Re: 1948 Limo Super 8
Posted by Wat_Tyler On 2022/4/15 6:52:00
Interesting read, and my sincere best wishes in getting your car sorted out.
I did some extensive reading on breaking in engines over the last couple of years. I bought a new Harley in 2020 and ordered the engine Stage IV upgrade which includes new barrels, pistons and rings. The upgrade kit was back ordered (kind of like everything else in 2020), so I took delivery of the bike, broke it in, took it back to the shop when the kit came in, and had to break it in again after the kit was installed. Joy - not!!! So I got some practice. On to what I did based on my research.
Apparently, the biggest trick in breaking in an engine is getting the rings to seat properly. Everything you read says to avoid one continuous speed, full throttle acceleration, and high RPMs. But this one article said that, for best seating, vary the pressure and direction on the rings systematically. This is different on a bike, of course, but it should equate to a low-rev flathead inline by accelerating from, say 1400 RPM or so to maybe no more than 2500 RPM and then decellerating in the same gear back to the 1400 and doing it again. The point is to vary pressure on the rings directionally to help them seat. I'm currently doing this with the '47 Deluxe I bought last winter, but I can't speak for the first 250 miles on it since the seller put those on it. I'm almost done the 500 miles and it should be ready for its oil change and the road after that.
Anyway, I used this method on the bike for its 500 mile break-in cycle before it went back to the shop for its dyno-tune. Using my method, the chief wrench got comparable horsepower and better torque readings with the big kit, and mine is a little one. Plus, the factory rating for the kit called for a redline of 6200 RPM and he only dyno'ed mine to 5000. I chuckled all the way home. I don't think I've ever had that bike much past half throttle - there's just no need. Oh, it doesn't use oil between changes, either.
Please file this in the For What It's Worth category.
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