Why focusing on lobe separation is not really productive.

In this video we go over what's actually happening at the valve and what the engine actually 👀"s
Powellmachineinc.com

[@rageracing6435]

Excellent video. I’ve been building engines since the 90’s. One of my most favorite part is studying the camshaft. Over 30 years later I’m still learning. Back in 1995 I first jumped on the big rocker ratio bandwagon. The machine shop I had setting up my heads explained to me back then how it changes everything at the valve. Changed lash. Changes spring requirements. Changes duration and timing events seen at the valve. It was an awakening moment for me that really got my mental gears turning on camshaft and valve train dynamics. Cool video. Thanks for putting this information out there.

[@powellmachineinc]

@rageracing6435 very welcome

[@clintonsmith9931]

I am way too old to work in the industry anymore but love to watch and learn your business and really learn what I never knew when younger. Keep it up!

[@powellmachineinc]

@@clintonsmith9931 ty!, glad it's helping

[@MarineGrunt]

I'm with you on that one . As youngsters ( I'm 75 now ) , we didnt concern ourselves with LSA ..or most anything else . Our primary concern was getting pushed back in the seat when we hit it , and the sound . It had to go lumpity lump ...or it was wasted money .

[@powellmachineinc]

@@MarineGrunt lol, understand!

[@deankay4434]

Clinton, like you I am in that boat. Day-dreaming about what if I went back knowing what I know now. First having a job where you learn & enjoy. Second, in 1980, buying $1,000 dollars of Berkshire-Hathaway stock would now be $2,470,000+ million today in 2024. Who a thunk it! 😮😊

[@joecurmaci5880]

Me too

[@JakStoll]

I have been thinking about this for a bit now and I totally get what you are putting down... thanks for talking about it ... very helpful

[@powellmachineinc]

Absolutely, glad to do it

[@DanielSmith-yp7mw]

I used to think about this backwards. Picking an LSA for an application and the duration numbers built off of that. Understanding LSA is more of a result than it is an input helps me get away from the whole "this lsa for a street motor, this lsa for a track motor.." etc. and not be so wrapped up in getting the best LSA. Your videos cleared that up for me and now this one is further clarification. Thank Daniel.

[@powellmachineinc]

@@DanielSmith-yp7mw absolutely! Glad to help

[@deankay4434]

This informative discussion requires watching 3 or 4 times, just to grasp it all. Thanks kindly Daniel for openly talking about this subject that even I can understand. lol😮

[@powellmachineinc]

@deankay4434 glad to do it!

[@randyperdue52]

You did a good job of explaining valve events...it's more than a 128 formula... 😉 Certainly has made me think more about the relationship and not just LSA...

[@powellmachineinc]

@randyperdue52 that's the goal 👏

[@YourFriendlyHoodVampire]

@@b_hallwhy are you so hardup about the "128" ""formula""? You got something invested in it? You commented on every single comment, And you only are subscribed to like 8 channels. Are you a bot? Is this David Vizard's shit posting account?

[@hotrodray6802]

The 128 is designed to determine a spec that optimises scavenging and gets the mixture moving through the intake valve as soon as possible as the intake valve chases the piston down the bore... Resulting in better cylinder filling. Applied duration will determine overlap and idle and rpm power band characteristics. It's to be a better solution than throwing a dart. When the piston is starting and stopping 233 times per SECOND the LSA becomes less important because of the clock time involved is so miniscule. Of course it is recognized that a tighter LSA improves low/mid torque. Remember mixture has inertia and momentum and stretches like a rubber band.

[@YourFriendlyHoodVampire]

@ you aint gotta tell me, This is all basic engine tuning knowledge. Two strokes especially will teach you the importance of flow. Then theres intake resonance and blablabla. Which goes back to the original thing of, valve events matter. LSA does not. 128 formula is someone with a misunderstanding of multiple subjects beyond engines, and a habit of shoving esoteric numbers into a calculator. It just makes no sense.

[@randyperdue52]

@@hotrodray6802 I get it...I'm not coming from a racer standpoint just from a street rodder point of view. The 114 LSA on my current cam seems to make my engine a little "lazy" down low but I chose it because of other factors like PTV clearance with stock valve reliefs ('89 5.0) but 2.02 intake valves on the Promaxx heads...should have changed the pistons, ha!

