Carba1984 Posted August 17 Author Report Share Posted August 17 Now that you say it, I think they are welded and closed. about idling, is it normal that the best way it behaves is with the screws released? Link to comment Share on other sites More sharing options...
johny Posted August 17 Report Share Posted August 17 No normally, as long as the throttle cable isnt too tight or the fast idle incorrectly adjusted, the engine should stall if the screws are completely undone. Then to get it to idle you have to use the screws.... Link to comment Share on other sites More sharing options...
Carba1984 Posted August 17 Author Report Share Posted August 17 1 minute ago, johny said: No normally, as long as the throttle cable isnt too tight or the fast idle incorrectly adjusted, the engine should stall if the screws are completely undone. Then to get it to idle you have to use the screws.... The throttle cable is correct, the fast idle well adjusted, I'm clear that there's a problem with the carburetors Link to comment Share on other sites More sharing options...
johny Posted August 17 Report Share Posted August 17 So looks like air is getting in somewhere. The engine wont stall even with the stop screws undone and if you close the butterfly plates by twisting the spindles by hand? Link to comment Share on other sites More sharing options...
johny Posted August 17 Report Share Posted August 17 Does it continue to run if you completely seal the mouths of the carburettors with something so no air can go in? Link to comment Share on other sites More sharing options...
Carba1984 Posted August 17 Author Report Share Posted August 17 8 minutes ago, johny said: So looks like air is getting in somewhere. The engine wont stall even with the stop screws undone and if you close the butterfly plates by twisting the spindles by hand? I don’t know, I’ll check Link to comment Share on other sites More sharing options...
Carba1984 Posted August 17 Author Report Share Posted August 17 7 minutes ago, johny said: Does it continue to run if you completely seal the mouths of the carburettors with something so no air can go in? I think the engine turns off, I’ll check too Link to comment Share on other sites More sharing options...
Peter Truman Posted August 17 Report Share Posted August 17 Before I rebuilt the SU’s on the daughtersMk2 Spit I put plastic end caps on the LH spindle end of the rear carb and one on the RH end of the front carb well it had to reduce the leakage by half! Link to comment Share on other sites More sharing options...
Carba1984 Posted August 17 Author Report Share Posted August 17 (edited) 49 minutes ago, Peter Truman said: Before I rebuilt the SU’s on the daughtersMk2 Spit I put plastic end caps on the LH spindle end of the rear carb and one on the RH end of the front carb well it had to reduce the leakage by half! And where did you get those caps? Edited August 17 by Carba1984 Link to comment Share on other sites More sharing options...
Carba1984 Posted August 29 Author Report Share Posted August 29 Guys, I'm back to the mess, in the summer I put the distributor at the Maximum revolutions and that's how I wear it now, yesterday I checked with the strobe gun and I see that I take it at 48 degrees BTDC, off the scale!! Is this normal? The car works well on the road Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 29 Report Share Posted August 29 48 deg is very not normal can happen on the 6 cyl if the damper ring is loose but not on any 4 cyl at 48 something is not right this could be a problem with the pointers rather than the base engine especially as you have been chasing this for too long make a piston stop and check the TDC pointers are OK Pete Link to comment Share on other sites More sharing options...
JohnD Posted August 29 Report Share Posted August 29 (edited) Carba, Pete is correct (of course!). The pulley on the nose of the 6 crank doubles as a crank damper to suppress torsional vibration, not needed on the shorter 4 cylinder. It does so by having a thin rubber sleeve between the hub and the outer ring (the 'inertia ring'). That rubber was little different from tyre rubber, and it's remarkable in the heat and oil of the engine bay that the rubber is still there! After 50 years it often no longer works as a damper, and sometimes loses adhesion with the metal, allowing the inertia ring to rotate. That carries the timing marks which become nonsense. Check that real TDC, measured with a piston stop, coincides with indicated TDC. If not, your pulley must be rebuilt or replaced. Just marking real TDC won't help as the ring will move again! John Edited August 29 by JohnD Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 29 Report Share Posted August 29 you can make aa piston stop by adding a bolt into and old spark plug and fit in No1 plug hole . remove all plugs and turn engine BY HAND to make a piston touch the stop bolt, mark the pulley turn back one full turn to again touch the stop and mark the pulley TDC is halfway between the two marks it should tie up with your timing pointers ???? dont forget to remove the piston stop when you have finished or it can get expensive !!!! Pete Link to comment Share on other sites More sharing options...
