slight concern with chain tension

PostPost by: tdafforn » Thu Jul 05, 2007 2:59 pm

Hi All,
Got the engine almost back to one peice. Now have the cams turning with the crank. One concern however.
(note I have converted the engine to use a longer stroke 711m block. )
on connecting the chain to the cams I found that unless I got the tensioner quite tight the chain would jump teeth on the crank sprocket.
Is this normal
It now all runs fine, but the chain is quite taught between the cam sprockets. If I push down on the chain reasonbly hard, then the tensioner gives a little and I get the 13 mm slack in the chain between the cams, otherwise the slack is more like 6mm. Is this a problem?
I have also noticed the the tensioner plunger is in more that it was with the standard block. Is this a result of a taller block and longer chain? I have noticed there Burtons sell a longer plunger, is this for the 711m block?
sorry for so many questions, I just worry about the disaster of a valve, piston colision (one of my nightmares!)
Cheers
Tim
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PostPost by: CBUEB1771 » Thu Jul 05, 2007 3:25 pm

Tim,
The first thing I would check is alignment of the chain tensioner plunger to the pendulum bracket that carries the tensioner sprocket. With the 711M conversion you raise the pendulum bracket with respect to the plunger and they probably don't contact each other correctly any longer. The Elan Factory sells a special pendulum bracket specifically to solve this problem with the 711M conversion. I also know of people who have brazed an extension onto the pad on the pendulum bracket to restore proper contact. I don't know what the application is for Burton's longer plunger. Good luck (actually I should say good engineering).
Russ Newton
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