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View Full Version : Are Overdrives worth it?



crankin
05-29-2011, 11:28 PM
I am thinking about dropping some money on an overdrive (a Fairey one to be exact)...but have not really found a huge amount of details on them.

I know about the makes and models and the pros and cons of each, but what I really want to know is if they are worth it!

I have read that on tried old engiens that you really will not see any improvement. Roverdrive states that thier product helps mpg and reduces noise...but said that this will not increase speed. Fairey Overdrives seem to increase speed and power. But I have not heard anyone talk about the before and after.

Whats the truth to all this? Can someone chim in with if it is worth it or not?

bkreutz
05-29-2011, 11:34 PM
One way you can replicate the experience of an overdrive is to drive around for a while without using high gear, then do the same thing only this time use high gear. Big difference. The confusion about gaining top speed comes from people expecting to go faster because of higher gears when the engine doesn't have enough power to do it. It can occur where you can go faster without overdrive, but that's normally because there isn't enough power in a higher gear (overdrive) but a numerically lower gear is a better power match. I like them because of the lessening of noise and engine speed, plus it gives me more options, sometimes there are hills where one gear is too high but the next lower is too low, the overdrive gives me an option between the two. In the end it's personal preference.

Lalo88DK
05-30-2011, 12:55 AM
First of all if it's speed you want you have bought the wrong car :p .
But I think if you can find a Fairey overdrive in good working condition and one that doesn't whine, it's worth the money. I have a Fairey overdrive in my Series III 88" 2,25 Diesel, and I am very pleased with it so far. I used to have a Ashcroft high ratio transfer box in my last 2,25 petrol, and that was not a good combination (lack of power).
You do get better MPG with a Fairey overdrive and Higher cruising speed, and it does reduce the engine noise, quite a bit (if the Fairey is not whining).
I never go above 55 mph with overdrive (without 48 mph) they are not really built for speeds above 55 mph, (Series trucks are perfect for small British country lanes) of course they can go faster, but try and listen to the engine :eek: if you want your engine to last, don't push it too hard and too long, trying to reach highway speeds to keep up with traffic, especially not if it's a diesel.

But if you really want to go faster, and save fuel, you can fit Range Rover diffs (does destroy offroad ability some what when crawling), Fairey overdrive, taller road tires 235/85-16 and freewheeling hubs, fit a Kenlowe fan, instead of the belt driven original.
But I'd say that a Fairey overdrive is a good investment.

73series88
05-30-2011, 01:16 AM
i got a fairey last fall and it made all the difference.
i lucked out and got a pretty quiet on. i couldnt do the highway very well
with out making the motor scream. 6 hour highway ride to winter romp this year i couldnt have done it without the overdrive. it is nice for spliting gears up hill when the one your in isnt quite enough. i would recomend one. on back roads its not that im going faster just not making the motor rev so high. IMO
aaron
2.25 doesnt have enough power for range rover diffs.
ive left my overdrive on by mistake and thought something was wrong with the truck
its was basically the same as having fulltime rrc diffs
no power wouldnt barley make it up hills. lucky it was only for a few minutes.

stomper
05-30-2011, 06:11 AM
I will agree with everything that has been said above about the fairey overdrive. Drive your truck around town at 55mph. listen to the engine. now slow down to 45mph. the engine will quiet down considerably. This is what it will sound like at 55mph with the overdrive engaged.

I honestly cannot imagine traveling long distances without one. With a good unit, and a good synthetic oil, the whine is minimal on mine. Usually only when you back off the throttle and coast some will you hear a bit of a whine.

My engine is not tired, so I don't know how that will affect things, but mine will accellerate up a slow gradient in overdrive from 45-55mph. and I will engage the overdrive in 4th at a speed as low as 35mph. I use it around town when I have the room to cruise without stopping and starting for traffic or lights. Not just on the highway.

Buy one, you won't regret it.

I Leak Oil
05-30-2011, 06:43 AM
Think of an OD as nothing more than 5th gear on your tranny. At a given RPM it will allow the wheels to turn faster, allowing the vehicle to go faster. Or, at a given MPH it will allow the motor to turn slower, increasing MPG and decreasing wear and tear on the driver.
A 2.25 isn't always able to push an OD fast enough on hills and such though. An OD is NOT a power adder, which is what some people confuse it with.
I bought my superwinch OD brand new 17 years ago. It's well worth it to me and what I do with my truck. It's getting tired and screams like a banchie so I'm looking at a Roverdrive next.

siii8873
05-30-2011, 07:39 AM
<P>I have a santana OD.&nbsp; where would parts be found for it?&nbsp; I do not need any but could some time.</P>
<P>&nbsp;</P>

TeriAnn
05-30-2011, 08:02 AM
<P>I have a santana OD.&nbsp; where would parts be found for it?&nbsp; I do not need any but could some time.</P>
<P>&nbsp;</P>

Heystee automotive in the Netherlands is reproducing Santana overdrives and selling parts to maintain the older Santana overdrives.

http://www.heystee-automotive.com

Paul also sells a very high quality disc brake conversion for Series trucks.

