J-type overdrive relay

[lordleonusa]

I am trying to determine exactly WHEN, or indeed WHY, Triumph stopped using a relay in the overdrive circuit on the GT6, Stag and TR6?

It seems to have occured about half way through production of the Mk.3 GT6, possibly at the same time that the J-type overdrive was introduced?

It has become apparent that it was a mistake on Triumph's part to eliminate the relay on the cars with the overdrive switch in the gear-knob, because the thin blue & brown wires which go up the center of the gearlever are far too thin to carry the current to the switch and hence have a bad habit of overheating, melting, short-circuiting and even catching fire!

I can only imagine it was an attempt to placate the 'bean counters' and try and save money near the end of production.

I can probably get close to a date as far as the GT6-3 is concerned, by looking up the commission numbers in my factory workshop manual, but I do not have one for the Stag or the TR6.

Thanks in advance for any help in this matter.

L

  

[Smallfry]

The "hold" current draw on the solenoid fitted to the J type is about half that of the one on the D type, and the "pull on" current draw is wayyyyyyy less.

Not enough to damage a switch directly, and as every manufacturer is always looking for ways of saving a few shillings........................

[lordleonusa]

Thanks very much for your reply.

It isn't the switch on the gear knob that is getting damaged, it's just the thin wires up the gear lever, the blue and brown ones that have the stereo speaker connectors on the ends.

L

[Richard B]

GT6 never had J'Type.

The Stag TR6 & 2000/2.5 all dropped the relay when they got the J'Type.

As Smallfry says;

Quote:

The "hold" current draw on the solenoid fitted to the J type is about half that of the one on the D type, and the "pull on" current draw is wayyyyyyy less.

same goes for the D'Type solenoid and the A'Type solenoid which the bigger cars had.  It's called Progress.  :-/

[gilesdive]

I suppose you could argue that if you don't need a relay due to reduced current, there is no point in fitting one as it gives you more connections to potentially give a problem.

Personally I would rather have a relay on it. I had problems with those pathetic little wires snapping on my Spit, but it became academic when the lever snapped and I fitted a dashboard switch for it (similar to MGB).

[lordleonusa]

[quote=Richard_B]GT6 never had J'Type.

That's interesting, it is my understanding that after KE20,0001, probably from September 1972 until the end of production in 1973, the GT6-3 did get the J-type overdrive, and at the same time lost the relay

[quote=Richard_B]The Stag TR6 & 2000/2.5 all dropped the relay when they got the J'Type.

I have studied all of the Stag wiring diagrams and ALL of them have the relay and a gear-knob overdrive switch, throughout the entire production from 1970-1978, although the overdrive itself changed from A-type to J-type in Sept 72, when it became standard fitment on all Stags.

The TR6 only had the steering column stalk overdrive switch, and again A-type, which changed to J-type in Sept 1972.

I don't have any information on the Saloon/Estate cars at the moment, but ISTR that they only got the gear-lever mounted switch.

L

[lordleonusa]

Further to my above message:

I have compared the wiring diagrams, for the cars above, and see that the Stag relay is wired a little differently from the [gt6 & gt6-2], which also differs from the early GT6-3, which again differs from the generic wiring diagram for an overdrive relay shown in my auto-electrics book.

I'm not sure which one is the best to use at the moment, but am investigating!

One thing that I am sure of is that an In-line Fuse (10 Amps?) should go between the LIVE feed and the relay.

The Lucas overdrive relay was # 126792 or the alternative # 141769A.

To add another level of confusion, the markings on the relays changed around 1991, (AFAIK).

The Lucas relay is marked as follows:

C1: Contact Terminal
C2: Contact Terminal
W1: Winding or Coil Terminal
W2: Winding or Coil Terminal

My auto-electrical book gives equivalents to the more familiar modern relays as follows:

C1 = 87
C2 = 30/51
W1 = 85
W2 = 86

BUT, believe it or not, I have an 'instruction publication' by Lucas # XXB734 showing something different, ie:

C1 = 30 (+feed)
C2 = 87 (normally open contact)
W1 = 86 (winding feed)
W2 = 85 (winding earth)

Now, that's curious! Surely, they cannot both be right?

Now we have a dilemma, four different overdrive relay wiring diagrams, for Stag, early GT6, late GT6 and generic and two variations of relay connection equivalents, surely they cannot all be correct?

Does anyone know what's going on here?  ??)

