Non-Overdrive Benefits?

[Fanch00]

My 3000 is a non-overdrive car. This is intriguing, I have seen very few cars without this option. This is how the first owner ordered it (he also didn’t take wire wheels but he selected the hardtop and heating). I wonder: was there (or is there) any benefit to not having the overdrive?

 

[NutmegCT]

Other than saving money, I'd think not. But if the original buyer only wanted to cruise on country roads, at moderate speeds, buyer probably didn't really "need" overdrive.

Remember "free wheeling" in older American cars?

 

[Bob_Spidell]

Short answer: No.

The non-OD cars had a taller final gear (differential) of 3.54, which makes the car somewhat slower 'off-the-line,' but at freeway speeds (70mph+) NVH is uncomfortable and fatiguing. I have a 3.54 rear end and sometimes wish I had a 28% OD instead of the 22% OD it came with. Properly maintained--mostly, just clean oil--the Laycock de Normanville should be trouble-free for over 200K miles, but the electrical controls can occasionally be troublesome.

Wire wheels can be a PITA, even the 60-spokers are too weak for really hard driving--I broke several spokes with them on my BJ8--esp. with grippier radial tires. Untrue wire wheels at least contribute to the notorious 'scuttle shake.' But, the BN7s with disk wheels, triple carbs and center-shift transmissions are some of the rarest Healeys (64+/- IIRC). They can fetch a pretty penny.

 

[Michael Oritt]

Non-overdrive/disc-wheeled cars provided one benefit at the time: A lower price, which probably lured folks to the dealership where the vast majority of purchasers elected to buy cars equipped with wires and OD. The 3.5 final drive ratio compensated somewhat for the lack of overdrive but apparently not enough to make this model popular.

Ironically, 3-5 diffs are now very much in demand for their ability to reduce revs to around 3K at 70-75 mph in an OD-equipped car or, like mine, one that has a Toyota 5-speed tranny, and Mike Lempert's aftermarket 3.5 differentials sold very well when produced.

 

[vette]

Maybe if the car is intended for competition only the non-overdrive and disk wheels would have been desirable.

 

[Jack T]

As several responders have stated above, the 3.54 rear gear ratio is the largest benefit. Having driven mine with both the original 3.91 and the 3.54, I can say the car is much more relaxed on back roads with the 3.54. There are times when I never feel the need to use the overdrive where I would have with the 3.91. And running the 3.54 in combination with a 28% overdrive on the highway keeps the revs down at 70 mph.

 

[Fanch00]

Thank you all !!
Now I wonder if I should convert to overdrive ! I guess it means not just adding the Laycock overdrive unit to the gearbox, but changing the whole gearbox, right

 

[Bob_Spidell]

I don't think so; the OD requires a gearbox adapter though. The electricals would be the tricky part; do you have a blanked-out OD switch on the dash?

 

[BobHaskell]

The gearbox output shaft is different for OD and non-OD (longer). The gearbox and OD are the same length as the non-OD gearbox.

 

[vette]

I believe if I was going to go to pulling the trans and adding an OD I would just go to one of the Nissan or Toyota 5 speeds.
I Have an original OD with probably the 22% OD with a 3.54:1 rear gear and it is not sufficient for me.

 

[Bob_Spidell]

The gearbox output shaft is different for OD and non-OD (longer). The gearbox and OD are the same length as the non-OD gearbox.

Ah, right. Probably a good time to go through the gearbox anyway.