Subject: [Healeys] Overdrive and RPM

From: john spaur <[email-masked]>
Date: Mon, 19 Aug 2013 09:20:38 -0700

I searched the archives and could not find any posts to help me.

Driving in gear at 3100 RPM with the overdrive engaged, the tach will 
drop about 1000 RPM when I take my foot off the accelerator. When I 
put my foot back on the accelerator it is the RPM comes slowly up 3100.

When I do the same thing with the OD disengaged, the tack will show 
very little decrease in RPM's. When I press on the accelerator the 
RPM's come back to 3100 very quickly.

What might be causing the RPM drop with the OD engaged?

John Spaur
'62 BT7
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From: Bob Spidell <[email-masked]>
Date: Mon, 19 Aug 2013 17:29:13 +0000 (UTC)

Sounds like your O/D 'kickdown' switch--the one that is supposed to prevent the O/D from disengaging unless forward torque is applied to the drivetrain--is behaving bass-ackwards. 

Bob 

-------------------------------- 
Bob Spidell - San Jose, CA 

----- Original Message -----

John Spaur 
'62 BT7 

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From: Michael Salter <[email-masked]>
Date: Mon, 19 Aug 2013 19:43:42 -0400

Ok that makes sense.
My guess is that either the operating valve needs adjustment (go by the lift
of the ball rather than the position of the lever) or the pump pressure is low
probably due to a worn or damaged accumulator.
Try adjusting the valve first if that doesn't work you need to check the
pressure.
Michael S

-----Original Message-----
From: "john spaur" <[email-masked]>
Sent: b2013-b08-b19 7:13 PM
To: "Michael Salter" <[email-masked]>
Cc: "[email-masked]" <[email-masked]>
Subject: Re: [Healeys] Overdrive and RPM

At 3100 RPM when I flip the OD switch it does not seem like the OD
engages until after I back off on the accelerator. It seems like I
need to accelerate and decelerate to get it to engage. Once I know it
is engaged it seems to stay engaged until I turn it off and then
punch the accelerator. Then I can feel it disengage. The difference
in RPM's is not a lot because I have a 3.54 diff.

John Spaur

At 01:40 PM 8/19/2013 -0400, Michael Salter wrote:
>Hi John,
>For good diagnosis we need one more piece of information..
>When the overdrive is engaged and you are doing 3100 RPM is the
>speed of the car higher than when the overdrive is not engaged at 3100 RPM.
>I suspect not and that the overdrive is not actually "engaging"
>until you lift off the throttle.
>If that is the case then the cause can be as simple as maladjustment
>of the overdrive operating valve or as complex as low oil pressure
>in the overdrive or even worn cone clutch linings.
>
>Michael S

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