[Richard B]

Quote:

That's interesting, it is my understanding that after KE20,0001, probably from September 1972 until the end of production in 1973, the GT6-3 did get the J-type overdrive, and at the same time lost the relay

To quote Graham Robson Triumph Spitfire and GT6 "Documents preserved by the factory show that a change from Laycock D-type to the new J-type overdrive were proposed for 1974, but all GT6 owners know that this never happened, as the car was withdrawn from production at the end of 1973."

[lordleonusa]

That's very interesting!

My source is my factory workshop manual, the big red one, which clearly shows the GT6, from KE20,001 as having NO relay for the overdrive...

Surely, if those particular GT6s were still using the D-type O/D, then they MUST have used a relay?

Unless, of course the workshop manual was printed, with the expectation that the J-type was to have been included on the post-KE20001 cars, that seems a little unlikely though.

As for Graham Robson, I hardly trust anything that comes from him as being accurate any more.

Can anyone with a very late GT6-3 confirm one way or another if they actually got a J-type please?

I know that some of the late year Spitfire 1500's got the J-type.

Thanks

L



  

[Richard B]

I will agree that the Stag does not have a relay controlling the feed to the solenoid; however the OD wiring on the early Stags is fed from an ignition controlled relay and on the later Stags fed from the electric window relay! Maybe they were more concerned about the load on the ignition switch than the load through the OD switch?

Early Stags had A-type, late Stags had J-type.

The Mk I 2000/2.5 had the steering column switch, the MkII 2000/2.5 had the gearstick switch. All Mk I's and early MkII's had the A-type and the relay, the late MkII's had the J-type and no relay.

[lordleonusa]

My basic point with all this discussion is that some of the Triumphs fitted with the J-type did NOT have a relay fitted, and if they also had the gear-lever mounted switch, then the electrical load, and/or physical chaffing, on the small wires going up the gear-lever often cause short circuits & fires...this is confirmed by rarebits4classic's Bill's opinion in the overdrive relay thread from last March/April.

This is how mine suffered, and I am presently using a toggle switch instead of the gear-lever switch that I would like to reconnect, but I only have one spare set of gear-lever wires left.

It is my hope that if I retrofit a relay, using the wiring diagram for the GT6-3, up to c/n KE20,000, then I can give those small gear-lever wires a much better chance of survival.

Can anyone suggest a suitable in-line fuse ratting for the overdrive switced power supply?

And does anyone have any ideas about why there are different sets of equivalents, detailed above for the original relays W1/W2/C1/C2 and the new relays 85/86/87/30 ???
and which one is right!
  
L

[bodders1]

lordleonusa wrote:

... using a toggle switch instead of the gear-lever switch that I would like to reconnect, but I only have one spare set of gear-lever wires left.

If it's any help, rarebits Bill sells replacement OD gearstick looms for not a lot of pennies.  I believe he manufactures them himself.

[lordleonusa]

Thanks, that is a useful piece of information.

I'm waiting for Bill to finish his research into his uprated steering column UJs, one of which I intend to order, and I will probably add a few sets of gearlever od wires to that order to save postage to the USA, and replenish my supply.

L

[Glenn]

I seem to remember reading that the J-type solenoid has a very low current draw (although I haven't checked with my meter - if no one posts an approx figure I will measure this later).

I should imagine the gearstick wiring is adequate for the job, although possibly rather marginal.  However most cars I have seen have frayed cables where they enter the small connector at the O/D switch and I wonder if this is where the problem lies.  I'd imagine a bit of deft work with the soldering iron and some heat shrink would improve this area.  Can those small connectors be bought from anywhere - I've never seen them?

That the factory fitted J-types wired with no relay suggests that you don't need one.  However that's missing the point - it's your car and you should do the work that gives you maximum satisfaction and pleasure.  Of course there would be no harm in a retro fit relay if that's what you want to do.

Having inconsistent wiring instruction is certainly confusing.  However on a standard 4 terminal relay it would not matter if you swapped over C1 and C2.  Perhaps the polarity of the winding terminals doesn't matter either?

[lordleonusa]

RustSpot wrote: I seem to remember reading that the J-type solenoid has a very low current draw (although I haven't checked with my meter - if no one posts an approx figure I will measure this later).

L >>>That would be interesting to know. I still do not have a rating for the in-line power supply fuse?

