Cam and chain

[74er]

A couple questions as I want to keep at it tonight:

1975 2.7L Cam and chain question

Does it make a difference if you use the CIS method vs. the high lift method in Wayne's book? I have a CIS engine but found the high lift method the easiest to understand so I timed the Cams to that. I installed SC cams with CIS pistons with 1.5mm overlap.

I have C clamps holding the chains tight now. Can I remove them and install the tensioners without loosing timing?


Thanks.

[Eagledriver]

I don't know what the "high lift" method is. SC cams have a range of use from .9mm to 1.5mm. so you are at the retarded end of the spectrum but that should be fine.

-Andy

[74er]

Thanks. The high lift method is where you put the crank at Z1 and rotate the cam to get your overlap value. But this method is supposed to be used for overlaps at or above 2mm.

[JFairman]

Originally Posted by Eagledriver

I don't know what the "high lift" method is. SC cams have a range of use from .9mm to 1.5mm. so you are at the retarded end of the spectrum but that should be fine.

-Andy

If his intake valve lash is correct at .004" and the intake valve is open 1.5mm at TDC (intake and exhaust valve overlap) before the intake stroke, cam timing is at the advanced end of the spectrum listed above not the retarded end.
That would be better for low rpm power and acceleration leaving stop lights and corners during low speed city and around town driving.

[K Sykes]

Originally Posted by 74er

A couple questions as I want to keep at it tonight:

1975 2.7L Cam and chain question


I have C clamps holding the chains tight now. Can I remove them and install the tensioners without loosing timing?


Thanks.

You can remove them without losing timing, IF, you keep enough tension on the chain that it does not drop a tooth either on the cam gear or the one inside the case. It's surprisingly easy to loose that tooth. Very good practice to check the timing again once the tensioner is installed.