by Peter Champness » Mon Mar 15, 2010 11:14 am
Now that I've finally got around to activating my forum account, I shall cautiously try to list some of what I've done to the car.
Cautiously because I know how much other people know about Ginettas, and I am always acutely aware of not walking on thin ice! Here goes...
The engine started as a twin-Stromberg one (probably about 78 bhp, but that depends on which spec sheet you're reading), coupled to an overdrive gearbox. The car was apparently re-engined by the factory in the early eighties, so the Strombergs were the absolute last gasp of the carburettor world, with completely fixed jets and needles - no adjustment whatever.
But the gearbox turned out to be the Holbay-spec close-ratio one, and the overdrive is a J-type, so it's as nice a set-up as any G21 left the factory with.
I'm extremely lucky to live in a village which is also home to a real old-fashioned car workshop, where the three geniuses build shiny new competition cars, rebuild old competition cars, and also service local smokers for light relief. There's a 1500bhp 4WD rolling road, and full machine shop, as much tea as you can drink, and a genuine affection for engineering of all sorts. Including building a replica Willys jeep out of plywood, but that's another story.
The car is stll Rootes-based through and through, but with some modifications... Back end is still as standard, but I did manage to find the taller-ratio final drive from a Hunter axle on eBay. Never expect driveshaft replacement on an axle like that to be easy; it took a 45-ton press to get the old bearings off the driveshafts, and according to the steam-engine workshop that did it, the jig was starting to bend when the bearings finally surrendered. New AVO dampers at the back with adjustable collars, polybushes on all the links, andf that's it for that end.
Standard propshaft (new UJs) leading to the J-type OD. The original unit began getting slow to engage, so I did loads of research, discovered how much it costs to refurbish one, and then found a Hunter GLS gearbox and overdrive on eBay (again - whatever did we do before eBay?). Do the swaps, and the new gearbox proves to drop out of 3rd occasionally, but the OD unit is in fine order after I cleaned the solenoid. So back to the older gearbox, but while the engine's out of the car, and my working life is fairly quiet (self-employed freelance, so up to me to some extent), why not think about improving the go department a bit?
I like making things. And what came out of last spring was the plan to keep the engine standard, but give it throttle bodies and fuel injection. I had already replaced Joe Lucas's 'distributor' (more like a blunderbuss, given that the ignition scatter can spread across 15 degrees) with a completely electronic '123' system - looks like a distirbutor, and it does distribute the spark to 4 plugs, but scatter is down to a very few degrees.
Suzuki motorcycles provide a huge range of throttle bodies, but the most important thing is to be able to line them up with the inlet ports, so I started with a Holbay DCOE manifold, and then got hold of a set of K1 bodies (eBay, £120) which can be split apart and re-spaced to suit the manifold. Fairly time-consuming because you have to remove all the secondary butterflies and associated motorcycle plumbing, but straightforward if you do one thing at a time. The throttle quadrant was fun to build; if you retain the motorcycle throttle quadrant, you'll find the accelerator pedal becomes a very short-travel switch, with little movement between closed and wide open - so you need to make a larger, more graduated one.
Then how are you going to attach the throttle bodies to the manifold? After losing money to an internet shark who was selling flanges on the Locost website, I got a local machine shop to make up four suitably lovely flanges, and applied silicone hose and shiny clips to join all together. Add in the planning and 'design' of the necessary fuel feeds (low-pressure pump from tank to swirl-pot, then high-pressure pump to fuel rail and regulator, then return to tank - and that's complicated too, by the fact that a low-pressure pump is expecting some back-pressure and gets really confused if there isn't any) and you might wonder why you started in the first place.
Then there's the ECU. My mentors all said words like 'Emerald' and 'Omex' , which I diligently researched and found price tags of several hundred pounds and features which would be redundant for my application. I also discovered that people who know about fuel injection are almost universally incapable of explaining the details of it with any clarity. So I began to learn about the real-life application of all that knowledge from the ground up. And despite sneers from those who work on ECUs that their customers are paying lots of money for, I opted for Megasquirt, the open source software solution which you can design to your own requirements.
In the end I had it built by a very helpful man in East Anglia, who charged me about £250 for the complete thing, box, loom, PC cables, basic maps, software etc. And when I'd got it all joined together, the damned thing actually started.
It took a few days of computering and a few hours on the rolling road to get it running anywhere near properly, but without mentioning it, Andrew the rolling road genius dd a power run when I was only about half way through the mapping, and the dyno showed 93bhp. On an otherwise standard engine.
I've been fine-tuning the mapping since then, and the car is so drivable, with torque and power that are useful rather than silly, and it gives about 28mpg when you're going for it, and up to about 33-35mpg on a long cruise. Interestingly, the mpg figures seem to be better at 85mph than at 65mph. French autoroute, honestly, officer.
Oh, and I really do live with the car on a daily basis. I drive it anywhere and everywhere, often on long trips up motorways - it's so much more engaging than any modern, and it's quicker than many, too. Since I'm abut six feet tall, I've lowered the seat pans and got some nice seats. And an alloy radiator out of a Fiesta. And, as Spadge shows, a clock out of a Mig21. It's mechanical, so you have to wind it up every four days or so, but it's wonderful. It's got two separate stopwatches built in, and all sorts of other functions which I could explain if I could read the Russian instructions. I asked an aviator friend why a mechanical clock in an eighties fighter, and he replied that it would be useful after the magnetic pulse from the nuclear strike had blown all your avionics - you could still navigate.
That's quite enough waffle from me. The NewsMag Editor has asked me to write as much as I dare about living with the car, so if I say any more here I won't have anything left for that. But if you want to know the grisly detail of all this, do please get in touch, and I promise I'll cure your insomnia.
