What is the typical life I can expect out of these at the drag strip? Customers making 2200 HP on these have reported changing them out every 30 passes or so
Why aren’t these rods made out of forgings?
Unlike a forging in which the aluminum is literally pounded into the shape of a rod, this material is is cold worked, forced through a die at extreme pressures, to form the billets from which the Aluminum Connecting Rods are CNC’ed from. This work hardening builds the strength, grain structure, elasticity, and general characteristics that makes these Aluminum Connecting Rods superior to common forgings. This proprietary alloy is then further artificially aged and heat treated, then stress relieved though additional manufacturing processes.
Why do I need an aluminum connecting rod in my engine?
On many high horsepower engines, an aluminum connecting rod acts like a shock absorber between the piston and the crankshaft. Without this cushion, the bearings may flatten, the crankshaft may crack, or the main caps will start walking/shuffling, or even break. Using an aluminum connecting rod ensures that all these components can withstand the stresses of a high horsepower engine
What clearances do I need to run with an aluminum connecting rod?
When running an aluminum connecting rod, your running clearances need to be adjusted as the aluminum connecting rod will grow more than a steel rod. A piston to head clearance of .060″ minimum is recommended. Sides clearances need to be increased by .002-.005″ over the steel counterpart, depending on application and oil viscosity used. Wrist pins typically need to be run tighter than their steel counterpart as the heat from the piston transfers to the rod and increases running clearances during operation. Rod bearing clearances typically are run .001-.002″ looser than with steel rods as the parting lines tend to burnish into each other during initial operation. Connecting rod to engine block clearances should also be kept to a minimum of .060″.
Can I run my Aluminum Connecting Rods without a pin end bushing or can the pins be press fit?
You cannot run a press-fit pin on an aluminum connecting rod, but for most applications, we recommend not using a pin end bushing, as the aluminum is an excellent bearing surface and bushings tend to come loose when the pin end of the rod is heated. We recommend you send your wrist pins to us for final pin fit, if need be.
What bearings do I run with an aluminum connecting rod?
Many race bearings are offered for numerous applications with dowel pin holes already drilled in them. Tangs were not intended to prevent bearings from spinning. They are just used to locate the bearing side to side. As the aluminum connecting rod grows more than a steel rod, the bearing bore actually grows enough to allow the bearing to become looser than bearing manufacturer recommendation, requiring that a dowel is used to secure the bearing in location. If your bearings are not offered drilled for your application, R&R can modify them for you for a small fee.
Do I need to pre-heat my oil when running an aluminum connecting rod?
No, but it is always good practice to get the engine up to operating temperature before subjecting it to high loads. This will provide longer life for all engine components. As aluminum heats up, it actually loses tensile strength, but gains ductility, which aides in its function to act like a shock absorber without breaking. Aluminum Connecting Rods that fail before their life cycle typically are subjected to stresses prior to being fully warmed up.
Can an aluminum connecting rod be rebuilt?
While yes we can resize both the pin end and the big end of the rod, usually aluminum will stress fracture long before this is needed and should be replaced as a maintenance item.
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