mark davies Posted December 31, 2013 Share Posted December 31, 2013 hii used johns advice on cam timing for 2500 just one qustion iv fitted cam with its matching followers then double stacked no 1 and 6 do i rhen messure the height when they open and close so that they are the same then button up camthanks Quote Link to comment Share on other sites More sharing options...
GT6 M Posted January 1, 2014 Share Posted January 1, 2014 8621 wrote:hii used johns advice on cam timing for 2500 just one qustion iv fitted cam with its matching followers then double stacked no 1 and 6 do i rhen messure the height when they open and close so that they are the same then button up camthankstotally lost on this top oneand this bottom one, could ye elucidate it better please.!M Quote Link to comment Share on other sites More sharing options...
JohnD Posted January 1, 2014 Share Posted January 1, 2014 If Mark is referencing this John, then he may mean "Equal Lift on Overlap" as a method of setting the cam, which I have advocated. This relies on the fact that a Triumph four and a six can both be considered as two half engines that are mirror images of each other across the midline (an only partial analogy!) and 180degrees out of synch.Both Nos 1 and 6(or 4) pistons will be a TDC simultaneously, but if No.1 is on the firing stroke, while No.6 is between the ene dof one (Otto) cycle and the beginning of the next. BOTH valves are open, the exhaust closing and the inlet opening, and Triumph camshafts are 'symmetrical', with the same profiles on both valves and the same spacing.So, set the crank at TDC (no.1 and No.6) and then the No.6 cam lobes so that they are the same distance from the midline, giving the same lift on each of the No.6 valves. THEN you can "button up" the cam drive, link crank and cam via the chian an sprockets.The more conventional method uses the 'magic number' that the cam grinder gives you, the angle After TDC when No.1 Exhaust valve should be at max lift. Both methods are equally valid, unless you have a most unusual cam grind, that makes it non-symmetrical, but witha conventional cam ELoO can be used if you don't know the number.John Quote Link to comment Share on other sites More sharing options...
mark davies Posted January 1, 2014 Author Share Posted January 1, 2014 yes i used your method john with piston stop actually i did it 4 times because i couldnt believe how simple it wasso just to clarify i measure the lift on no 6 and when its equal i m therei can always double check when i refit the head as per workshop manual once again thanks john Quote Link to comment Share on other sites More sharing options...
mark davies Posted January 1, 2014 Author Share Posted January 1, 2014 iv never had the need to fit camshaft in the past so i rang a dozen motor repairers in town they all made it sound like black magicin fact half of them declined because they said they could not do iti have the practical skills to do the job but need to understand the theory so in conclusion have a go dont second guess yourself Quote Link to comment Share on other sites More sharing options...
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