Moss Motors, Ltd

I have a 1973 tr6. The carbs have been rebuilt, synchronized, and tuned by a gentleman who works on foreign classics for a living. He also checked compression in all cylinders. I replaced the plugs, wires, cap, rotor, points, coil, and fuel line and filter. The car runs great when you start it from cold. Runs great when you start driving, but the longer you drive it the worse it runs.  When it starts running bad it backfires a bit and sputters gradually. Then it progressively gets worse. This is my first foreign classic and am running out of ideas. Could it be something with the vaccuum advance?

What carbs are you running with? On a later vehicle this would have me looking at the automatic choke, particularly on a Weber??

More details and we can fix it!!

steve

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To a man equipped with only a hammer, most problems look like nails

This one sounds heat-related.  I'm not a Triumph guy, but others have reported similiar complaints and the cause was vacuum leaks at the carb - intake manifold - block gaskets which opened up as the engine heated up.  Ensure the carbs and intake manifold bolts are torqued to specs.

The car has stromberg cd-175's. I have a header blanket so i am not cooking the starter, hood, carbs and everything else. Thank you for some ideas, i will start checking the vaccuum lines and torque on bolts. If any thing else comes to thought please let me know. thank you very much guys!!

Hm!, dont know Strombergs too well but I do know that they have temperature compensators on them.On SU HFs this mechanism is a pain in the posterior! It makes setting up the carbs difficult, you have to keep blipping the throtle every minute or so to make sure that fuel is fresh and cool etc. etc.. Even when you think you have the mixture set right, the mechanism overleans the mixture on a really hot day or in heavy traffic. Igot rid of the relevant parts in my set up and life is now much less painfull!! - - - - - -  woops,sorry folks got on my soap box there!

But seriously, can you easily enrichen the mixture by the same controlled amount [ so that you can revert to current setting again easily] on both carbs and go for a spin in the heat and see if things are better or worse??  Other thoughts, what fuel are you running with? What CR is the engine? Use lowest grade fuel if possible , stay away from alcohol in the hot weather [and  if that doesnt raise a comment or two I'd be surprised!], if poss.  Hope this helps,  - - - - - cheers   steve

 

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To a man equipped with only a hammer, most problems look like nails

Thank you everyone! I found the problem to be the condensor. It was a faulty part and so far the replacement isnt. Thanks to other suggestions I was fortunate to have found a couple of potentionally troubling issues in the near future and corrected those as well. Never rule out new parts is the lesson! 

Good to hear, and thanks for the update!

Consider replacing your points with one of the electronic ignitor kits.  Major league improvement in the engine ignition system performance - guick starts, smooth idle, improved acceleration and cruise.  Once installed, you will never have to adjust or "tune it" again.  I put the Pertronix kit into my "T"-series MG, and will never go back to the old points.  Worth every penny!

Hey that is good news. New parts but nowadays we have no idea where [or when] they are made! I suppose theres a case to be made for testing out all the spares that we store/carry in case of an emergency. Not much point if, in the middle of nowhere, you find that the spare is defective eh!    Enjoy!!                         cheers    - - - - - - steve

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To a man equipped with only a hammer, most problems look like nails