Cam Size Chart: Cam Size Comparison Chart | Sizing Guide

Some people often consider the camshaft as the core component of the engine. You may also call it the brain of the engine if you want to. The camshaft is this much crucial because of its functions. Mainly it controls the opening and closing of the valves. You can read the best cam for stock twin cam 88 and how many miles is a twin cam 88 Good For?

In this article, we are going to present some size charts regarding cams with easy explanation. But this is not the only topic as we will also discuss some related topics to provide you a better vision. Hope we will be able to present this piece nice and smoothly. Keep reading till the end.

Cam vs Camshaft

It is confusing, right? Are both of them the same? Is there any real difference between these two? It is very easy to get confused. Basically, a cam is a rotating metal that is responsible to provide motion to something. And the camshaft is a shaft that consists of a bunch of cams. Hope you now have a clearer idea.

Factors to consider before choosing a camshaft

Choosing the right camshaft is not a kid’s job. You are going to build an engine and that is why you require a camshaft. And this is a very technical thing to do. Without enough knowledge, you will not be able to build an engine yourself let alone supply it to the customers.

The following are the necessary factors to consider before choosing a camshaft. Let’s have a look.

1. The cam card: This is the first thing you have to look at. You can bisect some crucial information about the cam here. Almost all the cam cards are the same in this manner. Basically, the first section of the cam card provides you general information. After the general information, you will also see some other vital information. All the information is necessary. You have to be very careful about every bit and piece of the information here.

2. Duration: The duration of the cam provides us information about how long the valve will be open. This information is possible to measure in two forms: duration when the lift is 0.050 inches and the duration advertised. There is a problem with the advertised duration. It will be always a large number since the companies want to impress you with numbers. But it can be bigger in perspective of the lower point of measurement on the lobe close to the base.

4. Lift: You can say this is the easiest term out there to understand. The lift can be measured in inches and the measurement generally indicates the length of the valve when it is raised. Between the two types of lifts, the lobe lift refers to the exact size of the lobe measured at the nose. And you will get the gross lift when you multiply the lobe lift by the rocker ratio. Usually, the cam card always provides information about the stock ratio. But you can alter the gross lift by changing a little something- the ratio of the rockers.

5. Lobe Separation Angle: The LSA (Lobe Separation Angle) is also known as the LDA (Lobe Displacement Angle). Generally the LSA means the phase of the intake and exhaust lobes with each other. It is the distance between two peak lifts. Peak lift on the side of intake lobe and peak lift on the side of exhaust lobe. Almost all the cams will fall under the range of 104-116 with nice idling.

6. Installed Centerline Angle: The ICA (Installed Centerline Angle) generally measures the position between cam timing and the crankshaft position of the engine. If you install the ICA straight-up, the LSA will be equal to the ICA. You can also advance the ICA of any cam to get your desired performance from any engine.

7. Camshaft Type: There are basically two types of camshafts. The flat tappet and the roller. You can call a cam flat tappet if its lifter surface is a flat plane. In case a lifter fails to rotate, the cam will accelerate more than the usual and it would result in a failure. And the roller cams, you can call them tiny casters. Roller lifters always stay in place because of the lifter bore or with the help of link bars.

Cam size chart

We are providing some figures here to show you how it will perform practically. And if you can match the figures with the equipment recommended, it will be a very good build. Let’s head into the charts.

Vehicle 1

Features of Cam

 PowerTorqueFuel EfficiencyIdle QualityRacingPulling
HydraulicUp to 195°1000-3200 rpm of operating range1600-2000 rpm rangeBest choiceStock type smooth idleNot recommendedGood for heavy pulling
Duration@ .050

Recommended Equipment

Axle RatioCompressionEngineComputer FriendlyIntake ManifoldIgnitionExhaustRecommended pressuresTransmission
Stock, 3.50:19.0:1 or lessStock engine in good conditionVery friendly without any modificationStock/ torque type/ aftermarket 2 planeAftermarket distributor/ recurved stockSmall tube headers or Stock exhaust95 psi (if valve on seat), 240 psi (if valve open)Manual/ stock automatic

Vehicle 2

Features of Cam

 PowerTorqueFuel EfficiencyIdle QualityRacingPulling
Hydraulic195°-210°1500 to 4000 rpm of operating range.1800- 2600 rpmGood choiceGoodNot recommendedGood for light pulling
Duration@ .050

