How to read a Cam Card

Jeff Smith, former editor of Hot Rod and Car Craft magazines, offers up his explanation of how to decipher those complicated camshaft information cards that come with your camshaft purchase. Starting with the basics and then diving into more difficult terminology, Jeff explains the important details required to fully understand exactly what your cam card is telling you!

[deankay]

The one tool that guys & gals don’t have in the tool box, is a crank degree wheel. My degree wheel says Mr. Gasket 1969. I have two other as loaners don’t seem to come when you need them. But you did a sweet job of laying out the numbers everyone should at two times in their life. 1st is when ordering & spring kit to match if needed, 2nd time is what they know is true as they bolt the timing cover on!
Thank you kindly for sharing Sir. (ASE master since 78, retired)

[rubberbandman]

sick video mate 15 year auto mechanic from australia still learning everyday cheers

[danielalejandrodiazgarcia]

wow, the way that you explain the information related to camshaft specs was very clear, now I'll understand more how select an specific configuration to power my engine

[cesarmacias]

great video jeff, i started in the car hobby since i was 15.i learned a lot of cars reading your articles in magazines like car craft, hor rod etc... keep posting videos please, and congratulations for your channel.

[goinjones]

Super informative, I couldn't figure out why the LSA and centerline were different! Thank you!

[ChiefCabioch]

The first event on a cam is the exhaust, advancing the came means both events happen earlier, narrowing lobe centers from 112 to 108 means retarding the exhaust, and advancing the intake, widening the lobe centers is the opposite, normally aspirated engines will like earlier intake and later exhaust openings and closings, Blown, turbo, and crank driven blowers want wider lobe centers, less valve overlap so your boost doesn't go out the exhaust and more manifold pressure is retained, the volume of piston and cylinder head chamber is at a minimum at and during the overlap event, engines using blowers, turbo, and crank driven turbos can purge that cylinder volume of gasses very fast, if you notice a top fuel car at its staging rpm, you'll notice a lot of fog coming from the header, that's raw fuel and air being pushed out of the cylinder, on ALL roots type blowers, they are constant displacement blowers, meaning they will only make (X) manifold pressure, adjusting the pullies tells you how soon, or how late the engine sees the pressure according to its RPM, tubos are sized according to inlet compressor size, and Exhaust turbine housing size both diameter and volume, compared to each other.

[ronsmith]

In my opinion, valve overlap is most important because it depends the vacuum power brakes if or when it works. Any more than say 40 degrees, power brakes will start losing power brakes and one starts having a "lopey" idle. You also start losing gas mileage with more than 45-50 degrees or more on valve overlap. On "race cars" it doesn't matter, but on street cars yes it does.

[ronaldlewis]

Well done and thumbs up for me! I've degreed cams for years I learned from a mechanical engineer a long time ago and was glad because he taught me all about the flow bench and 3 angle and back cutting the valve . Thanks for sharing I'm just an ole Motor Head!!

[Michael-sry]

Good stuff!! Very clear explanation!! Great job!!

[Tonys_Garage]

Thank you very much for this video. I am swapping a cam out in my 5.9 magnum and I had no idea what the card meant. I was trying to find out whether or not my cam was already advanced and now that I see the center line is at 110 and the LSA is 110 I know if I put it on the dots I am TDC. I appreciate that more than you know.

[randyoehlert]

I thought the SBF rockers ratio was 1.6. You said that they are 1.7.
Now i have to look thus up. 😅😅
Enjoyed your video. Thanks

[davidciesielski]

Thanks, I like the way you explain things!!! Please talk about lsa ....bottom end, top end. idle ect.... also stop using fram filters...

[catfissh]

When you say install “straight up” do you mean just install it dot to dot? Reason I ask is because my cam has a 111 ICL and a 114 LSA and I was looking into if it needed to be degreed because it broke 3 valve springs, luckily they are dual so I didn’t drop valves

[jimmyjimbo]

Question: Can you determine the intake centerline from reading the cam specs with the intake opening and intake closing figures listed on the cam card? Example: I have a Crane Cams hydraulic roller for a SB Chevy (#119841) that gives all of the cam specs, but... doesn't list the intake centerline. Is there a way for me to know if the cam has any advance ground into it before I install it and degree it? Thanks much, Jim

[henrythomas]

What if the cam specs say lsa 107/117? That ends up being 110 lsa but does it mean lobe centerline angle is 107?

[willwills]

So my lobe separation is 112 and my intake center line 108 so do I install my sohc camshafts on the factory timing marks

[jayfaircloth]

Can u identify a sbc roller rocker cam by these numbers? On front of cam is, 1126x Jlyo on the back of cam is cr253. There is an s also on the back of cam middle way cam.

[ErnestoSantana-kqim]

Good video, can you please tell me what's the rocker ratio on my 2010 6.1 hemi ? Thanks in advance

[samuelcruz]

Would a 219-227 cam need upgraded valve springs??

[racecar]

is it possible to degree a cam without a cam card ?