Engine assembly question......
 

Which is the preferred method of assembly?

1) install and torque heads and then add the cam housings.

2) install heads but don't torque, install and tighten the cam housings and then torque the heads.

3) install heads but don't torque, add the cam housings but don't tighten to the heads,
torque the heads and then tighten the cam housings.

The reason for this question is that while pre-fitting parts, I had the cylinder head nuts tightened but not torqued. When I attempted to place the cam housings on the heads the (long) studs on the top of the heads seemed to need a little wiggle room for the housings to slide on easily.

Thks,

Choice #3 is the method I used. As you noted, it's helpful to have the cam housing pins lined up perfectly when installing the cam towers, and installing the cam tower loose and dry to "register" the heads does the trick.

Once the heads were torqued, I did torque the cam towers down temporarily so that I could insert the cam and make sure that it spun freely without binding, which would indicate distortion of the cam tower due to uneven head height. You wouldn't want to find out that you had a problem after applying sealant.

There are numerous threads about this - some assemble the heads to the cam towers on the bench, then install the heads/tower as an assembly.

GK

We install the cam towers on the heads while on the bench. We even install the cams rockers and set the valves while on the bench. I've been told and seen pictures and thats how the factory assembled them. I have seen people miss align the dowels and screw up the cam towers trying to do it after the heads are on the cylinders.

You can't do number 1. If the heads are torqued prior to installing the cam tower the chance of having the locating dowels align is almost impossible.

Number 2 is how we build high performance engines where critical dimensioning is paramount.

Number 3 works when we're performing a generic overhaul where dimensions are known and less critical.

Thanks, all, for the input!

Henry,

What do you think of the method above by installing the towers to the heads and then put it on as an assembly