Subject: [Healeys] Overdrive pressure drop

From: Simon Lachlan via Healeys <[email-masked]>
Date: Fri, 30 Jul 2021 15:11:57 +0100 boundary="----=_NextPart_000_0001_01D78555.3E111420"

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Hi,

I've been having issues with my OD. Similar to someone else quite recently..

The OD would engage and disengage properly at high revs but once the car was
cruising along at low revs, the OD would somehow act like it was on the
verge of dropping out &/or dropping back in.

It may be electrical, but I doubt it. The solenoid goes in with a nice
robust click.

I was thinking that it would be pressure related. So.....

I've bought a gauge from OD Spares here in UK and got the car up on axle
stands.

I did the test procedure much per the Del Border article which I sent out
the other day.

1.	Pressure is good, at the top end of 470 to 490 with gearbox oil
cold. ie 470 to 490 psi at 1500 rpm in 4th and then same in 4thOD after a
momentary drop. (40wt non-detergent).
2.	When I go out of OD, brake and switch off, the pressure drops to nil
at once. Which is, apparently and according to the article, WRONG.

I am now leaning towards something in the so-called "ball valve", items 33
to 37 on page 2 of attached. 

Does the above seem like a good place to start? 

Could, say, a worn spring or a piece of dirt in that area cause these
issues?

The names of these valves, "Operating valve" at top and "Ball valve" at
bottom seems to vary with every article I read.

The "non-return valve" and the "check valve"..are these the same thing and
are they what BMC calls the "Ball valve", item 37.

Thanks, hopefully!

Simon

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link=3D"#0563C1" vlink=3D"#954F72"><div class=3DWordSection1><p =
class=3DMsoNormal>Hi,<o:p></o:p></p><p class=3DMsoNormal>I&#8217;ve been =
having issues with my OD. Similar to someone else quite =
recently&#8230;&#8230;<o:p></o:p></p><p class=3DMsoNormal>The OD would =
engage and disengage properly at high revs but once the car was cruising =
along at low revs, the OD would somehow act like it was on the verge of =
dropping out &amp;/or dropping back in.<o:p></o:p></p><p =
class=3DMsoNormal>It <i>may </i>be electrical, but I doubt it. The =
solenoid goes in with a nice robust click.<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>I was =
thinking that it would be pressure related. =
So&#8230;&#8230;&#8230;&#8230;&#8230;<o:p></o:p></p><p =
class=3DMsoNormal>I&#8217;ve bought a gauge from OD Spares here in UK =
and got the car up on axle stands.<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>I did the =
test procedure much per the Del Border article which I sent out the =
other day.<o:p></o:p></p><ol style=3D'margin-top:0cm' start=3D1 =
type=3D1><li class=3DMsoListParagraph =
style=3D'margin-left:0cm;mso-list:l0 level1 lfo1'>Pressure is good, at =
the top end of 470 to 490 with gearbox oil cold. ie 470 to 490 psi at =
1500 rpm in 4<sup>th</sup> and then same in 4thOD after a momentary =
drop. (40wt non-detergent).<o:p></o:p></li><li class=3DMsoListParagraph =
style=3D'margin-left:0cm;mso-list:l0 level1 lfo1'>When I go out of OD, =
brake and switch off, the pressure drops to nil at once. Which is, =
apparently and according to the article, WRONG.<o:p></o:p></li></ol><p =
class=3DMsoNormal>I am now leaning towards something in the so-called =
&#8220;ball valve&#8221;, items 33 to 37 on page 2 of attached. =
<o:p></o:p></p><p class=3DMsoNormal><o:p>&nbsp;</o:p></p><p =
class=3DMsoNormal>Does the above seem like a good place to start? =
<o:p></o:p></p><p class=3DMsoNormal>Could, say, a worn spring or a piece =
of dirt in that area cause these issues?<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>The names of =
these valves, &#8220;Operating valve&#8221; at top and &#8220;Ball =
valve&#8221; at bottom seems to vary with every article I =
read.<o:p></o:p></p><p class=3DMsoNormal>The &#8220;non-return =
valve&#8221; and the &#8220;check valve&#8221;&#8230;.are these the same =
thing and are they what BMC calls the &#8220;Ball valve&#8221;, item =
37.<o:p></o:p></p><p class=3DMsoNormal><o:p>&nbsp;</o:p></p><p =
class=3DMsoNormal>Thanks, hopefully!<o:p></o:p></p><p =
class=3DMsoNormal>Simon<o:p></o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p><p =
class=3DMsoNormal><o:p>&nbsp;</o:p></p></div></body></html>
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From: Henry G Leach via Healeys <[email-masked]>
Date: Fri, 30 Jul 2021 17:04:49 +0000 4EJfa0wo+92F8ZhHMaj1O3Xthn51CCGZFkw87VIPlWaulQNkdotNai7qSnGfJpiRAsLWGUFeVKl9fRTJbdGcwcJcvZYx0X9l1VwVQo8CrCFpCwgycuP5kBfF