TeriAnn
05-30-2011, 08:24 AM
Whats the truth to all this? Can someone chim in with if it is worth it or not?

If I still had a 2.25L engine I would consider an overdrive to be an essential enabler for driving my truck in the hills.

When you are driving highways on hills without an overdrive you often find your engine bogging down, the temperature needle creeping and your truck loosing speed in one gear and revving too high in the next lower gear. So you are either floored going through a ton of gas or going too slow but with your engine in a sweet RPM range. Where the overdrive really shines is being able to split gears to get that RPM that puts your engine in its happy sweet spot and getting the best speed and best fuel economy.

Third over was my best friend on mountain highways, second over on some really steep mountain secondary roads.

If you find yourself driving into a stiff headwind on the slightest grade, third over can put a lot less stress on the engine and give you better fuel economy.

The 2.25L petrol prefers to highway cruise at around 3200 RPM, which depending on your tyre size is around 50 to 55 MPH. Fourth over will allow you to cruise 60-65, depending upon tyre diameter and still be in the engine sweet RPM range. However you have to be careful here. If there is any head wind or uphill or your tyres are too tall you may loose in fuel economy. The harder your engine has to work the more fuel you burn. If you have to press down on the accelerator to maintain 4 over you will be seeing filling station a lot sooner.

If I still had a 2.25L engine I'd buy one just for the third over gear option and consider the other gears to be just added benefits. :thumb-up: :thumb-up:

If you get one, stay on top of the oil. Makes all the difference in the workd for OD longevity.

73series88
05-30-2011, 09:15 AM
YEP

scarter
05-30-2011, 09:18 AM
I am new to the forum, and I have no personal experience with a Fairey unit, but have recent experience (last several weeks) with a new Roverdrive in my '63 SWB, 2.25 gas. I run a Rochester I recently rebuilt using a 50 main jet, I also use the stock oil bath air filter. Before overdrive, and daily driving to/from work, etc., which here is about 19 miles each way on 2 lane roads, the Series averaged about 15 mpg without overdrive...this with fairly fresh engine (7:1). I checked fuel usage yesterday again after a couple months getting used to Roverdrive (splitting on hills, etc. as has been mentioned), and it gave just over 19 mpg. Point is not carb choice, rather the decrease in fuel usage. It is also quite smooth engaging/disengaging, and very quiet when engaged. So it is saving on fuel, wear & tear, and is far more pleasant to drive. I also drive about 55 when engaged. It will run 60-65 if called on, but not through hills.
I am glad I put the Roverdrive in, it is doing what I was after.:thumb-up:

tmckeon88
05-30-2011, 10:02 AM
I installed a new Roverdrive last year after my Fairey disintegrated. (I put over 100,000 miles on the Fairey unit, which was not new even when I got it in 1994.) I can't say enough good things about the Roverdrive unit- it's quiet, it was fairly easy to install since I had holes drilled for the Fairey anyway, it doesn't add any noise to the truck and it lowers the engine speed for highway cruising. It also offers some gear splitting capabilities and engages and disengages crisply. Their customer service is good. My Series IIA's tendency to slip out of third gear has also disappeared, making me think the old Fairey was so worn all the gears were a little sloppy. So I would recommend it.


Tom

robert wood
05-30-2011, 12:32 PM
You wrote

'I have read that on tried old engiens that you really will not see any improvement. Roverdrive states that thier product helps mpg and reduces noise...but said that this will not increase speed. Fairey Overdrives seem to increase speed and power. But I have not heard anyone talk about the before and after.'

Functionally the effect of a Fairey or a Roverdrive on your vehicle will be exactly the same as they have identical ratios. One cannot give you any more speed or power than the other. The things that will differentiate the two brands are reliability and operating noise.

