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How to Choose a Camshaft: User Buying Guides

Building a powerful engine starts by choosing the right parts. As such, knowing how to choose a camshaft is quite important. If you don’t choose the right camshaft, you are most likely going to run into a lot of problems.

Camshafts are particularly very important and should be picked out before any other part of an engine is machined or ordered. Don’t be like every other engine builders who simply pick up a camshaft. Rather choose a camshaft that supports the type of engine you are building.

Perhaps you are building an engine that will give you more torque for racing, increased horsepower for towing, or improved drivability for everyday driving. The kind of gear and transmission will the engine have will also determine the type of camshaft you can use.

How much you are willing to spend is also another factor to consider when choosing a camshaft. Camshafts can also be referred to as the brains of the engine. One of the main functions of the camshaft is the operation of the exhaust and intake valves.

Your choice of camshafts has a direct impact on the horsepower, torque, idle quality, and so on of your engine. Understanding the specifications of a camshaft can help you choose the right one for your needs.

In this article, you’d get to learn the types of camshafts, how to choose one, the cost of one, and so much more.

How to Choose a Camshaft

To choose the best camshaft for your engine type, you’d need to consider a plethora of choices. Despite an informative product review, the whole process of choosing a camshaft is a very daunting task.

Why risk making a bad choice when you can easily take note of things to consider when you want to choose a camshaft. Consider the following factors below:

Compatibility

Investing in a camshaft only for it not to be compatible with your make model is frustrating. Consider the compatibility of a camshaft before buying one. Ensure the type of camshaft you want to buy is compatible with your make model because there is no point buying what is not compatible with your engine.

Check the specification of your engine to determine what will work and what wouldn’t. Find information about your engine on your maker’s product detail page or in catalogs from reputable companies like Comp Cams.

A camshaft is a technologically advanced and very specific part of an engine. So, even the smallest discrepancy can result in potential risks of engine damage. In that case, if the reason you want to choose a camshaft is for modification purposes, be sure the camshaft is an exact match.

Build Quality

Inspect the type of material used in building the camshaft when choosing one. Generally, camshafts are made of cast iron and steel. Cast iron and steel are different in structure, thus varying in hardness and toughness.

While steel camshafts can handle more mechanical load than cast iron camshafts and can be likened to OE camshafts, cast iron camshafts have a harder surface, but that does not mean they have a shorter lifespan.

Ensure you inspect the camshaft such that they are inductively hardened on the surface and precisely machined. Note that steel camshafts are less expensive than cast iron camshafts.

Valve Lift

One of the easiest terms to understand when talking about camshaft is the valve lift. Valve lift measured in inches refers to the amount of lift the valve is raised from the seat in the cylinder.

Choosing between the two types of lift (the lobe and gross lifts) is an important factor to put into consideration when picking out a camshaft. To determine the lobe lift, measure the lobe on the cam at the nose of the lobe.

Similarly, to determine the gross lift, multiply the lobe lift by the rocker arm ratio. Increasing the valve lift of a camshaft will allow more air and exhaust to move through the engine. Increasing the rocker arm ratio will increase the valve lift.

Duration

Duration is a term used to indicate how long the valve stays off its seat, expressed as degrees of crankshaft rotation, not camshaft rotation. Manufacturers often list two types of durations, advertised duration, and duration at .05 inches.

The universally agreed-upon way to measure the camshaft duration is to start measuring at .050 inches of the tappet movement. As such, when the lobe lift moves the tappet up to .050 inches, the duration is measured from that point.

But the advertised duration is the degree of rotation of the crankshaft. Measuring the duration of a camshaft involves taking the intake duration and the exhaust duration.

Performance

Like other factors, the level of performance a camshaft offers is a major factor to put into consideration when choosing one. Depending on how much torque and power you are looking for, you can choose a camshaft based on the power and performance it offers.

Some camshafts focus solely on high-performance that allows you to get the best performance within a large range of speeds. If you are after a small boost of performance, then a cheaper low range camshaft will give you what you want rather than a more expensive premium camshaft.

But if you want to considerably boost the performance and torque of your engine, then go for a heavy-duty camshaft option that will give you higher RPM.

Lobe Separation Angle

On a camshaft, measuring the distance in degrees from the intake lobe to the exhaust lobe is the lobe separation angle. Importantly, take note of the lobe separation angle, as it is relevant in the proper functioning of an engine.