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Simon-yes, there are two balls which control the pressure in the unit.=
=0AIn the operating valve which is engaged by the action of the solenoid=
,=0Adirt is a possible issue. There is a very tiny hole drilling in the=
=0Astem of the valve which allows the oil to circulate. That opening can=
=0Aplug with debris and stop the flow. Oil from the accumulator goes thr=
u=0Athis valve and lifts the ball allowing the operating cylinders to mo=
ve=0Aforward on the clutch producing the overdrive. When the ball is sea=
ted=0A(solenoid off) oil does not pass and is dumped into the OD sump.=
=0AYou can see that this tiny drilling is very important and must be kep=
t=0Aclear. Often rebuilders suggest to enlarge the hole to 1MM. It may=
=0Achange the dwell time of the OD action, but its has a better chance o=
f=0Astaying clean...a theory not proven.=0AThe other ball is on the oil=
 pump and that is the one that Del=0Asuggested needed a new spring or ex=
tended plunger to enhance=0Apressure-another theory.=0AAs you measured n=
o pressure when out of OD, that is due to the ball=0Aproperly seating on=
 the valve and reliving the pressure that operates=0Athe two pistons. If=
 you move the lever or engage the solenoid you=0Ashould get 470 lbs. aga=
in.=0AI would suggest cleaning the valve-use a magnet to get the parts o=
ut=0Aand don't use a shop rage to clean them (no lint). If all is ok in=
 the=0Avalve body you need to look further into the accumulator and o-ri=
ngs=0Aand piston rings. I suggest you contact David at OD Spares for som=
e=0Aadditional advise. Hank=0A=0A=09------------------------------------=
-----From: "Simon Lachlan via=0AHealeys" =0ATo: "Healeys"=0ACc: =0ASent:=
 Friday July 30 2021 7:32:48AM=0ASubject: [Healeys] Overdrive pressure d=
rop=0A=0A=09Hi, =0A=0A=09I=E2=80=99ve been having issues with my OD. Sim=
ilar to someone else quite=0Arecently=E2=80=A6=E2=80=A6 =0A=0A=09The OD=
 would engage and disengage properly at high revs but once the=0Acar was=
 cruising along at low revs, the OD would somehow act like it=0Awas on t=
he verge of dropping out &/or dropping back in. =0A=0A=09It _may_ be ele=
ctrical, but I doubt it. The solenoid goes in with a=0Anice robust click=
. =0A=0A=09I was thinking that it would be pressure related. So=E2=80=A6=
=E2=80=A6=E2=80=A6=E2=80=A6=E2=80=A6 =0A=0A=09I=E2=80=99ve bought a gaug=
e from OD Spares here in UK and got the car up on=0Aaxle stands. =0A=0A=
=09I did the test procedure much per the Del Border article which I sent=
=0Aout the other day. =0A=0A=09* Pressure is good, at the top end of 470=
 to 490 with gearbox oil=0Acold. ie 470 to 490 psi at 1500 rpm in 4th an=
d then same in 4thOD=0Aafter a momentary drop. (40wt non-detergent).=0A=
 =09* When I go out of OD, brake and switch off, the pressure drops to=
=0Anil at once. Which is, apparently and according to the article, WRONG=
.=0A=0A=09I am now leaning towards something in the so-called =E2=80=9Cb=
all valve=E2=80=9D,=0Aitems 33 to 37 on page 2 of attached. =0A=0A=09Doe=
s the above seem like a good place to start? =0A=0A=09Could, say, a worn=
 spring or a piece of dirt in that area cause these=0Aissues? =0A=0A=09T=
he names of these valves, =E2=80=9COperating valve=E2=80=9D at top and=
 =E2=80=9CBall=0Avalve=E2=80=9D at bottom seems to vary with every artic=
le I read. =0A=0A=09The =E2=80=9Cnon-return valve=E2=80=9D and the =E2=
=80=9Ccheck valve=E2=80=9D=E2=80=A6.are these the=0Asame thing and are t=
hey what BMC calls the =E2=80=9CBall valve=E2=80=9D, item 37. =0A=0A=09T=
hanks, hopefully! =0A=0A=09Simon =0A=0A=09

