Understanding Camshafts - Part 1 (Lobe Shape)

The camshaft is to an engine as a conductor is to an orchestra. A lot rides on having the proper camshaft selected for your engine application. In Part 1 of this Steve Tech on camshafts, Steve Morris discusses lobe shape and the importance of choosing the right shape for your expected performance goals. Stay tuned for Part 2 & 3 on camshaft design.

[@rodneybyrd9516]

Harold Brookshire (Ultradyne Cams, RIP) was a genius at that closing ramp on his lobes, which I think were almost all asymmetrical. Even his early work at General Kinetics and later work at Lunati (VooDoo, etc.) had those carefully calculated closing rates.

[@craig8187]

Absolutely, @50 & @200 numbers are the biggest factors. The time(duration) that the valve spends in these areas is huge as compared tonthe time the valve spends in the lift area say .100" either side of full lift. Hence , head flow number at peak valve lift is not as important to think about as flow figures within the range up to 'about' 80% of peak lift. Great vid 👍

[@lightmetalinc.6488]

Thanks for the insight Steve, looking forward to the next one!

[@edwardchascsa4191]

This is from Steve Morris engines u tube. Good stuff. Check him out

[@jhook2050]

I really enjoy the camshaft profiles differances per application..Would you have or know who would be able to grind a cam with the LS firing order 4-7/2-3 swap for 572 mopar wedge

[@VGHCX]

Good video. So, how many degrees of rotation does a camshaft stay at maximum lift? It seems like it is there less than 1 degree of rotation. Help me understand please.

[@grantk.3860]

Awsome info thanks!

[@mikes.1882]

The bounce will happen coming off the peak or not at all unless yoyr spring is weak and you have resinance, which means weak valve springs. While we are discussing lobe geometry, why since the invention of roller lifters in a chevy engine did the following ramp mirrior the leading ramp?

[@mikes.1882]

Just say I don't know.

[@VGHCX]

Can anyone answer this question? How many crankshaft and or camshaft degrees does the valve stay at peak lift in an engine? It seems to me based off the lobe designs the valve stays at peak lift only 1-3 degrees at most. And that is if using a roller cam.

[@23steph13]

Who can I go to when I'm ready to get an asymmetrical cam grind for ls?

[@Kelford-Cams]

Awesome video, explains it perfectly

[@JCnordic2983]

So an rv cam for efficiency what would be a lift increase over a oem cam?

[@hemi5.7villain]

I'm new 2 your channel quick question for you I have a 2007 Chrysler Aspen 5.7 Hemi I'm looking to put a cam in there from the Jeep Grand Cherokee with tha 392

[@beachboardfan9544]

Is there no mean of dampening the bounce?

[@MrTech1210]

So Ive just bought a pair of reprofiled camshaft’s for my Vauxhall XE engine and they are sold on a fast road basis and fit to the engine on it’s standard timing markings because the clearance are said to be safe. Out of interest before fitting, i measured the lobes on my original cams and they were 44mm, but the upgraded cams had shorter lobes at 40mm. Now I would of thought the upgraded cams would have higher lobes, or atleast the same size for valve lift. Can anyone explain why this is? Do the upgraded cams give me more valve opening durations over the standard ones? Turned engine over by hand several times and it feels perfectly ok as in no valves colliding with the pistons. I’m just a bit curious. Piper cams they are and claim to give a power increase of 12bhp. I’ve already got a direct cold air duct and a large bore 4-2-1 exhaust manifold with a 2” straight through pipe. I’m excited to see how well the power gains with be. But very curious about the lobe sizes being different. Also, it occurred to me that is it necessary to change the valve springs to accommodate the upgraded one or would the standard springs be ok?

[@JG-kv4oi]

Probably reground on an OEM core and they took some off the backside (180° from max lift) to get your new profile. I don't believe they can add material on a reground cam.

[@bigredracer7848]

27👍's up Steve Morris

[@salvatorehayes2753]

Does Anyone Know If A .315" Lobe On A 252 Advertized Duration (200 @ .50") Is A Harsh For Rhe Valvetrain? Its In A 1.65 Rocker. This Is A GM 3800 V6 (231CuIn). Im Specing A Camshaft And Im Constrained To Very Short Durations To Keep My Overlap In Check For My Desired LSA. Its A Daily Driver Turbo Car. Originally I Speced The Intake Lobe .344 With 252 Duration (202 @0.50") But I Figured That Was Far Too Agressive On The Valvetrain For A Daily Driver.

[@mikes.1882]

This guy is full of crap

[@townsendliving9750]

Someone should get a high speed camera and set up a test rig to show the bounce, I'd like to know how someone figured out about the bounce, how the hell would you know that. Be cool to see it in high speed

[@milojanis4901]

It's called a spintron. Spintron is a cylinder head set up with a valvetrain that's to be tested. It's bolted to a dummy block that may not even have any pistons installed. Then, specially mounted high speed camera's and a laser detect how, and when, valve float and bounce happen. This is a condensed explanation of what's actually going on.......

[@townsendliving9750]

@@milojanis4901 nice, very good explanation

[@jtcustomknives]

I seen some high speed video of valve float.

[@peterzetterberg9665]

damn good video

[@johnshackelford6965]

1970 340 374 hp Tommy Bosher look in the mirror say Dodge Chrysler Plymouth DART 3 times.

[@ChielScape]

I hope this series ends in the actual math and formulas that describe the entire lobe. Duration at X lift doesn't tell me enough about what a cam does.

[@magnusdanielsson2749]

Its actually very complex math. If you go speed-talk forum and search post made by udHarold you can get a feel for the math involved. There is also some text and videos out there with by Billy Godbold from comp cams on the subject. Just dive into the rabbit hole! 👍😄

[@greenman7yyy]

Nothing about a camshaft if "OBVIOUS" to anyone who decides to watch a video, that alleges to explain how they work.

[@peggyparrow2059]

Really ? Opening lobe on left side, you must have a reverse rotation engine ?? Most engines turn clock wise when looking at the front of the engine ?

[@stephenfaulkner1448]

Here is what I dont understand. Why does the cams for high performance cost a shit ton more than a basic one made of the same metal? No matter the specs. It is the same trouble and material no matter the setup. Either way all you do is put the numbers in the grinding machine. Why charge more?

[@everydaydose7779]

> R&D cost Plus slapping performance/race in the product is automatically expensive

[@jtcustomknives]

Supply and demand. Less people to buy performance cams so the price has to be worth the less sales.

[@3694-k5s]

Diamonds are just rocks and gold is just like lead too...

[@davidboggs7519]

Ok this is a thing with "engine builders" intake center line is not relevant to lobe separation angle absolutely. And here's why, lobe separation is ground into the cam and can't be changed. Intake lobe center is ground into the cam but it can be changed. So if you have a 3500 hp drag and drive car, and it constantly shakes the tires you can retard the cam 4 degrees to take out some of the torque, but you're not changing the lobe separation in the least. This isn't that complicated !