Triumph Spitfire MkIV

Dicky Blighter · Post by **Dicky Blighter** » Thu Apr 29, 2010 12:48 pm

I started this project over 18 months ago but had to put on hold for while because of health problems so last week decided to finish it off:

Dicky Blighter · Post by **Dicky Blighter** » Thu Apr 29, 2010 12:52 pm

Wiring has been tidied up since these pictures were taken and distributor removed and blanked off.
The brown wire on the EDIS was for tacho signal but it worked fine with the megajolt signal so also removed that wire.
Everything works really well, next project is too add an auxillary input for temperature and use that to advance ignition a bit when cold and also control electric fan.

Dicky Blighter · Post by **Dicky Blighter** » Thu Apr 29, 2010 12:55 pm

It's fitted in this, 1971 spitfire with a 1500cc engine.

NITROPIXIE · Post by **NITROPIXIE** » Thu Apr 29, 2010 8:07 pm

Hey there Dicky

That certainly looks like a fun summer car. Sorry to hear you have had health problems and hope all is well now.

A friend of mine had a Spit but lost interest in it and its now rusting away at the garage where i do my cars. Such a shame, maybe if i run out of projects i may get my hands on it myself and get her going again. She does require a bit of welding up.

One thing i would suggest on your 3rd picture is that you could lengthen the hoses from your carbs to the T piece. Is that a restriction in the pipe going to the MAP sensor??? It would probably be more beneficial to utilise 2 of these, one for each side of the T-piece on each carb branch and then a small reservoir to the MAP sensor, which will help smooth out the vacuum signal some more. What we are trying to do is make it harder for the air to be robbed from carb to carb and easier from carb to MAP sensor.

As for a fan control, I have seen someone very successfully gluing a fan control switch onto a flat piece of the radiator. Ths would be better as megajolt does not have built in hysteresis which is what you need in a fan controller ideally. The motor can switch off and on too much without hysteresis and shorten the life of the motor from start-stopping. Just something to think about

How has the car been to drive? have you noticed much of a difference??

Dicky Blighter · Post by **Dicky Blighter** » Fri Apr 30, 2010 8:45 am

Thanks for your comments. Yes that is a restrictor in the take-off, it's actually a 0.6mm mig welding tip, I've now taken it out and gettting a very stable reading, it was a bit twitchy before that - the take-off adaptors have a very small hole in them anyway (about 0.5mm same as the standard vaccuum take-off that used to go to the distributor).Doesn't seem to be much robbing between the carbs but they are pretty accurately balanced now anyway. I think what is happening is that the take offs are acting as restrictors and the fairly long pipe run to the megajolt is acting as resevoir/damper. Might add a small reservoir and see if it makes any difference.
Hadn't thought about the hysteresis aspect of fan control so will probably stick with a thermal switch, I have already got a couple of surface mount sensors I could try sticking to either radiator or possibly top of thermostat housing. If that doesnt work I've got one that can go in the hose via an adaptor.
As far as driving is concerned it's like a different car since I fitted the megajolt, smooth tickover, easy to start and no flat spots with the map I'm using at the moment (courtesy of another spitfire owner. The old distributor, a Delco, was very worn and causing all sorts of problems and if I set timing up it was changing all the time. The rebuilt carb with needle s to suit the stainless sports exhaust system and air filters help as well of course.
The car has had new floors, inner and outer cills, and loots of other welding to the structure but still needs rear wings and some work on the bonnet before a repaint but no rush for that because as long as the mechanicals are tip top and it drives well I'm not too bothered what it looks like - suprises the boy racers when they can't catch you.

Dicky Blighter · Post by **Dicky Blighter** » Tue May 04, 2010 10:50 pm

Another picture showing blanking plate where distributor was, the small screw in the middle secures a 10mm thick disc on the back that stops the oil pump drive jumping out of engagement.
The bit with the wires on rad top hose connection is a thermal switch that will be used to control an electric fan, a la Nitropixies suggestion, only testing at moment hence grotty wiring. Slight snag with the fan I have, it came off a Rover 200 and is complete with cowling that is a perfect match for the size of the rad. unfortunately it has to go on front of radiator and it sucks air through from the engine side so not sure how welll it will work.