The connecting rod bolts are vital components of your engine's rotating system, for these ensure that the connecting rod itself does not give way to too much tension load from the crankshaft. The bolts must be able to bend slightly when the crankshaft rotates, so they must be made from a high-strength material that can withstand such tremendous rotating strain. If not, continuous crankshaft rotation would break the bolts, the connecting rod caps would collapse, and you would experience what is called a
thrown rod. In whatever way, you must preclude this disaster by choosing the best bolts for your connecting rod.
Shop Talk 101: The right bolt specifications
Connecting rod bolts are made from highly durable materials such as pure aluminum, stainless steel, steel, brass, nickel alloys, and silicone bronze. The last four mentioned are a bit prone to corrosion, but with regular oiling, this deterioration can be prevented. The first two are highly rust-resistant, and their life can be extended with regular oiling.
These bolts come in different looks. Some have rounded, flat, hexagonal, and embossed heads, but what you have to remember is that the right type of nut must pair with a specific bolt. Cap style and through-bolt-these are the two cap retention styles for the bolts of the connecting rod. You will not have a problem with this matter because auto parts stores provide the appropriate nut or cap when you purchase a bolt.
Another thing is that threaded bolts are said to be better than non-threaded ones, for the
threading provides a good grip on the bolt slot wall. You can also find bolts with a wave design instead of the thread; this design is said to support and strengthen the rod. Buy bolts with rolled threads instead of cut threads because these are stronger.
Shop Talk 101: Other considerations
It is very important that your package includes a torque specifications document. Connecting rod bolts are installed with a very specific torque. Tightening the bolts to an incorrect torque will render these fasteners useless, thus leading to another replacement. Lastly, it can never be stressed much that you need to purchase a bolt specific to the make, model, and year of your vehicle, since every car operates at its best only when the matching components are installed.