Edmond Posted September 27, 2008 Report Share Posted September 27, 2008 My recently acquired TR4A (1965 model) has a non-overdrive gearbox. Given the betterment I found when I converted my MGB to overdrive I would plan to do the same with the TR. The steering column on my TR has 1 stalk on each side: lights on left, indicators on right I think - where would the overdrive switch go if there is an indicator switch already there???. Patently I'm missing something! Quote Link to post Share on other sites
ianc Posted September 27, 2008 Report Share Posted September 27, 2008 The overdrive switch is mounted on the right of the column, together with the trafficator switch. A special escutcheon (611974) is used to house the 2 switches. They are just visible in the photo on page 42 of Bill Piggott's "Original Triumph TR4/4A/5/6". Ian Cornish Quote Link to post Share on other sites
Tr4Tony Posted September 27, 2008 Report Share Posted September 27, 2008 Alternatively; i have relocated the choke cable pull on my TR4, and replaced it with a Revington TR toggle overdrive switch to actuate the OD .... very effective at speed and you can get to it with the fingers on your left hand whilst still on the steering wheel .... which is essential if you want to be ' quick through the bends' .... talk to RTR ... Regards Tony Quote Link to post Share on other sites
Edmond Posted September 27, 2008 Author Report Share Posted September 27, 2008 Ian - many thanks for putting me right. Much appreciated. Ed Quote Link to post Share on other sites
Edmond Posted September 27, 2008 Author Report Share Posted September 27, 2008 Tony - a very neat solution. Many thanks. Ed Quote Link to post Share on other sites
4Mal Posted September 28, 2008 Report Share Posted September 28, 2008 On my TR4, I have a long handled flick ( momentary switch ) located on the dash to the right of the steering wheel. This means I can flick the switch without my hands leaving the wheel. This is linked to a Revington logic box that means overdrive disengages on flicking the switch or when changing gear. There is also a warning light that shows me when overdrive is engaged and that is fitted where the more than useless Rheostat used to be. Quote Link to post Share on other sites
ianc Posted September 28, 2008 Report Share Posted September 28, 2008 Like Tony and Mal, I too have a Revington logic box and have mounted the flick switch on the right of the column as my trafficator switch is on the left of the column (as is standard on all modern cars, so avoiding confusion when moving from my Xantia to the TR). One can contrive a piece of bracketry to permit two switches to be mounted on the right of the column, with the stalks at different angles so as to avoid confusion. Because I have a non-standard steering wheel and could never stop the horn being activated without any action by me (not a good idea!), I moved my horn to a switch with a short lever on the right of the column, so I have both overdrive and horn switches on the right, but with different length arms and at different angles. Ian Cornish Quote Link to post Share on other sites
Edmond Posted September 28, 2008 Author Report Share Posted September 28, 2008 Tony/Mal/Ian = what type of overdrive units did you use? Original A type TR4A or 2000 saloon modified? Presumably the Logicbox would prevent any disasters when selecting reverse if having forgotten to disengage the OD (I was within a split second of doing that in the MGB today...the effects of not being used to having sunshine patently!). Quote Link to post Share on other sites
Tr4Tony Posted September 28, 2008 Report Share Posted September 28, 2008 My OD Unit is a TR / Stag a type competition unit. Similar to the 2000 but stronger clutch material, bigger accum. piston and 8 engagement springs instead of 4 (this is why a 2000 unit is NOT suitable for a TR in my opinion, even though it can be made to fir with judicious bodging). Irrespective of type (either A or J from any combination) the Revington Logic unit will work. Make sure you get a good quality momentary switch though and connect it up to the right polarity (negative) otherwise you will terminally damage the unit. Regards Tony Quote Link to post Share on other sites
Rhodri Posted September 28, 2008 Report Share Posted September 28, 2008 Edmond, if you engage reverse, or first, the overdrive should disengage as the inhibitor switches should only allow it to engage in 3rd, 4th, and if wired up 2nd. I guess the B would have the same system. Quote Link to post Share on other sites
