Spitfire bits and bobs

Well the ignition system lasted all of 200 miles before it failed. however the problem was easily tracked down the case was live with 12vdc when this shorted out it cut the ignition out. The fix is in progress and will be refitted to the car soon.

Other stuff that has been done is chase down the leak in the inlet manifold and seal the exhaust. Whist i had the manifold off the car i fitted non waxstat jets to the carburetters. This was not entirely easy as i had to modify the linkages slightly. All went together easily but i still have a high idle speed, looks like throttle spindles are next on the list.

As well as this i used the opportunity to fit the 02 sensor to the exhaust manifold, the gauge now works and without to much fiddling i now now that at idle the car puts out %3.0 Co and is slightly lean on full throttle. I will leave well alone until after the cars MOT and then tweak some more.

The last news is that i bought engine and radiator valances off an Ebay seller, it was spur of the moment but at least it one job i can now finish. The radiator valances i have made will be put on ebay once finished.

Spitfire Electronic ignition part 5

The ignition unit is now finished and working. I'll have to use the car a bit to see if it;s reliable. The finished picture is shown below. I will add a picture in the car soon.

There were a few teething troubles which were caused by my lack of ability more than anything else. I fried a total of 3 transistors, 1 diode and 3 resistors. Oh and gave myself a 300v shock bonus !

The other thing i noticed was a poor spark on the conventional points system. One new 12 volt Bosch blue coil helped no end. Should have done that sooner. what an improvement !

I still have a few tests to run, like shorting out part of the PCB circuit and seeing if the 300V rail drops when the spark output is at 1000 sparks per second. Now a thousand sparks a second is something to see and hear i'll try and post a clip at some point.

Another job is to reset the ignition timing as it probably a little out, a job for tomorrow.

However my main concern is reliability, to this end i'll keep the old coil and ignition module in the car for a while.

Driving

Oh my god new coil + new Ignition module what an improvement. Better idle, less choke. revs quicker when you blip the throttle and no hesitation either. BHP / Torque has also been improved especially from 3000 RPM onwards. I used to struggle to get to 70MPH but now it get there easily. It make the spitfire an altogether better experience. If it lasts i think i'll call this one job done.

Or will i there is a option to increase the output from 45mJ of energy per spark to 110mJ per spark. Now i probably don't need it but curiosity might get the better of me. I would have to rewind the transformer add another zenner diode and 1uf capacitor. that would give me 375volts and double the stored energy. all this equals bigger spark.

Spitfire Electronic ignition part 4 !

Oh dear did i say i would leave this subject, well that did not happen. When trawling the Internet i found a design for a multi spark discharge ignition. this appears to be similar to some the the MSD ignitions. I reasoned that i could make the PCB assembly myself for a fraction of the cost of the MSD system.

So the good bits are i think this will be the best ignition to date.

The bad is that i will have to make a PCB board solder the bits on and get it working, None of which i have done before.

The PCB was the first challenge. Using the front cover of a magazine, a laser printer and bits from Maplin i was able to make the PCB. Beware if you are going to do this as the chemicals involved are not nice. For that reason i will leave the actual details out from this post. However if you still want to try it contact me for the details.

As we speak i have nearly put all of the components on the PCB as per the pictures below, the rest will hopefully go on next week and i can give it a go.

Other things that have been happening - The interior of the car has gone back in and The gear lever has been shortened as per the pic below the new gearbox has now done 400 miles so I'm calling that project Done at last! The stereo has been fitted as per my wife's instruction so i had to find a place for some speakers.

So where do you fit speakers in a spit? I finally ended up making a place behind the seats as per the pictures below. The boxes are 18mm MDF with some Alpine speakers picked up from Halfords. Now all i have to do is cover the MDF with carpet and i can call that job done as well.

Yet another job started is the front Radiator valances, I pick the ally sheet up some time ago but have yet to get to start the job however i finally made the valances. They are not fitted yet as i will need to tidy them up and paint them. That will have to wait for warmer weather before i complete it. I will also have to make the engine valances but the material i bought was to small. um bugger! When i find some more ally sheet at a bargain price i will buy it for them.