Chilp3 Posted March 1, 2016 Report Share Posted March 1, 2016 Good evening. I'm adding this post on behalf of a fellow Register member and friend who runs a 1973 US restored Triumph TR6. The car is presently running twin SU carburettors. The following is a list of symptoms and work undertaken so on the car to try and identify the problem. Sadly so far we have been unable to get the car to start and run properly. TR6 running on twin SUs One day running perfectly and then after a few weeks without use engine will start but not run. Much back firing and un-burnt fuel being thrown out All plugs go sooty black within a minute Points, rotor arm, distributor and plug leads all ok No leaks from failed gaskets, split vacuum hoses etc. Air filters all ok All indications point towards carbs but cannot see any obvious issues i.e. floats at correct height, dash pots filled correctly, slides working and needles all ok Any advice or suggestions would be greatly appreciated as we are at a bit of a loss as to what to investigate next. Best Regards, Peter Quote Link to post Share on other sites
peejay4A Posted March 1, 2016 Report Share Posted March 1, 2016 Condenser/capacitor dead? Quote Link to post Share on other sites
Peter Cobbold Posted March 1, 2016 Report Share Posted March 1, 2016 (edited) Peter, I'd suspect carbs last of all. Sparks more likely to be the culprit, so: -- It fires when the starter is operated, then fails to run when starter has finished? Could be the coil requiring 12 volts when a coil for use with a ballast resistor is what's needed. What were the sparks like when it died? -- What disy if fitted? - there were some unusual USA-spec disy with vac-retard capsule and so forth. -- If the cylinder head retains the USA-spec low compression try setting the static spark timing to 16-18 BTDC, rather than 11-12 of the stock UK engines. -- has the fuel gone 'off'? how old is it? -- lots of dodgy ignition parts around - rotor arms, etc. How do you know they are good? happy hunting Peter Edited March 1, 2016 by Peter Cobbold Quote Link to post Share on other sites
barkerwilliams Posted March 1, 2016 Report Share Posted March 1, 2016 Peter, I'd echo Peters comment how do you know electrics are good? Known good substitution is the best way, but as a first step get the engine running after dark,in the darkest spot you can find and look for any green arcing around the distributor and plug leads. Alan Quote Link to post Share on other sites
brucer Posted March 1, 2016 Report Share Posted March 1, 2016 +1 for condenser. Had very similar symptoms and this was the solution Quote Link to post Share on other sites
Chilp3 Posted March 3, 2016 Author Report Share Posted March 3, 2016 Good morning, Sincere thanks as always for peoples time and effort in responding to this post. Taking on-board all of the comments and feedback I have tasked my friend with buying a new condenser, distributor cap and leads. I have suggested he gets the cap and condenser from the Distributor Doctor to ensure he doesn't make the problem worse with poor quality parts. The leads I have suggested he sources from Magnecor as they are also of known quality and I have these fitted to my car. I will let you know if we're successful in due course as I think it's always best practice to give feedback either success or more challenges!! Best Regards, Peter Quote Link to post Share on other sites
TR NIALL Posted March 3, 2016 Report Share Posted March 3, 2016 Don't forget Peter to only change one thing at a time and retry after each change,hopefully you'll then find the Lone Culprit. Quote Link to post Share on other sites
Chilp3 Posted March 7, 2016 Author Report Share Posted March 7, 2016 Good morning, Thanks again for everyone's posts thoughts and well wishes which is always greatly appreciated. I'm pleased to confirm the fault was diagnosed simply as a failed condenser so normal service has now been resumed. Best Regards, Peter Quote Link to post Share on other sites
peejay4A Posted March 7, 2016 Report Share Posted March 7, 2016 Not often I'm right first off but the symptoms were compelling. I'm glad you're sorted. Quote Link to post Share on other sites
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