overdrive survivability?

[adkrover]

After giving up hope of ever getting the illusive Roverdrive, I decided to send my screeching Fairey down to George at RDS for a rebuild. He checked it out and said it was shot having been poorly rebuilt by the last person and the damage to the case was beyond repair. The PO of my truck purchased it as a rebuilt unit from a common dealer we all know well and it screeched so bad the day he put it in that he never ran it again. When he called the dealer, they told him that they are all noisy and there was nothing he could do about it. I guess they were selling it as rebuilt but must have sourced it from a less than adequate rebuilder. Since he sold the truck to me before finishing the project, he never had a chance to run it more than a few miles and now I've inherited the bad unit.

George recommended either putting what was salvagable from the guts of mine into an old donor case or for nearly twice the $ he would sell me a new unit. The discussion continued and eventually we talked about engines. Since I have a non stock engine (4 cylinder GM conversion) he is concerned about the extra power the overdrive would have to endure. It sounded like the Fairey is marginally successful in a stock 2.25 engine and sure to be destroyed by anytihng more powerful. Therefore, now if I purchase a new or rebuilt unit, he won't give me a warantee. Fair enough I guess. So..... the question is, does anyone have experience with the survivability of a properly rebuilt Fairey in an application that is non stock powered?

Thanks

[leafsprung]

gears

I think the OD would be ok as long as you were conservative with its use and conscious of regular maintenance. Considered the HR t-case? You can still use a PTO too. What part of the case is damaged? I might be interested in the parts of your old OD for a pet project if you decide to junk it.

[greenmeanie]

I have a Chevy 292 inline 6 in my NADA 109. That was installed using a Scotty's adapter ring onto a stock 6 cyl gearbox and Fairey overdrive. Now the truck was in no condition to be driven when I got it and is now under rebuild so I cannot guarrantee the condition but it apparently sat behind 165hp and 250lbs of torque (10 spline rear end too!) for at least 10 years without issue. The PO did say he was very conservative driver though.

The suppliers won't warrantee a non stock installation because of the potential for V8 firebreathing monsters blowing it through the back of the truck. As they have no idea what power figures you are applying to it they simply can't say it will work in good faith.

As Ike says, if you treat it nice I wouldn't expect any issues behind the Gm 4 pot. People in the UK use them behind Rover V8s.

Cheers
Gregor

[jp-]

There is nothing that can't be fixed, unless the case is split in two. We have some guys where I work that could tig weld up any damage to the case from a spun bearing, and a machine shop that could recut the housing. See if you can find a machine shop and ask them about the cost of welding and recutting the aluminum housing. As far as the toughness of the Fairey, it does fine behind my 2.6 six cylinder lump. As Ike suggests, I use it only in 3rd and 4th and almost exclusively on the highway. No 1st gear overdrive hill climbs, that will kill them for sure no matter what engine you have.

[Mercedesrover]

Trust George...He knows what he's talking about. I would spring for a rebuilt unit, keep it well oiled with quality oil, use it where you should and you'll be fine.

[giorgio]

I do not know the current situation, but I paid for a Roverdrive last year, and had to wait months for it to be finally deliveried, but it did come. I think it may have been because I went ahead and ordered, and "paid" for it, even though I do not believe my card was charged until it actually shipped. It is a beautiful piece of machinery. They even send along the socket wrenches needed for installation. It did require "minor" modification for adaptation to a NADA 2.6L which amounted to cutting two pieces of bracket/linkage and welding in a 2 " spacer. In my book, (Novice 101) that is more than a "minor" modification, but I got it done, and it works beautifully.

Maybe you just need to order it, and wait. I don't know the current situation.

[adkrover]

overdrive and high ratio diffs

Thanks for the good support. I am a pretty mellow driver and have never torn up a drivetrain so I think based on your suggestions I'll be ok on power. Thanks!

