Piston engines or all engines found in cars nowadays, except maybe a Mazda, rely on one component to make an important link between two moving parts. This component is known as a connecting rod or conrod and it keeps the piston and crankshaft working together.
A conrod acts as connective tissue that makes the movement generated and coming from the piston, usable by the crankshaft which then sends it to the wheels through various linkages. However small and simple they may look, connecting rods play a crucial role in an ICE engine and without even one conrod, the engine wouldn't be able to function.
Types of Conrod Designs
I-Beam
When cut apart, not that you should, an I-beam conrod looks much like the letter “I”, hence the name. I-beam conrods are the most common connecting rod design today. Why? Because this type of conrod has a rather inexpensive manufacturing process and they are able to keep up quite well with an off-the-shelf engine. There are also high-performance I-beam conrods but they are not that common.
H-Beam
If performance is on your mind, then a high HP engine is what you're probably looking for, therefore one with H-beam conrods is what you should get. An H-beam design allows an engine to run with a lot of HP even at low speeds without the structural integrity of the conrod being compromised. Because of this H-beam conrods are found in turbocharged and supercharged engines.
X-Beam
Also known as crossbeam engine rods, X-beam conrods are the most capable and advanced option. Due to their inner design, they combine the best features of both I and H-beam conrods. X-beam engine connecting rods are therefore light and strong which is what makes them great for cars that will spend their life mostly on a track.
Conrod Materials
Steel
What also affects the capabilities of a piston connecting rod is the material it's made of. Take steel conrods for example, they're made to keep up with the demanding conditions of a high HP engine. But when it comes to quicker acceleration times, steel conrods aren't the best. Although they can take high tensile forces, steel engine rods aren't light enough to keep you in a high RPM range.
Aluminium
This is where aluminium conrods are best. If you have a car that likes to rev, then aluminium connecting rods are for you. Just keep in mind that the car you have doesn't have a lot of HP as this can be detrimental to the lifespan of the conrods.
Titanium
If you want to have the best characteristics of both steel and aluminium conrods, then consider going for ones made of titanium. Titanium conrods are extremely light but also extremely strong. They can bare a lot of pressure but they can also spin fast, to keep your engine in that high RPM range, together with your turbo. But because of all this, titanium conrods are the most expensive option.
Signs of a Failing Conrod
Oil Pressure
Oil pressure is crucial in every engine and if you have a failing conrod it can have a negative effect on oil pressure. If you get a warning on your dashboard that there's low oil pressure, then there is a high chance that because of a bad conrod, oil isn't able to circulate properly and it can cause your engine to overheat.
Low Oil
Another issue you can have with the oil in the neigh is the lack of it. If not enough oil is circulating through the engine it could mean that a bad or failing conrod has made your engine consume more oil than it should. This way your oil level will always be low and it can get below the minimum requirement which can then cause it to overheat and lead to some serious damage.
Sounds
As a byproduct of the oil not being able to recirculate, you may also hear knocking sounds. These sounds will repeat a lot more when you rev up the engine and they will usually go away after a bit. That is when the oil is able to finally recirculate through the engine. But you shouldn't leave it so since this can cause more issues.
Hydrolock
A serious issue that could happen with a deformed piston connecting rod is Hydrolock. This refers to water entering the chamber of the piston(s). Hydrolock can also cause knocking sounds as well but it can easily be fixed unless there is a lot of water in the chamber. In this case, the spark will be affected and the water will make the cylinder rod either tilt out of position or even break. But if it's a little bit of water taking care of Hydrolock is going to be much easier
Final Words
The simplest components with the most straightforward operation are the most fundamental ones and the same goes for connecting rods. They are quintessential engine components that can make or break the way your car works even with the slightest deviation in their construction.
