Ken Young Posted February 27, 2016 Share Posted February 27, 2016 I have a 67 GT6 and it has suddenly developed a knocking problem with ignition. The problem literally started in between me parking to go to a shop and then starting the car again. The problem is most severe when accelerating or loading the car. I have done some diagnostics on the car as follows. The ignition vacuum advance / retard seems to be working alright. I can see the mechanism pulling in when I rev the car in the garage. However, there was a small, unidentified piece of spherical black plastic in the distributor. I couldn't find where it came from so may be related? The idle setting of the car increased and I noticed the linkage to the accelerator pedal on the entrance to the first carb needed tightening. As far as I could see this only seemed to affect the idle RPM, but it could be an indication of a carb problem and the mixture being too weak. Does anyone have any simple diagnostics I can try to work out what the problem is?ThanksKen Quote Link to comment Share on other sites More sharing options...
bob dunn Posted February 27, 2016 Share Posted February 27, 2016 Look inside the dizzy cap if a bit has fallen of its had it ,get a new cap. Quote Link to comment Share on other sites More sharing options...
daver clasper Posted February 27, 2016 Share Posted February 27, 2016 Could be worth changing the condensor and rotor arm. I've had both fail in the last 2000 miles (they were new). Can then used for spares if not the problem.Cheers, Dave Quote Link to comment Share on other sites More sharing options...
RobPearce Posted February 29, 2016 Share Posted February 29, 2016 Check the advance at idle. I've had distributors "stick" with mechanical advance on, which would leave you over-advanced at low speed. Normally repairable with a bit of wiggling and lube, but might need a strip-down and clean-up. Quote Link to comment Share on other sites More sharing options...
don cook1 Posted February 29, 2016 Share Posted February 29, 2016 When you say "knocking" do you mean pinking? What is the timing set (degrees BTDC) at idle. Quote Link to comment Share on other sites More sharing options...
Nick Jones Posted February 29, 2016 Share Posted February 29, 2016 Quoted from RobPearce Check the advance at idle. I've had distributors "stick" with mechanical advance on, which would leave you over-advanced at low speed. Normally repairable with a bit of wiggling and lube, but might need a strip-down and clean-up. I thing Rob has nailed it here. Advance mechanism has stuck in the advanced condition, which explains both the faster idle and pinking (if that's what you meant). My PI did this.....Nick Quote Link to comment Share on other sites More sharing options...
Jonny-Jimbo Posted March 1, 2016 Share Posted March 1, 2016 The spherical black plastic, might not be plastic and could be the spring loaded contact from the central connection on the dizzy cap. Quote Link to comment Share on other sites More sharing options...
don cook1 Posted March 2, 2016 Share Posted March 2, 2016 As Rob & Nick suggest. Mechanical means 'Bob Weights' or the shaft they're mounted on. Quote Link to comment Share on other sites More sharing options...
drofgum Posted March 4, 2016 Share Posted March 4, 2016 Quoted from Jonny-Jimbo The spherical black plastic, might not be plastic and could be the spring loaded contact from the central connection on the dizzy cap. Hi,Not too sure about this. If a GT6 Delco dizzy cap is like a Spitfire cap the center contact is fixed. The spring loading is built into the rotor. All the best, Paul Quote Link to comment Share on other sites More sharing options...
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