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<html><body>Simon-yes, there are two balls which control the pressure in=
 the unit. In the operating valve which is engaged by the action of the=
 solenoid, dirt is a possible issue. There is a very tiny hole drilling=
 in the stem of the valve which allows the oil to circulate.&nbsp; That=
 opening can plug with debris and stop the flow. Oil from the accumulato=
r goes thru this valve and lifts the ball allowing the operating cylinde=
rs to move forward on the clutch producing the overdrive. When the ball=
 is seated (solenoid off) oil does not pass and is dumped into the OD su=
mp.<div><br></div><div>You can see that this tiny drilling is very impor=
tant and must be kept clear.&nbsp; Often rebuilders suggest to enlarge t=
he hole to 1MM. It may change the dwell time of the OD action, but its h=
as a better chance of staying clean...a theory not proven.</div><div><br=
></div><div>The other ball is on the oil pump and that is the one that D=
el suggested needed a new spring or extended plunger&nbsp; to enhance pr=
essure-another theory.</div><div><br></div><div>As you measured no press=
ure when out of OD, that is due to the ball properly seating on the valv=
e and reliving the pressure that operates the two pistons. If you move t=
he lever or engage the solenoid you should get 470 lbs. again.</div><div=
><br></div><div>I would suggest cleaning the valve-use a magnet to get t=
he parts out and don't use a shop rage to clean them (no lint). If all i=
s ok in the valve body you need to look further into the accumulator and=
 o-rings and piston rings. I suggest you contact David at OD Spares for=
 some additional advise. Hank<br><br><div class=3D"reply-new-signature">=
</div><p>-----------------------------------------</p>From: "Simon Lachl=
an via Healeys" <[email-masked]><br>To: "Healeys"<br>Cc: <br>Sen=
t: Friday July 30 2021 7:32:48AM<br>Subject: [Healeys] Overdrive pressur=
e drop<br><br>=0A<div class=3D"WordSection1">=0A<p class=3D"MsoNormal">H=
i,</p>=0A<p class=3D"MsoNormal">I=E2=80=99ve been having issues with my=
 OD. Similar to=0Asomeone else quite recently=E2=80=A6=E2=80=A6</p>=0A<p=
 class=3D"MsoNormal">The OD would engage and disengage properly at=0Ahig=
h revs but once the car was cruising along at low revs, the OD=0Awould s=
