I have now taken the upper crankcase case back to bare metal. Do I need high temp primer or will UPol or similar etch primer suffice? I have the PJ1 for the head, barrel and cover and perhaps thinking of using it for the upper crankcase also, but wouldn't mind using an etch primer as it is now bare metal.
Thoughts welcome.
Incidentally for the top end bits, I was thinking of vapour blasting back to bare metal then high temp (etch) primer, then PJ1. Bit nervous about the beads in the vapour blasting becoming entrained somewhere - a thorough clean I suppose?
