It may not be the pump but the cam that is installed backwards. When I
rebuild my gearbox (the first one I ever rebuilt) I somehow managed to
replace the cam back on the shaft facing the wrong way. The cam was turning
but the top of the pump piston was not ridding on the cam surface but along
the edge. I had to pull the gearbox apart to remove the cam and turn it
around on the shaft. If you don't pay very close attention to the position
of the cam it is easy to put in on backwards.
Ron
61BN7
----- Original Message -----
From: "Rick Swain" <rjswain@hotmail.com>
To: "Healey List" <healeys@autox.team.net>
Sent: Wednesday, July 15, 2009 4:26 PM
Subject: [Healeys] Overdrive Problem
>I finally have my '59 BN4 back on the road with everything working except
>the
> overdrive. I checked the electrical side of things and it works fine.
> Solenoid engages and operating lever is adjusted correctly. I moved on to
> the
> hydraulics. I removed the operating valve and ran the engine in gear. I
> discovered that no oil was being pumped into the valve chamber. The
> gearbox
> was rebuilt by a friend who has worked on many British gearboxes. The
> overdrive was not disturbed because it had been working perfectly
> previously.
> The problem that prompted the rebuild was jumping out of gear.
> It has been suggested that when the gearbox and overdrive were
> reassembled,
> perhaps the oil pump cam was installed backwards. To check this I removed
> the
> oil drain plug, strainer and the plug that screws into the oil pump body.
> I
> then inserted a screwdriver against the oil pump plunger. I hoped it was
> stuck
> in its lowest position. I tapped upwards but got a very solid clunk. The
> plunger spring seems to be doing its job of forcing the plunger up. With
> the
> screwdriver against the plunger I turned the right rear wheel. I thought
> that
> if the cam was installed correctly I should feel the oil pump plunger
> moving
> up and down as the cam rotates. I can feel just barely perceptible
> movement -
> which to me indicates the plunger is not in contact with the cam. Am I
> correct? How much movement of the plunger should there be? Am I going to
> have
> to pull the gearbox to reinstall the oil pump cam right way round?
> Thanks for any help or advice.
> Rick Swain
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