Most of my driving is low speed, off road and back road driving so standard gears are fine. About once a week I go to town for gas and supplies so I spend 20 minutes one way on the open road so a high gear would be nice. I consider the OD to be more of a fifth gear than anytihng and the highway is a pretty flat road overall. Shouldn't be too hard on it.

I have plans to install a pair of Land Cruiser axles and diffs with 4.11 gears. Once that's done, will the gearing be too high to use the overdrive? Should i just put the $ into the axles and forget the OD?

Thanks again.

[TedW]

Sounds like you're at that in-between point.....

I've had a Fairey OD since '93 and have been very happy with it. I used to run 30x9.5x15 tires and really appreciated having it during long trips. However, I recently moved up to 235/85/16's, and with the increased tire diameter I almost (I said almost) feel like I could lose the OD and not miss it. Yes, it still comes in handy on the highway - I drive a fair amount at 50+ MPH so it's nice to have.
What tires are you running? I would think that between the higher diiffs and 16" tires you might not need the OD.

Just sayin'.

[carl k]

I have a Toro (similar design as Fairey but larger oil capacity) behind a chevy 250 (155 HP gross) in my NADA 109 Dormobile. It has performed well, but like the others, I do drive conservatively and only use it in third and fourth on the highway.

Carl K.

[gambrinus]

Do some math with any one of the dozen or so gearing calculators on the web and see what the 4.11 gears will do for you. The whole question of the OD may be mute. Any reason that you didn't consider a High Ratio xfer box?


RW

[yorker]

Because the HRTC and 4.11 TLC axles will give him the high range equiv. of ~3.55 diffs, even with the GM 4 cyl that is pretty tall gearing with (presumably) 32" tires

4.11 diffs give him the same reduction +- as a HRTC alone would. (4.09 vs 4.10)

4.11s will give him ~2722rpm at 55mph
4.7" "" " 3121rpm at 55mph

4.11 + HRTC= 2059@55mph


IMHO the 4.11 diffs alone are the solution he is looking for unless he finds he needs to go to a lower 4.56 or 4.88 diff ratio because of power concerns on road.

http://www.izook.com/gearcalc.htm

[adkrover]

I would like to update my axles to include front disk brakes and ARB air lockers both front and rear. I've heard a lot of problems with Rover axles breaking and I'm not even sure you can install ARB lockers in them. This led me to reading all about the Toyota axle conversions. That's where the Toyota axles came in and it's just forunate that they include 4.11 gears. I'm not opposed to higher ratio transfer cases but I've heard mixed things about their success. Right now I can run pretty strong with standard gears at 55mph cranking roughly 3000rpm. Of course my old speedo may be out of calibration, the 238/85/16 tires change things and the small tachometer is hard to get an exact read on. I'm sure either the OD or the higher ratio axles will give me the little extra I'm looking for but will it be too much if combined?

[yorker]

Just swap the axles and go from there. Keep it simple. An OD is another thing to fail. A HRTC with 4.11s would bee too tall a ratio even for a GM 4cyl IMHO. Try the TLC axles for a while and use your judgement.

[Tim Smith]

I would like to update my axles to include front disk brakes and ARB air lockers both front and rear. I've heard a lot of problems with Rover axles breaking and I'm not even sure you can install ARB lockers in them.

Just so you know. ARB's can be installed in the rover diffs. I know because I blew up one of those rear ends a few years ago.

Bill at Great Basin Rovers has the modified "thicker" ring gear so that the spacer ring failure I had would be avoided.

Also as a helpful reminder... When you lock the front and the rear diffs, you must make at least one tire slip in order to go forward. Unless of course, you are going in a perfect straight line and your tires have exactly the same air pressures in them.

Lockers are great but not the end all be all.

Cheers,
Tim

[adkrover]

Tim,

Thanks for the info. I already have the TLC axles and the rear is a 1 ton so I figure I might as well put them to good use. Also, where I drive, there are 3 seasons. Winter, mud and black fly season. The back roads are all made of sand and quickly turn to quicksand in the spring thaw. Dual lockers will be perfect for 2 out of 3 seasons.