Fernox

Taking into account that SU carburettors require a supply pressure of between 1.5 and 3 psi I would advise anyone fitting a fuel pipe around the engine bay to ensure that there is a continual rise in the pipe to the carburettors. This will help to avoid small vapour bubbles accumulating at high spots in the pipe and forming a large bubble (this acting as a shock absorber compressing and expanding with each stroke of the pump and not allowing any fuel to pass) therefore allowing the bubbles to rise to the carbs. where hopefully they will escape through the needle valve and into the float chamber/s. I see that the majority of petrol pumps currently for sale have an outlet pressure of 5 psi which I have found to be slightly too much for SUs and cause intermittant flooding. Regards, Colin

That is very interesting, My wife's Spit. 1500 has a very similar set-up and has run on AAQ needles for years. If I remember correctly the "Triumphtune" manual and also Moss recommend AAQ needles when fitting the sports exhaust system and K&N air filters to the Spit. 1500. Thinking about it you are probably correct regarding the pattern of performance although it has not been an issue for my wife. It is something I may have a go at sometime. Regarding the wideband sensor and gauge, I have fitted one to my TR2 after converting the SU H6s to HIF6s, and found it very helpful in setting them up. They tend to become redundant after that exercise is complete. Also I found that the sensor in the exhaust pipe is very easily damaged by thermal shock caused by droplets of condensation on start-up. I now always wait till the engine has completely warm up before switching it on. Regards, Colin

I have the AEM with Bosch sensor on my TR2. I made two mistakes. 1. I connected it so that it came on with the ignition before the engine started. The problem is that the sensor is very sensitive to thermal shock and starting a cold engine can cause small droplets of condensation to hit the sensor and damage it. The sensor failed so I replaced it and fitted a manual switch on the dash so that I could switch it on after the engine warmed up. 2. I welded the 18mm metric fine boss into the exhaust pipe slightly lower than the centre line (I should have removed the tubular manifold to get better access) which allows any droplets of condensation to find their way into the sensor. Otherwise I have found it very helpful in setting up the twin HIF6 carbs. which I have fitted together with the later longer TR inlet manifold. Regards, Colin

Regarding petrol pumps for TR2, 3 and 3a I have found that most of the current reproduction ones all have an output pressure of 5 lbs psi when the SUs require between 1.5 and 3 lbs psi resulting in intermittent flooding. The cause is not obvious and can result in a lot of time and money wasted chasing other possibilities. The suppliers said that they were all the same and all from the same source. I eventually solved the problem by replacing the diaphragm spring with the spring from the old pump. I have to say that the build quality looks to be otherwise very good. Regards, Colin