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!

[@rubberbandman2540]

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

[@danielalejandrodiazgarcia173]

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

[@ronsmith7739]

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.

[@cesarmacias6263]

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.

[@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.

[@ChiefCabioch]

@carstennobody7047 you didn't crash anything, you only made yourself look like an idiot...

[@onwplay0000]

@@carstennobody7047this isn’t about crashing someone’s dream. If you can be kind and generous like a gentleman, show the facts without the opinions then you’ll be accepted as a worthy just cause. Sharing your knowledge to push forward the never ending capacities of your fellow man is the point.

[@goinjones]

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

[@ronaldlewis4032]

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!!

[@MindDezign]

Help full , VERY ! Thank you

[@user-fi1nr4rf9e]

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

[@TheWyyldstang]

Awesome knowledge

[@Tonys_Garage66]

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.

[@davidciesielski8251]

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

[@gerryparente9334]

well done

[@jimmyjimbo61]

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

[@willwills100]

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

[@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

[@samuelcruz5191]

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

[@willwills100]

Any help would be greatly appreciated because I can't find anyone that knows how to degree my 1999 chrysler 3.5l v6 prowler with custom ground cams

[@davidrowland2354]

What does the valve timing mean. 006

[@72racecar]

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

[@michaelparadisis4076]

Hi Jeff thank you for this . my large camshaft 274@.050 has opening of 25 BTDC & 69 ABDC. If I advance it 4 degrees at the sprocket what will this do to opening and closing numbers? Opening earlier and close earlier. ?? Eg. would valve then open 29 and close at 65? Thank you kindly. Mike.

[@gregivey183]

All cam figures are in relation to rotation of crankshaft in degrees lift relates directly to cam lobe height Single cam ohv has overlap built in advancing this moves both inlet & exhaust...or that is the way I hear what he is saying

[@russcole5685]

Yes, you have your correct

[@jayfaircloth7422]

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.

[@cameronbenty1764]

I would suggest you call the tech line at comp cams and see if they can help you. They would have all of the part numbers relative to their cams - and today they are the largest builder of roller cams on the market - its probably one of theirs.

[@willwills100]

And my cams was ground 4 degrees advanced

[@ErnestoSantana-kq2im]

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

[@jeffsmith2003]

Like many things that Chrysler does - the ratios Intake to exhaust are not the same. Intake is 1.6:1 while exhaust is 1.66:1

[@ErnestoSantana-kq2im]

@jeffsmith2003 thank you so much master

[@ErnestoSantana-kq2im]

@jeffsmith2003 i got a bad lifter/ cam so I'm in the process of upgrading to a better performance one but have been searching everywhere and can't find the stock cam lobes separation angle on my 2010 grand cherokee wk1 srt8 6.1, if you can find that information for me it'll greatly appreciated, thanks again

[@RonSavage01]

Where on the cam card does it show suggested valve lash?

[@jeffsmith2003]

If you look at the cam ca image at 12:00 minin, you will see toward the top where it says valve adjustment - if this was a mechanical cam, thats where the lash would be at like 0.020-inch. The do not give you a hydraulic adjustment - typical is 1/4-1/2 turn from zero lash .

[@imaginebeyondlimits]

Kindly explain how to find angle for end of opening Ramp and Beginning of closing ramp by cam shaft drawing . Make video on actual Camshaft drawing for various calculation.

[@coreyellisart6877]

You never explained the duration you just explained how they standardized

[@zaxpage9003]

I find it ironic you have a summit hat on. They can't even give out their cam info because they don't know it...they only know some of the info...real idiots at summit.