Mountainman wrote:
I've had great luck with milling about 20 of these heads. No copper Cote. I'm too afraid of changing my engine building from how I was taught, although the copper stuff is intriguing if it is filling in little imperfections, especially on these rough blocks. I've tested my engine with very heavy towing in the mountains, had a seized thermostat that caused a boil over, and a failed coolant fitting that caused another boil over, plus several 4000 rpm runs, and my milled head has survived. So I think milling is safe, but if the copper Cote passes the same torture tests, or as soon as I see it last for 200k on lost members engines, then I'm all in. Would save time and money to skip the machine shop!
How much are you milling off the heads? Its kinda important for others to know.
I you look up the specs for Cometic and FelPro MLS gaskets, they specify a smoothness factor on both the block and head. IDK the exact number but its almost a mirror like finish.
(kinda excessive if you ask me)
They also say not to use any additional sealers because there is already a coating on the gasket.
Spraying on something like copper coat just adds a layer of security for those who have doubts about meeting that "smoothness factor."
Myself, I use Mopar spray gasket adhesive (red sticky stuff).
IDK who makes the MLS head gasket for the CRD but all the major manufacturers seem to have the same specs.
In the racing world of high HP, high compression turbocharged/supercharged/nitrous engines, MLS head gaskets are the norm. Some of those guys are reusing their MLS gaskets. But they drill out the rivets, separate and clean each layer, then reassemble with some spray sealer on each layer.
Of course in these situations, lifted heads and blown head gaskets are also the norm. And they are only going 1/4 mile at a time. But its whatever it takes to get the car back on the track for the next run.