ianc Posted September 29, 2008 Report Share Posted September 29, 2008 Revington's logic box is available in positive and negative earth versions, I believe (certainly was when I bought mine some years ago - you need to specify which version you need). Ian Cornish Quote Link to post Share on other sites
North London Mike Posted September 29, 2008 Report Share Posted September 29, 2008 My recently acquired TR4A (1965 model) has a non-overdrive gearbox. Given the betterment I found when I converted my MGB to overdrive I would plan to do the same with the TR. The steering column on my TR has 1 stalk on each side: lights on left, indicators on right I think - where would the overdrive switch go if there is an indicator switch already there???. Patently I'm missing something! Ed As an alternative I use a Works Healey mod with the switch on the side of the alloy gear knob. A little trick and very handy as its all done with the thumb and ideal for joint operation with a gear charge Quote Link to post Share on other sites
BrianC Posted September 29, 2008 Report Share Posted September 29, 2008 On my TR4, I have a long handled flick ( momentary switch ) located on the dash to the right of the steering wheel. This means I can flick the switch without my hands leaving the wheel. Just like the overdrive switch location on the sidescreen cars. I must admit I prefer this to the standard column-mounted overdrive stalk although I don't find it takes long to adjust to the different operation when swapping between my TR3A and Lynda's TR4A. What I do have a problem with is the floor-mounted dip-switch in both cars, and would love to have a dash mounted switch wired in parallel to allow use of either, but that's another story Quote Link to post Share on other sites
Edmond Posted September 29, 2008 Author Report Share Posted September 29, 2008 The logicbox seems a hard to ignore piece of kit, judging by the number of you that have it! This has got me thinking - what are the must have upgrades that a TR4A could benefit from in the interests of (a) greater reliability and ( efficiency in terms of either fuel consumption or performance? I want to keep the car as near original as possible and will use it primarily for touring with the necessity to do some motorway work. Lumention, alternator, overdrive? Ed Quote Link to post Share on other sites
67_gt6 Posted September 29, 2008 Report Share Posted September 29, 2008 Hi Edmond I too have a non-O/D 4A. I had an O/D on my GT6 so am well aware of the benefits however after 9k miles have yet to add it - most of my driving is city or country roads where I am happy to keep it on the cam in 3rd or 4th. See my thread on 'opinions sought on selling car' to see what I have done to mine - I would say that the must have is a good quality rear suspension telescopic damper conversion, although for safety's sake if it hasn't been done already you need to strengthen the front suspension lower fulcrum brackets. New carbs and a reconditioned distributor also made a massive difference to my car. andy Quote Link to post Share on other sites
BrianC Posted September 30, 2008 Report Share Posted September 30, 2008 (edited) ...what are the must have upgrades that a TR4A could benefit from in the interests of (a ) greater reliability and (b ) efficiency in terms of either fuel consumption or performance? I want to keep the car as near original as possible and will use it primarily for touring with the necessity to do some motorway work. Lumention, alternator, overdrive? If you are considering essentials: Lumenition: No - just make sure your distributor and points, rotor arm and cap are in good condition. Alternator: No - if you do a lot of night-driving with additional lights, then just fit the heaviest-duty/capacity battery you can find and the dynamo will suffice (also a lot more reliable and less sensitive to heat from the exhaust than an alternator. Overdrive: Yes, yes, yes! - this not only improves fuel consumption, but for many of us is one of the main joys of driving a TR. Edited September 30, 2008 by BrianC Quote Link to post Share on other sites
Edmond Posted September 30, 2008 Author Report Share Posted September 30, 2008 Brian - thanks. I think I will relegate Lumenition and an alternator to a possible phase 2, that is, I'll see how the dynamo and distributor get on. I'm so used to a 6 speed high geared diesel that driving a 4 speed manual, and a relatively low geared one at that, sounds really strained. Now to look out for a type A overdrive! Ed Quote Link to post Share on other sites
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