I have decided to control it using the "Blue Relay" (PN 1259750-6) as described in several previous posts. I have sourced and obtained all of the the necessary parts to do this except for the drivers control switch. I plan to use a right side steering column based switch as did the 123GT and I would like it to appear "stock". My problem is that I require a momentarily on switch that meets these requirements and am banging my head on the wall in coming up with a solution.
All and any contributions would be greatly appreciated. Anybody have any ideas???
FF

I bought a momentary switch from a place on line that sells Triumph vintage parts. I'll look up the address etc if you need me to.

Is it on the steering column stalk like the original?? I like it that you think outside the "box". After all this O/D was used on almost every British car of the era!
Great idea. Please let me know their name if you are able to remember it..
FF

You will love the overdrive! It makes an already wonderful car even better. I used the headlight flasher switch in the turn signal switch along with two relays. It works beautifully. I had planned on adding an indicator light, but found I really didn't need one. Enjoy!

Thanks "Bud", I really can't wait.
FF

What O/D are you putting in? If it's a J-type, you don't need a relay (unless you insist on using a momentary switch). J-O/Ds are cool with direct wire to a on/off switch... such as one from a early 140.

Another nice option would be the right side stalk from an 1800 (along with the cool little pink light on the dash). That is momentary, and would require a relay. But they look good.

Using the headlight dipper switch on the floor... yea, you could do that. Personally, I would not. I like to depress the clutch (partially) when engaging the overdrive. Not that it's necessary, it just makes me happy to know the clutch is slipping a little, thus easing the full force of engagement on the O/D unit. And that's the same foot as the dipper switch, of course.

--
-Matt I ♥ my ♂

I hadn't realized that the 1800 OD switch is momentary. The 123GT is wired with an on/off stalk.
Its a D type unit. I know that what you said about no relay on the J type is correct but I never understood why. Anybody know?

Hello,

The "D" style solenoid initial amperage draw is high as it has to pull a mechanical linkage to engage the overdrive and therefore requires a relay.

Even the early 140 with a "D" style overdrive used a relay.

The "J" solenoid opens small fluid ports and requires far less amperage and does not have to have a relay.
--
Eric
Hi Performance Automotive Service (formerly OVO or Old Volvos Only)
Torrance, CA 90502

I hadn't realized that the 1800 OD switch is momentary. The 123GT is wired with an on/off stalk.
Its a D type unit. I know that what you said about no relay on the J type is correct but I never understood why. Anybody know?

the overdrive on off switch is not a momentary switch. If you remove the cover on the steering wheel thee is an undrilled reenforced area for the lever switch. I bought one new for $50 but can't remember from which usual suspect. even used one in my triumph.

I recently aquired a 1960 Volvo 121 & 122 Instruction manual. In it, it says that in order to engage the overdrive on a M31, use the pull down switch under the steering wheel.

Napa sells the exact switch: ECH PP6003 https://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=ECHPP6003_0215726176

Also, I was just thinking: have you moved the high beam switch from the foot switch to the indicator switch? It would actually be kind of nice to use the foot switch as the O/D switch. You could do a heel to toe with the clutch pedal and the foot switch. It would work great for down shifts.
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1959 Volvo Amazon 121

Now THAT is a really GOOD idea!!! Perfect. The switch is already there. It is redundant. It is momentary. I want the stalked headlight flasher. (So did the rest of the world) You have really made my day!!!
Thank You.
FF

I use the unused turn signal switch (the high beam switch) to activate my OD through a latching relay from a 240. I also use the green turn signal light for the OD on light (some diodes and resistors to dim the light). The high beam switch on turn signal stalk needs a relay to give the latching relay the right signal to activate. I have a writeup on how to set it up.

Paul
malloy1_at_prodigy_dot_net

¿So?
--
George Downs Bartlesville, Oklahoma