[Mgs] Determine build date for an O/D transmission?

Mon Nov 11 12:44:16 MST 2019

The '78 dash has an "Accessory Switch" that can be added.  I have a factory
blanking plate over that switch right now. If I go with the dash switch,
that is where it will go. I would like a light as well, but I prefer the
correct look.

I will probably pull the lever off of my non-O/D and use it, at least
initially.  I will need to run the wires. If the wiring wasn't already a
mess on this car from the PO, I would be more concerned about it being
correct and using the shifter switch

(That and it is a CBB '78, so I am not that concerned apparently)

--
Andrew

On Mon, Nov 11, 2019 at 12:06 PM Max Heim via Mgs <mgs at autox.team.net>
wrote:

> It just occurred to me that this may not be as easy on a later car. A
> metal-dash car already has the hole in the dash for the toggle switch.
> There is probably not a handy hole in the 78 dash, and the “vintage-style”
> chrome-bezel toggle switch would look out of place.
>
> For a while I had a Radio Shack “glowing blue” toggle switch installed (to
> remind me to switch off the OD), which might look more in keeping with the
> plastic dash. I was a little dubious about it handling the load, but it
> held up fine. The solenoid doesn’t draw much. I don’t really think there is
> any reason to run a relay, or the vacuum switch — a simple ON/OFF in series
> with the lock-out switch on the transmission works fine.
>
> I don’t understand how a momentary push button switch (Bert’s suggestion)
> would even work...
>
>
> --
> Max Heim
> '66 MGB
>
>
>
> On Nov 11, 2019, at 9:32 AM, Max Heim via Mgs <mgs at autox.team.net> wrote:
>
> Exactly. I have a 1977 vintage blue label OD transmission in my 66. I have
> a dash-mounted switch to the left of the steering column. The wiring
> couldn’t be simpler. No weird expensive parts. The straight (as opposed to
> crookneck) dash OD switch is cheap.
>
> You might not think the dash switch is as convenient as the gear lever
> switch, but it is really pretty ergonomic. You can flick it with the side
> of your hand while it is still in contact with the wheel — you don't have
> to go groping for it.
>
> --
> Max Heim
> '66 MGB
>
> On Nov 11, 2019, at 8:08 AM, Charley Robinson via Mgs <mgs at autox.team.net>
> wrote:
>
> I've swapped OD gearboxes into two CBBs.  In both cases I used the gear
> levers from the original non-OD transmissions.  I don't see any reason that
> you can't use the gear lever you already have for the OD box.
>
> As to the OD switch, I'd put it on the dash if I had an open spot for it
> that was handy to my right hand.  In the CB cars the wiring and switch are
> already installed but there's no reason you can't find the white circuit
> that Paul mentioned and run a wire from it to your switch and from the
> switch to the lockout switch on the OD box.  Looks like there are a couple
> of switches in the Moss catalog that would look OK on the dash.  The switch
> is just a SPST that can handle the solenoid current.
>
> My $ .02,
>
> CR
>
> On 11/11/2019 7:35 AM, Andrew Lundgren via Mgs wrote:
>
> I have a '78. The transmission is a blue label, but the seller doesn't
> have the shift lever.
>
> A lever for a '78 is not a cheap thing, and my son who is driving it a lot
> right now likes the Walnut MG logo shifter it has.  So I'm looking at
> options for how to install the O/D switch.
>
> From the moss catalog, it looks like the '76 switch won't work with the
> '78. So I might have to buy the parts to put together the shifter switch or
> put it in the blank accessory switch above the fan on the dash.
>
>
>
> On Mon, Nov 11, 2019, 1:45 AM PaulHunt73 <paulhunt73 at virginmedia.com>
> wrote:
>
>> None of that is to do with the OD itself.
>>
>> Which gears it operated on is a function of the linkages on top of the
>> gearbox, and you can have it on 3 and 4 or 4 only as you wish.  When the
>> TCSA was introduced in late 76 to control 'surging' a third switch was
>> added to the top of the gearbox that operated in 2nd and 4th, and this was
>> wired in series with the OD switch operating in 3rd and 4th to produce a
>> 4th gear only output controlling the TCSA and vacuum advance.  I suspect
>> that was not very reliable as it was an external micro-switch so it was
>> deleted and the gearbox components changed so the switch operated in 4th
>> only, as done to the V8 several years previously.  The gearbox switch now
>> controlled both OD and TCSA.
>>
>> The gear lever itself changed for the 77 model year to incorporate the OD
>> manual switch, but that can also be fitted to any year, or the 77 converted
>> back to some other switch, as you wish.
>>
>> The wiring prior to 77 was from the manual switch on the dash or the
>> column, to the gearbox switch on a yellow and a yellow red, then from there
>> to the solenoid.  For 77 on it was from the ignition supply on a white to
>> the gearbox switch, then from there to the manual switch on the gear lever,
>> and from there to the solenoid.
>>
>> Black label or blue label determines which speedo is compatible - black
>> label was used on CB cars and used a 1280tpm speedo.  Blue label was used
>> on RB cars and used a 1000tpm speedo.  But speedos can be recalibrated if
>> you end up with the wrong combination.
>>
>> So as a 78 it should have a blue label OD and the manual switch on the
>> gear lever, as the column switch - which together with the plastic dash was
>> new for the 77 model year - won't have that function.  But if the car has
>> the earlier RB dash and column switches you don't need the gear lever
>> switch, which is prone to shorting out and causing harness damage.
>>
>> PaulH.
>>
>>
>> ----- Original Message -----
>> Not so much. It will be a a bit still until the transmission arrives.
>> (Freight from NY to UT) I'm just trying to figure out which shifter it
>> should have had as well as which gears it should work on.
>>
>> I'm going to be putting it into a 78, but the current owner is still
>> trying to track down the shifter from his friend, the previous owner. He
>> doesn't know if it was a late shifter or an early one.
>>
>> I'm trying to determine how to wire it in.
>>
>>
> _______________________________________________
> Mgs at autox.team.net
> Donate: http://www.team.net/donate.html
> Suggested annual donation  $12.75
>
> Archive: http://www.team.net/pipermail/mgs http://autox.team.net/archive
>
> Unsubscribe: http://autox.team.net/mailman/options/mgs/charley38@twc.com
>
>
> _______________________________________________
>
> Mgs at autox.team.net
> Donate: http://www.team.net/donate.html
> Suggested annual donation  $12.75
>
> Archive: http://www.team.net/pipermail/mgs http://autox.team.net/archive
>
> Unsubscribe: http://autox.team.net/mailman/options/mgs/mvheim@sonic.net
>
>
> _______________________________________________
>
> Mgs at autox.team.net
> Donate: http://www.team.net/donate.html
> Suggested annual donation  $12.75
>
> Archive: http://www.team.net/pipermail/mgs http://autox.team.net/archive
>
> Unsubscribe: http://autox.team.net/mailman/options/mgs/mvheim@sonic.net
>
>
> _______________________________________________
>
> Mgs at autox.team.net
> Donate: http://www.team.net/donate.html
> Suggested annual donation  $12.75
>
> Archive: http://www.team.net/pipermail/mgs http://autox.team.net/archive
>
> Unsubscribe: http://autox.team.net/mailman/options/mgs/lundgren@byu.net
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://autox.team.net/pipermail/mgs/attachments/20191111/9991b19a/attachment.htm>