[@TimothyArnott-m7z]

Hey Daniel, Tim here, this is probably the BEST cam lobe/design vids I've ever seen.......concise, no BS, and opened my eyes to a few things I wasn't paying attention to, or knew....all I can say is THANK YOU SIR!!!.....I enjoyed thoroughly!!!....I hope u and Brent can work together.....he's pretty snazzy on cams.......I think his and your understanding, will produce some KILLER grinds for his, or whoever app... oh, so are you now Powell Cams??....not Powell Machine??....we (I) wud need new T-shirts......btw, the Gaterman's in our FE are working AWESOME!!.....TY again sir!!....PEACE to you!!

[@powellmachineinc]

I have 2 channels and 2 divisions in my business, ty, glad it's helping! And we appreciate ur business!

[@kelleymaggio7800]

Dude, you're awesome 😂 I watch all your stuff, and you definitely have helped me out with your knowledge, and I appreciate that aspect. But the way you try to explain to the internet Pro stock keyboard racers/engine builders is priceless! I have probably commented on videos 20 times in 5 years. You're a good dude, man.

[@powellmachineinc]

@kelleymaggio7800 glad it's helping! That's the goal!

[@johnchartrand5910]

Truth, we have always done our best educated guess on new builds, the great thing is on the dyno we can easily test with the cam to see what the engine wants. This lets us get closer on our next cam for that particular engine.

[@powellmachineinc]

@@johnchartrand5910 absolutely 💯

[@nadronnocojr]

Thank you for sharing , and dealing with the comments , I’m not an engine builder , but I find it fascinating, enjoy the channel keep up the good word ….proud. 99 Dakota rt owner

[@powellmachineinc]

@@nadronnocojr glad u enjoyed

[@brianalbrecht4423]

it is nice to see someone really into what he is do'n.....!..!..that will leed to sucess...!..without a dought...!..its not a question of IF...it becomes a question of "when"...when u look @ get'n the most air into a motor quicker...when the valve opens & when it closes IS what needs to be focused on...!..absolutily makes sence...!..its basic...!..but people hardly ever talk about that aspect of a cam...thank u Daniel 4 shear'n this with us....!..i hope i got that right...?..that was my take away on the video....?

[@powellmachineinc]

@brianalbrecht4423 absolutely, 😊 🙏

[@mikegreer9041]

The more i watch Cam videos, the more i like free valve technology.

[@powellmachineinc]

@@mikegreer9041 lol, definitely

[@Chauvin-r9u]

I'm sorry but I got a dumb question where is that free valve technology I don't see it never seen it

[@stevecunningham2759]

Thanks for the deep content! You need more subscribers

[@powellmachineinc]

@@stevecunningham2759 ty!

[@craigmatthews5887]

Great explanation of cam / valve geometry & relationship. Really good video.

[@powellmachineinc]

@craigmatthews5887 thank you!!

[@mkymouseful]

Out of confusion comes knowledge! It makes my head hurt too, but I am fascinated about cams and what the motor likes.

[@powellmachineinc]

@@mkymouseful absolutely 💯

[@billythebake]

Sounds like my sophomore year chemistry professor, he would tell us, "confusion is the first step in learning"

[@powellmachineinc]

@@billythebake definitely

[@BobbyBiancaniello]

Great Video Daniel. It's funny we call ourselves "Cam Designers" but in reality we are Valve Motion Designers!

[@powellmachineinc]

@BobbyBiancaniello I'm just a 8th grade hillbilly trying to make sense of it all, but really appreciate you.

[@TheGundamZero]

I'm just glad good honest mechanics like you are still arond.

[@powellmachineinc]

@@TheGundamZero we really appreciate that 💯

[@SalterRacingEngines]

GREAT VIDEO DANIEL

[@powellmachineinc]

@@SalterRacingEngines thank you

[@SalterRacingEngines]

@powellmachineinc yeah man I hope people take the time to understand that

[@powellmachineinc]

@SalterRacingEngines It's confusing people, several totally missed how "at lash" the duration is larger.. I thought I was clear?

[@SalterRacingEngines]

@@powellmachineinc well I'm on the road I got to pick up an engine tomorrow so I can't read the comments but that's kind of typical you know it goes back to what you and I talked about on the phone the other day. The ones that are sincere try to teach them the ones that are mean get rid of them

[@SalterRacingEngines]

@@powellmachineinc I thought it was very clear myself

[@roberthirshfield3571]

I’m so glad these people like you that really understand this stuff thank you for sharing your knowledge

[@powellmachineinc]

@roberthirshfield3571 I'm just learning to! Glad it's helping

[@Mr688895]

Great video. All of these videos have been very informative. Definitely changed the thought process for sure.

