[Healeys] Overdrive pressure not releasing.

Michael Salter michaelsalter at gmail.com
Sun Apr 17 13:03:07 MDT 2022 

Actually Bob I've never used an  "O" ringed accumulator.
I spent a little time many years back looking into using "O" rings on the
accumulator but couldn't resolve the issue of the ring being chaffed when
passing over the radial drillings in the accumulator body.
Does anyone know how that has been solved?

M

On Sun., Apr. 17, 2022, 2:49 p.m. Bob Spidell, <bspidell at comcast.net> wrote:

> Michael,
>
> Sounds like you're implying the O-ringed accumulator is superior to the
> metal ring (OEM) type? Wish I'd known about it when I rebuilt my O/D (I
> bought the DWM 'uprated' accumulator).
>
> I'll throw out another, very unlikely, potential cause: the cone clutch
> could be stuck together. I've heard of this happening, but have never
> experienced it my self--nor has anyone I know--but it's theoretically
> possible (esp. if the clutch is excessively worn). Could this be the reason
> the manual is adamant about replacing the 8 strong springs, of two lengths,
> that oppose the operating pistons on overhaul, regardless if they still
> seem robust?
>
>
> On 4/17/2022 9:31 AM, Michael Salter via Healeys wrote:
>
> Simon,
> Based upon your synopsis I conclude that the operating valve is NOT
> opening when either the solenoid lever or the setting lever is being moved
> to the position where the operating valve ball would normally be lifted off
> its seat.
> This conclusion is based upon your discovery that the pressure in the
> accumulator, as indicated on the gauge, does not leak away overnight.
> There is a small clearance between the operating valve push rod and the
> overdrive housing. If the operating valve ball was indeed lifted off its
> seat all the oil in the accumulator would, over time, leak past the
> operating rod thus discharge the accumulator.
> This process would indeed take some time but would certainly completely
> relieve most, if not all the residual accumulator pressure overnight.
> If however the operating valve ball is still in contact with its seat
> (i.e. not being lifted) the oil pressure would not reach the small
> clearance between the valve push rod and the housing and, other than past
> the accumulator rings there is nowhere for that pressure to be relieved.
> I would presume that Overdrive Spares installed an accumulator with an "O"
> ring rather than the original cast iron rings. If the original type
> accumulator piston was still fitted, oil would seep past the cast iron
> rings to relieve the pressure, albeit very slowly, and again the
> accumulator pressure would be discharged overnight..
> The cam on the operating shaft, the one which lifts the operating valve
> push rod and thus the operating valve ball, is locked to the shaft with a
> small taper pin. I would guess that the taper pin has either fallen out or
> sheared.
> Bad news is that this pin cannot be accessed without removing and
> disassembling the overdrive.
>
> M
>
> On Sat, Apr 16, 2022 at 1:19 PM Simon Lachlan via Healeys <
> healeys at autox.team.net> wrote:
>
>> My OD is driving me mad and I definitely need some inspired advice. A bit
>> of background first. I’ll try to lay out all the facts in a logical
>> sequence. (I’m increasingly reluctant to link ODs with logic!)
>>
>>    1. I’d say that the OD has done +/- 15k miles since a total rebuild
>>    by Overdrive Spares here in UK.
>>    2. The OD had issues before Christmas (21) and was sorted out by OD
>>    Spares. The accumulator was uprated and pressure issues sorted.
>>    3. OD functioned 100% on the few times I’d been able to take it out
>>    since then until..
>>    4. One day, the OD stopped functioning.
>>    5. I checked the electrics. All fine there so I delved a bit deeper.
>>    6. It had fried its solenoid which I replaced. But…
>>    7. That did not fix the problem so…
>>    8. I decided that the operating valve’s adjustment might be off so..
>>    9. I bought a dial gauge and hoped to sort it out precisely rather
>>    than by “feel”, which I lack in this area.
>>    10. Prior to using the gauge I decided to see if the OD was
>>    functioning at all so I raised the car on stands and fitted my pressure
