Opti wrote:
Ive heard a lot of contradicting info, with break in oils and periods. Ive got to the point if its a roller motor, i drop some decent conventional in it, run the piss out of it for a few hundred miles, drain it and put the good stuff in it.
Break in oils and procedures are super important on flat tappet cam motors though
Yeah, if you don't have a flat tappet cam to worry about, oil selection and such isn't terribly important for break in and there's no need for the long high rpm runtime at startup. Just fire it, get the rpms up a bit for good oil flow until it starts to warm up and you're sure it's not leaking coolant or anything, then get some load on it (drive it). Oil-wise, use whatever is appropriate for the thing viscosity wise. Even synthetic will work, although unless the engine is turbo-ed or otherwise likely to cook a conventional, I'd run the cheaper stuff for break in.
Once you're ready to drive the thing, don't wind the rpm all the way up for the first miles, but definitely get some decent load on the motor to make sure the rings are well seated (doesn't have to be WOT though). I'd say 2/3 throttle and 2/3rds of redline should be a good metric.
So I'm no expert on car engine break in, but I've rebuilt more that a couple cycle engines in my life, and I always thought proper heat cycling was key to a successful break-in.
From my engine builder, roller cam and rocker SBF:
"Again unless I have given you specific instructions, run any name brand conventional 10w30 motor oil. I always do two quick oil changes, about 75-100 miles apart, then cut the filters open to make sure there is nothing in there. After 1000-1500 miles, feel free to run any oil you are comfortable with, whether it be conventional or synthetic.
Now onto the piston rings, the way we hone nowadays and the rings we use, rings are typically seated within minutes, after a few full heat cycles, the rings are surely seated. Take precaution to minimize washing the cylinders with gas on initial startup, if all goes well on the first start, run the engine for a few heat cycles. Feel free to do a leakdown and you will see the rings have seated almost immediately. Once you are comfortable, by all means go ahead and start banging gears. If there is a problem with the engine it will rear it's ugly head quickly. I don't follow or buy into the 1000-2000 mile break in theory, I run my engines hard right from the get-go, and my engines are no different than the one I built for you."
