Pinking under load with electronic ignition

Standard & electronic conversions

Pinking under load with electronic ignition

Postby Pete Bags » Tue May 08, 2018 11:38 am

Hi all,

Several months ago, while some welding was being done on the car, I thought it a good idea to have the old standard dizzy converted to electronic at the same time - this was done by the lovely guys at Charles Ware. I have noticed that almost always under load, and usually only in 4th, that the engine is pinking. I thought that I would retard the ignition using the micrometer adjusting knob, but the knob just spins, with no clicks - is this disabled as part of the dizzy conversion? The engine is a warmed up 1098 with a 731 camshaft, HIF carb and LCB freeflow exhaust, just in case this makes a difference.

So, I guess I will need to rotate the whole of the dizzy in order to slightly retard the ignition, and hopefully get rid of the pinking. Some advice please - do I turn the dizzy clockwise or anti clockwise? And how far do I need to turn it to test it out - ie a few millimetres or a centimetre or two? Currently the engine idles very nicely - if I retard the ignition to cure the pinking, can I expect the idle to change, and if so, should I adjust the idle on the carb?

Any thoughts from the forum are very much welcomed!

Many thanks,

Pete
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anti clockwise to retard, may need to increase rpm,if the knurled nut is revolving, is the vacuumm advance connected,???
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Thanks for this - the tube from the carb to the dizzy is connected, but it does look as though the converted dizzy has the micrometer adjuster disconnected. I'm going to try rotating the dizzy anticlockwise, and I also hear that using premium fuel might help as well. We will see!
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When the distributor was converted did they change the advance curve also?

I would look at the timing at idle with the vacuum pipe disconnected. Once that is determined I would retard the timing by 5 degrees first. Then take it for a drive. If that does not fix it, check total advance by revving the engine to about 3000rpm with the vacuum advance pipe hooked up. IIRC total advance should be around 35 degrees (someone will chime in if I am incorrect). Once the timing is sorted out you will need to readjust the idle speed.

Another thing that could cause pinking is a lean mixture. Since you did not say anything was adjusted on the carb I would leave the carb alone until the ignition is sorted out to your satisfaction.
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I'm not sure what happens when a dizzy is converted to electronic, so I don't know about the advance curve.

I will try retarding the ignition bit by bit, so see if the pinking stops under load - interesting what you say about running lean, but the new exhaust has a black soot coating, so that would surely suggest it is running a bit rich if anything - but willing to try all sorts to cure the pinking!

Thanks for the suggestions.
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What colour are your plugs,
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Update - I rotated the distributor a little bit anti-clockwise, and this has definitely helped almost eliminate the under-load pinking. As woodywoodchipper had mentioned the plugs, I had a look at them, and the colour was a perfect and healthy tan - so that looks like the carb is set up well. I did have to adjust the slow idle to increase the rpm, as retarding the ignition did slow this down a bit too much. I don't have a strobe, so I've no idea how the timing is using the notch markers, but it does sound and drive much better now!

Thank you for all your help and suggestions!

Pete
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