JE provided these straight wall high nickle carbon steel wrist pins. We do not recommend tapered pins for turbo engines as they tend to flex and grab the small end rod bushing and spin it. The nickle in the alloy gives the pins toughness and helps the tensile strength as well. It is important to get pins with beveled ends as they help the pin locks to wedge tightly into their grooves in the pistons.
Since no company makes off-the-shelf MR20DD rods and the stock rods are so spindly and completely unsuitable for a turbocharged motor, we had these rods custom-made for our project by Carrillo. Carrillo is our favorite premium rod company with the most exceptional quality. In our long period of time spent building engines and racing, we have yet to see one failure of a Carrillo rod that was the rods fault. The only time one of these rods has failed is when some other part failed first the broke the rod.
Carrillo rods are machined from forged blanks made of their own proprietary steel alloy called Carrilloloy. We presume is its a very high grade of high nickel and molybdenum steel. The forged blanks give proper grain flow around the big and small ends of the rod which greatly improves strength over simply machining the part from a wrought alloy blank.
The big end of the rod features Carrilo’s optional stepped cut which gives full thrust support but reduces weight by removing excess material while maintaining more than enough strength for our modest power goals. The beam of the rod uses Carrillos often copied Radius Slot design which is seen as the rib in the center of the cutout. This gives more material to improve fatigue and bending resistance without adding weight. You can see how we got rid of the odd tapered feature on the small end of the rod and are now full width for additional strength and piston pin support. Carrillo worked with JE to make sure that the beefed up small end of the rod, worked correctly with the wider and stronger pin bosses in our custom pistons.
We opted for Carrillo’s optional CARR bolts. These bolts are made out of a multiphase steel alloy similar to ARP custom age 625 alloy but slightly stronger at an amazing 285,000 psi. Typical racing rod bolts of at tensile strength of about 200,000 psi for example. CARR bolts can be retorqued an infinite amount of times, unlike stock torque-to-yield bolts that should be replaced every few times and other racing rod bolts that need to be replaced after 10-15 tighten and loosen cycles.