[@powellmachineinc]

@@Mr688895 glad it's helping

[@lykinsmotorsports]

Excellent video!

[@powellmachineinc]

@@lykinsmotorsports thank you!

[@jesse5000]

Thanks Daniel! I need to watch it at least one more time, but I like your train of thought here.

[@powellmachineinc]

@@jesse5000 thank you

[@donaldhalls2189]

Great information, thanks for sharing, all the best to you and your loved ones

[@powellmachineinc]

@@donaldhalls2189 absolutely, ty,

[@100amps]

A lot more is making sense to me now. Thanks Daniel.

[@powellmachineinc]

@100amps 💯, glad it's helping

[@brentsmith9121]

Great information , I know I have looked at lobe separation from the standpoint of what I’ve experienced but never really thought about valve timing being different from cam or lobe timing , I have in the past used 1.8 rockers on a mild cam to help increase the lift and duration at the valve but did not know how much it actually effected it , but never once thought about the speed of the valve or velocity , would love to learn more about how open and closing timing is determined for an application ,

[@powellmachineinc]

Glad u enjoyed

[@69L88]

Great talk Mr Powell, I totally get your thought process, your explanation is clear. But when you look at cams in a catalog they are engine family, rocker ratio, type ie solid, hyd., Lift, duration and Lsa. OK, simply put the tighter the Lsa or the smaller the number, the more overlap you will have, with a given set of lobes, make the lobes bigger, more duration, keep the same Lsa, more overlap. Basically you need overlap to evacuate the combustion chamber, and also put a draw on the intake tract. You can have to much overlap or to tight of an Lsa, if your cylinder head has great low lift flow, and you have proper, good exhaust system, especially at lower engine speeds 1500 to 4500 RPM. But if the engine settles down above that and acts correctly, from let's say 4500 to 7000 RPM, you make the Lsa wider, or a bigger number to decrease the overlap. And of course that is accomplished by changing the opening and or closing points of one or both lobes, keeping the same designs you started with. Also, positive overlap does not match well with cast iron exhaust manifolds or bad exhaust systems in general. Thanks, Daniel, keep up the good work, your a man who cares, that's obvious. PS how is the new Berco.

[@aslacker]

Reverse engineering from valve events to cam specs. Love it.

[@powellmachineinc]

@@aslacker glad u enjoyed

[@inscoredbz]

Ive heard others say lsa is just a product of where the engine needs it's valve events to happen. I totally understand that, but for us weekend warriors that might build 15 engines in our lifetime, all that information gives a good idea of how it will act in the engine. Tighter lsa will have a more peaky narrower powerband, where a wider lsa will stretch on out and better for boost because of less overlap. Your not pushing intake charge out the exhaust because its still open. I still don't understand how tfe cam can be ground with say 230° but at the valve you have 233° unless its the rocker ratio changing it. Maybe you explained it and i just didn't get it. My guess is most rockers are off on what they are advertised as slightly as well, which will change things up a bit too. As always though, i still learned from you and thats always appreciated. I never thought about lash and going to a larger rocker ratio needing more to keep it the same. That makes perfect sense, and getting lash to tight puts it on the lazy part of the ramp instead of the quicker part. You made me think this time. Now my head hurts. I appreciate the information Daniel.

[@powellmachineinc]

@inscoredbz you're not grasping the difference between lifter motion and valve motion, the rocker is a multiplier.

[@inscoredbz]

@powellmachineinc that's what I was figuring, the rockers. Thanks

[@Gmamounis]

I love this channel there's so much data I'm glad I subscribed

[@The340king]

There's an art to getting the right cam timing. I have tried several different ways to manipulate the opening and closing events to achieve a specific output. Some have been more successful than others. Probably the oddest one was using a wide LSA on a street stock engine and advancing it a lot. That engine picked up torque without losing HP. The driver hated the cam because he couldn't hook it up coming out of the corner. I use some simulator software that has proven to be fairly accurate on the shapes of the curves. The accuracy of the numbers is off depending on the dyno, but the comparative curves are accurate.

