Words by Robin Bradley
Pictures by Howard Schroeder, Midwest/Ultima
Following our article back in June about Midwest Motorcycle Supply's Ultima program and the Evo and TC 'A' engine rebuild programs, we were contacted by Brian Brace, the Program Manager and lead engineer for the Ultima Products program, and he told us more about the machine shop services that they offer to their dealers …
The article we published in June was as part of our 2019 series marking the 35th anniversary of Harley's now venerable Evo platform - arguably the engine that not only saved Harley-Davidson, but that created the foundations of the aftermarket we have seen "evolve" ever since.
Brian told AMD that at Ultima it is their engine cases that are the "rock solid foundation to our motors. These cases are extremely beefy and built to handle high horsepower and torque. CNC- machined in-house from C356-T6 aluminum castings, all Ultima case halves are line-bored as a married set to insure a perfect center line, with Colony Machine chromoly cylinder studs to top them off.
|Ultima engine cases|
"The flywheel halves are pressed together with our custom 80 ton press – and with .008” press fit on the crankpin, shifting of the flywheels is never an issue. Then the final assembly is trued to no more than .002” total run-out."
|Ultima crankshaft assemblies|
Brian says that Ultima cylinders are machined to tight tolerances and honed in-house. Every cylinder is plateau-honed with diamond stones in torque plate fixtures that insure a perfectly square cylinder top to bottom. All the 4.25 inchers are baked and slowly cooled to stress-relieve the liner, with the 3.875” and 4” bore cylinders having a thicker liner (therefore stress-relieving is not necessary). Cylinder bores are held to very tight tolerances within +/- .0001”.
"Ultima cylinder heads are machined to tight tolerances also," says Brian. "All valve seats are cut in- house on Newen fixed turning machines. Every head is then assembled using high quality components from Pac Racing, Ferrera and AV&V. All heads use chromoly spring retainers. The 140” CNC-ported heads use titanium spring retainers. Compression releases are standard in all of our heads and after assembly every head is vacuum tested to insure the valves seal completely."
|Ultima cylinder heads|
All sub-assemblies then come together on the assembly line, where the short block is then assembled, with every engine getting a high-volume billet oil pump. Camshafts for Ultima engines are manufactured and ground by Andrews to Ultima specs. Johnson hydraulic roller lifters are then installed in the lifter blocks with chrome or black powder-coated lifter blocks, cam cover and Ultima pre-programed ignition module installed to finish off the lower end.
"Then the engine reaches the test stand. At this point it is run with an electric motor to prime the oiling system. Oil pressure and compression are checked at this point and after passing these tests, the carburetor is mated to the intake manifold. The motor is then cleaned up and inspected for leaks. Finally, the motor is bagged and boxed in sturdy spray foam packing and ready to ship to your door."
Brian went on to explain that having all these capabilities in-house puts them in a superior position to be able to let their dealers share in their experience and expertise.
"Basically, there isn't much we can't do. Our engine rebuilding service is available to our dealers worldwide. By offering this service, the dealer's customer gets a quality rebuild complete with a 6- month, 6,000 mile warranty.
"However, it doesn't stop there. We are also offering this service for S&S and Harley-Davidson Evo V-twins as well - adding another option to get that motor rebuilt correctly, and at an unbeatable price."
Ultima offers this service for all Ultima engines, 80" thru 140", and select Big Twin Evolution style engines and the Twin Cam "A". Ultima machine shop services extend from the crankshaft and cases to the cylinders and heads. This includes, for Evo models, "True and Rebuild" for the Evo crankshaft; disassemble inspect, fit new rod set to new crankpin and bearings, balance and reassemble with sprocket or pinion shaft as an additional option.
"We will bore the case for big bore cylinders (Evo and Shovelhead) and recondition the deck base gasket surfaces.
MIDWEST MOTORCYCLE SUPPLY