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Motorhead Memo: Digging on the Shovel

By Kip Woodring

Motorhead-web

2016 marks the 50th annual opportunity to buy a Shovelhead. Better do it sooner than later as they are already worth more than Evos in today’s marketplace. “Worth” is not always the same thing as value, but the reality is that finally… finally… the Shovelhead is getting the respect and attention it deserves. The last of the built-to-be-rebuilt Harley engines, flawed yet fabulous in ways we are about to revisit and explore.

First, the disclaimer: with neither space nor inclination towards an all-encompassing history, we’ll be limited here to engine, transmission and primary drive tidbits. There are books and websites aplenty to give you the poop on bright bits, colors choices and banality ad nauseum, regarding the Shovel’s 18-year reign as Harley’s flagship. I don’t much care, so if you do feel free to look therein. Besides, some of the facts and fables about the engine alone, in its various incarnations from 1966 through 1984, would make for a pretty good sci-fi saga. So, in my best imitation of the late, great Rod Serling, next stop: the Highlights Zone.

It’s October, the summer of love hasn’t happened yet, the Stones and the Beatles are fighting it out on record charts, Vietnam has turned sour, supermodel Jean Shrimpton puts the mini skirt on the map, Batman and Star Trek premiered on TV, and president Lyndon Johnson has just signed into law a newly-created agency known as the Department of Transportation. Which of these events eventually has the most impact on the newly introduced Shovelhead we shall see, but at the time, it remained what Harley Big Twins had been, for over a decade, the largest- displacement motorcycle engine you could buy. Only Norton and Royal Enfield offered even 750cc motorcycles, and 500cc was a big bike, so the 1200 (and change) cubic centimeters that came with a spanking-new Harley 74” had its appeal. The pity is, it would be another five years before you could buy this engine without buying the 750-pound motorcycle it powered. Not that the first FX in 1971 was a featherweight, but to my mind it showcased what a good 74” could do… unfettered. To fathom what I mean by that, we need a simple chronology, so here it is.

1966—Dresser H-Ds were already plenty chunky, particularly with the addition of a twin-shock swingarm frame and electric starter. To haul the avoirdupois, more power was needed. The Panhead had served well, but never without its limitations, so in true Harley fashion, a new top end was stuck on the existing bottom end. Specifically, the Sportster-derived heads were changed from 90-degree valve angles to a more modern, shallower, cooler-running 78.5 degrees in the new combustion chambers, and straighter, more efficient ports with a larger intake valve. Piston crowns were thinner so pistons were lighter, even on high-compression (8.0:1) FLH models. There were no more rocker covers for rockers rocking in the heads themselves, because the new top end had actual rocker boxes! Lending the shape that gave the new top end its name, you could say that Shovelhead rocker boxes really rocked! (That might have a little to do with the very distinctive sound of a Shovel engine as well.) Voila! 10–15 percent more power! Even using the old Panhead Linkert carb and FL low compression of 7.4:1.

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All these good new parts were bolted to a Panhead bottom end. In fact, the top ends were interchangeable, so all these years later the infamous phrase “Pan-Shovel” can leave you wondering.

1967—Oil rings were changed from three-piece to one-piece design, the better to reduce oil consumption. The first Harley carb to feature an accelerator pump was added… the infamous Tillotson!

1968—A new aluminum-bodied oil pump, with larger pressure feed gears, replaced the old steel one. A better Prestolite starter motor and Bendix was introduced which helped a lot on cold winter mornings. The hand clutch-operated assistant/booster, better known as the “mousetrap,” was eliminated in favor of a new release arm, linkage and cable.

1969—No real mechanical changes, for reasons revealed in 1970. But, it’s worth noting that the sum total of all models of these “flatside/generator/kidney” Shovels produced in four years amounted to a mere 29,877. IMHO it’s these machines that represent the epitome of “shovelness.” Nice narrow primary and timing sides, adequate power, kick and/or electric starting and nice details abound… mostly good stuff. Naturally, I’d want to throw out a lot of the bad. First and foremost, toss the points and mechanical advance in favor of electronic ignition, convert to a 12-volt alternator, upgrade the carb (probably to a CV) and for God’s sake… synthetic 20/50 and a good spin-on oil filter! Second (my preference, though I’d never say it about another machine), toss the motor into a light, rigid frame—or at least make something close to an FX version of the existing chassis. With the same goal in mind, add lightness and remove the unnecessary… period. Think about it. No federal compliance to worry about and sheer simplicity in the bargain. Thing is, with such a small number of original machines left to choose from, it might be a form of sacrilege to chop up a survivor at this point. The alternatives we’ll discuss in a bit.

1970—The Shovel top end gets a new bottom end. The only time that’s happened to a Big Twin… I’m pretty sure! From “flatside” and generator to “cone” and alternator in one fell swoop, accomplished via some major changes to the primary drive as well. The outer primary got a removable clutch inspection cover and a bulge in front to clear the stator and rotor, as well as the new spring-loaded compensator (shock absorber) living inside. Oh… and no more “standard” kickstarter. Then, there’s the single bolt intended to hold the head pipes to the engine… never a complete success and never changed from that day forward. Net results? All-around improvements, even though the ignition still involved points, condenser and mechanical advance. Downside? Width and weight added.

