David,
Most everyone you ask will have different - sometimes contradictory - ideas
about the best way to break in an engine. Whichever break-in oil you use, it
should be changed right away. Recommendations are from after the first
fifteen minutes of running to no more than the first 1000 miles. There are
special break-in oils available, for example from John Deere. If I were you,
I'd just use some name brand straight 30W oil. Pre-oil the engine by either
spinning the oil pump shaft with a drill motor (counter-clockwise), or pull
the spark plugs and crank the engine over until you get a good oil pressure
reading. Now, the engine is oiled and ready to be fired.
When it first starts running, keep it at 2500 to 3000 rpm no load for about
fifteen minutes. Keep a sharp eye out for leaks (oil & gasoline) and engine
temperature. If everything is OK, then shut it off and change the oil if you
like. Now you are ready to drive it around. Now is the time to start giving
it some full throttle; not real high rpm's, but full throttle to put
pressure on the rings so they seat. It's important that you have a
thermostat that's at least 180F. Some people like to use even higher
temperature for break-in. Of course, don't let the temperature get too high,
which could indicate some kind of problem like not enough piston or bearing
clearance or cooling system problem that could cause hot spots. Ideal
break-in is probably around 190-210F, varying rpm's from 2500-4500 and
plenty of full throttle time.
Many new engine manufacturers are recommending single viscosity oil because
they last longer. On the other hand, I think multi-viscosity is better and
especially if you change the oil every 4-5k miles. The second number is the
one that counts, as it refers to the hot viscosity. The 'W' in 30W doesn't
stand for 'weight', it stands for 'winter' and it's the viscosity of zero
degrees F. Additives are used to stabilize the viscosity versus temperature,
but they have some disadvantages. 10W-30 or 15W-30 seems to me to be a
reasonable compromise between, say 5W-50 and straight 30W oil.
BTW, using a 50 weight oil to increase oil pressure is, in my mind, specious
thinking. While it's true that low oil pressure is a bad sign, for example
bearings going bad, the reverse is not the case. You want good oil flow, not
high pressure per se. If you are racing the engine and the oil temperature
is 250F and the viscosity of water, then a 50 weight oil makes sense. But
putting 50 weight oil in for normal driving so you get 70 psi instead of 60
is just a bad idea.
Starting up a new engine is, or should be, a fun experience. I hope it is in
your case.
Bob
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