I just bought an N scale F7 B. Spectrum A/B unit loco set on clearance at my LHS. I know it doesn’t match up to more expensive engines, but the price was right. Both units are powered, which suprised me. The brand new set runs pretty good, kinda loud gear growl with the two units under power and just a tad jerky, but not bad at all for my display loop running needs. Two questions: The directions mention that the performance will improve with a few hours run time…what exactly does that mean? I have to admit, I have a Spectrum SD45 that runs quieter and smoother, but is 2 years old. I am operating my small layout on DC and have no real plans to upgrade yet. Is it o.k. to run two powered units or am I harming the motors in the locos and making the set run poorly? Thanks ----Rob
Basically that means the gear(s) and worm will “lap in,” or basically grind against each other and create nearly microscopic groove patterns on the faces of the parts that fit smoothly together, improving the contact between them. The drive train will quiet down somewhat and operating friction will reduce somewhat.
What I do with my HO stuff (N should be the same, pretty much) is run it a few hours, then go back and put a bit of grease on the gears (not too much! You’re not trying to carry away heat - just lubricate the sliding faces) and a teensy-tiny dab of oil on loco side rods and axle bearings (just enough to make the contact surfaces damp with oil, not drippy or dust will stick, giving you a horrible mess over time).
A good break in means running the engines forward and reverse on 15 minute intervals changing the speed from slow to medium every 5 minutes. Do this for a couple hours or so. After luricating, it is a good idea to run the engine on a seperate floor loop for 15 minutes so any loose oil or grease doesn’t get slung on your layout track. After this session, wipe down the wheels and power frames.