Need for overdrives?

Technical questions and answers
Bumpkin
Posts: 428
Joined: Sun Feb 06, 2005 8:51 pm
Location: Mid Cornwall

Post by Bumpkin »

Image
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Home made overdrive rod.
4 SWB Series 88s
2 SWB Series 2s
1 300 TDi Disco
1 200 TDi Disco
1 3.5 V8 Disco
1 4.6 HSE P38
1 2.5 DSE P38
1 V8 90 County
1 Ford Connect Van.
tallergypsy
Posts: 7
Joined: Thu Dec 31, 2009 1:05 am

ROVERDRIVES

Post by tallergypsy »

Thanks for that.

The most encouraging thing about this discourse has been that no one denies that an overdrive is a worthwhile bit of kit on a stage one or an early 110. We are not expecting to make a fortune selling LT95 overdrives. If we only ship 25 a year for the next five years the exercise will have been worthwhile. We will have more than broken even and met a whole lot of interesting people to boot.

Once again thank you for your input.

Ray
map1275
Posts: 972
Joined: Mon Jul 21, 2008 2:48 am
Location: Brisbane, Australia

Post by map1275 »

Off the track more than a little.... however we don't get too many members from North America....

http://cgi.ebay.com/ebaymotors/ws/eBayI ... 500wt_1182


Is this really what ordinary L-R's with a tart-up job, oil leaks, overspray and total non compliance with North American specs are fetching?
The listed Series III doesn't even meet Silver Dollar Ser II spec and a blind man could see the evident problems.
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Mik
Posts: 194
Joined: Wed Sep 20, 2006 10:25 am
Location: Denmark

Post by Mik »

Ray,

I've got a taller Disco gearing in my LT95 - would that cause any problems for using one of you units ? - except for the added gearing of course :)

Thanks
Michael
Michael
109" 1982 SIII CSW Stage 1 V8
109" 1965 SIIA FC
1991 RRC Vogue SE
tallergypsy
Posts: 7
Joined: Thu Dec 31, 2009 1:05 am

Post by tallergypsy »

You can still fit a Roverdrive but you have to specify a 28 tooth output gear when you order. Ray
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Mik
Posts: 194
Joined: Wed Sep 20, 2006 10:25 am
Location: Denmark

Post by Mik »

ok, thanks .)

Michael
Michael
109" 1982 SIII CSW Stage 1 V8
109" 1965 SIIA FC
1991 RRC Vogue SE
Davo
Posts: 76
Joined: Mon Aug 06, 2007 3:54 am
Location: Fitzroy Crossing, Australia

Post by Davo »

Ray, it would be good to see them available but if you're serious about selling them in Australia for bigger engines like the V8s and Isuzu diesels then you should resolve the problem Roverdrives have with extreme heat. You may remember me contacting you about mine burning oil when running at 100kmh with only a little 2.25 petrol pushing it along at temperatures in the low forties. Up to about 35c or so it's always been fine, but any hotter and even a good synthetic will go black.
tallergypsy
Posts: 7
Joined: Thu Dec 31, 2009 1:05 am

Post by tallergypsy »

I do recall we had some discussion of this a couple of years ago but seem to remember that your Series had a higher horsepower than normal engine? In a series vehicle, boosting horsepower will cause more heat than normal simple because of the higher RPM. Our Series overdrives have always run hotter than the Defender ones do simply because the gearbox output shaft rotates a lot faster. This causes more frictional waste heat.

I've done many tests running Series overdrives with souped up engines (never at 40 degrees I must confess.) The hottest spot in the drive train is not the Roverdrive but the lower part of the transfer case which gets a good ten degrees hotter than the overdrive. You can easily see this with an infrared thermometer.

I can't recall an instance where oil went black in a Series Transfer case and Roverdrive with a standard engine but can believe it happens with such high ambient temperatures. Does this have a negative effect on the the way the overdrive works? One would want to fit Viton O rings or you will certainly get weeps.

In MD11B powered Land Rovers the Roverdrive is going to run cooler than what you have experienced. Vibration rather than heat is going to be the challenge.

Ray
djam1
Posts: 52
Joined: Thu Jun 02, 2005 10:59 am
Location: Karratha WA

Post by djam1 »

I may be interested as Davo says for Australia it will need to deal with heat.
45 Degrees C Ambient and 60 Degree road temperatures and 120 Km/h would be my expected use.
Oh and I dont want the gearbox to be weaker either.
I know Im not asking much lol
Davo
Posts: 76
Joined: Mon Aug 06, 2007 3:54 am
Location: Fitzroy Crossing, Australia

Post by Davo »

I suppose there's a bit more horsepower, but it's still just a 2.25 petrol. The Roverdrive was always fine with that motor - until we were driving through the Pilbara and it was in the low-to-mid forties.

