NON-DETERGENT 30W. Use it for first fire up, drain and replace filer. NON-DETERGENT for at least 500 miles.... usually I go with 20-50 Castrol (older engines) after that, or Synthetic.
GM additive. Anyone have the part number of the additive... only used once for NEW ENGINE break in period... then change at 1000 miles.
Interesting tidbit from Porsche: They "dry run" (oil is added, no water, nor fuel) by hooking it up to a giant motor and running the sucker at redline for 30 minutes! Reason for no water nor fuel is to reduce hazardous spills. Obviously they have oil in the engine. Just that way when someone buys a new one, and hits the Autobahn... engine is fully ready to go! They also measure the power of the polyphase motor to calculate engine performance on a cylinder by cylinder basis to catch any potentional problem. I don't have the rereference, but it was a SAE tech article a few years back.
tradin1... no problem on sepage with a NEW motor, but had a few with rings that never seated. Someone else did the motor, ran synthetic oil, and always smoked. Pulled pistons, berryball honed it, new rings... ran fine after that. Cylinders were glazed.
LandCroozer... every notice how hot the engine runs after a rebuilt. Lots of friction between cylinder walls and the rings. That is what needs to "seat in". Basically any metal to metal area is peaks and valleys... so you start with the Rocky Mountains.... then get Texas Hill country landscape!
Tom :usa: