Stag Cooling

In the current Feb/Mar 2016 Triumph World magazine there is an article by John Eklund from Sydney who drives his Stag as a daily driver. John is not on our Stag Forum and I noticed today that David Clark Automotive in Sydney is not on either. David is now. Maybe John is a client of David Clark. John’s Tahiti Blue does look very nice with his chrome 15″ wire wheels. I am a bit of a fan of wire wheels and one day I hope to have a set on our Stag.

John has written up 7 Modifications to aid the cooling of a Stag V8 in everyday traffic.

Modification 1:- I agree that a Smiths capillary type gauge is a very good idea. The dual gauge with an oil pressure gauge is the ideal. An idea that Andrew Richards came up with was to put a 50 ohm variable resistor (Potentiometer) in series with the wire that connects to the temperature sensor. Using a Thermal Infra Red Heat Gun the temperature at the sensor is obtained. Adjust the 50 ohm variable resister so that the needle is in a position in the gauge that would indicate the desired temperature. You might have for example, have 85 degs as mid way on your gauge. If the gauge moves above half way then there maybe an overheat situation. You can get a 50 ohm potentiometer for about $10 at Jaycar.

Modification 2:- Addition of an elec fan is a good insurance idea. I notice that John has removed his mechanical fan. Recently I was driving our Stag in 30 deg plus temperatures in heavy traffic when smoke appeared from my Davies Craig Elec Fan. The fan had failed big time. Luckily I have kept the OEM fan on the engine and after dealing with the burnt wires I was able to continue without any further incident. At this stage I have not replaced the Elec Fan as the OEM engine fan does the job. Image if I had removed the engine fan, I would have been going no where. My advice is not to rely purely on the Electric fans. The engine fan may rob a few horses from the engine but in the end who cares. We are not racing these cars.

Modification 3:- Secret Spoiler. Have to agree damn fine idea. Cheap, can’t be seen and works. In winter after fitting one of these I could not get the engine to run hot enough. The TCCV have 5 of these for sale at $55 each plus postage. See attached.

Modification 4:- Upgraded radiator. Our Stag still runs the standard radiator and no issues. The Werribee Radiator Man says that he can build a 3 core radiator to be more efficient than a 4 core. No need to spend the money on an alloy radiator.

Modification 5:- Expansion Bottle or Header Tank. Jim Ostergaard has fitted an expansion bottle off a VW Passat which runs on 22 psi. Jim has fitted his in the same place that John has. Disadvantage that you can’t easily get at the fuses. I have fitted one of Chris Spain’s (Stagweber UK) Alloy Header Tanks with float switch that sets off a buzzer if the water level drops. Can highly recommend the Stagweber Header Tank. Does not interfere with the fuse box.

Modification 6:- Elec Water Pump or other pump. Triumph Spares in Fairfield fitted a external mechanical pump to a TCCV Members Stag and it seems to work fine. From memory the pump was off a Mazda. As most of you know I had a pump failure when I was 100 KMs north of Melb in Oct 2012. There was a faulty batch of 12 vane pumps hit Australia but they had soft gears and they just wore away until they didn’t pump any more. Jim Ostergaard is the pioneer of fitting the Davies Craig Elec Water Pumps. Jim’s conversion features on the Davies Craig Website. I modelled my EWP conversion on the way that Jim did his Stag. The Digital Controller is set on 80 degs on our Stag and I don’t have any issues with the EWP. I personally think this is the best thing you can do to the Triumph V8. On a recent TCCV/ACT event to Griffith in NSW the temperatures ranged from 32 to 38 degs C. Damn hot on the ears with the roof lowered at 37 degs driving though Shepparton. Contact John Benson at Davies Craig (03 9369 1234 or 0418 130 600) for a great deal on their EWP. The Digital Controller can be wired to operate the Front electric fan. The best feature of the EWP is that it continues to run for a few minutes to prevent a heat overload in the engine. Via the Digital Controller the engine temperature can be adjusted to 75, 80, 85, 90 or 95 degs. No way I would fit the OEM mechanical pump to our Stag again. Leon Himmelfarb has relocated the alternator to the upper left hand side of the engine and fitted the EWP where the alternator was fitted.

Modification 7:- Radiator cowls are available new from Stagweber and are a good addition. I am looking to get one. I agree with John that the engine fan will give more horsepower if removed but will you notice the difference. The EWP will also give you more power but I have the EWP as it monitors water temp far better than the OEM pumps.

Everyone will have their ideas on getting their Triumph V8 to run reliable and cool. I change the coolant with Nulon green every 12 months. Radiators will deteriorate so keep an eye on flaky fins. Alloy radiators look great but the copper ones still last very well. The radiator in our Stag still looks like it may be the original one and I will look at replacing it this year.

In the engine I have been using Penrite’s new Triumph 20-40W oil. Runs out around $55 for 5 litres.

I guess this will generate some discussion with the group.

Cheers, Graeme


Hi Graeme

Yes it is OK to make my a/c article available to the forum. I did the a/c installation about 10 years ago, and the article has been circulated with the SA Club and to others who have enquired interstate. It is also on the SOC SA website (but in the member section). The installation was a lot of fiddling about, as can be seen from the article, but worth it in the end.

One thing I should say and I am copying Richard in on this is that if I had my time again I would investigate in more depth converting the standard heater box. There are a few reasons for this:

  • the factory heater / cooler box is mostly vacuum controlled, with some electrical and mechanical controls, which introduces many complexities. The vacuum and electrical control system is similar to the Series 1 XJ6, but with the added complexity that the Stag uses a single slider to control the heater, change the flaps, switch in the a/c and modulate the temperature – all too much!. After playing around with it off and on (and the controls are a sod to get access to) I decided to simplify the system and put in a separate heater knob (vacuum controlled), which effectively is what the XJ6 system uses. Before I was having trouble with the heater coming on with the a/c etc.
  • although sourcing a factory heater / cooler box made this part of the installation easier, getting the controls to operate effectively has been more problematical. Effectively I have made modifications to the original system to make it simpler and more reliable.
  • availability of the heater / cooler box (US mainly). I understand that most or many US Stags had a/c, but only a relative few Australian and UK Stags were ordered with it. I also understand that the factory heater / cooler boxes are now hard to come by. Mine was easy to come by at the time – a couple of phone calls, but I think I was just lucky. So once I located this unit there was no reason to investigate further converting the existing heater box.
  • I understand that a number of the later upmarket 2500’s had integrated a/c installed, in which the heater box was taken out and modified. This was done aftermarket in Australia. Although the Stag and 2500 heater boxes are not interchangeable (or so I have been told) it could be worth obtaining a 2500 one that has been converted to see if it and the controls could be cannibalised to modify a Stag heater box and controls. Alternatively a wander through a wrecking yard looking at other car heater / cooler boxes might be fruitful. Having said all that and the work involved I am pleased with what I have done, and it has made the car a lot more usable – we can go out in any weather, in particular very hot days. I also did not want to put in an underdash unit (where the parcel shelf is).

PS I think that the heater vacuum valve and knob I used was from a Rover 3500 (not sure now – I scrounged a couple of possible controls from a wrecking yard a few years ago but this was the only one I was happy to use. The Jag XJ6 heater control is a slider type and not readily adaptable. The location of the valve and knob (RH edge of parcel shelf) and the rest of the controls are shown in the attached photo.

Cheers Vic

Workshop Notes: Vic's Stag a/c install Workshop Notes: Vic’s Stag a/c install (452 KB)
Workshop Notes: Vic's Stag a/c install (photos) Workshop Notes: Vic’s Stag a/c install (photos) (395 KB)


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