Cam Chain Tightness

[P Clingman]

Does anybody have any thoughts on how tight to make
the cam chains during cam timing adjustment? In Wayne's
book it said to make the very tight by clamping the idlers
and adjust the cams with them tight. I noticed if you check
them after you loosen the chains a little the value goes up by as much as .05. So my question is how tight are they when engine is running with carrera tensioners and if you do your adj with them
to tight then during engine operation wouldnt the values would be out of spec? Thanks Palmer

[GBStu]

I had the same thought this weekend after timing my cams:

As Wayne's book suggested, I clamped the tensioner arms "quite" tight and timed the cams to 1.26mm (49.6 thou). My actual measured values were 52 and 51 thou. After replacing my non hydraulic tensioners I measured again, now they were 47 and 46 thou. I removed the tensioners, re-clamped the arm and measured 52 and 51 thou.

I’m guessing that this is why there’s a tolerance on the timing?

[kstylianos]

Tightness is not as important as equal tension on both chains. Cam timing is dynamic (cam timing retards as RPM's increase and vise versa) and making sure both chains are tensioned and timed equally will ensure both cams will advance/retard together. And yes, that why there is a timing 'range'.

[P Clingman]

How be shure you have the same tension on both chains when you are
doing your adj if one is tighter during adjustment the the will have diffrent values when the hydro tensioners give them equal tension
when engine is running. Its kind of tuff to be exact with a c clamp
or vicegrips. Has anybody ever tryed to presserize the tensioners
with air or oil I would think you could get equal tension that way
Thanks Palmer

[350HP930]

Lube your chains too since it effects their length enough to make a difference.