Carba1984 Posted August 29 Author Report Share Posted August 29 Guys, I don’t understand, I don’t know what is TDC Link to comment Share on other sites More sharing options...
Colin Lindsay Posted August 29 Report Share Posted August 29 https://dannysengineportal.com/top-dead-center-is-when-the-piston-is-at-the-top-of-its-stroke/ Loads of pages on the Net, this may help explain the theory, but actually doing it is always a different matter! 1 Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 29 Report Share Posted August 29 TDC is short for Top Dead Centre ie when piston is at top of its stroke the timing pointers on the crank pulley and timing cover should show this but they can be wrong . we use a piston stop to check as there is a good amount of crank rotation when the piston is at TDC so having two fixed positions (a piston stop) and half the marks is a very accurate way to get actual top dead centre and check your triumph made pointers Pete Link to comment Share on other sites More sharing options...
Carba1984 Posted August 29 Author Report Share Posted August 29 I know!!! But in Spanish it’s PMS 😂 Thanks a lot 1 Link to comment Share on other sites More sharing options...
Carba1984 Posted August 29 Author Report Share Posted August 29 So, when piston number 1 is in the TDC does it have to match the mark of the pulley in 0 degrees? Link to comment Share on other sites More sharing options...
johny Posted August 29 Report Share Posted August 29 Exactly but remember theres a TDC compression stroke and TDC exhaust stroke and the pulley mark will show zero degrees for both.... Link to comment Share on other sites More sharing options...
Carba1984 Posted August 29 Author Report Share Posted August 29 2 hours ago, johny said: Exactly but remember theres a TDC compression stroke and TDC exhaust stroke and the pulley mark will show zero degrees for both.... I'm not sure if I understand you, I have to take into account if it's compression or if it's exhaust? When piston 1 and 4 are up they have to coincide with 0 degrees When piston 2 and 3 are up they have to coincide with 0 degrees too Correct? Link to comment Share on other sites More sharing options...
Carba1984 Posted August 29 Author Report Share Posted August 29 I can check the TDC using a camera that I can put in the compression chamber Link to comment Share on other sites More sharing options...
johny Posted August 29 Report Share Posted August 29 ok yes do that and when the piston is at TDC the pulley must show zero degrees👍 Link to comment Share on other sites More sharing options...
Carba1984 Posted August 29 Author Report Share Posted August 29 Ok, I’ll do that, thank you very much, I’ll tell you Link to comment Share on other sites More sharing options...
Pete Lewis Posted August 29 Report Share Posted August 29 as there is a lot of crank rotation with the piston approaches and leaves TDC a camera wont be accurate it will see the piston position but you cant be sure of the crank which can be way out there is around 10deg rotation either side of TDC with no obvious piston movement sorry a fixed piston stop is the best way Pete Link to comment Share on other sites More sharing options...
Iain T Posted August 29 Report Share Posted August 29 Buy one of these, easy to use. Take out all the spark plugs as it makes it easier to MANUALLY rotate The engine. One check to see if it's a compression stroke is to put your finger over the plug hole. You can feel the compression. Then install the stop and rotate clockwise and anti clockwise. Mark each stopped position on the pulley. TDC is half way between the two marks. 48 degrees at tick over has to be a record! Iain https://www.ebay.co.uk/itm/394654047120?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=UlyIrJAdQnS&sssrc=4429486&ssuid=cEUMQlgRQ_y&var=&widget_ver=artemis&media=COPY Link to comment Share on other sites More sharing options...
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