When the engine was first produced, the Shovelhead had a shallower combustion chamber, larger valve drop for both intake and exhaust, better porting, and stronger valves and pistons. I always break 'em in this way, my motors tend to hold up really well.The Shovelhead engine is a motorcycle engine that was produced by Harley-Davidson from 1966 to 1984, built as a successor to the previous Panhead engine. These things have a 3-31/32" stroke, the piston speed and the ring pressure on the cross-hatched cast iron is an engineering problem in itself. That's the point of the painstaking break-in procedure I described. "The motor might just be tight and need more time to loosen up and break in., "Īgain, you're right, of course. "I'm not a fan of Castrol oils, but I don't believe it would degrade that fast." They work OK for anything made in Taiwan, I'd say they catch the big chunks. They use a drop-in pleated paper filter nowadays, a vast improvement over the old dog-hair filters of the '60s and early '70s. Yes, everything gets thoroughly cleaned according to best practices, everything is pre-lubed at assembly, the entire oiling system is pressurized on the bench, flow to all passages checked, oil pump relief valve is checked, and then after installation the motor is not started until the oil pressure is up. We all wish that the kitchens in restaurants were as clean as the inside of my motors at build. I've tried it on a couple of motors, but it is too soon to tell how it is really holding up. Next question: S&S Cycle strongly recommends Mobil 1 Synthetic 20w-50 in their performance motors. But the reason for my question today is this I would have thought that any of the premium motorcycle oils today would be enormously better than anything that was available 35 years ago. Now I know there are a lot of genuine experts here, and I am most grateful for the wisdom shared here. Seriously, you could not miss the difference. So I drained out the 20w-50 Castrol, replaced it with 20w-50 Rev-Tech, and the motor sounds great. Not happening on the motorcycles, at least not today. I understand, I used to run a small fleet, we sent out samples on everything that had anything to do with our class 7 and class 8 trucks. I'm sure someone here will warn me about the necessity of oil analysis. I have no idea what happened to this oil, but it looked like when I drained it out. The motor did not sound like what it should when the lubrication is right. Speed varied, two short hops of about a mile or two with a shutdown, easy road miles generally hanging around 45-50 mph, some backing down from 55, plenty of variance in rpm and a lot of throttle activity oriented toward good oil scavenging.īy the time I got back, the degradation of the oil was unmistakable. Cool overnight, careful warm up, and the 57 mile break-in ride today. The rings seated in the first hundred yards, no mistaking it. Started it again, run for 30 seconds and off to cool. Started the bike and shut it off in a few seconds, let the ring edges cool. Crank pin, rod big end rollers, and right main rollers new, fitted at the middle of spec or slightly tighter, all within 0.0002" of the target. This was stock stroke, new wristpin bushings, Keith Black pistons and rings at 0.0025" on an appropriately flex-honed cast iron cylinder wall (fitted to size with Sunnen stones, old nomenclature might have been AN-300, not sure), Kibblewhite valves in cast iron intake and phosphor bronze exhaust guides, all sealed, and new timing gears, Andrews BH cam and Jim's Machine pinon gear, lash fitted perfectly. Never used it before, and will never use it again. So today I ran a new one about 57 miles on the Castrol 20w-50 that is supposed to be special for air-cooled V-twin motorcycles. You can hear it and feel it in the motor. The new timing gears and new rings on cast iron cylinder walls seemed to eat the good stuff out of the oil rather quickly. I've built more of these motors than I can remember, I think somewhere along the line I realized just by observation that the oil was not doing real well with the initial startup. Truth be told most of these motors leak so much the additives are being continually refreshed anyhow. So if I'm seeing oil temps of 220 I'm not too worried about a 2,000 mile interval, at 240 we're probably looking at sooner. HD published something many years ago that said every twenty degree increase in temp cut the life of multi-vis oil in half. On a cool day like today (mid-forties to low fifties) the oil temp was right at 200F and the head temp hung right around 345F to 350 F. On the basis of experience, I have always started out a rebuilt motor with fresh oil, an oil change at about 50 miles, then again at 500 miles, and then according to ambient temp and use. The HD Service Manual for Shovelheads (the Big Twin produced 1966 to 1984) specifies an initial oil change at 500 miles and then every 2,000 miles thereafter.
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