[peppy]

Originally Posted by smokintr6

I would replace them with whatever your research tells you is best, but I would start with all new studs. Maybe that's what you intended to do, and I didn't understand they way you wrote it. I would have to scan my notes to see what I used last time...they may have been all steel, I just don't remember, and I don't want to speculate. I have seen some builders commenting that doing half the studs in 993 Dilivar isn't a bad decision either. The Dilivar lasted 20 years the first time, there's no reason to suspect it wouldn't continue to provide that level of service now. I don't mean to muddy the waters of you research anymore than to suggest that you have all new studs to start with, even though the steel uppers should be possibly OK.

911st, Nickasil is a coating that can be bored or honed through into a naked cylinder wall. The Nickasil coating can then be reapplied by companies that specialize in that process.

Alusil is not a coating. The whole sleeve has the same composition, a monolithic if you will. Using corse stones and a Sunnen hone you can "bore" the cylinders out, but they are still alusil. You must then use a finishing process to raise the silicon (not silicone) particles to the surface. Silicon particles are hard to provide wear resistance, and require a special piston ring. I have spent several weeks of my free time researcing this topic, and there is an overabundance of information and misinformation out there. One easy source of good info is the Porsche 944 and 944 turbo factory service manual, as all 944's had Alusil blocks. You can also still find some information on Kolbenschmidt, the OEM.

I do not know if you can Nickasil plate on a bored out Alusil cylinder, I was not aware that you could... maybe someone can set me straight on that.

My understanding is they can take alusil cylinders, bore them, and then replate with nikasil.