CRITICAL: BUY QUALITY
Performance aftermarket fastener manufacturers offer much higher tensile strength fasteners that are specifically designed for racing applications. ARP, for example, offers threaded fasteners that boast 170,000 psi, 190,000 psi and 220,000 psi. In other words, instead of hitting the local hardware store or Internet source for imported who-knows-what-or-where-they-came-from fasteners, stick with reputable U.S. [...]
METRIC NUT GRADES
The grade system for nuts is a number that represents 1/10 of the specified proof load stress (in kgf/mm2). The proof load stress corresponds to the minimum tensile strength of the highest grade bolt that can be used with that nut.
GRADE CAUTION
Although it is common for Grade 5 bolts to feature three slash [...]
THREADED FASTENER GRADES
by Mike Mavrigian
photos by author
Grade 5 steel bolt. Three radial line marks. Theoretically, this bolt will feature a 120,000 psi minimum tensile strength.
The grade label specifies the minimum strength properties the fastener is intended to meet. Industrial fasteners are also marked with a label that identifies the maker of the fastener. Grade markings [...]
Routing the plug wires in aluminum tubing for this custom engine was simply an exercise in “being different.” The tube nuts and sleeves that meet the spark plug boots are for cosmetics only (the nuts and sleeves are epoxied in place).
Straight 3/8-inch tubing runs from the fuel log to the carburetor inlets. Since I wanted [...]
TUBE-PLUMBING WITH –AN TUBE NUTS AND TUBE SLEEVES
by Mike Mavrigian
photos by author
If hard lines are preferred to flexible hose, but you want to connect using AN 37-degree seating/sealing, you’ll use tube nuts and tube flares on metal tubing. The hard line (steel, aluminum or stainless steel) must be flared, using a 37-degree flaring tool. A [...]
In an effort to fit the ring package into an ever-decreasing available piston area, oil rings are getting thinner, to the tune of 2mm or so.
Top rings in Cup applications are being used in the 0.8mm-thickness range.
Moly-faced top rings continue to be popular due to increased ring lubricity and heat reduction. Nitrided rings also offer [...]
Race Rings
Reducing friction and weight while maintaining needed sealing presents challenges to pro race engine builders.
by Mike Mavrigian
Evolutionary and revolutionary changes are constantly taking place with regard to pro-racing piston ring applications. To gain a bit of insight in terms of what’s happening at the moment, I spoke to two leading sources, including Mahle-Clevite’s Bill [...]
Custom pistons are available in any configuration, but knowing what’s needed to order them requires careful measurement and sound decisions.
Once the data sheet is accurately completed, your order begins to forge blank slugs.
Initial machining begins with pin bore placement.
Here the rod small end passage is machined, based on your reported small end width.
With ring grooves [...]
MAKE A MOLD
Simone also told me that Diamond Racing now offers a very cool epoxy chamber mold kit that can absolutely save the day in terms of what your application demands. The kit (an A-B pair of epoxy cans, a mixing stick, nitrile gloves and a spark plug hole plug) it sells for a measly [...]
ORDERING CUSTOM PISTONS
When an off-the-shelf slug won’t do, you need to turn to the custom boys.
by Mike Mavrigian
photos by author
Need a set of custom slugs to work with your new heads and your bore/stroke combo? A ton of info is required before a piston manufacturer can begin to execute your order. By the very nature [...]
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