omehow act like it was on the verge of dropping out &amp;/or=0Adropping=
 back in.</p>=0A<p class=3D"MsoNormal">It <i>may</i> be electrical, but=
 I doubt it.=0AThe solenoid goes in with a nice robust click.</p>=0A<p c=
lass=3D"MsoNormal">&nbsp;</p>=0A<p class=3D"MsoNormal">I was thinking th=
at it would be pressure=0Arelated. So=E2=80=A6=E2=80=A6=E2=80=A6=E2=80=
=A6=E2=80=A6</p>=0A<p class=3D"MsoNormal">I=E2=80=99ve bought a gauge fr=
om OD Spares here in UK=0Aand got the car up on axle stands.</p>=0A<p cl=
ass=3D"MsoNormal">&nbsp;</p>=0A<p class=3D"MsoNormal">I did the test pro=
cedure much per the Del=0ABorder article which I sent out the other day.=
</p>=0A<ol style=3D"margin-top:0cm;" start=3D"1" type=3D"1"><li class=3D=
"MsoListParagraph" style=3D"margin-left:0cm;">Pressure is good, at the=
=0Atop end of 470 to 490 with gearbox oil cold. ie 470 to 490 psi at=0A1=
500 rpm in 4<sup>th</sup> and then same in 4thOD after a momentary=0Adro=
p. (40wt non-detergent).</li>=0A<li class=3D"MsoListParagraph" style=3D"=
margin-left:0cm;">When I go out of OD,=0Abrake and switch off, the press=
ure drops to nil at once. Which is,=0Aapparently and according to the ar=
ticle, WRONG.</li>=0A</ol><p class=3D"MsoNormal">I am now leaning toward=
s something in the=0Aso-called =E2=80=9Cball valve=E2=80=9D, items 33 to=
 37 on page 2 of attached.</p>=0A<p class=3D"MsoNormal">&nbsp;</p>=0A<p=
 class=3D"MsoNormal">Does the above seem like a good place to=0Astart?</=
p>=0A<p class=3D"MsoNormal">Could, say, a worn spring or a piece of dirt=
=0Ain that area cause these issues?</p>=0A<p class=3D"MsoNormal">&nbsp;<=
/p>=0A<p class=3D"MsoNormal">The names of these valves, =E2=80=9COperati=
ng valve=E2=80=9D=0Aat top and =E2=80=9CBall valve=E2=80=9D at bottom se=
ems to vary with every article=0AI read.</p>=0A<p class=3D"MsoNormal">Th=
e =E2=80=9Cnon-return valve=E2=80=9D and the =E2=80=9Ccheck=0Avalve=E2=
=80=9D=E2=80=A6.are these the same thing and are they what BMC calls the=
=0A=E2=80=9CBall valve=E2=80=9D, item 37.</p>=0A<p class=3D"MsoNormal">&=
nbsp;</p>=0A<p class=3D"MsoNormal">Thanks, hopefully!</p>=0A<p class=3D"=
MsoNormal">Simon</p>=0A<p class=3D"MsoNormal">&nbsp;</p>=0A<p class=3D"M=
soNormal">&nbsp;</p>=0A</div>=0A</[email-masked]></div></body></=
html>

