Podcast Episode 27 – Camshaft Basics


So as I have been learning more about building engines, I have been digging more and more into camshafts.  And it seems like the more I learn, the more I realize I don’t know.

So I thought I would start a series about camshafts to pass on what I have learned.  And I thought it would be good to start with the basics.

First, I will mainly be covering the traditional American V8 with a single camshaft in the block and overhead valves.

The most common type of camshaft in traditional muscle car engines is a flat tappet.  That means that the bottom of the lifter or tappet is flat.

Like this

Camshaft Basics

Image courtesy of Comp Cams

There are two options for lifters like that, hydraulic and solid.

Solid are the simplest, they are a machined piece that makes a solid connection between the cam and the pushrod

Next are hydraulic lifters, and they have a small piston that is pushed up by the engine oil to eliminate the need to set valve lash.

Camshaft basics

Image courtesy of Comp Cams

And here is the more basic solid lifter:

Camshaft Basics

Image courtesy of Comp Cams

Here is a roller hydraulic cam:

Camshaft Basics

Image Courtesy of Comp Cams

And a solid roller note the link bar to keep the lifters from rotating:

Camshaft Basics

Image Courtesy of Comp Cams

Here is a picture that shows the differences in the lobe shapes of flat and roller camshafts:

camshaft basics

Roller cam on the left, flat on the right

And here is a graph that shows the difference that shape change makes in how much the valve is open:

Camshaft basics

lunatipower.com lift chart

And there is a link to a web page that has some more pictures, and some cutaways of the types of lifters for your viewing pleasure – Lifters Link

As always, please leave feedback via comments, or email me at pat@themusclecarguy.net


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