>>    gauge.
>>    11. I get a reading of 500psi rising a bit when I rev the engine but
>>    I’d suppose that would drop when the oil warms up.
>>    12. BUT, and this is where things go pear-shaped…moving the little
>>    lever on the RHS up and down does not engage/disengage OD. There is no
>>    change on the gauge to show OD engaging or disengaging.
>>    13. AND, the gauge stays at 500psi even when the engine is off.
>>    Moving the lever 20 times has zero effect. Stayed at 500 overnight!
>>    14. Of course, I checked for dirt in the operating valve area. None.
>>    15. Likewise, the tiny hole in the “valve – operating” (the spindle
>>    thing which the ball sits on)….that’s clear. And surely, the pressure would
>>    diminish overnight if something in that area was partially obstructed?
>>    16. When I remove the pressure valve, there’s a small spillage – no
>>    more than you’d expect – but repeating the pressure gauge process only
>>    returns the same results.
>>    17. I see in the bible according to Norman Nock that “Holding this
>>    lever with your thumb and index finger, you should be able to push the
>>    lever down lightly about ⅜” until you feel a slight spring pressure
>>    resistance. The lever should go down another ¼” after encountering the
>>    resistance……” ie there’s about ⅝” movement up & down in that lever. Well,
>>    my lever does move and does lift the ball, but there’s not ⅝” movement
>>    there. Could that be the problem area???
>>    18. Almost finished…keep reading!
>>
>> So, I’m stumped. Every time I learn something new about the OD, it has a
>> new trick to baffle me.
>>
>> I’ve no 100% sure way of telling whether it’s gone into OD  and stuck
>> there or whether it’s simply not going into OD at all.
>>
>> I’ve done a lot of reading through my books and collection of advice from
>> the various gurus and found reference to ODs being stuck but those seemed
>> to be to do with “weak springs” which, particularly after a long lay-off,
>> wouldn’t disengage. The cure for this being a good smack on the steel plate
>> sandwiched in the OD from below. Well, that seems to be a stuck mechanism
>> issue whereas I’m facing a hydraulic conundrum. Or am I?
>>
>> There is what is usually referred to as the “pressure relief valve”
>> adjacent to the accumulator. The name suggested that pressure might be
>> stuck in that area….but surely not overnight?
>>
>>
>>
>> Any ideas? I am particularly reluctant to take the gearbox and OD out.
>> You’ll recall the ridiculous business of the defective clutch kit? Well, I
>> forget whether we had the box in and out 3 times or 4. I’d hoped not to do
>> it again so soon or ever for that matter.
>>
>>
>>
>> I’m hoping for a miracle of course but some sound advice would be a
>> godsend…………
>>
>>
>>
>> Thanks,
>>
>> Simon
>>
>>
>> _______________________________________________
>> Support Team.Net http://www.team.net/donate.html
>> Suggested annual donation  $12.75
>>
>> Archive: http://www.team.net/pipermail/healeys
>> http://autox.team.net/archive/healeys
>>
>> Healeys at autox.team.net
>> http://autox.team.net/mailman/listinfo/healeys
>>
>> Unsubscribe/Manage:
>> http://autox.team.net/mailman/options/healeys/michaelsalter@gmail.com
>>
>>
> _______________________________________________
> Support Team.Net http://www.team.net/donate.html
> Suggested annual donation  $12.75
>
> Archive: http://www.team.net/pipermail/healeys http://autox.team.net/archive/healeys
> Healeys at autox.team.nethttp://autox.team.net/mailman/listinfo/healeys
>
> Unsubscribe/Manage: http://autox.team.net/mailman/options/healeys/bspidell@comcast.net
>
>
> _______________________________________________
> Support Team.Net http://www.team.net/donate.html
> Suggested annual donation  $12.75
>
> Archive: http://www.team.net/pipermail/healeys
> http://autox.team.net/archive/healeys
>
> Healeys at autox.team.net
> http://autox.team.net/mailman/listinfo/healeys
>
> Unsubscribe/Manage:
> http://autox.team.net/mailman/options/healeys/michaelsalter@gmail.com
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/healeys/attachments/20220417/d6d7d4b6/attachment.htm>

More information about the Healeys mailing list