[Healeys] Overdrive disengages

[Bob Spidell]

Hi John,

What keeps the O/D from disengaging immediately when you open the dash 
switch is the 'throttle switch.' When the O/D is actuated there is a 
parallel circuit that will keep the O/D activated until you press the 
accelerator pedal, theoretically preventing reverse thrust from damaging 
the O/D. The parallel circuit runs through the throttle switch on the 
scuttle (firewall); it sounds like you need to adjust it. It's a simple 
adjustment using a certain diameter--I don't recall it offhand, but I'll 
look it up if you need it--drill bit under the throttle stop levers. 
There's a small shaft off the throttle mechanism that opens this 
switch--it's just a set of points and a cam inside--with a lever with a 
pinch clamp. Just loosen the pinch clamp, set the bit under the throttle 
stop plate and tighten the clamp.

If you O/D is actuating consistently within a couple seconds or so then 
your solenoid, operating lever, operating shaft and ball 'valve' are 
correct. The 'stick-a-drill-bit-through-the-lever-into-the-housing' 
method is notoriously unreliable; the proper setting is best achieved by 
measuring the lift--IIRC, it's 1/32" but not sure--of the operating 
shaft at the top of the O/D hydraulic section.

Bob


On 7/1/2023 11:55 AM, John Spaur via Healeys wrote:
>
> Hi All,
>
> My overdrive is functioning again after replacing the accumulator 
> housing and piston but it is exhibiting an odd behavior which I 
> believe is related to the adjustment of the setting lever.
>
> When I open the toggle switch, the OD will sometimes disengage 
> immediately instead of waiting until I blip the accelerator. When I 
> adjusted the setting lever, I could not use a 3/16” dowel to line up 
> the lever with the hole in the housing. I had to advance the lever 
> clockwise a bit to get the OD to engage when the toggle switch was 
> closed. This has always been the case and this issue is mentioned in 
> some articles.
>
> Do I need to fiddle with the setting lever adjustment some more? If 
> so, do I rotate it clockwise or counter clockwise?
>
> Any other thoughts?
>
> TIA,
>
> John Spaur
>
> ’62 BT7
>
>
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