Quote:
Originally Posted by JayJay
I was unaware of the requirements for finish quality, but it certainly makes sense. In my case it was a freshly decked head and a freshly stoned block but still leaked. Replaced with the copper-treated graphite and no issues.
Jim Brierley makes a good point. If you use the copper spray on the graphite gasket it does stay tacky and is a bear to remove. I've had to pull heads twice after installing that way and the graphite gaskets split down the middle, had to scrape both the head and the block. Copper gasket is definitely easier to remove. On the other hand, hopefully when we install a head gasket it's for keeps.
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I lean more to the mindset that I thought people knew. In a nutshell, this modern technology gasket needs modern technology machine work. I use a CBN cutter on my Surfacer which produces a mirror like finish. Many Model-A engine rebuilders have this level of machine capability however, likely there is more that do not. Just because it is a freshly machined head or block does not mean the surface finish is satisfactory. In the day, Ford used a segmented stone with coolant to finish the surface. This produced a finish even nicer than what dry-stoning a valve seat produces. A cut with HHS or Carbide cutters will never produce the proper RA finish.
Also, typically when Copper Coat must be used on a head gasket, it is band-aiding something. Prove me wrong on this.
