Fitting a Fairey overdrive to a Holden-powered SIIA?

[65ClassicLandy]

Hi fellow Land-Rover fans,

I am new to the forum and a recent buyer of a 1965 SIIA 88in Station Wagon. It's the first one I have owned, but, I'm not 'new' to Land-Rovers.

I purchased it in December 2014 from the previous owner in QLD. He had imported it from NZ about 2 years prior.

One of its earlier owners, in the 80s had some modifications done. These include:
- fitting a Holden Red 186 3.1L 6-cylinder motor
- Rover 90 diffs

The gearbox, though, is a Land-Rover unit. Just driving it locally in the suburbs it seems quite noisy, as if it needs another gear e.g. 5th or an overdrive unit. Not to mention that it 'screams' when travelling on the freeway.

Has anyone fitted a (Fairey) overdrive to a Series Landy with a Holden power plant? If so, has it been a satisfactory exercise?

I have been told that fitting 'taller' tyres is another option and could reduce the noise somewhat. It currently has Firestone Destination A/T 225/75R16 (from what I can make out from a photo). [The car is currently with the mechanic.]

And, I would achieve better fuel economy with either option.

I would appreciate any advice and information from AULRO's wealth of knowledge.

Regards,
Philip

[Homestar]

Hi Philip, welcome to the forum.

Yes, I've had a Fairey overdrive behind a Holden 6 - was ok, but they aren't the strongest bit of kit and the one I had was noisy, but I don't think they all are - the Fairey behind my LT95 box (it's a different unit) isn't noisy.

Fitting 750/16 tyres would improve things a bit too.

Note that these nothing that will improve your fuel economy too much short of selling it and buying a Prius. (Don't do that!!!!)

Remember that these vehicles were designed to run at 80 odd KMH give or take, so running them at highway speeds is always going to make the scream although the OD will help and a healthy Holden red engine will have enough power to move it along just fine with the OD engaged.

Post some pics when you get it back from the mechanics so we can see your pride and joy.

Cheers - Gav.

[JDNSW]

More or less as said. But the '90' diffs are 3.54:1 (but check the actual ratio - standard 2a is 4.7, but very early 90s were as well) and there should be no need to have an overdrive as well as the higher ratio.

The Holden engine is less happy at high rpm than the original engine, which if in good condition, will contribute little noise at highway speeds - most noise is tyres, wind and rattles, helped by the total lack of insulation. On that subject, well worth the effort as far as cruising noise goes - a number of years ago I repainted my 2a, and while doing so, replaced all the body rubber; for the next few years, it was quieter than it had ever been. This included putting rubber plugs in all the unused holes in the bodywork, and fitting neoprene sealed foam strips to all bolted panel joins such as the floor panels.

The Fairey overdrive is, as stated, fairly weak, although it will last if never used except in third and fourth, and never run low in oil. The oil really needs to be checked every 1000miles as they often throw oil out the breather, or if a leak develops in the seal to the transfer case they can rapidly empty the reservoir. I have fitted an extended breather on mine.

Some Fairey parts are very expensive and hard to find. Watch out if buying a second hand one, as they are prone to wearing out the splined joint to the gearbox output shaft, and the overdrive end of this joint is the overdrive input shaft and very expensive. Also, if buying one, make sure you get all the parts - often the dog or spline off the gearbox output shaft has been lost, as have part or all of the lever and linkage, as these are loose parts.

John

[mick88]

G'day Philip,
welcome to the forum.
Sounds like you have an interesting vehicle there, not many have crossed the Tasman.
With regards to the Rover 90 diffs, I assume the objective of the previous owner was to modify the gearing, which may or may not have ended up being the case if they were still the 4.7's as John said. I think some Rover's that had overdrives were fitted with 4.1's too. So it would be worth checking your diffs ratio's for certain.
With a Holden 186 high ratio diffs such as 3.54's are a good thing.
I have had both Fairey and Toro overdrives behind Holden powered Land Rovers (with standard 4.7 diffs), whilst being ok, if you can afford it, the Roamerdrive unit is a better option. Whilst not cheap, they are good.
I currently run a 186 in my series 3 88" and it has 3.54 diffs, a Romerdrive, and it handles the combination well. It works for me. However I don't run 7.50 x 16 profile tires though, nearer to a 6.50.
If you have the 4.1 ratio diffs these would match up well with an overdrive.
Good luck.


Cheers, Mick.

[Dark61]

I must admit when I first brought home the series 3 109 I was pretty appalled by the performance , not having driven one on the road before. It was high up on my list to get an overdrive, but I've got used to being the slowest thing on the road now and with a line of vehicles behind me. I just pull over from time to time and let them all go by. Its quite liberating! I suppose what I am saying is give it a bit more time and you may get used to it without having to spend a good deal of money. I also had a disc brake conversion on the list but again , I've learned to brake well ahead with the gears.
cheers,
D

[mick88]

With the tires I have and the 3.54 diffs, 1000 RPM is approx. 33 kph in 4th gear and 44 kph with overdrive engaged.
That's going by the Garmin GPS and tacho, for what it's worth.


Cheers, Mick.