A slight discrepancy in the configuration of the lobe separation angle will affect the timing of the exhaust and intake valves, causing a negative effect on the engine.

Costing Details

Price is one of the deciding factors when it comes to choosing a camshaft. When considering the costing details, do not neglect engine servicing and oil change costs. In summary, it can cost you about $1500 – $2000 to replace a camshaft.

When you purchase a camshaft, you are not only buying a camshaft, but you will have to purchase a lot of different other elements for the installation. Note that a custom camshaft made specifically on the basis of your engine’s specification may cost more than some of the shelf kind of camshaft depending on the make and model of your car.

The parts you’d need to buy along the cam depends on the make and model of your car, which can cost between a $150 and $300 range. Additional cost may be incurred from other engine parts that will support the camshaft and engine.

In a few cases, you can do camshaft repair, which may cost you less. Camshaft repair includes grinding the camshaft neck into a repaired size and installing thickened bushings. Ensure to check the seats of the camshaft in the cylinder head or cylinder block. Perhaps you will need to repair the seat of the camshaft.

Type of Camshaft?

Majorly, two types of camshaft exist, namely the roller and the flat tappet. These two camshafts are further subdivided into two options: hydraulic and solid. As such, we can categorically divide camshaft into four basic variations in all based on the type of lifter they use.

Hydraulic Flat Tappet Camshaft

A significant feature of the hydraulic flat tappet camshaft is that its base is flat, and it rides on a cam lobe face. Within the lifter bore, the base of the hydraulic flat tappet camshaft rotates slowly, which promotes proper oiling.

The main benefits of hydraulic flat tappet camshafts are that it requires minimal maintenance, economical cost, and requires little to no valve train noise. At the same time, the limitation of the hydraulic flat tappet camshaft is that it has a limited RPM range and longer-term wear.

Hydraulic Roller Camshaft

Some of the key benefits of hydraulic roller camshafts are that they reduce friction and valve train noise. Also, they require less maintenance and offer more power than the conventional hydraulic flat tappet camshafts.

Although hydraulic roller camshafts have the same internal design as hydraulic roller camshafts, they do not rotate within the lifter bore. However, the downside of hydraulic roller camshaft is that they are more expensive than any other form of flat tappet lifter.

Solid Flat Tappet Camshaft

Solid flat tappet camshafts are originally designed as a race engine lifter. A solid flat tappet camshaft is beneficial to an engine as it increases the engine’s RPM and profiles aggressiveness better than the economic hydraulic flat tappet.

The limitations of the solid flat tappet camshaft are that it limits the RPM range of an engine and requires periodic valve adjustment. Unlike the hydraulic flat tappet camshaft, the solid flat tappet camshaft does not have an internal cavity or a piston, and it does not expand or contract with the engine’s temperature.

Solid Roller Camshaft

Solid roller camshafts are designed for high-performance streetcars, as they offer the best performance in all four variations of camshafts. The key benefit of solid roller camshafts is that they offer maximum performance and reduce friction.

The solid roller camshaft features a durable lobe that can withstand valve spring pressures. And like solid flat tappet camshafts, solid roller camshafts produce more noise than hydraulic camshaft systems, especially when they are still cold.

But when they are adjusted to a tight lash setting, they offer better throttle response and performance. Solid roller camshafts can be reused on multiple engines. Nevertheless, they cost more than flat tappet lifters.

How to Tell what Camshaft I have?

Sometimes you can’t exactly pinpoint what you have, but you can at least be as close to the type of camshaft you have. Different cam makers use different numbers to identify their cams. The stamped numbers on the gear of the camshaft have nothing to do with what grind you have on your camshaft.

Another misconception is that people try to identify a camshaft based on the casting number inscribed in-between the lobes. An easy way to identify the camshaft you have is to measure the main journals. Measuring the camshaft lift will also give you an idea of the type of camshaft you have.

In both cases, you will need a caliper, preferably a digital caliper. To determine the camshaft lift, measure the distance from the toe area to the heel area, and subtract your answer from the base circle size, which is the circular part around the bottom of the lobe.

Look through catalogs to determine which camshaft is close to the figure you got, as that is most likely the camshaft you have.

Conclusion

In summary, knowing how to choose a camshaft will help you make that perfect choice to get the most out of your engine. Note, there is more to camshaft than this short article.

Don’t get down to operating on your engine if you haven’t fully understood what a camshaft is all about. Refer to our other articles about camshaft to get your facts straightened out first.

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