Ray

bobzinak
05-30-2011, 04:21 PM
fairey overdrive owners must take care that the pivot bolt on the overdrive lever does not touch on the tranny, it will transmit the tranny noise through the lever..and it will whine loudly..found this outwhen I have to remove overdrive linkage, when I replaced it the overdrivew was horribly noisy..food for thought. over drives do make things quieter, but probably not worth it if you just do local trips..if you think acceleration is slow now, with an over drive in 4-over it is nonexistant. I have a fairey, and do enjoy being able to select 3-over when 4th is to steep..the price of an overdrive, even at todays prives, buys alot of petol..bobzinak.

Duckman
05-30-2011, 04:51 PM
I have been seriously considering adding an overdrive unit to my Series III Lightweight. Not looking for a cross country cruiser but living in Dallas I need to be able to get on the hwy to go anywhere and doing 55 right now has the engine spinning way too fast for my liking.

Is there any big advantage between the Roverdive & Faiey units?
Pro's? Con's? Any special maintenace required for either unit?

Thanks.

Terrys
05-30-2011, 08:06 PM
One thing to keep in mind is that your power transmission always goes thru the OD, whether it's engaged or not. Fairey's are reliable enough on their own, but the splines of the adapter on a Fairey are smaller than the Roverdrive and Toro (No longer available unless you find a used one) The Santana OD was pretty bullet proof.
I have seen several Fairey adapters striped out, If you off-road, and especially if far from home and tools, keep your original intermediate gear in your toolbox, along with either the special socket, or, in an emergency, a long drift. If you strip your adapter, you'll have no power transmitted from the gearbox to the TC.
I picked up a used Fairey, and completely rebuilt it, but I'm really on the fence about putting it in , as I don't do any highway driving with my 88.

LR Max
06-01-2011, 11:56 AM
If you do any highway driving, yes. You need an overdrive.

This past weekend I cruised over 100 miles to Alabama, wheeled all day, and drove back. Rolling with an overdrive made it A LOT easier.

That is the only time I use mine. In town traffic, never.

But that overdrive plus a seriously healthy engine and highway cruising isn't a problem.

3 issues with the overdrive I have (have a fairey with many miles on it, wasn't rebuilt when I put it in):

1. The stupid handle rattles...ALL THE TIME. I put a bungee around it but one of these days I'll figure out how to make it not rattle.

2. The unit is LOUD. Like, 2x louder than anything else. I wear ear plugs when I drive it.

3. I think the syncros in it are shot. I can engage it, but can't disengage without a nasty gear grinding noise.

I'd say rover drive. I hear nothing but great things about them, especially from guys who put a lot of miles on their series trucks. If you do get a Fairey, rebuild it before installation!

rejeep
06-01-2011, 01:44 PM
I purchased my Roverdrive before I even took delivery of my series truck about a year ago...
fantastic improvement in drivability and really cant imagine driving a series truck on the hwy without one..
even around town in 40-45 mph zones the 3 1/2 gear is just perfect..

galen216
06-01-2011, 02:54 PM
1. The stupid handle rattles...ALL THE TIME. I put a bungee around it but one of these days I'll figure out how to make it not rattle.



Mine did this too. Where the linkage connects to the OD the opening in the linkage is much larger than the connection on the OD. When I put the Pin back in I forced a washer in between the linkage and connection on the OD. The rattle is now gone.

My transmission is out at the moment. I'll try to take a picture b/c I don't thing I am explaining very well.

Momo
06-01-2011, 10:37 PM
Max, on every Fairey OD I've had (3 or 4 now), the large bolt holding the lever to the linkage has backed out over time. If this is what's happening on yours, a drop of threadlocker should do the trick.

luckyjoe
06-02-2011, 07:41 AM
Galen,

There are plastic strips with a hole in each end, that form a loop when bent back on themselves. They were part of the hardware kit and when installed, keep tension on the linkage so it doesn't rattle. You can still get them from RDS, or cut them from a soda bottle.

Max - not sure if this is related to your rattle or not...

TedW
06-02-2011, 12:28 PM
IIRC you can go to your local Ace Hardware and get some really thin nylon washers that will stop the rattle. You may need to drill them out to fit, but no biggie.

LR Max
06-02-2011, 06:41 PM
LOL, sorry for the hijack thread...but while we are here...

Yeah, I think my bolt is backing out and I do not have a plastic thingie on there. Thanks for all the recommendations but really, I'm thinking of pulling it, selling as is (needs rebuild...and little plastic thingie) and installing a rover drive.

Why? Because I'm tired of looking at my girlfriend before each trip and telling her, "See you when we get there" :rolleyes: