[Healeys] Overdrive pressure or clutch slip Step 2!
Bob Spidell
bspidell at comcast.net
Fri Apr 26 21:36:03 MDT 2024
re: "The solenoid makes a healthy click and visibly lifts the lever, say, ¼”
Sorry if this has been covered, but how did you adjust the lift on the
operating valve? The typical 'stick a drill bit in the hole on the side
opposite the solenoid' technique is known to be unreliable, the best way
is to measure lift at the operating valve/shaft; 1/32" is the correct
distance IIRC.
Bob
On 4/26/2024 4:15 PM, Simon Lachlan via Healeys wrote:
>
> Bob,
>
> Thanks for this.
>
> I’ve determined this much:-
>
> After, say, 5 miles the car started slipping in/out of OD. It was a
> slower in/out than one would obtain with the dashboard switch. Sort of
> slipping in/out. Not “dropping out” so far as I can determine.
>
> Per Michael’s advice, I removed the operating valve and charged
> up/down hills and along a Motorway. No slippage. At all. I concluded
> that the clutch on the flywheel was not slipping. (TG, as it’s
> practically brand new).
>
> I then replaced the all the valve components under a gauge, jacked the
> car up/wheels off the ground and spun up the engine..into gear and
> switched on the OD. A steady 500psi which remained steady with the
> engine off until I engaged/disengaged the OD a few times. Which, from
> memory, is what one would expect. At this stage I cleaned out the rod.
> No dirt detected in little hole but could easily miss a flake of paint
> or a piece of swarf……
>
> The solenoid makes a healthy click and visibly lifts the lever, say,
> ¼”. Appears(!) healthy. OD seems to go in and out as it should and not
> slip but wheels are off the ground so not a fair test for slippage.
>
> The whole OD was rebuilt, by OD spares about 15 years ago since when
> it’s had a fairly relaxed time and about 15,000 miles. Very seldom
> more than 80mph and usually cruising at 65mph on Motorway. The front,
> pump end, was rebuilt by ODSpares in late 2021. Car has a 28% OD and a
> 3:54 diff so 65mph is fairly relaxed rev wise.
>
> Have not delved into Throttle Switch, Relay or Solenoid yet. Will do
> so, in that order, when weather permits test drives.
>
> Thank you everyone for your help and attention in this matter,
>
> Simon
>
> *From:*Healeys <healeys-bounces at autox.team.net> *On Behalf Of *Bob Spidell
> *Sent:* Friday, April 26, 2024 7:17 PM
> *To:* gradea1 at charter.net; healeys at autox.team.net
> *Subject:* Re: [Healeys] Overdrive pressure or clutch slip Step 2!
>
> I lost the plot (not unusual): Have we determined, for sure, that the
> problem is 'slippage,' which would most likely be due to wear in the
> O/D cone clutch? Or have we determined that Simon's O/D is 'dropping
> out' which, to my thinking, would be caused by the 8 strong springs
> overcoming hydraulic pressure (and causing the brake ring to slip or
> disengage, no?).
>
> On 4/26/2024 10:03 AM, Hank Leach wrote:
>
> Ok the pressure gauge implies that the hydraulic system is in good
> condition and that will effectively produce overdrive when the
> cone clutch is pushed forward in the box. When OD is *not
> required* the solenoid is inactive and the 8 springs in the unit
> have to keep the cone clutch in the rearward or in direct drive
> position.
>
> These are stout springs and normally are strong enough to engage
> and hold the clutch without slipping, overcoming the hydraulic
> influence-which should be draining at this point..However if the
> springs are misinstalled in the wrong position or not properly
> mounted on their tabs upon assembly or previously "coil bound"
> from that procedure or wear, they will not function to keep direct
> drive solid without slipping.
>
> The clutch material should outlive all of us and is not normally,
> or easily, replaced. All you have to keep the car in direct drive
> are those 8 springs and their pressure.
> -Hate to say it but if the re-assembly was defective, the gearbox
> needs to come out and OD removed and checked for correct spring
> fit-at that time I would replace the 8 springs (about $100 from
> Moss) as a routine repair. (photos from my article in AH Mag) Hank
>
> From: "Bob Spidell" <bspidell at comcast.net>
> <mailto:bspidell at comcast.net>
> To: <healeys at autox.team.net> <mailto:healeys at autox.team.net>
> Sent: April 26, 2024 at 9:37 AM PDT
> Subject: Re: [Healeys] Overdrive pressure or clutch slip Step 2!
> Spitballing ...
>
> I went through my BJ8's O/D a few years ago. The car had 64K miles
> on it when I bought it (approx. 1984), and about 215K* miles on it
> when I did the overhaul. The O/D cone clutch was serviceable--and
> AFAIK didn't slip--and I reinstalled it. If new cone clutches were
> readily available I /might/ have bought new, on principle,
> depending on cost, but all I could find was a re-manned one from
> DWM. To me this implied they didn't often need replacement,
> whereas known wear items like the accumulator are offered by
> several vendors (I would have installed one with an O-ring if I'd
> known about it).
>
> All this to say, unless the car has extremely high mileage and/or
> the O/D has been abused somehow I'd be surprised if the clutch is
> worn 'to the bone.' Obviously, slippage in the cone clutch would
> cause Simon's car's symptoms; if so, the problem will get
> progressively worse (and more consistent). I think one way to test
> an O/D clutch would be to really lug the car pulling an uphill
> grade in 4th-O/D, if the clutch is going to slip it would do it
> then (as would a worn engine clutch). There's also a (remote)
> possibility that, for some reason, O/D pressure fluctuates during
> driving.
>
>
> * Anyone else have this many or more known miles on a Healey?
>
> bs
>
> On 4/26/2024 4:51 AM, Michael Salter wrote:
>
> "What I can’t do is understand the leap to the OD cone clutch?"
>
> Fair question.
>
> Between the flywheel and the rear wheels there are only 2
> places where "slippage" can occur these are the clutch and the
> overdrive's cone clutch.
>
> The gearbox, other than the cone clutch in the overdrive, is a
> go/no go arrangement, i.e. no "slippage".
>
> The rear wheel splines, believe it or not, can also produce
> "slippage " if they are in really bad condition but I presume
> that isn't the case here.
>
> The test that you just completed resulted in no driveline
> slippage when the overdrive was disabled.
>
> You are reporting slippage when the overdrive operating system
> is enabled so it follows that further diagnosis of that is
> required.
>
> Yes, your next step would be the same test drive, i.e. full
> engine torque on an uphill grade, to confirm that the slippage
> issue has returned now that the overdriveoperating valvehasbe
> re-installed.
>
> I would do this test drive BEFORE making any adjustments to
> the overdrive valve or solenoid in order to confirm that
> meerly installing the overdrive operating valve resulted in
> the slippage issue returning.
>
> Hope the weather improves, beautiful day here.
>
> M
>
> On Fri., Apr. 26, 2024, 7:24 a.m. Simon Lachlan,
> <simon.lachlan at alexarevel.plus.com> wrote:
>
> Hi, Thanks for this.
>
> Not sure I understand fully.
>
> Once I’d finished the test drive with the OD operating
> valve out of the car, I returned the rod, ball, spring etc
> and put in the gauge rather than the nut. And got 500+ psi.
>
> What I can’t do is understand the leap to the OD cone
> clutch. Not arguing…just saying no comprende. As I sat in
> the car, I was thinking that the function of the OD seems
> OK and that it’s being interfered with by something in its
> circuitry……relay, solenoid or throttle switch. That’s
> probably wishful thinking as I really don’t want to be
> swimming in those waters.
>
> I did, as a matter of course, clean out the tiny hole in
> the rod but didn’t detect any blockage….which doesn’t mean
> much as something minute could have been inside and been
> washed away by the detergent/hot water then WD40…..
>
> After someone’s advice – some time back – I’ve got another
> rod whose aperture has been drilled out to 1.5mm. This was
> “to allow the OD to disengage faster”. Don’t recall if I
> tried it. Could that rod be any help here?
>
> The ball seems to be sitting square on its seat and the
> tip of the rod, where the ball sits, is not worn or chipped.
>
> Residual pressure….. goes to 500+ when I switch OD ON and
> stays there until, engine and switch OFF, I energize the
> solenoid a few times whereupon it drops to zero.
>
> Another test drive(s) seems called for. But the hood is
> off to enable access and the forecast is grim for the next
> week.
>
> Very open to more suggestions. Thanks,
>
> Simon
>
> *From:*Michael Salter <michaelsalter at gmail.com>
> *Sent:* Friday, April 26, 2024 12:14 AM
> *To:* Simon Lachlan <simon.lachlan at alexarevel.plus.com>
> *Cc:* Healeys <healeys at autox.team.net>
> *Subject:* Re: Overdrive pressure or clutch slip Step 2!
>
> Okay, then it is confirmed that neither the clutch (on the
> flywheel) nor the overdrive cone clutch (in it's normal
> drive condition) are producing the slippage.
>
> From this we can conclude that even when the overdrive
> solenoid is *_not_* energized the slippage is occurring at
> the overdrive cone clutch and that for some reason
> hydraulic pressure is finding its way into the overdrive
> operating cylinders even when the overdrive operating
> valve is closed.
>
> This can be caused by leakage past operating the valve or
> residual pressure.
>
> The question of residual pressure can be resolved by
> checking that the bleed hole in the bottom of the long
> overdrive valve push rod is not blocked.
>
> Whether or not hydraulic pressure is leaking past the
> operating valve ball can be checked by ensuring that the
> ball is clearly on its seat when the operating valve is
> *_not _* energized.
>
> M
>
> On Thu., Apr. 25, 2024, 3:38 p.m. Simon Lachlan,
> <simon.lachlan at alexarevel.plus.com> wrote:
>
> Of course. Isn’t that how I got the 520psi?
>
> *From:*Michael Salter <michaelsalter at gmail.com>
> *Sent:* Thursday, April 25, 2024 6:19 PM
> *To:* Simon Lachlan <simon.lachlan at alexarevel.plus.com>
> *Cc:* Healeys <healeys at autox.team.net>
> *Subject:* Re: Overdrive pressure or clutch slip Step 2!
>
> Question ... when you got home and did the pressure
> test I presume that was AFTER you had put the valve
> with the "top hat", ball, spring and valve rod cap and
> washer back into position?
>
> M
>
> On Thu., Apr. 25, 2024, 12:29 p.m. Simon Lachlan,
> <simon.lachlan at alexarevel.plus.com> wrote:
>
> So, here is Michael’s “Step 1” completed. (See his
> email, below).
>
> 1. Removed the operating valve and, just for
> luck, disconnected the two wires into 3^rd
> /4^th switch. Took the car for a spin. Up/down
> longish/steepish hills, 10 miles on motorway.
> Various rpm…..no slippage at all.
> 2. Had a puncture…..nail in tyre. Rear RHS. Flat
> as a pancake at once. Nearly onto rim. Nail! I
> imagine the inner tube is shredded and the
> tyre may be a write-off. (Usually are!).
> Anyhow, I bore you with this as I’m convinced
> that I’d never have got the wheel off without
> the little scissors jack which I carry to get
> the car up the first few inches until the
> Healey jack comes into play. Just a suggestion…….
> 3. Got home and jacked car up to test pressure.
> Steady at 520psi which, I recall, is plenty.
> Stayed at 520 across rev range. Dropped very
> slowly once engine was off and dropped to zero
> as I engaged/disengaged OD a few times. Which
> is normal I think?
> 4. Solenoid makes a robust “click” when it should
> and engages the OD when activated.
>
> So what’s a sensible “Step 2”??
>
> I have been urged to check the setting of the
> Throttle Switch (TS). Assuming that the slippage
> returns (and why wouldn’t it?), I’ll short the TS
> out to see if that fixes it. If it does, I’ll
> check the adjustment.
