Prime engine?

[moto x]

I just got my 4g63 all assembled what is the best method to prime the engine with oil and what weight oil should i use for first start up. Its cold here in the winter 20 F.

 

[Mr Peepers]

Spinning the oil pump sprocket with a drill before you put the timing belt on is probably the best way. If you already have all the timing components on then I say unplug the MPI fuse and coil pack, then turn it over for 10 seconds, wait 20 seconds, turn it over another 10 seconds etc etc until the oil light turns off and/or you see pressure on the oil pressure gauge. You can also take the valve cover off or just look under the oil cap to make sure oil is getting to the head. After that you should be good to fire it up.

I always recommend 5w-30 or 0w-30 if you can find it for oil in general, no matter what time of year since oil is always too thick for startup, and volume/flow, not pressure, equals lubrication. ~90% of engine wear occurs at startup(every start up, not just after rebuilding the engine) since the oil is too thick to lubricate properly

The first number is the viscosity index at 75* F in a multigrade oil and the second number is the viscosity index at 212*F(oil operating temp during street use). You want the oil to be at 10 cS(centiStrokes) at 212*, which is what any xw-30 will do. The higher the number, the thicker the oil, so having the lowest(thinnest at stratup) first number and 30 in the second is ideal. Remember, there is no motor oil(currently) that is too thin at startup, and flow(not pressure) equals lubrication.

There may be some exceptions, so you can find out exactly what your engine needs by going by the golden rule that for every 1000 rpm there should be 10 psi of oil pressure at operating temp. There is no oil that will get you that at start-up, so get as close to it as possible, and make sure it reaches it during the operating temp of oil. It takes ~30 minutes of driving to get oil to its operating temp(212*F), long after the coolant is at its operating temp.

Basically, go with the lowest first rating and 30 in the second rating. Use castor oil for break in, and change the oil/filter after the first 20 miles of driving. Break-in procedures are personal preference. I seem to agree with MotoMan's veiw.