1971—AMF ownership and a new VIN numbering system as well as a carb switch from Tillotson to Bendix/Zenith. Willie G.’s FX appears… not a moment too soon… at a svelte 565 pounds half full of gas!

1972—New oil pump gears

1973—New oil pump scavenge gears and new pinion gear. Oh, and no more hand-shift option!

1974—Can’t think of a thing. But everyone seemed to want a “74, 74”! The alternator Shovel was pretty well in its prime at this point.

1975—Still prime, still no changes

1976—Keihin carbs and no more “dead man” throttle. From here on, snappy performance from the carb with a snap-shut throttle (shades of modern times indeed) partly because of no more low-compression FL option. (Although, in hindsight, that might have been a bad decision… as we’ll soon see.)

1977—Breather gears get messed with, the transmission get a new main drive gear using caged bearings and the countershaft gets caged needle bearings

Uh-oh… Trouble ahead for the “Troublehead!”

1978—Whoo-eee! 80 friggin’ inches (really almost 82) courtesy of an increased bore, a longer stroke… and the DOT! (Remember them from 1966?) You see, AMF H-D was at the point where quieter mufflers and baffled air cleaners were killing power… to say nothing of stupid-lean carb jetting and limp cam timing mandated by new smog rules. Also, by now a dresser it was scaling in at over 800 pounds—give or take… mostly give! Frankly, a lot to ask of a 50-some horsepower, de-smogged, hot-running, over-taxed, old-tech engine. In other words, the best way ahead at the time (as it does most of the time) seemed like adding inches to compensate.

The visual giveaway between 74” and Shovelhead 80” cylinders is fin count… 10 for the former and nine for the latter.

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But the big deal was the revised heads (and to a lesser, still heat-related degree, the “steel strut” 8:1 compression pistons they worked with). Which, among other details, are noted for having longer (¾”) reach spark plugs. If things are apart, you can spot a ’78-on head by the flat, so-called “rubber band” manifold, instead of the O-rings used up until then. The trouble with these “Troubleheads” was poor choices for heat resistance. (First, even though the ignition was now electronic, the advance was not. The same old wandering, inaccurate spark timing was hardly a giant step forward in temperature control!) Then, the initial choice of valve guide material (steel) on much hotter-running 80-inch “smog” engines allowed the valve stems to stick or seize. A quick change in both dimensions and materials (iron alloy) helped. So did hardened valve stems—a mid-year upgrade. The other thing, valve seats, was probably the worst problem and harder to solve. The mere two- to three-thousandths of interference fit into the heads let the seats literally drop right back out of the heads if they got hot enough… and they often did. These early seats were also less than robust in terms of dimensions and materials, so issues ensued, distortion and cracking being a couple of common ones. Jerry Branch and other aftermarket wizards picked up on the solutions quicker than the factory would acknowledge them. The cure amounted to heavy-duty, robustly-dimensioned, hardened replacement valve seats, not only installed more tightly, but nearly “heat-proof.” All well and good… now… but back then was when (and why) the term “Troublehead” was coined! The whole sad saga amounted to “getting the lead out”… in the worst way. Not entirely H-D’s fault, since they had no say in the early formulations of the mandated unleaded fuels—particularly variable after the oil crisis(es)!

1979—No big changes, still sorting out details of the new 80” engine and starting to plan an even newer one

1980—Screwing around with valves, guides and seats continues, but the big news was belt drive on the FX Sturgis. Double belt actually, requiring a little re-engineering of the starter arrangements, to make room for the wide belt. The rear drive belt is now a hallmark of Harley design. The primary belt, on the other hand, lasted a whole two model years, never to be seen again. Too much trouble, two major flaws and all the aftermarket had to do is fix it, which they did, so that’s the only type of primary belt system that exists today.

The short primary, five-speed rubber-mount FLT premiered this year as well (oddly enough, with an enclosed chain drive), instantly proving to be a game changer… and smooth survivor.

1981—The buyback from AMF. No more 74”s. Solutions to the troubles with “Troubleheads” and great leaps in reliability and rideability. Small refinements continue, the most notable being the second-generation electronic ignition called V-Fire II. From this model year to the end of Shovelhead production, these are desirable machines, probably the best of the lot in today’s market for classic Big Twins. Yet only third on my list, behind flat-side Shovels and mid-70’s 74”s.

1982—FLT series gets a higher output alternator. The FXR shows up, gets tested by magazines and sells Harleys to people who never even considered them before.

1983—All four-speed Shovels get a rear belt. Five-speed Shovels do not… go figure. Third time’s a charm for the electronic ignition. The V-Fire III has no mechanical componentry and works very well.

1984—No updates. By June 1984, Shovelhead engines were done.

Worth noting: When the Shovelhead was introduced in 1966 it had no direct competitors. By the time it went out of production damn near every manufacturer on earth had a big-displacement touring machine that made the venerable Shovel seem obsolete. The Shovel endured through thick and thin for the company that produced it, got through tariffs and changes in ownership, emissions hassles, quality control variables… and a whole lot more! Even though The Motor Company quit building it (and, unlike the Evo, dropped it like a hot rock, in terms of parts support afterwards) the Shovelhead never really died. The aftermarket and the market itself have made it immortal, whether you keep an original on the road or build a “new” one with a non-Harley engine.

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