[Healeys] Overdrive disengages

Sun Jul 2 18:01:31 MDT 2023

The problem with my O/D was not related to hot days. I would start the car cold and drive for a while. The O/D would work fine. But after everything was hot, if I disengaged the O/D, it would not reengage. Replacing the accumulator housing and piston fixed that.

There are two adjustments.

1. The setting lever that activates the O/D when the toggle switch is closed. That is the one that is supposed to be set with a 3/16 drill bit. The setting lever moves when the toggle switch is closed and the solenoid pulls the arm on the valve operating shaft up. The other end of the setting lever has a paddle inside of the O/D that pushes the shaft of the operating valve up. On top of that shaft is a ball bearing, plunger and spring. It can be accessed by removing a bolt on the top right hand side of the O/D. The movement of the ball bearing is supposed to be 1/32 or .040. I don’t have the equipment to measure the movement and 1/32 is not perceptible to my eyes. Never really has been.

This is my second healey, I had one in high school. I have never been able to use a drill bit to adjust the setting lever. If I line up the hole in the lever with the hole in the O/D casing, the O/D will not engage. For my O/D, the lever needs to be rotated clockwise slightly past the hole in the casing. Setting it is trial and error.

2. The throttle switch is controlled by the accelerator pedal. I need to adjust that switch because my O/D is disengaging as soon as I open the toggle switch on the dash board. It should not do that.

John

’62 Bt7

From: Healeys [mailto:healeys-bounces at autox.team.net] On Behalf Of Tom
Sent: Sunday, July 2, 2023 2:53 PM
To: m.g.sharp at sympatico.ca
Cc: healeys at autox.team.net
Subject: Re: [Healeys] Overdrive disengages

I noticed my overdrive disengaging when I've run it for a while on a hot day, so this discussion has been interesting.

Are we discussing two different adjustments, one on the overdrive unit itself,  using the 3/16 drill bit method described by Norm Nock in his tech tips book, and the other the switch controlled by the accelerator pedal?

I'm interested in the former right now, so if you could clarify the .040 or 1/32 you're measuring, that would help.

thanks!

Tom

On Sun, Jul 2, 2023 at 5:10 PM m.g.sharp--- via Healeys <healeys at autox.team.net <mailto:healeys at autox.team.net> > wrote:

Perhaps I am missing something, but 0.040” is not equivalent to 3/16”

From: Healeys <healeys-bounces at autox.team.net <mailto:healeys-bounces at autox.team.net> > On Behalf Of Hank Leach via Healeys
Sent: Sunday, July 2, 2023 1:24 PM
To: 'Bob Spidell' <bspidell at comcast.net <mailto:bspidell at comcast.net> >
Cc: 'healeys at autox.team.net <mailto:healeys at autox.team.net> ' <healeys at autox.team.net <mailto:healeys at autox.team.net> >
Subject: Re: [Healeys] Overdrive disengages

Bob's got the procedure.  Use a .040" feeler gauge (or 3/16 drill) under the throttle stop (1/5 of the throttle opening).  Connect a 12V test light to the fuse box and the top terminal on the throttle switch. (Good example in Haynes Manual page 124). Light should go out at this adjustment. Solenoid adjustment should be as Bob describes and work smoothly-no binding. Hank

-----------------------------------------

From: "Bob Spidell" 
To: healeys at autox.team.net <mailto:healeys at autox.team.net> 
Cc: 
Sent: Sunday July 2 2023 9:20:10AM
Subject: Re: [Healeys] Overdrive disengages

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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