atlas transfer case. He is planning on running that in a defender. He doesn't often visit this forum, but I can send him the link and he can give you details on the setup he was planning if you are interested.

The torqueflight 727 is a 3 speed with no overdrive or lockup. I don't think it'll help.
But factory parts are available to bolt the TF727 to a LT230. I have the parts from that setup here.
My 1.003:1 LT230 came attached to a TF. I kept the adapters and scrapped the gearbox for $20.

 

[Slynax]

Hi guys, I'm Serenity's mate doing the defender build.

Dougal, I was going to have a gear vendors overdrive between the 727 and the atlas. Although hearing the reply gusgus got about it makes me nervous, I'm hoping that because the 727 isn't overdriven it won't be too harsh for the GV. I'm fairly sure I mentioned the details of my project to GV and they didn't point out any problems for me, but once again still a significant difference in application.

I may have to enquire further about your 727 to lt230 adapter parts also Dougal.

Sorry it might not be much help, but if there's anything else I can pass on I'd be happy to help. Sounds like a pretty cool project gusgus, best of luck making it happen.

 

[Dougal]

If you haven't found it already, there's an Isuzu Landy section on AULRO (Australian Landrover Owners). It'll be well worth calling in there, pretty much all the driveline options for a 110/defender as well as 90's, 130's, series and stage 1's are on there.

At the moment I think JustinC on there is/was considering the TF727, he tried the ZF HP22 behind his 4BD1T and kept blowing them up. Even with all the advice and parts from Ashcroft they kept dying.

The TF727 was factory fit to automatic rangerovers from around 83 when the started to about 86 when they went to the ZF 4sp auto.

Hi guys, I'm Serenity's mate doing the defender build.

Dougal, I was going to have a gear vendors overdrive between the 727 and the atlas. Although hearing the reply gusgus got about it makes me nervous, I'm hoping that because the 727 isn't overdriven it won't be too harsh for the GV. I'm fairly sure I mentioned the details of my project to GV and they didn't point out any problems for me, but once again still a significant difference in application.

I may have to enquire further about your 727 to lt230 adapter parts also Dougal.

Sorry it might not be much help, but if there's anything else I can pass on I'd be happy to help. Sounds like a pretty cool project gusgus, best of luck making it happen.