I know you've been on tours through Australia, but I would guess that was during the Dry season which is the coolest time of year and of course the best time for travelling. I would suggest flogging the hell out of a Roverdrive in the Pilbara and Kimberley during September to November, when the extreme heat combined with very long roads would be a very good way to test them. The heat up here is one of those things that you just can't understand until you've lived through it for quite a while!

By the way, why do you call the Isuzu diesel an MD11B? I'm guessing it's the same as the 4BD1?
5988
Posts: 692
Joined: Fri Mar 13, 2009 8:57 pm
Location: Lincolnshire

Post by 5988 »

I would think the need for an LT95 overdrive is quite limited,

mainly due to the engines in front of them
While a normal series with 2.25 cant realy cope with the permanently high gearing (with tuned engine mine can in flat areas, however id not want it in the lakes/Wales/Scotland where its more hilly) the V8 has the power and torque to easily cope (given the RRC gearing isn't far away from where a stage 1 with OD would be) so i cant see many people fitting them when changing the transfer case ratio is much cheaper, where as a normal series permanent gearing increase isn't practical
for that reason my S2 88 still runs an overdrive (very noisy fairey .....which i want shut of, but standard gearing isn't an option for the motorway driving i do, RR diffs wont work due to the hilly places and there's no way i can afford a roverdrive), the stage 1 will get a fairey one as i have it - if its noisy ill stick so RR transfer gears in (why oh why did Lr gear it down as much as the 2.25's :( ) . In the case of the S2 one day i will get one, cant cope with the fairey for much longer, but for a LT95 with V8 in front of it there are so many other options i cant see it beeing worth while

Also will the box be strong enough - given the V8 is almost twice the power and torque of a 2.25, the fairey one seems essentially the same ....id be dubious of one of them on an LT95 long term
how do they cope on oil give the LT95 runs engine oil not gear oil - or are they completely different design
djam1
Posts: 52
Joined: Thu Jun 02, 2005 10:59 am
Location: Karratha WA

Post by djam1 »

Davo wrote:I suppose there's a bit more horsepower, but it's still just a 2.25 petrol. The Roverdrive was always fine with that motor - until we were driving through the Pilbara and it was in the low-to-mid forties.

I know you've been on tours through Australia, but I would guess that was during the Dry season which is the coolest time of year and of course the best time for travelling. I would suggest flogging the hell out of a Roverdrive in the Pilbara and Kimberley during September to November, when the extreme heat combined with very long roads would be a very good way to test them. The heat up here is one of those things that you just can't understand until you've lived through it for quite a while!

By the way, why do you call the Isuzu diesel an MD11B? I'm guessing it's the same as the 4BD1?
Send me an overdrive I am in the Pilbara and will test it for you
Jamie_grieve
Posts: 41
Joined: Wed Dec 02, 2009 12:10 am

Post by Jamie_grieve »

tallergypsy, have you done any destructive testing on the Fairey overdrives for the LT95? I'd be curious about what actually kills them. Since this thread started I've just bought a Fairey overdrive. I don't need it right now but they can be hard to find. I paid £100 for this one in Dumfries. I had one years ago before the PTO for the winch went in and abused the snot out of it. I used it in 1st & 2nd gears, pulled a car trailer for a few years and it was fine. My engine was a 3.9V8 with carbs.
Bumpkin
Posts: 428
Joined: Sun Feb 06, 2005 8:51 pm
Location: Mid Cornwall

Post by Bumpkin »

Jamie
One of the main reasons for overdrive failure on the smaller series units is oil starvation. This was cured on the LT95 unit as it is splash fed. I dont know quite how gears and stress work but i do know the most common way to trash a lt95 overdrive is to put to much torque through the unit in the lower gears.This usually results in the rear of the casing cracking sometimes quite spectacularly. There was usually a small ally plate in the cab on Stage 1s advising against using the overdrive in 1st and 2nd.
Terry
4 SWB Series 88s
2 SWB Series 2s
1 300 TDi Disco
1 200 TDi Disco
1 3.5 V8 Disco
1 4.6 HSE P38
1 2.5 DSE P38
1 V8 90 County
1 Ford Connect Van.
tallergypsy
Posts: 7
Joined: Thu Dec 31, 2009 1:05 am

Post by tallergypsy »

I ordered in some bits to build prototypes. I'll run one on the ISUZU 110 around Europe in the summer and probably in Morocco in October. Please keep an eye on the Roverdrive website for progress reports.

And thank you all for your input. Much appreciated and valuable.

Ray
Roverdrive Gear Corporation
Vancouver.
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