Tanks for the memories.

A couple of months have passed since my last update on the white car and, somewhat surprisingly, plenty has been done in that time. Of course, along the way more issues requiring attention have been unearthed and added to the jobs list, but that’s pretty much par for the course when dealing with 40 year old British automotive technology.

The last post ended with one of those ‘what the hell will I find in my crusty old fuel tank’ cliffhangers. Teased almost to breaking point by the suspense I set about removing it so that I could have a good peer inside. The tank is surprisingly simple to access and subsequently remove – the boot trim needs to be removed (mine was held in place by an interesting assortment of self-tapping screws) after which the tank appears in all its glory nestled just behind the rear seat.

Behold the beauty.

Before removing the tank, the gubbins connecting it to the car need to be detached. In no particular order there is the filler hose, the breather hose, the outlet pipe and the fuel gauge sender unit. None of these gave too much trouble – although it’s worth noting that removing the rear seat provides much better access to the clamps holding the filler hose onto the tank inlet. The sender unit is held in place by a circular retaining ring – it is released by simply driving it anti-clockwise via a rubber mallet and a flat-headed screwdriver located carefully on its lugs until it can be pulled free (taking care to feed the float mechanism out through the hole without damaging it). The tank itself is held in place by four bolts – two at either end. Once removed, the tank can be carefully extracted from the car.

no tank
The easy route to greater luggage space.

Surprisingly, given the build up of sediment in my fuel filter, the tank appeared to be in pretty good condition. There was hardly any sediment in the bottom and very little in the way of surface rust, either inside or out. The tank did yield one surprise – a yellow plastic nozzle from a fuel can which must have fallen into its petrolly grave many moons ago. Given its potential to block the fuel outlet it was removed and added to my rapidly expanding ‘strange things I have found hidden in the white car’ collection (I’ll probably have enough to dedicate an entire blog post to this at a later date).

The car is gradually giving up its sordid little secrets.

Whilst the tank gained a fairly clean bill of health, the fuel gauge sender did not get away quite so squeaky clean – the float was half full of fuel so obviously had a hole in it somewhere. I checked the float in the parts car to see if it could be swapped over but unfortunately it was in the same sad condition so I ordered a new one online. Luckily floats for these Smiths sender units are fairly common between British cars of the era so I could buy one from my local Mini spares retailer instead of having to wait for international delivery.

New float vs old float (yes I did remove the attached fluff before fitting)

Once the float was replaced, I refitted the tank and its associated bits and bobs – having robbed the sender unit locking ring from the parts car to replace the rather mangled one on the white car. In hindsight I could have got away with not removing the tank at all but as least now I have the peace of mind of knowing that it’s not full of gunk or rust or plastic yellow nozzles.

With the tank replaced, I turned my attention to the rest of the fuel system – the first job being to clean up the mess that was my fuel pump. I carefully removed the worst of the sediment with a screwdriver before blasting away the remnants from the pump body with a tin of carb cleaner. The filter was gently cleaned in petrol to avoid damaging the gauze. I replaced all of the rubber fuel hoses with high-quality Gates Barricade R14 fuel hose (not forgetting the short length attached to the tank outlet). Australian unleaded does not presently contain ethanol like UK fuel does so problems associated with prematurely degrading fuel hoses don’t seem to be as rife here, but it pays to future-proof. To complete my rebuild of the fuel system the newly-rebuilt carbs were fitted, which look great – even if I do say so myself.

Mmmmm – minty fresh carbs.

Next in line for a good groping by my wandering hands was the ignition system, which you may remember from my previous ramblings had issues involving melted wire. Being a later 2500, the car is fitted with a ballast ignition system which means it runs a 6v coil instead of a 12v coil. During normal running a ballasted circuit feeds the coil with 6v, whilst a second un-ballasted circuit runs from the starter motor which feeds the coil with a full-fat 12v when cranking. The idea is to temporarily provide a bigger spark when starting the car, thus helping to overcome cold start issues. A good idea really.

Instead of an old-school ballast resistor, by the late 70s Triumph were using a length of ballasted wire to feed the coil – this made for a neater installation and, let’s face it, it was probably cheaper too. Sadly, 40 years of resisting the passage of electrons had rendered it a twisted mess of melted insulation and wire, most likely earthing out sporadically at various points along its length. The car can’t have been running well when it arrived at the breakers yard.


Luckily the rest of the engine bay loom had been spared from damage by the self-destructing ballast wire, so I had no further work to do other than deciding how best to reinstate this circuit. The options were to a) fit a new length of ballasted wire b) try to re-sleeve the existing ballasted wire c) fit a length of normal wire, do away with the ballast resistor and fit a 12v coil instead or d) fit a length of normal wire and a separate ballast resistor. Option A would involve sourcing a new length of wire of the right length and resistance, plus knowing that it might go all melty again and take out half the loom with it, Option B would require me to unwrap the loom both in the engine bay and behind the dashboard and Option C would potentially cause cold starting issues. I therefore chose sensible Option D and put in an order for a ballast resistor, which I mounted neatly next to the coil.

The ballast resistor in its new home.

The melted remnants of the ballasted wire were carefully chopped out of the loom and a new length of 15A white wire (in keeping with the BL wiring colour scheme of the day) was run from the ballast resistor back through the grommet in the nearside end of the bulkhead and down to the car’s fuse box. From there I piggybacked onto the fused white circuit, which is live whenever the ignition is switched on.

The shadowy origins of the coil ignition circuit.

All in all it looks pretty neat and cost less than $30 to fix. All that remains is to tidy up the engine bay wiring by re-wrapping with some loom tape but I’ll spare you the blog post on that one…



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