when putting your main bearing caps back together for final assembly, what if anything do you coat the bolt threads with??

 

You need to use a thread lubricant that corresponds to the torque specs you are using. Since I use ARP fasteners, I use the lube that they supply, called "ARP Moly" lube. The chart here http://www.arp-bolts.com/pages/tech/images/fasttorq.pdf gives some general guidance wrt torque specs using ARP Moly lube. Notice how the specs for oil are higher, that's 'cause it's more slippery than the moly lube and therefore requires more torque to achieve the same clamping force.

Rich Krause