As many of you may already be aware, Cherri and I had some problems with the TR8 on our recent trip accross the Nullabor for the WA Nationals.
We endured a very hot day travelling from Eulca to Norseman, with the temperature gauge virtually off the scale, even with the air con off. There was nowhere to stop – no shade, no emergency help . . . nothing really, so we pressed on and hoped for the best. On arrival at Norseman, the radiator boiled as soon as we slowed down to enter the first servo in town. It was clear that the thermo fan was not working at all and clearly this was the main cause of our problems.
Their equivalent of our RAA were very efficient – the local guy was there within 10 minutes and his garage just a few blocks away. We got the car there after it had cooled down sufficiently and after a coolant refill, allowed it to cool overnight, and scheduled a review of the problems first thing the following morning.
Nothing would get the thermo fan to go, so a new one was needed. Luckily, the only fan that this place had in stock was exactly the same as the one fitted to my car. How lucky was that! This was fitted with consumate ease, and given that it is a “puller” rather that a “pusher”, care was taken to ensure that the polarity of the motor was reversed.
We also took the opportunity to check the thermostat, and even thought his seemed okay, we replaced it with a new and cooler one. The water pump appeared okay, so after settling up the bill, we were on our way to Esperance.
For the following week, the car behaved reasonably well, but on the hotter days, or when sitting in traffic just idling, it still sent the temp gauge way past where it should have been.
On getting the car back home (covered transport from Perth) I set about considering what else could be wrong that would cause the car to overheat. All sorts of theories were considered, such as was the timing out? If the timing is too far retarded, this will cause the engine to run hotter than it should. I had the gauge checked – no problems with that. So, looking for some divine guidance, I called Ian Wilson who agreed to have a look, and possibly get the car onto a dyno to check the E.F.I. settings under load and see what the cooling system was doing.
First thing we found was the gauge was clearly not reading correctly. But why? It checked out fine by the VDO gauge shop. Ian put a temporary earth cable between engine and body . . . . an immediate reduction of 15 degrees at the gauge! Now I am at best an amateur about car electrics, especially Lucas. But my understanding is that there is a voltage stabiliser gizmo installed in these things that may not necessarily work with after market accessories. This may well have been the reason that the VDO Oil Pressure Gauge also seemed to provide odd readings and had already been removed in favour of the standard oil warning light.
So the solution here was to remove the VDO gauge and go back to the factory temp gauge that had been previously disconnected. Ian stressed the importance of a factory sender unit – nothing else would do. So back in my garage, I set about connecting another earth strap between engine and body, and reconnecting the factory temp gauge.
But here is the scoop . . . . as I had just been reading the instructions for the installation of a puller fan in a Datsun 240Z that I am helping to build for a friend of mine, it occured to me that the guys who installed the fan to my car way back in Norseman had not reversed the fan blades. I do remember them saying, make sure that the polarity of the motor was reversed, but no mention of changing the fan blade around. So I took out the thermo fan and sure enough, the side that said “This side of the fan must face to the rear of the vehicle” was the wrong way around.
Now I must confess, I was of the opinion that when installing these gadgets as a retrofit, all that neede to be done was to reverse the polarity of the motor. Clearly, this is incorrect. After turning the blades around, the additional airflow was astonishing. Interestingly, the previous airflow sort of seemed to be okay, but as is now clearly demonstrated, it was producing just a fraction of the flow required to cool the engine properly.
So there you have it – all very simple in the end. Stick to the factory gauge and sender unit . . . there is nothing wrong with them. Make sure the engine is really well earthed, and follow the instructions when retro-fitting a thermo fan.
Oh, and as an aside, I had noticed that the cold start was not as instant and smooth as I remembered from my previous ownership of this car. Previously, it would start first time every time no matter what. Now it was taking sometimes three goes before it would assume an idle. But after installing the additional earth strap . . . guess what? Instant start up has resumed! So perhaps the voltage drain and insufficient engine earth was causing a bad reading in the computer? Ah, the mysteries of older cars will keep my brain active for many years, I’m sure.
See you soon in my “cooler” TR8.
Roger Lange