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[email-masked]

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From: Bob Spidell via Healeys <[email-masked]>
Date: Fri, 30 Jul 2021 10:50:36 -0700

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Sounds to me like your hydraulics are OK; sounds more electrical to me. 
I had similar symptoms with an intermittent OD relay; I fixed it in a 
hotel room in Canada by opening up the relay and filing the points (and 
replaced it when I got home).

I suspect--and it's only a guess--that you get the drop out/in symptom 
at lower revs because most of us--racers aside--spend the vast majority 
of time cruising at 2-2.5K RPM, so you get that symptom in that regimen 
more often.

Bob

On 7/30/2021 10:04 AM, Henry G Leach via Healeys wrote:
> Simon-yes, there are two balls which control the pressure in the unit. 
> In the operating valve which is engaged by the action of the solenoid, 
> dirt is a possible issue. There is a very tiny hole drilling in the 
> stem of the valve which allows the oil to circulate.  That opening can 
> plug with debris and stop the flow. Oil from the accumulator goes thru 
> this valve and lifts the ball allowing the operating cylinders to move 
> forward on the clutch producing the overdrive. When the ball is seated 
> (solenoid off) oil does not pass and is dumped into the OD sump.
>
> You can see that this tiny drilling is very important and must be kept 
> clear.  Often rebuilders suggest to enlarge the hole to 1MM. It may 
> change the dwell time of the OD action, but its has a better chance of 
> staying clean...a theory not proven.
>
> The other ball is on the oil pump and that is the one that Del 
> suggested needed a new spring or extended plunger  to enhance 
> pressure-another theory.
>
> As you measured no pressure when out of OD, that is due to the ball 
> properly seating on the valve and reliving the pressure that operates 
> the two pistons. If you move the lever or engage the solenoid you 
> should get 470 lbs. again.
>
> I would suggest cleaning the valve-use a magnet to get the parts out 
> and don't use a shop rage to clean them (no lint). If all is ok in the 
> valve body you need to look further into the accumulator and o-rings 
> and piston rings. I suggest you contact David at OD Spares for some 
> additional advise. Hank
>
> -----------------------------------------
>
> From: "Simon Lachlan via Healeys"
> To: "Healeys"
> Cc:
> Sent: Friday July 30 2021 7:32:48AM
> Subject: [Healeys] Overdrive pressure drop
>
> Hi,
>
> I’ve been having issues with my OD. Similar to someone else quite 
> recently……
>
> The OD would engage and disengage properly at high revs but once the 
> car was cruising along at low revs, the OD would somehow act like it 
> was on the verge of dropping out &/or dropping back in.
>
> It /may/ be electrical, but I doubt it. The solenoid goes in with a 
> nice robust click.
>
> I was thinking that it would be pressure related. So……………
>
> I’ve bought a gauge from OD Spares here in UK and got the car up on 
> axle stands.
>
> I did the test procedure much per the Del Border article which I sent 
> out the other day.
>
>     cold. ie 470 to 490 psi at 1500 rpm in 4^th and then same in 4thOD
>     after a momentary drop. (40wt non-detergent).
>  2. When I go out of OD, brake and switch off, the pressure drops to
>     nil at once. Which is, apparently and according to the article, WRONG.
>
> I am now leaning towards something in the so-called “ball valve”, 
> items 33 to 37 on page 2 of attached.
>
> The names of these valves, “Operating valve” at top and “Ball valve” 
> at bottom seems to vary with every article I read.
>
> The “non-return valve” and the “check valve”….are these the same thing 
> and are they what BMC calls the “Ball valve”, item 37.
>
> Thanks, hopefully!
>
> Simon
>
>

