Sunday, May 13, 2012

EFI part 1 - The Fuel Tank

My GT6 was born with twin Stromberg carburettors. They're simple, reliable and moderately tuneable. More distinguished species of Triumph, however, had Lucas mechanical injection. I thought about fitting it, but getting the tuning right seemed to involve shims, shuttles and springs... not to mention running three times widdershins around a church at midnight for luck. Not for nothing is Lucas known as Prince of Darkness.

The modern solution is electronic fuel injection... as fitted to every new car. The first part of the conversion was the high pressure fuel pump. Some conversions use an external pump, fed from a surge pot (essentially a small second fuel tank) by a booster pump. I didn't like that much fuel-filled plumbing 12 inches from my left buttock, so opted to have a surge pot and injection pump fitted inside my tank. Tanks Inc ( sell kits for just this purpose.

Here you can see the Walbro pump and filter, and the small tray which acts as a surge tank to prevent the pump running dry on corners. The white nylon pipe is the fuel return, so that if the tank gets really empty, the surge tray will stay full as long as possible.

I had the tank converted by Greg of Fuel Tank and Radiator Specialists here in Brisbane. They fixed my Herald tank a couple of years ago after ethanol petrol ate through old epoxy repairs. Greg cleaned the tank and welded in a sunken section for the pump to bolt up to. It was pressure tested and returned good as new. I shouldn't have to worry about fuel leaks or dirt in the fuel system when the car returns to the road.

The surge tray was installed sideways for two reasons. Firstly, if it had been positioned fore-and-aft it would have interfered with the fuel gauge sender arm. Secondly, the car will probably be subjected to greater G-forces from cornering than acceleration or braking.

And here is the finished article, having passed inspection. The recessed pump fitting means that the boot floor will still lie flat. The wiring and two fuel lines are the next steps.

Saturday, May 05, 2012

Parts that almost fit

When it arrived, my GT6 was worn out. The interior was cracked, rotten or missing, the mechanical parts were sloppy or broken and the remaining trim was corroded, bent or had fallen off years ago. So, a lot of parts have needed to be replaced, either with original parts from other cars or newly made parts.
The interior was easy. Nearly everything's available new, mostly from Newton Commercial. The trim has been remanufactured to a high standard and fits well. One exception is the seats which, being a high-back style unique to US-spec cars, are being re-covered locally. Rebuilding the comfortable cabin has been fun. The mechanical bits are more expensive to replace but with a bit of reading, trawling the web and a good machinist, it will soon be purring like new.
The exterior trim is trickier. A lot of parts from old cars are available, in varying conditions. But as well as old parts, a lot are available new. It sounds amazing, but out there somewhere people or companies are making bits for old Triumphs. In photos they look shiny, and it's even nicer when they arrive and you unwrap a parcel full of new Triumph treasures. But offer the shiny new goodies up to the car and the smile fades.
In short, most don't fit.
Example: A GT6 Mk3 rear badge. I bought a good second hand on, but it still had a few small blemishes, so I ordered a new one. What I got is a recreation which looks like an original until you put them side by side. The moulding shape is slightly different, the pin spacing is different (only by half a mm but that's enough to stop it fitting) and it has a few small blemishes in the casting. I know, these are tiny issues but they mean that it won't fit without me drilling out the holes in the car's panel, and to a perfectionist it will stand out as a cheap copy.

Example 2: my GT6's chrome 'horseshoes' were badly pitted and beyond salvage. New ones are available and very shiny and not hugely expensive so I bought 'em. Like the badge, they don't quite fit. The originals were a one-piece pressing, admittedly made from soft metal which doesn't last forty years very well but perfectly shaped. The new ones are made from three sections tacked together. With a bit of filing of the end points and the freshly painted tail of the car, they could probably be made to fit... sort of. Again, to a perfectionist the small gaps where the casting doesn't follow the panel curves will scream "bodge". And I'm not sure how well they will hang on once the car is on the road.

The next bits of trim to sort out are the bumpers. The original ones are dented and the chrome is worn. And guess what - there are stainless steel replacements being made, and like the badge and chrome trims, they look very shiny on my computer monitor. But will they exactly match the originals? I just can't say. It's too big a punt getting them shipped to Australia to find out. The old ones will get repaired, rechromed and refitted.
Some good news. Some bits I've bought have fitted as advertised. Here's a teaser...