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Still not 100% sure as to what's causing the none start when hot, been playing around with the pick up air gap for the electronic ignition and found that the info given by the supplier is not entirely true so are at the moment in negotiation for a solution.
Also been looking at the heat shield which Ive now extended so the whole underside of the carbs are covered.
Fabricated a plate from 2mm ally with 7mm spacers to give an air gap between the original shield and the new one.
New shield in place, bolted to the original plate.
Side view showing how far the new heat shield covers the underside of the carbs.
Gave the car a run out then stopped for 10 mins parked up in the garage to retain as much heat as possible and she started after about three cranks with the throttle wide open, i may be on the right track but i still feel there's an issue with the electronic distributor. The dizzy shaft has 0.5mm side float which will give a fluctuating air gap when running, while the focal length for the pick up is 0.08mm to 0.10mm which is well below the half mill side float.
The manifold and just about the whole exhaust system has been wrapped which made no difference, ive also tried the higher octane unleaded petrol, checked the carbs over float height etc and made adjustment but still no solution. The distributor was brand new with built in electronic ignition but it looks like the dizzy may of been a cheap copy that's why i am now turning my attention to the ignition components although i can't understand why a hot ignition would cause problems to not start but ok when cooler.
How's your mixture? As my old 150 Stombergs wore out I had to keep enriching the settings as it was stuttering in the mid-range with them set to what had been the optimum. Eventually the mixture got so rich that I got starting problems both hot and cold, which triggered me to change the carbs. It hasn't missed a beat since.
Having said that, the only actual breakdown I've had was down to the modern MSD multispark ignition module failing at full throttle (my fault I believe as my 'work in progress' header tank had just dumped a load of boiling coolant all over it) -
Phew! Lucky I had those cones on my head when I set off.
My point is that modern electronics can both help and hinder an old car. Perhaps your distributor has a fault that only manifests itself when hot. I'd be inclined to change back to a standard distributor and see if it cures the problem. If it does, you have your answer. Good luck.
My thought's also about trying another dizzy, the engine originally came with out a dizzy so i bought a replacment so whilst i can see the benefit of trying another i am waiting to see if the supplier will send a replacment electronic dizzy. I am keeping an eye out for a points dizzy for a GT6 if its a resonable price.
Right from the beginning i have just assumed the new electronic dizzy/coil supplied was ok but your comment/link has got me thinking that maybe there's a problem with the coil getting hot or may be a lower supply voltage when hot and cranking the engine over. I also have a high torque starter motor fitted which was second hand so maybe the starter motor draws more current when hot which in turns drops the supply voltage to the coil on a hot start up. This weekend i intend on doing a few checks with a muti meter on the ignition system.
One thing i have just found out today is the coil has a primary circuit reading of 1.0 omhs, i was always under the assumption a 12v coil with no ballast resistor had a primary winding resistance of 3.0 omhs and a 6v coil with ballast fitted had a primary resistance of 1.5 omhs so i am slightly concerned as to the 1.0 omhs reading. Have emailed the supplier to see what they say.
Food for thought and if any body can add to this then please do so.
Had the car out today at a local classic car show, alas i did not put it on show as i was too late to register so parked up with every body else and had a walk around, car's from my past on display but none of the Italian exotic cars which was a disappointment had hoped to see maybe a Lancia Spider or Fiat 124 spider, me thinks one of these could be the next project, just need to find a suitable one which at the minute is like looking for hens teeth.
Cars from the late fifties through to the sixty's have similarities in body shape, this i was led to believe was a genuine AC and not a kit. What i found surprising was the huge size of the wheels and tyres compared to whats on the navigator but they certainly did not look out of place.
The XK150 is one of my favorite old jags, this one was in great shape both internal and external. Triumph TR3, great example.
Mint american classic.
Left the best till last. Car shot with what is becoming the obligatory castle in back ground.
Even though it was parked in amongest every day cars it still drew attention, when i arrived back at the car there was a father and son debating as to what it was, the son was taken pictures to check the reg out to see what information he could find on the web, so i decided to put them out of their misery and tell them what it is, which surprised both of them. They said they had seen the car passing through the show area and decided to walk through the parking fields to find it.
Even on the way home i was stopped by a guy in an MGB who wanted to find out what it was, may be it was because i over took him so wanted to know what it had under the bonnet, plus he commented on the popping exhaust noise, music to the ears i never get tired of lifting off and hearing the pops and crackles.
There's quiet a few castle around about here, so it may become a challenge to position the car in front and take a picture.
Had the car out this evening and caught the front valance again, time to alter it once and for all before it really gets caught and does a lot of damage.
Sorted the front valance out cut about 100mm off the lower edge which has brought it in line with the anti roll bar height from the road surface, hopefully that will be the last of the problems.
Finished the round gear knob and also made another gear stick this time slightly longer to see which length suits the car.
Cheers guy's for the feed back.
The general consensus is for the long shaft with smooth ball end which is what i decided to go with.
Very nice.
Is that the last of the finishing touches?
Good luck, Paul.
I don't think i will ever stop tinkering with the car Paul i am always looking for things to make and do plus it's one of those cars that potentially will never be finish.
Today July's issue of Complete Kit Car arrived with the final article on my build, the photos in a old worldly cobbled street look the part and show the car off really well so thanks to the magazine team especially Adam.