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    Sounds to me like your hydraulics are OK; sounds more electrical to
    me. I had similar symptoms with an intermittent OD relay; I fixed it
    in a hotel room in Canada by opening up the relay and filing the
    points (and replaced it when I got home).<br>
    <br>
    I suspect--and it's only a guess--that you get the drop out/in
    symptom at lower revs because most of us--racers aside--spend the
    vast majority of time cruising at 2-2.5K RPM, so you get that
    symptom in that regimen more often.<br>
    <br>
    Bob<br>
    <br>
    <div class="moz-cite-prefix">On 7/30/2021 10:04 AM, Henry G Leach
      via Healeys wrote:<br>
    </div>
    <blockquote type="cite"
      cite="mid:32d7457e41365c17ea022d3f0294c0dbfb69d112@webmail">
      <meta http-equiv="content-type" content="text/html; charset=UTF-8">
      Simon-yes, there are two balls which control the pressure in the
      unit. In the operating valve which is engaged by the action of the
      solenoid, dirt is a possible issue. There is a very tiny hole
      drilling in the stem of the valve which allows the oil to
      circulate.  That opening can plug with debris and stop the flow.
      Oil from the accumulator goes thru this valve and lifts the ball
      allowing the operating cylinders to move forward on the clutch
      producing the overdrive. When the ball is seated (solenoid off)
      oil does not pass and is dumped into the OD sump.
      <div><br>
      </div>
      <div>You can see that this tiny drilling is very important and
        must be kept clear.  Often rebuilders suggest to enlarge the
        hole to 1MM. It may change the dwell time of the OD action, but
        its has a better chance of staying clean...a theory not proven.</div>
      <div><br>
      </div>
      <div>The other ball is on the oil pump and that is the one that
        Del suggested needed a new spring or extended plunger  to
        enhance pressure-another theory.</div>
      <div><br>
      </div>
      <div>As you measured no pressure when out of OD, that is due to
        the ball properly seating on the valve and reliving the pressure
        that operates the two pistons. If you move the lever or engage
        the solenoid you should get 470 lbs. again.</div>
      <div><br>
      </div>
      <div>I would suggest cleaning the valve-use a magnet to get the
        parts out and don't use a shop rage to clean them (no lint). If
        all is ok in the valve body you need to look further into the
        accumulator and o-rings and piston rings. I suggest you contact
        David at OD Spares for some additional advise. Hank<br>
        <br>
        <p>-----------------------------------------</p>
        From: "Simon Lachlan via Healeys" <[email-masked]><br>
          To: "Healeys"<br>
          Cc: <br>
          Sent: Friday July 30 2021 7:32:48AM<br>
          Subject: [Healeys] Overdrive pressure drop<br>
          <br>
          <div class="WordSection1">
            <p class="MsoNormal">Hi,</p>
            <p class="MsoNormal">I’ve been having issues with my OD.
              Similar to
              someone else quite recently……</p>
            <p class="MsoNormal">The OD would engage and disengage
              properly at
              high revs but once the car was cruising along at low revs,
              the OD
              would somehow act like it was on the verge of dropping out
              &amp;/or
              dropping back in.</p>
            <p class="MsoNormal">It <i>may</i> be electrical, but I
              doubt it.
              The solenoid goes in with a nice robust click.</p>
            <p class="MsoNormal"> </p>
            <p class="MsoNormal">I was thinking that it would be
              pressure
              related. So……………</p>
            <p class="MsoNormal">I’ve bought a gauge from OD Spares here
              in UK
              and got the car up on axle stands.</p>
            <p class="MsoNormal"> </p>
            <p class="MsoNormal">I did the test procedure much per the
              Del
              Border article which I sent out the other day.</p>
            <ol style="margin-top:0cm;" type="1" start="1">
              <li class="MsoListParagraph" style="margin-left:0cm;">Pressure
                is good, at the
                top end of 470 to 490 with gearbox oil cold. ie 470 to
                490 psi at
                1500 rpm in 4<sup>th</sup> and then same in 4thOD after
                a momentary
                drop. (40wt non-detergent).</li>
              <li class="MsoListParagraph" style="margin-left:0cm;">When
                I go out of OD,
                brake and switch off, the pressure drops to nil at once.
                Which is,
                apparently and according to the article, WRONG.</li>
            </ol>
            <p class="MsoNormal">I am now leaning towards something in
              the
              so-called “ball valve”, items 33 to 37 on page 2 of
              attached.</p>
            <p class="MsoNormal"> </p>
            <p class="MsoNormal">Does the above seem like a good place
              to
              start?</p>
            <p class="MsoNormal">Could, say, a worn spring or a piece of
              dirt
              in that area cause these issues?</p>
            <p class="MsoNormal"> </p>
            <p class="MsoNormal">The names of these valves, “Operating
              valve”
              at top and “Ball valve” at bottom seems to vary with every
              article
              I read.</p>
            <p class="MsoNormal">The “non-return valve” and the “check
              valve”….are these the same thing and are they what BMC
              calls the
              “Ball valve”, item 37.</p>
            <p class="MsoNormal"> </p>
            <p class="MsoNormal">Thanks, hopefully!</p>
            <p class="MsoNormal">Simon</p>
            <p class="MsoNormal"> </p>
            <br>
          </div>
        </[email-masked]></div>
    </blockquote>
    <br>
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