[@powellmachineinc]

Definitely, whatever is working

[@3rd-Eden]

I'm here to learn, thanks for taking the time to educate

[@powellmachineinc]

@@3rd-Eden our pleasure 🙏

[@JamesBower-l9d]

Thanks again for the honesty. I’m going to have you grind a cam of your choice for my bbc I’ll give you a shout tomorrow, God bless and keep moving forward!!!

[@powellmachineinc]

@@JamesBower-l9d 💯, be glat to do it

[@patrickwendling6759]

Thank you for your knowledge and videos

[@powellmachineinc]

My pleasure!

[@craig8187]

Good stuff. Exactly, the cylinder doesn't know what a camshaft is, it simply knows available flow throughout the valve motion available. Showing LSA in a catalogue, or even just duration and LSA is simply marketing aimed at making people who know nothing about camshafts feel like they know a lot! Lobe numbers are really only properly applicable for comparison sake when comparing one cam to another in an otherwise exact same combo. So refreshing to hear some sensible cam talk without all of the marketing based hype and formula 👍

[@powellmachineinc]

@@craig8187 glad to do it!

[@dannydurham5716]

Thanks Daniel

[@powellmachineinc]

@@dannydurham5716 my pleasure 🙏

[@JasonBauder-ki9ji]

That's a great reason why people pay for consultations. A little advice from a professional on a video call goes a long ways, it can be the difference between doing it right the first time and redoing it time and time again. Time and time again gets really expensive.

[@richardmoerke9329]

Ok! This is all good advice,information. I agree on the stuff you are saying. I want to make a motor. I have been to the box store. I really don’t find what I want but I pick a cam. So how do I get a guy like you in this picture? You seem to match up with all the different people I watch all the time and try to learn from each of them.

[@powellmachineinc]

@richardmoerke9329 just shoot us a email us

[@Sunspot-19]

Good evening, Danielsan!! Time to take in more information and insights from your Dojo!!

[@powellmachineinc]

@@Sunspot-19 lol, you crack me up! Enjoy 😉

[@Sunspot-19]

@@powellmachineinc Gotta say, Job Dun!! Hadta try an give you a chuckle... Really do appreciate you and your channel. As a retired machinist, I do enjoy seeing the few of us that still ply the trade. I was in an aerospace related, small shop that did occasional engine work. At that time, we didn't have the groovy machinery that is available today. Setup was the bulk of every job. 99% was go/nogo for tolerance.

[@waltercarpenter2439]

I enjoy your channel the more I listen to you talking valve events the more questions I have. Could you recommend any books that may help me understand in depth the concept better? The more knowledge I can have the better I could talk to someone like you when I need a camshaft. THANKS

[@powellmachineinc]

I will put something together and do a video

[@waltercarpenter2439]

@@powellmachineinc awesome

[@MarineGrunt]

Most of what I learned in the cam challenge , I will never use . What I will use is the knowledge that , as you stated , selecting a cam out of a catalog is guesswork ...period . I see now that most cam cards are inaccurate and if you're a serious racer ...you don't select your cam out of a catalog . For the serious folks ? Having a cam builder , providing that cam builder with as much information about the engine and your desired goals as possible . Next on the list would be a reliable Dyno guy , one using the headers you provide ...with 8 sensors . At that point , you should have a good idea of what should happen . For a guy like me ( Old truck , big motor , and a penchant smokin the tires when nobody's looking ...a catalog cam is probably gonna be okay . Merry Christmas to the family .

[@powellmachineinc]

@@MarineGrunt absolutely agree 👍

[@richardvanmarter8780]

There's a lot to consider, if you stick to your trade you'll reach a master/ engineer level, I think combining dyno results is what will get you to the top of your game, I like the info on the effect the rocker ratio has on the valve events, I believe overlap is a good starting point for selecting a cam, the range of overlap is very different depending on application, I just selected a cam for a 461 Pontiac stroker I spent more time studing and running math that it will take to bolt the engine together, I would like to run the combinatin on the computer dyno program that Eric Weingartner used before the cam challange.

[@powellmachineinc]

@richardvanmarter8780 yes, overlap is very important

[@kevinclancy.]

another great video, you explained it all great. question on the assymetrical lobes: you had a saying, something like "open 'em fast, close em soft" or something like that. It made sense to me that you can open a valve fast but don't close it that fast because the spring can't control that kind of quick action and might bounce. are you saying that most cams have assymetrical lobes because of this?

[@leebornaman5508]

So logical. Excellent description even for novices. Have you analyzed how manufacturers achieve results from variable valve timing components. How accurate? A viable solution for added performance?

