Posted Sunday, April 19, 2009 @ 01:20 PM
Painting the magnesium case will protect the case from corrosion, especially on salty locations (near the sea).
On all engines overhauled by me I use the following procedure:
1) Assemble the short block (engine without cylinders and accessories)
2) Clean it with acetone or nitrate thinner and air dry, mask any hole and everything you do not want painted. Mask the pushrod tube sealing surface on the case, the cylinder mating surface on the case and everything where
3) Apply one light coat of wash primer (best are primers specifically for Aluminium)
4) Apply one coat of polyurethane enamel (the colour you wish, dark is better)
5) Clean and paint the cast iron cylinders with black high temperature paint
Now you can proceed with the final assembly.
Advice: no paint between case and cylinder base, no paint below bolts and nuts and everything that must be torqued or you will loose your torque due to paint collapse between the parts.
Enjoy with your new engine!
ciao
Eugenio