It is time to update this thread re the valve covers for Dad's Engine. There's been a fair amount of discussion on this in that thread, but I'll bring the rest of it over here.

You may/may not remember, but I'm using these valve covers, although the color has yet to be determined.




The problem is that these were designed to use the big wing nuts, and I don't want to use them. In fact, I'm going to use stainless socket-head cap screws (SHCS's). However, on the two holes on the inside edge of each cover the head isn't much larger (.365") than the hole in the valve cover (.3125"), and I don't think that's enough "purchase". Here's how that looks:




Given that, I did a test today. Here's a piece of aluminum drilled .3125" the same as the valve cover and then counterbored .4375":



Here's the screw and a washer turned down to fit:




And, here's the screw and washer in the counterbored hole:




So, that's the plan. The screws and washers are on order and should be in next week. But, I'll wait until they come in to do the counterboring as the heads might be a different height and require a different hole depth.

 

Now that the "how" has been outlined, I have a question for y'all: How deep do I want to recess those cap screws? I've been thinking to make the top of them flush with the top of the valve cover, but they could be a bit lower than that to make them slightly recessed.

Thoughts?

 

I would say flush.

That is odd that they still made the indent in the cover. It looks like there would be two more bolts down below.

 

Flush or a little above.
Definitely not below the surface.

 

Here's what it looks like from the intake manifold:




These covers are TALL and come inside further by far than the stock covers.

 

Kyle says flush and Jim says flush or above, but not below. So, something like this?

 

What about adding an o ring to fill the gap from recessing the bolt.
I think it would look nice and keep crud out of the gap.

 

They do make blue o rings.

 

Why not just barely counterbore, maybe enough so the washer is flush? That way there's no place for the crud to go.

 

I think that is best option. How thick is the metal below the holes?

 

Here's the drawing from Post 91. It is about 4 1/4" from the top of the valve cover to the deck, and there's metal the whole way.




This pic may show it better:

 

Not a fan of the whole head on top, as in your CAD section.

 

Close to flush.

 

There is no 'like' button, but I'm liking it where just the top of the knurl is peeking above the surface.

 

The CAD drawing was just to show the issue with the diameter of the head and the bore. Sounds like consensus is, as Jim said, just peeking out above the top. Maybe 1/8" or so, and I assume similar to the one I posted above? (I was pleased when I saw it, finished, as the head and washer sit in perfectly, like it was planned that way.)