Valve guide and seat machining systems once were dominant only in aftermarket stock engine-rebuild shops.
However, today’s systems have grown beyond those shops and have found popularity with builders of high-performance engines for automobiles and motorcycles.
A lot of valve guide and seatmachining systems are found in drag racing and NASCAR team shops. These shops produce new engine heads by machining them close to size with CNC equipment, and afterwards touch up the seats with a manual system that is dedicated to that process.
One such system is the VGS-20 valve guide and seat machine from Sunnen Products Co. (www.sunnen.com). The system allows shops to set up and run any head to 48-in. long, and it is designed for precision machining of everything from stock valve jobs to custom, full-race work.
Optimal speeds on the VGS-20 eliminate chatter to ensure superior finishes and geometry.
The system’s power head tilts 12 degrees left and right to align, within seconds, to valve guide centerlines, seat centerlines or 90-degrees to flat surfaces, while a head-holding fixture easily rotates and locks to perfect alignment for drilling, tapping, boring and other machine work.
One VGS-20 handles complete head rework functions – installation of valve guide inserts, spot facing of valve guides and bosses, cutting of valve insert pockets, simultaneous multi-axis cutting of valve seats, drilling and tapping of threaded studs, removal of brake exhaust studs, and bronze guide liner installation and reaming.
“If a shop doesn’t use a system such as the VGS-20, they have two costly alternatives. One is CNC equipment such as a 5-axis machining center, and the second is hand grinding tools, which are a labor intensive,” Richard Woodward, automotive sales coordinator at Sunnen, said.
What sets the VGS-20 apart from other such systems is that it’s accurate, repeatable, rigid and easy to operate, Woodward added. These qualities are the reason that companies such as Harley Davidson Motorcycle Co. and Jasper Engines use the machine for their high-end performance products.
For Harley Davidson, a special fixture on the VGS-20 lets the company set up and machine two of its V-twin motorcycle heads simultaneously. Woodward said the system gives users a personal hands-on touch that they can’t get from CNC equipment.