[@billythebake]

Interesting video! What you're saying makes sense to me, because I always wonder what's going on in the combustion chamber, the exhaust Port, the exhaust pipe, the intake... Now, as a theoretical exercise, when you took that last cam, and added 10° to the exhaust - but stacked it all at the exhaust opening side... I wonder how that would affect the running of the engine Now we're opening the valve 10° earlier, so we get 10° less of push on the piston before we release the pressure in there by opening the valve. Yeah, it starts the exhaust cycle sooner, and gives more time to get exhaust out - but combustion pressure has a little less time to shove the piston down the bore. I'm guessing you win some, and you lose some on that trade-off. Seems that exhaust lobes tend to have a little gentler action overall than intakes (at least on a lot of builds) - What would you think about maybe moving the exhaust opening ahead only 5°, but using a much faster acting lobe, to get the valve up far enough off the seat that it's able to flow a bunch of air out? I've been told that the faster the exhaust valve opens, the greater the tendency for the engine to be affected by the exhaust header. In other words, it gets more sensitive to changes in header, length and diameter Thoughts?

[@powellmachineinc]

Definitely

[@atlasintegrations4114]

So thinking from Valve Events to Cam is a new approach and makes sense. The camshaft industry doesn't want that because they have too much tied up with them telling you what cams they have; not you telling them what cam you want. So the big question is this: What dictates the ideal valve events for a specific build? Where do you start? What is the "Rule of Thumb" when it comes NA or FI or Nitrous; or desired RPM range of operation; or application?

[@powellmachineinc]

Trust me, I'm still trying to get enough data to make use of it, but... this is the way

[@sjcottsi]

Does that Cad cam have an integral distributor drive gear? I have a 500 engine that I would like to go roller with just to get rid of the flat lifter using all the same specs as a stock cam. I would think you could cut the iron gear off a stock cam, bore it and key it to fit on an extension of the steel cam with a bolt and washer that would serve as a cam button. Then you wouldn’t have to worry about a brass or Melonized gear.

[@powellmachineinc]

def could

[@sjcottsi]

@@powellmachineinc There might be a market for this. Guys restoring their Eldos that don’t want to worry about the cam.

[@paulshurmon138]

Thanks for the video.

[@powellmachineinc]

@@paulshurmon138 you bet

[@deanleonard7857]

I’ve read a couple books on cams and it’s still voodoo to me. I will note a lot of static or background noise as I watched. Still good. Thx.

[@powellmachineinc]

@@deanleonard7857 fan running on the junkie gopro...

[@Gmamounis]

Reciprocating mass needs buffer zones... valve lash ....spring ..and flex. I always start at the beginning and work my way into the cam

[@BeetleatWar]

In Germany you usually get the Advertised Duration, LSA, Valve Events/Lift and Lift at TDC - it depends a bit on the company

[@V8Lenny]

In Finland I have never seen LSA mentioned, thats why I thought it is some american thing.

[@BeetleatWar]

@@V8Lenny in Germany you have Problems getting the duration @0.050 - if you are lucky you getting Duration @ supposed lash.....

[@V8Lenny]

​@@BeetleatWarI think in Europe is usually used duration at 1mm

[@GeorgeFarahGNR]

Im gonna need a powell cams hoodie! I like the logo!

[@powellmachineinc]

@@GeorgeFarahGNR yes sir, we gotcha covered

[@boharris8179]

Wher you boys located? I'm digging the knowledge brother. How'd yall do with the Eric Weingardner cam challenge

[@bruce1816]

Thanks Daniel, is there a relationship between valve spring pressure and lobe velocity? Controlling the valve to stay with the cam is tough. Especially when valve springs can vary quite a bit right out of the box, so spring height kind of goes out the window.

[@powellmachineinc]

@bruce1816 definitely, but more so, the weight of components and rpm ect, play a major role

[@scottosborne8735]

Overlap required? Exhaust scavenging potential? Fuel? Application?

[@powellmachineinc]

@@scottosborne8735 so many variables

[@MostlyOldPartsAndRust]

That was very interesting! Thank you Daniel for the explanation! I have a question about small block Mopars in particular, do the software take into account the crazy 59° lifter angle? That drastically effects the valve motion. I assume that it would not, but wanted to ask. Thank you!

[@powellmachineinc]

@MostlyOldPartsAndRust it doesn't, but in that small of movement I doubt it's actually changing anything, do you have any data to support this ?