Recommended Equipment

Axle RatioCompressionEngineComputer FriendlyIntake ManifoldIgnitionExhaustRecommended pressuresTransmission
Stock or 3.20 – 4.20:19.5:1 or lessStock in good conditionVery friendly without any modificationStock/ torque type/ aftermarket 2 planeAftermarket distributor/ recurved stockSmall tube headers or Stock exhaust105 psi (if valve on seat), 265 psi (if valve open)Manual/ stock automatic

Vehicle 3

Features of Cams

 PowerTorqueFuel EfficiencyIdle QualityRacingPulling
Hydraulic210°-225°2000-4800 rpm of operating range2400-3200 rpmGood choiceFair with lopeBracket Racing (mild)Not recommended
Duration@.050
Mechanical220°-235°
Duration@.050

Recommended Equipment

Axle RatioCompressionEngineComputer FriendlyIntake ManifoldIgnitionExhaustRecommended pressuresTransmission
3.70:1 or higher10.3:1 or lessStock in good conditionSome modification requiredStock/ torque type/ aftermarket 2 planeAftermarket distributor/ recurved stockSmall tube headers or Stock exhaust110 psi (if valve on seat), 280 psi (if valve open)Manual/ stock automatic

Vehicle 4

Features of Cams

 PowerTorqueFuel EfficiencyIdle QualityRacingPulling
Hydraulic225°-240°2200-5400 rpm of operating range3000-4000 rpmAverageRough idleBracket drag racing, oval track racing (limited)Not recommended
Duration@.050
Mechanical235°-250°
Duration@.050

Recommended Equipment

Axle RatioCompressionEngineComputer FriendlyIntake ManifoldIgnitionExhaustRecommended pressuresTransmission
3.90- 4.50:110.5:1- 11.0:1Needs some modificationsSome modifications requiredAftermarket performanceAftermarket distributor/ recurved stockHeaders120 psi (if valve on seat), 300 psi (if valve open)W/high stall converter (automatic)/ Standard manual

Vehicle 5

Features of Cams

 PowerTorqueFuel EfficiencyIdle QualityRacingPulling
Hydraulic240°-255°3200- 7500 rpm of operating range3800-5000 rpmAverageRough idle (with heavy lope)Bracket drag racing, Oval trackNot recommended
Duration@.050
Mechanical250°-265°
Duration@.050

Recommended Equipment

Axle RatioCompressionEngineComputer FriendlyIntake ManifoldIgnitionExhaustRecommended pressuresTransmission
Over 4.20:110.5:1 to 12.0:1Needs some modifications (competition type)Some modification requiredAftermarket performanceAny good aftermarket oneCompetition headers125 psi (if valve on seat), 325 psi (if valve open)Automatic w/high stall converter/ Heavy-duty manual

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An interactive camshaft calculator where engine builders can see how valve overlap (and boost efficiency) is affected by a camshaft’s physical design. Check here for camshaft rpm range calculator.

FAQ

What does a cam do for performance?

You can say engine building is kind of a recipe. The more you tweak the materials, the more new items you get as output. If you change the way the cams are situated in the camshafts, you will get different results.

For instance, if you push the cams a little bit ahead, it will make the intakes do the opening and closing faster. As a result, you will get an improved low-end torque. And if you decide to retard the cam, it will make an improvement in the horsepower by sacrificing low-end torque.

What does a bigger cam do for an engine?

Bigger means better. Well, in almost all cases. But a too big cam may not be an ideal choice for you. As in almost all cases, the stock and light-mod heads won’t be able to flow more air if the valve lift touches the figure of 0.550 inches. Thus, if you push any further, it won’t bring any good results. Instead, you may hurt the power output as the airflow will be reversionary.

However, if you intend to build an aggressive racing vehicle, then going big is the option.

How do I choose an engine for my cam?

Your question is wrong. Well, we are trying to say that you should not choose a cam first. The cam choice should be last. Though it may not seem the trend, it is the right path to follow. Anyway, you can choose an engine by matching the rpm range with other components of the vehicle you are working with. 

What is considered a mild cam?

If the camshaft is a towing or an RV one, it is generally considered as a mild cam or in other words- an economy cam. This type of cam has usually narrower Lobe Separation Angle (LSA) which is 112-114 degrees.

Conclusion

Choosing the best cam for you or for your customer is not a piece of cake. You have to consider a series of factors before building the engine. If you choose something wrong, the whole build will be useless. That is why you have to be extra careful during the build.

Our primary focus of the article was to give you some practical figures (cam size charts) to help you with the cause. We also tried to clear out some basic specifications too so that it does not go over your head. If we miss anything, do leave a comment. Have a good time.

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