Engine Break-In Oil

Some engine builders like to use API CJ-4 diesel motor oil as a break-in lubricant for new engines. That’s because it contains plenty of zinc (ZDDP) to protect flat-tappet camshafts. Apparently this oil is being replaced with a new formulation, API CK-4 and CK-4/SN (SN means the oil meets current year API standards). And just

Got questions? We’ve got the answers—the Summit Racing tech department tackles your automotive-related conundrums. This week, we’re providing tips on proper engine break-in. Bill M. • Summit, IL Q: I have a Chevy big block that I’m going to use specifically for drag racing. I was wondering, what is the best way to break-in a