Among the most highly-stressed fasteners in XPAG/XPEG engines are the four bolts that attach the flywheel to the crankshaft flange. These relatively small bolts, along with two tapered locating pins, are all that restrain a heavy 24-pound flywheel spinning at thousands of revolutions per minute. If these bolts loosen or shear - and there are documented cases of this happening on an XPAG engine - the flywheel will be launched into the air long before the engine can be shut off, cutting through the clutch cover, the transmission cover, the interior and the dash of the car, and potentially causing severe injuries to the driver's legs.

Because of their size and location, flywheel bolts are relatively difficult to loosen or tighten adequately - during an engine rebuild they are often found to be damaged by previous dis-assembly and re-assembly. The bolt heads' sharp edges are often significantly rounded due to incorrect sockets being used or, worse, the bolts were last loosened with a chisel (I have actually found such bolts). But most dangerously, the threads are often stretched due to excessive "hand" torque being applied. Unfortunately, bolts currently available from the usual supplier are very soft, of suspect origin and have cut threads that are documented to shear well before the proper torque has been reached.

To improve this situation, I have commissioned a run of custom ARP flywheel bolts for XPAG/XPEG engines, made of superior 8740 chrome-moly steel, forged, heat treated and coated, with MUCH preferred rolled threads. My new flywheel bolts are almost three times stronger than original, are far superior to any others on the market, and can be confidently used in engines with stock or increased HP. I like the added confidence in using lock-wire, so the bolts have lock wire holes as original. You will notice that these bolts have smaller heads and larger flanges than the originals: the smaller heads remove mass, and the larger flanges guarantee greatly-increased clamping force. The bolts require only a 12mm socket for proper installation. These life-time bolts can safely be re-used, and should be torqued to 55-60 foot-pounds, lightly lubricated with your engine oil, per ARP's engineers.

A set of four bolts is $90, delivered.