Camshaft binding after tourqing head studs

[d_boyce]

Camshaft has a slight drag to it. I've re-done the head stud tightening sequence 3 times with the same results.

Suggestions please

-doug

[john walker's workshop]

then one of the heads is thicker or thinner than the rest, you could have a cylinder with a different height group, or the cylinder bases on the case are worn to different heights. year of engine/car?

[hobieboy]

I had the same issue last winter - replaced the camshaft (with a new one) and after installation, the right side has a serious drag. Measured the runouts on both cams and they are very small.

I finally "fixed" it by changing the torque pattern.

[d_boyce]

Head stud pattern or cam tower pattern?

This is a 3.6 liter that is a new rebuild. I had to partially take down one side after assembly to replace an improper set of rings and I'm in the process of putting it back together. When I first assembled the engine the camshafts did turn freely.

-doug

[hobieboy]

In my case, both...

[john walker's workshop]

a 3.6 shouldn't have the issues i described, especially one that's using the same parts it came with. uneven setting of loctite 574 between heads and cam tower could be an issue. were the heads removed from the cam tower to correct the ring problem, or were they left on?

[d_boyce]

Two of the heads were left on the cylinders.

Perhaps I should just start over with the cam tower install?

By the way, I really appreciate the advice.

-doug

[john walker's workshop]

yeah, i'd re-do that side.

[Wayne 962]

Clean everythiing real well too, prior to reassembly...

-Wayne

[hobieboy]

Yes, that's what I did as well - Removed the CAM tower from the head, clean everything really well & re-assembly. During my re-assembly, I did use different torque pattern than before. Rather than torque to 75% then all the way per Wayne's book, I also did many smaller increments with the CAM inserted in the tower.