Overdrive 6RA 31199 Relay Modern Alternative

thowman

New Member
After a lot of trial and error, I have discovered that the Speedy Spares supplied Relay for the automatic disconnecting overdrive arrangement, as fitted to most post 1965ish Rootes vehicles with Overdrive, comes with incorrect instructions.

If you are wiring an Overdrive into your van, and have the two direction momentary switch as fitted to Rootes vehicles - then you need to wire the relay in this way:



Note: There needs to be a loop wire between terminals 85 and 87. Also, from terminal 86, apart from the Yellow and Green wire coming from the Direct Drive side of the switch, there needs to be a wire to an earth with a resistor in it. If there isn't a resistor there, it will be shorting the circuit out, and possibly blow the fuse. I used a warning light as a resistor temporarily until I purchase a suitable one.

There is no wire fitted to terminal 87a.

Cheers

Andy
 

Panky

Administrator
Staff member
Excellent bit of work, that problem has flummoxed a few people:I


How refreshing
 

nickclubman

Active Member
Hmmm. May well be following this diagram this weekend. Any suggestions for a suitable dwitch? Cheers Mr.Thow
The only odrive switches I can see on eBay only have two wires to them.
 

thowman

New Member
quote:
Originally posted by nickclubman

Hmmm. May well be following this diagram this weekend. Any suggestions for a suitable dwitch? Cheers Mr.Thow
The only odrive switches I can see on eBay only have two wires to them.




You can buy the switches & relays from Speedy Spares. Alternatively for switches, look for anything Rootes post 65, Reliant Scimitar or Rover P4 on ebay. The relays are a standard 5 terminal crossover (changeover) relay rated at 30A, and you could find them at about half the price SS sell them for if you look hard enough.

The beauty of this set up is that once you change down to 2nd gear, the OD - if still switched on - will disconnect.

Don't forget the resistor - the warning light I used as a temp fix is around 20 Ohms, and works fine.

Regards

Andy

Perhaps Admin would like to make this a sticky? I spent hours searching the internet for this without finding a decent correct diagram.
 

admin

Administrator
Staff member
Done - can I put it on the website mechanical section too?
Speak of which if anyone is bored and wants a project I should probably update that section of the website with stuff learned in the recent past
http://commervanfan.co.uk/mechanical.htm if anyone wants to trawl the forum for what they think might be of general use and document it and the URL to the thread that would be most helpful!
 

thowman

New Member
quote:
Originally posted by admin

Done - can I put it on the website mechanical section too?
Speak of which if anyone is bored and wants a project I should probably update that section of the website with stuff learned in the recent past
http://commervanfan.co.uk/mechanical.htm if anyone wants to trawl the forum for what they think might be of general use and document it and the URL to the thread that would be most helpful!



Sure, go ahead.

Getting this right has taken a couple of days of my time and an extra half tank of diesel while fitting a new loom in a customer's van. The overdrive worked previously, but when I copied the wiring into the new loom, it was working of sorts, but having left site, the van started to blow fuses - making the van unusable. So, I had to go back to sort this out, which I did yesterday.

In the mean time I spent a lot of time on the Internet trying to find out the correct wiring for the modern relay Speedies sell. Basically, there is nothing on the internet that is correct. I had to join the Sunbeam Alpine Owners Club of Anerica forum to get to see their diagram of how to achieve the same with 2 normal relays - but so far they still haven't approved my registration, and I haven't been able see the diagram they guard so well.

Having gone back to my client yesterday to resolve this problem - it was a make or break to get the overdrive working safely, and we replicated the wiring off the van, on the bench with another solenoid, and found that the wiring he had did work, but the lack of a resistor meant that when the relay coil was discharging and changing over by flicking the switch to turn the OD off, it was shorting out and the wires were getting very hot. So, it had previously been a very unsafe installation, although it worked as it was momentarily putting a lot of amps through the wire. It was then I realised that we needed a resistor in that earthing wire to dissipate the discharging current. OK, so he has a warning light in the place of a resistor at the moment, but at least it works and is safe.

So, I think this is the only absolutely correct diagram that there is for this application.

PS. Could you also change the wording of the subject to

"Overdrive wiring diagram using modern relay in place of Lucas 6RA 33199 relay"

to make it easier for other people looking for it on google.
 

Gladys Crew

Well-Known Member
I have build a few relays that work perfect using 1 5amp and 1 30amp relay they work perfect in Gladys, my Superminx and also I sent one to Colin for tigger which he says is working perfect to, :) you must use an inhibitor switch or you risk the chance of it been left on when you put it in reverse which will cause serious damage to the overdrive [V]

Gladys & Bernie
 

thowman

New Member
I am sure that those particular 6RA relays are plentiful and now remanufactured. However, they are not the correct relays for the Rootes OD application which require a momentary on and off from the switch, rather than having a switch that is either on or off (as per a Triumph OD).

The 31199 relays are a bit thin on the ground. The 33302 & 33213 you have listed are wired differently to the 31199 - although you could adapt the wiring as per my diagram to make them work in the same way as the 31199.

Cheers

A

A wandering commer blog - http://commerblog.wordpress.com/
 

Enigma

Active Member
So forgive me if I missed something Andy...where you said you need a resistor and you temp used a bulb/light .............is a bulb/light quite ok to use permanently? I think it's quite a good idea to have a warning bulb/light on the dash anyway...?

''COMMER'EnSayThat''
 

thowman

New Member
quote:
Originally posted by Enigma

So forgive me if I missed something Andy...where you said you need a resistor and you temp used a bulb/light .............is a bulb/light quite ok to use permanently? I think it's quite a good idea to have a warning bulb/light on the dash anyway...?

''COMMER'EnSayThat''






The warning light bulb was the only thing I had to hand at the time that would do the job when I was doing a fitting of a loom at my customer's place many miles from my workshop. The bulb only has current flowing through it when you depress the switch to disconnect the od.It prevents a current spike in the circuit.

If you want to wire a dash warning light into the circuit, connect it at one end to terminal 87, and the other to earth. That will stay lit when the overdrive is engaged.

I'll explain more at Pandy, if you make it.

A
 

Enigma

Active Member
If I make it?? thanks for the vote of confidence hahaha:D:D ...ok thanks Andy;)

''COMMER'EnSayThat''
 
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