Shovelhead Engine Rebuild | Shovelhead Self Destruction

A Phoenix Rises!

1 After pulling apart the destroyed engine, we found these chewed up crankpins.

2 This connecting rod had seen better days as well.

3 Even the valve springs were toast!

4 All of the old engine parts took a bath so we could see what actually survived.

5 It took some big forces going the wrong way to snap these valve springs.

6 After the bath, we machined the valve seats.

7 A little headwork and some more cutting was done.

8 We took special care in the reaming and honing of the valve guides.

9 The honed and powdercoated cylinders were now ready to go.

10 The inside of the cases were treated with Glyptal enamel as a sealer.

11 New pistons were installed on fresh connecting rods.

12 The breather port was modified for much better breathing.

13 Once the motor was built, it was tuned on this slick engine stand.

I’ve seen some funny and some not so funny things while working in and around the V-twin industry. The engine featured in this story is decidedly unfunny, but once a person whose knowledgeable of things mechanical views the images of the engine “pre-rebirth,” they for some strange reason elicit grins and giggles. Indeed, it is a curious reaction folks have to the sorry state of affairs captured by the camera, giggling in the face of total destruction!

Andrew Rosa, the owner of Rosa Cycles in Huntington, New York, called me, “You’ve got to see this engine. You are not going to believe it.” It’s not too often I get a call from someone of Andrew’s experience informing me that I am not going to believe it. My curiosity was piqued; I beat feet to Rosa’s as he wanted to turn the engine around quickly to get the owner back on the road.

Milton came by at the day before I arrived to drop off the engine. Milton owns Halo Cycles in Queens, New York. He’s had the shop for a while and does a wide variety of customizing and tech/mech work from mild to very custom. Milton has been around the block and believes in not messing around when it comes to engine work. He goes to Rosa’s because of its well-earned reputation. Without being tooled up and having access to a dyno (a de rigeur tool these days for bike/engine tuning), boring bar, and power hone, why bother taking on deep engine work when you have acknowledged expertise so close by? So Milton sticks to his core and brings the really broken engine stuff to Rosa’s Cycles.

Frank, the owner of the bike this sorry engine came from, owns Hard Rider NYC clothing brand and rides this personalized and loved bike hard. One fateful evening, on the way home on the venerable Long Island Expressway, Frank heard what Milton described as a mighty “snap” similar to a large branch snapping and barely limped his way home. Milton recommended that Frank take the 1971 vintage shovel to Andrew. It really was by any measure a mess.

Andrew was able to salvage some parts, but most of what was reciprocating inside the engine was completely trashed. It is a testament to the power and magic of internal combustion that an engine in this state could run. The valve springs collapsed and snapped from the chaotic forces of things coming apart, and the engine was filled with metal shavings. The connecting rods got literally chewed up.

So how did Andrew rebuild this well-worn and beat-up lump? Well to be honest, this is a pretty regular occurrence at Rosa’s. It rebuilds engines all the time, the only difference is that most aren’t this dramatically worn out and giggle-inducing. Keeping budget in mind was part of the equation and Andrew was asked to keep the costs down and reuse as much of the engine as was possible and reasonable.

With the parts separated into piles—trash and reusable—the real work got underway. The parts that were keepers got a real thorough cleaning and check-over just to make sure they were worth putting back into the patient. The “list of important parts to replace” was modest considering the damage. A set of new Wiseco pistons were pulled off the shelf and all-new valvetrain components were sourced from the aftermarket, including lifter blocks, lifters, pushrods, etc.

New flywheels from Truett & Osborn, recognized as the masters of lower end spinnery, were called upon to provide exactly the right and perfectly balanced flywheel assembly. The breather window needed to be relieved slightly to keep pressures and cam timing in synch.

The list of parts that could be reused was short, luckily (and surprisingly) the new oil pump that was bolted on before the engine self-destructed was reusable after a solid inspection and cleaning and the rocker boxes were cleaned up and shipped out for a coat of luxurious chrome. The cam cover, as well as all the parts inside was toast and was not worth the effort to rebuild. Points ignition was retained although the points and condenser were replaced.

When all the parts were back and in hand, assembly began in earnest with the lower end being the first up for attention. Cases were sealed, left to dry, then heated, while bearings were put in the fridge—this procedure assures a good solid fit when race and case meet on the work bench. Watching someone like Andrew assemble the engine’s lower end is a no-drama affair.

With the lower end assembled, the pistons were installed on connecting rods that had been rebuilt, beautifully honed and powdercoated cylinders were then slipped atop Wiseco pistons and over Cometic gaskets with no fuss. The heads were set atop a set of James Gaskets and the unit tightened up, but not finally torqued.

Andrew finds it more convenient to conduct the last round of assembly on the test stand, and so at this point the engine was set into Rosa’s test stand. The cam chest was assembled, shimming checked on the cam, and the remainder of the valvetrain as installed: tappet blocks, lifters, pushrods, and tubes. The chrome cone was installed with its point’s ignition and fly weights. All bolt and fastener tightening happened at this point in the process and the last piece to go on was the S&S E with its intake manifold.

With a spin of a drag race starter, it came to life! Andrew dialed in the timing and carb adjustments while it was running, after which he put a fan on the engine to keep its temp within operating spec. Slipping a pair of bagger takeoff mufflers on the engine for some backpressure, he let it run a bit by revving it and taking it through a range of RPMs. The engine was mechanically quiet as a mouse, running smooth and strong. It sounded great and was smooth as silk.

Frank rides this machine everyday on New York’s City’s congested, pothole-infested streets. He relates his freshly rebuilt motor is more than enough old-school power to split lanes and ride hard daily.

Rosa Cycles
(631) 424-1235

**Halo Cycles
** (718) 326-3906