RS >>>I should imagine the gearstick wiring is adequate for the job, although possibly rather marginal.  However most cars I have seen have frayed cables where they enter the small connector at the O/D switch and I wonder if this is where the problem lies.  I'd imagine a bit of deft work with the soldering iron and some heat shrink would improve this area.  Can those small connectors be bought from anywhere - I've never seen them?

L >>>The fraying/chaffing problem certainly exists, but so does the overheating/burning out problem, I have experienced both. ie: Burning with chaffing, and without chaffing!

L >>>From observation, due to the relative 'softness' of the thin blue & brown gear-lever wires plastic insulation, and the small number of copper wires within, I wonder if the actual wires stretch and break inside their plastic insulation, thus increasing resistance and causing the burning?    

L >>>I'm thinking that this could be part of the problem, because when newly fitted those small gearstick wires seem to last perfectly well for up to about two years without (apparent) problems?

L >>>Those tiny connectors are (German?) speaker connectors.

L >>>It has been very annoying to solve the fraying/chaffing problem then still experience the burning problem. I really like the gear-stick overdrive switch and am determined to give it one last try, but WITH a relay!

L >>>I like the heat shrink idea, heck we sell it at work, albeit in small overpriced packets, but I already have some.

RS >>>That the factory fitted J-types wired with no relay suggests that you don't need one.  However that's missing the point - it's your car and you should do the work that gives you maximum satisfaction and pleasure.  Of course there would be no harm in a retro fit relay if that's what you want to do.

RS >>>Having inconsistent wiring instruction is certainly confusing.  However on a standard 4 terminal relay it would not matter if you swapped over C1 and C2.  Perhaps the polarity of the winding terminals doesn't matter either?

L >>>That's what I thought, since there are several variations of overdrive relay wiring, that would suggest that they are interchangeable, as indeed would the Lucas internal diagram, It looks to me like C1 & C2 are interchangeable, and W1 & W2 may also be interchangeable?

L >>>Aren't there any electrical gurus on the board?

L >>>There don't seem to be any on the TSSC board either?

L

  

[heraldcoupe]

I have long been aware of different wiring arrangements for the D-type overdrive. The Vitesse and Spitfire Mk1-3 have different arrangements, both are logical and work fine. The looms are correspondingly different.

I've never been aware of J-types on GT6s from the factory, but my knowledge of the GT6 is largely from received wisdom, rather than my own research. A late edition of the Mk3 parts list should confirm if/when the J-type was fitted.

There are two primary causes for failure of the gearstick wiring. Firstly there is the obvious scope for chaffing where the harness exits through the gearstick. Less obvious is that the terminals to the switch can make contact with the metal gearknob if not pressed fully home. Either case can lead to electric shocks or fire.

Cheers,
Bill.

[bodders1]

lordleonusa wrote:

That's what I thought, since there are several variations of overdrive relay wiring, that would suggest that they are interchangeable, as indeed would the Lucas internal diagram, It looks to me like C1 & C2 are interchangeable, and W1 & W2 may also be interchangeable?

L >>>Aren't there any electrical gurus on the board?

Not an electrical guru, but I did study electrical and electornic engineering at university 20 years ago, and been b*ggering around with computers ever since.

You can reverse the polarity of the winding in the relay coil with no adverse effects.  The current creates a magnetic field to attract a piece of soft iron and cause the mechanical movement to operate the switch inside the relay.  It doesn't matter which way round the magnetic field is oriented.

The J-type solenoid current draw is well within the safe working capabilities of the wiring and switch in the gearstick mounted overdrive switch as fitted 30 years ago.  Over time mechanical stresses can damage the sleaving (which hardens and can crack with age and cold)  
When refitted my overdrive wiring, I used wery thin heat-shrink sleaving to protect the small connectors at the top, and also a thicker piece to provide additional protection to the wires where they enter the gearstick.

hth
bodders1

[Glenn]

The gearbox on my 2000 is from an August 1974 registered car with J-type overdrive.  It draws 2.2 amps at 12.8 volts.  If this current is exceeded as the O/D engages, my meter isn't quick enough to register.  It doesn't visibly exceed this reading anyway.

The wires to the gearknob switch appear to be slightly finer than a reel of 4.5 amp (55W) automotive wire I have handy.  I don't want to cut it up to determine the thickness and number of strands so sorry I can't be more scientific.

[lordleonusa]

Many thanks guys for your helpful input to solve this issue.

L