PRI 2017: Mark Williams’ New 4-Inch Bore, 9-Inch Drag Race Case

Mark Williams knows a thing or two about building componentry that can take a beating, and at this year’s PRI Show, his company is showing off their latest and greatest engineering designed to improve efficiency, durability, and longevity.

MW’s new 4-inch bore, 9-inch rear cases reduce internal friction and improve service life by utilizing a large 4-inch angular contact bearing — the largest used in any MW case to date — in a reliable thru-bolt design. The case is clearanced to fit 10-inch ring gears, and is optioned with steel or aluminum bearing caps and can also be upgraded to ceramic ball bearings. MW adds a 7/16-inch pinion stud kit to complete the setup.

“It’s got the 4-inch bearing up front and 100 percent ball bearings in the pinion support — we’ve been able to do it without having a two-piece pinion support. Before you had either had to have that support in order to get the double ball bearings, or you had to taper it in the back. On the side bearings, there’s more “meat” in the race, so the bearing is stronger,” explains MW’s Andrew Dickson.

Right now, we’re the only company with a 4-inch ball angular contact bearing. – Andrew Dickson

The case sports a large 1480 pinion yoke like would be used on a Pro Mod or radial car — something that’s going to give the case the punishment it was designed to take.

“With the extra metal around the race — the bigger diameter bearing — the inside is still the same size, but the outside is larger so you can get more metal in there to make the bearing stronger,” Dickson explains. “Essentially the outer race is thickened up. On a standard 3.812-inch race case, the outer race gets a little thin and they can tend to break, so we’re trying to address that. Right now, we’re the only company with a 4-inch angular contact ball bearing.”

The larger bearing ultimately results in less rolling resistance, and that’s easily identifiable in person, as you can effortlessly turn the yoke by hand and spin the ring and pinion — and that all equates to less parasitic loss in performance on the track.

MW uses 7075 alloy where possible (the yoke is billet aluminum) in this and many of their cases, but do employ a quality grade of aerospace casting alloys throughout its construction.