>
> Suggestions would be more than welcome……I do dread
> having to take that box out again. I’ve got a very
> adequate ramp and a very strong volunteer(?) but,
> regardless of all that, it’s still quite a task.
> And, like a few of us, I’m not as young as I once
> was. I’ve always enjoyed the lines from the manual
> which I reproduce, below. ���Gently ease”!?!
>
> Thanks, Simon
>
> *From:*Michael Salter <michaelsalter at gmail.com>
> *Sent:* Monday, April 22, 2024 3:21 PM
> *To:* Simon Lachlan
> <simon.lachlan at alexarevel.plus.com>
> *Cc:* Healeys <healeys at autox.team.net>
> *Subject:* Re: [Healeys] Overdrive pressure or
> clutch slip
>
> *_Correct diagnosis is 1/2 the repair!!_*
>
> First you need to confirm whether the clutch (on
> the flywheel) or the overdrive is causing the
> slippage.
>
> To do this you ABSOLUTELY MUST disable the
> overdrive as a badly misadjuster overdrive
> operating valve can produce similar symptoms.
>
> To do this I would remove the overdrive operating
> valve completely. (There are other ways but this
> is absolutely definitive).
>
> Now drive the car up a long hill where you are
> amle to use full throttle at around 3000 RPM
> (maximum torque) for a few seconds. If it is the
> clutch (on the flywheel) that is causing the
> slippage these operating conditions. Test this a
> few times to be sure.
>
> If there is no slippage we have confirmed that the
> overdrive clutch is at fault.
>
> Step 1 completed. Please report results. MS.
>
> On Mon., Apr. 22, 2024, 8:08 a.m. Simon
> Lachlan via Healeys, <healeys at autox.team.net>
> wrote:
>
> You may recall the very extended overdrive
> and clutch saga last year. Long story
> short(ish)…
>
> OD was slipping in and out depending on
> oil temperature.
>
> Correctly diagnosed pressure. Checked with
> gauge.
>
> Attempted rebuild…going only so far as
> accumulator and related seals.
>
> Stymied as could not get pump out. Turned
> out to have been “fixed” at some stage
> with some form of “chemical metal” which
> was coming loose/apart.
>
> Took it up to OD Spares who fixed it..new
> housing etcetc
>
> Why not a new clutch I thought? Sensible
> while you’re in the area looking at a 30+
> yr old item.
>
> New clutch…no good. Noisy, wouldn’t
> engage/disengage/play at all.
>
> Gearbox out again.
>
> Refit clutch. Presumed I’d made some
> beginner’s mistake.
>
> Refit gearbox…no good. Same
>
> Can’t recall whether I tried again. Lost
> count and enthusiasm by now.
>
> Turned out that the new clutch kit was
> defective. (Thanks Mirek) (Genuine B&B
> from AHSpares).
>
> New one did work.
>
> Saga over until yesterday.
>
> Same sort of symptoms…..
>
> All’s well for first 10 or so miles. Then
> the dreaded slippage(?) starts. But it’s
> not quite the same. Reminds me more of a
> slipping clutch. (But NO smell)
>
> Symptoms continue if it’s in or out of OD.
>
> Symptoms reduce at speed.
>
> Yes, plenty of oil. Over the full mark.
> Looks very clean. Pretty sure it’s 40wt
> non-detergent topped up with 30wt
> non-detergent. (Or vice-versa). Am
> confident in state of the filter, magnets etc.
>
> No, I have not pressure tested it yet and
> yes, I dread restarting the whole bloody
> process all over again. I’m not sure I can
> face taking the box out again once, let
> alone multiple times.
>
> What I want and experience tells me I’m
> unlikely to get is a miracle cure!
>
> One initial question…..do OD relays either
> work or not work? ie, can the relay hover
> between on and off which might lead to the
> OD coming in and out? I think that could
> happen if the switch is off but the unit
> still hasn’t got the message to disengage
> from the bulkhead switch.
>
> And a supplementary….how do I bench test
> the relay?
>
> Simon
>
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