WWDiesel wrote:
Keep in mind when you resurface these heads, you may lose a very thin nickel coating that was OEM applied by the factory to the mating surface.
I just recently learned of this special coating which makes this engine head quite unique compared to most others.
After having worked at a automotive machine and speed shop, I have always been under the impression that any head could be machined, but this one is a little different!
That's interesting for sure, and I don't claim to know half what you know WW. But, removing any coating would just make them equal to a VW aluminum head or Subaru, and ARP's have been proven to keep the seal on the VW's anyhow (and tty bolts for that matter). And repeated runs at 4,000 rpm's has left my HG seal solid after 30k miles. I'm pretty sure the fellow with the high power CRD (makes the ball bearing turbos) had his head resurfaced, and I haven't heard him having trouble.
In addition to that, heads tend to warp a bit, which leads to cracks if clamped strait with heat and pressure, and the fire ring indentation on a used head is WAY out of factory spec for smoothness. I think we will see many failures of HG's in the long term (100-200k) because the micro pathways that gases and coolant can follow. Geordi's solution of spray gasket may just stop this slow break down of the seal, but I just go for a new factory like seal because that's how I was taught by the gasket manufacturers. Well over a dozen of my resurfaced heads out there, no complaints yet.
FWIW