Triumph Repair: auto ignition vacuum pipes, vacuum pipes, upper radiator hose

Question
QUESTION: What does the auto ignition vacuum pipe system do and why is it important?  Should I replace the fuel traps on a regular basis? And can they be put in the wrong way?

ANSWER: Hi Dave,
You will have to tell me what kind of car you are working on first.
Howard

---------- FOLLOW-UP ----------

QUESTION: sorry:  1974 Triumph TR6

Answer
Hi Dave,
The TR-6 had several changes in vacuum designs. Some had a vacuum advance unit and a vacuum retard unit on the distributor. Generally all vacuum retard units are powered by direct manifold vacuum. Vacuum advance units are powered by "Ported" vacuum. (vacuum that comes from the flange of the carburetor.) Most TR-6 cars have had most of the vacuum lines and other devices like a thermostatic switch in the upper radiator hose removed and discarded. Some of the cars that came with both units had the vacuum retard unit blocked off by the factory. All of this was in attempts to get clean emissions.

To ID a vacuum retard unit or an advance unit just look at the distributor rotation. This one rotates counter clockwise. Think of the PULL of vacuum and if it looks like it is pulling the rotor in the direction of rotation then it is a retard unit and if it looks like it is PULLING against rotation, it is an advance unit.

If you have a port on the carburetor for vacuum I like to use vacuum advance. If there is no port on the carb then you are committed to using vacuum retard.

If you are restoring this car to original you need to contact Moss Motors or some one like that to see if you can get a vacuum diagram for your car.

Howard