[@CK-mf6du]

Is it a good practice to look at advertised duration when thinking about the intake closing? Past few motors I've done I've shot for 8 to 1 dynamic compression to keep it on pump gas? Iron heads. Some guys say that is irrelevant, but wouldn't it be more meaningful when considering the rocker arm ratio, vs the .050 number? I use the advertised vs .050 to get an idea of the intensity. Just to add, these are just street motors that I'm trying to get a usable powerband out of.

[@powellmachineinc]

Yes to figure dynamic, @ .006 ivc is the only # to use

[@DesignForVision]

Great video Daniel! Are you familiar with "Dirt" sbc 358 10.5 to one static comp. spec motors for circle track.

[@powellmachineinc]

@@DesignForVision me mostly to drag race stuff, but only rollers

[@AINTNOTHINGEASYINLIFE]

On direct injection does that change things when figuring out what grind your doing???

[@jarlnieminen4307]

Thank you! LSA is just a nice short cut.

[@powellmachineinc]

Lsa isn't a shortcut to anything

[@jarlnieminen4307]

@powellmachineinc what's a shortcut?

[@tracycurtright2671]

I had no problem seeing that at the camshaft degrees is different than at the valve degrees. I couldn't understand how you could say there was no symmetrical lobes until I watched this on my phone with a Dyno sim program open on my computer then I seen what you meant.

[@powellmachineinc]

They're are some symmetrical lobes, but not any good ones

[@jmflournoy386]

Makes perfect séance

[@powellmachineinc]

Ty!

[@jmflournoy386]

@@powellmachineinc lots of great info will have to watch again I liked the explanation of moving timing points while maintaining overlap poiints, way I do it but never worked it out like that I usually select my target compression pressure, then the physical compression and intake close then do the overlap triangle etc If I mo then go around again fudging depending on rpm giving up low end by intake close later (more duration) while watching the overlap triangle (idle, power brakes, reversion) no magic LCA If I retard the IC I increase the mechanical CR go around again

[@tracycurtright2671]

Right off the bat let me say I'm not arguing with you. So if I throw lobe separation out the window l want a hydraulic roller SBC 1.6 rocker ratio, say mid 220°-225° duration 355, 10.3 compression ratio how do I choose a cam that will run power brakes. I know if I pick 110° lobe separation I will have enough vacuum to run the power brakes, 15ish inches Hg? I realize that you might not have to yworry about the power brake that often. What number of degrees exhaust closing, intake opening am I looking for?

[@powellmachineinc]

@@tracycurtright2671 lsa is irrelevant to your goal, overlap is the problem

[@tracycurtright2671]

@powellmachineinc well in simple terms what is the maximum overlap if I was wanting power brakes? I'm not trying to be a smart ass I really want to know

[@chevyrc3623]

Dang i am not done finish the video i am about half way just so i don't forget this comment man i knew it was different from cam or lifter movement to valve movement but man that's a huge difference and rocker ratio to man thanks for sharing i will keep that in mind on the difference so then what is you have a much bigger rocker ratio how can you calculate a duration or the valve event with the much bigger rocker ratio like say sbc from 1.5 to 1.85 as a example

[@chevyrc3623]

Now i finished the video so there is a lot i didn't get but maybe when i learn more as i go maybe i can grasped as much as possible. So um yeah it's just a lot i run a 2 barrel circle track wingless spec sprint car so it's just me learning as i go and hopefully understand more to

[@powellmachineinc]

@@chevyrc3623 that's all any of us can do

[@PeggyParrow]

My cam runs clockwise, but everybody shows on paper a cam lobe as if it runs counter clockwise ex. The left side looking at it is the closing ramp, not the opening ramp ?

[@powellmachineinc]

@@PeggyParrow you're confusing a profile trace with a physical lobe

[@kd5yut]

Does tighter lobe seperation help pull exhaust gasses out of the cylinder at the begining of the intake stroke due to the velocity of the gas moving through the headers pulling it out while both valves are open at the same time? Or have I been taught wrong?

[@powellmachineinc]

@@kd5yut did you watch the video and grasp what was being said?

[@kd5yut]

@@powellmachineinc duuuuh, yes

[@powellmachineinc]

@@kd5yut obviously not.....or you wouldn't have asked that question, maybe watch again.

