Z320 Posted October 9, 2023 Report Share Posted October 9, 2023 Rob, thank you for helping me. And: there is only "vacuum" and (unplugged) air flow on the pipe from the cab to the vacuum box with the car driving under load. If you rev the engine up in your workshop on what ever revs you want.....nothing happens al all. This is why "unplug the (advance) vacuum box for adjustig the ignition" is another fake story. Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 9, 2023 Report Share Posted October 9, 2023 53 minutes ago, RobH said: No Peter. When the butterfly is closed the hole is covered so there is no vacuum in the pipe and in any case there is virtually no flow through the pipe to carrry away condensate even with a vacuum. You would have to unplug the pipe from the dizzy occasionally, and run the engine at above idle speed to suck air through the tube and hope it takes any condensate with it . Thanks for the explanation Quote Link to post Share on other sites
stuart Posted October 10, 2023 Report Share Posted October 10, 2023 17 hours ago, Z320 said: Rob, thank you for helping me. And: there is only "vacuum" and (unplugged) air flow on the pipe from the cab to the vacuum box with the car driving under load. If you rev the engine up in your workshop on what ever revs you want.....nothing happens al all. This is why "unplug the (advance) vacuum box for adjustig the ignition" is another fake story. Not quite, there is vacuum to the capsule on a closed throttle, as soon as you open the throttle then it destroys the vacuum as the port in the carb is right next to the butterfly edge. So when adjusting the ignition at tickover thats when you should disconnect and plug the line at the capsule. Stuart. Quote Link to post Share on other sites
Smithfire67 Posted October 10, 2023 Author Report Share Posted October 10, 2023 2 minutes ago, stuart said: Not quite, there is vacuum to the capsule on a closed throttle, as soon as you open the throttle then it destroys the vacuum as the port in the carb is right next to the butterfly edge. So when adjusting the ignition at tickover thats when you should disconnect and plug the line at the capsule. Stuart. This is all turning out to be jolly interesting! Quote Link to post Share on other sites
Z320 Posted October 10, 2023 Report Share Posted October 10, 2023 (edited) 7 hours ago, stuart said: Not quite, there is vacuum to the capsule on a closed throttle, as soon as you open the throttle then it destroys the vacuum as the port in the carb is right next to the butterfly edge. So when adjusting the ignition at tickover thats when you should disconnect and plug the line at the capsule. Stuart. If the vacuum unit would cause anything at tick over with the ignition, what is the sense of disconnecting it, make „a proper“ adjustment of the ignition, connect it the next moment with all what it changes and drive the car this way? Why did I never understand this? Edited October 10, 2023 by Z320 Quote Link to post Share on other sites
BlueTR3A-5EKT Posted October 10, 2023 Report Share Posted October 10, 2023 4 hours ago, Z320 said: If the vacuum unit would cause anything at tick over with the ignition, what is the sense of disconnecting it, make „a proper“ adjustment of the ignition, connect it the next moment with all what it changes and drive the car this way? Why did I never understand this? Humour me here……How about….Triumph and Lucas did not talk to each other to correctly specify the distributor advance required for the engine. They must have done some dynamic tests though surely? On the wet liner engine. The Triumph advice is 4 crank degrees TDC static. ( should that have been distributor degrees, therefore 8 crank degrees?) The distributor gives 10 distributor degrees mechanical advance. (=20 crank degrees) That leaves us missing another 6 crank degrees to get to the most it should advance for an engine typically. (Notional 34 degrees at the crank) The vacuum gives an extra 6 distributor degrees, is it? ( 12 crank degrees). - At maximum manifold vacuum Perhaps out factory guidance was wrong to start with? What I do know is that my TR is less than simple to start with any static advance over 10 degrees. But that is another concern. Quote Link to post Share on other sites
Z320 Posted October 11, 2023 Report Share Posted October 11, 2023 (edited) sadly „I don’t know, but I can imagine“ is the reality on most forums, also here. I could explain all multiple faults in your „questions“, but I‘m tiered of explaining and take a brake from this forum. My advice @all: test what ever you have been told, have a close look, measure and you will see most talk is @&€!!?@ Good bye, Marco Edited October 11, 2023 by Z320 Quote Link to post Share on other sites
Smithfire67 Posted October 11, 2023 Author Report Share Posted October 11, 2023 4 hours ago, Z320 said: sadly „I don’t know, but I can imagine“ is the reality on most forums, also here. I could explain all multiple faults in your „questions“, but I‘m tiered of explaining and take a brake from this forum. My advice @all: test what ever you have been told, have a close look, measure and you will see most talk is @&€!!?@ Good bye, Marco I hope Marco comes back at some point....sounded a bit fed up? Quote Link to post Share on other sites
RobH Posted October 11, 2023 Report Share Posted October 11, 2023 (edited) Marco is correct and some time ago he made actual measurements (below ) which prove it. There is virtually no vacuum in the advance system at idle when the car is standing. I can understand his frustration when 'lore' is quoted to counter his measured facts. And here: https://www.tr-register.co.uk/forums/index.php?/topic/77987-centrifugal-advance-curve-and-vacuum-advance-on-my-tr4a/&tab=comments#comment-735767 Edited October 11, 2023 by RobH Quote Link to post Share on other sites
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