Checking the top dead center mark.

I got hold of this one https://www.compcams.com/top-dead-center-stops-14mm-bolt-style-heads-on-big-block-ford-cpg.html

I would be interested to know if the top dead center mark on my car Harmonic Balancer is correct.

Can this be used on a 1979 Ford 6.6 engine?

Some say that it would hit the valves and cause damage to the valves, is that possible?

 

It's possible, but not likely. But, to be on the safe side, just remove both rocker arms on the #1 cylinder, and then go ahead and check for TDC. You will be happier if you remove all 8 spark plugs before starting to check for TDC.

 

So this wasn't as easy a job for me as I thought, I guess I won't be able to do it.

 

Possibly find a friend who can help - the rocker removal/install is fairly simple. If you can change spark plugs, you can do the rockers.

 

It's not quite the same, to me.

I watched a couple of YouTube videos about what's inside the valve cover.

I think I understand your instructions , good instructions, when I remove the rocker arms for cylinder 1, the valves don't move and stay safe during the TDC check ?

When I install the rocker arms back in place, do the pushrods of cylinder 1 have to be in a certain position ?

Apparently the valve cover gasket on that side is also leaking a little from the back, I'd probably have to replace it at the same time if I open the valve cover.

 

That is correct, removing the rockers prevents any possibility of valve damage.
No, the pushrods stay where they are - it's easiest to re-install the rockers if the pushrods are "down" all the way.
The gasket will most likely be a bigger pain than the rockers or TDC check. NOT tough, just a bit of a pain.

 

Yes, I understand that the pushrods stay in place during the TDC check, but they still move up and down when I crank the engine. So the rocker arms are screwed in place when the pushrods are down, sounds reasonable.

Apparently the gasket would be easier to get in place if there were stud bolts in the valve cover.

 

The hard part is not locating the gasket properly, it's cleaning all the old, burnt gasket from the cover. The studs are a nice addition, and, yes, easier.

 

Okay, maybe the gaskets in my car haven't burned out badly yet, they were replaced last year at a garage...

I adjusted the ignition timing this spring and thought I'd also check that top dead center mark, of course I should have done that first.
I noticed that the ignition timing changes quite a bit when I changed the preload of the distributor springs.