[@damianokeefe]

This Is Good👍🏁

[@powellmachineinc]

Thank you

[@pizzle4420]

The cam is the brain of your engine

[@powellmachineinc]

Definitely

[@cuda6496]

I thought I was the only one having headaches by trying to understanding all this😂

[@powellmachineinc]

@@cuda6496 lol

[@wayneskelly4297]

Wow. Totally different way of looking at it. Back to the drawing board to figure some of this stuff out now. LOL

[@powellmachineinc]

Glad it was helpful!

[@luuna_5.7hemi75]

Do you have my engine done ? I like to have it done before thanksgiving

[@fernandohood1886]

Was there a correlation between the winning cams and the LSA?

[@powellmachineinc]

No

[@23steph13]

Will the stroker 4.00 crank fit in a LY6 block that has the oil squirters?

[@powellmachineinc]

Yes

[@23steph13]

​@@powellmachineincthanks

[@23steph13]

Hello. I'm looking to get a custom cam grind. I sent an email to the email on your website a few days ago.

[@daveb1870]

How much of this changes at operating temps?

[@VGHCX]

So, how many degrees do the cams on your program stay at PEAK LIFT for?

[@powellmachineinc]

1

[@VGHCX]

@@powellmachineinc Is this good, bad, or neither? Ideally wouldn't peak lift for as long a duration as possible be desired?

[@jakewade7388]

How important is overlap bias? Say a mild camshaft has -12 overlap @.050, One camshaft has -6 IVO and -6 EVC The other has -3 IVO and -9 EVC Same IVC and EVO. How would the power band differ? I’ve always wondered about this.

[@ericwright5419]

I got a one off grind would love to see what you would think the numbers are different to me than anything I have ever had

[@powellmachineinc]

Sure

[@ericwright5419]

@@powellmachineinc SBM W8 HEADS TURBO ON Methanol around 11to1 compression

[@powellmachineinc]

@@ericwright5419 that's not odd at all

[@ericwright5419]

@@powellmachineinc Thanks most everything made that I found was on a 108 LSA it was crazy looking for a core

[@Rob-q6i]

Have a selection of camshafts all for the same heads, rocker ratio, compression ratio, engine spec's, producing a span of + or - 30 hp on my 632 at similar rpm. Spanning 8 years of bracket racing, all for nothing, but creating sales at 2 different cam companies. Your videos have shown me how foolish I've been listening to their Tech Departments.

[@powellmachineinc]

Glad it helps!

[@flinch622]

No engineering happens without compromise. And if we hold on to an overlap number to suit purpose, then the compromise is to shift lsa and that will affect scavenging/VE.

[@powellmachineinc]

Overlap is doing the scavenging, not Lsa..... ivo/evc

[@flinch622]

@@powellmachineinc We agree, I think. The point I didn't make so well is... where the mass of exhaust is down the pipe as intake opens, and the relative effect on intake does get tilted by lsa just a bit. Maybe the simplest analogy is this. To nudge something with a ten pound sledge, hold it near the head. To get a hard hit, full arc from the end of the handle - in both cases, its ten pounds. So for the same overlap but two different lsa's, effective signal seen by intake should shift a little.

[@Shademax4273]

Even if the cam is symetrical these calculators still cant calculate valve lift Correctly even of you Could imput rocker ratioo?

[@powellmachineinc]

@Shademax4273 valve lift isn't the issue, anyone can calculate valve lift, duration and events are the problem

[@mikew6135]

The bad thing is the winner of the weingartner cam test just expect the cam off Woody nose and not all these complicated formulas. He beat everybody big time. Any explanation for that? If you were making a cam for a 6.2 3rd gen hemi with a Whipple supercharger at about 20 lb of boost with an RPM limit of 7,000 in a hot Street application what would your choice be?

[@powellmachineinc]

Bobby explains how he won, zi also explain why everyone else missed it on the exh side.

[@tonyalto1014]

I have always believed that lsa was a mathematical result of the opening and closing events you have chosen for a particular job or design.

[@YourFriendlyHoodVampire]

It's a happy accident from someone playing with a calculator, along with a misunderstanding of multiple subjects

[@b_hall]

A certain LSA gives a certain ivc to overlap ratio. Certain engine platforms like a particular ivc to overlap ratio. This applies to not all but the most common engine builds with the most common shelf cams. Just my opinion.

[@powellmachineinc]

@b_hall you have any data to back that up?

[@craig8187]

@b_hall , with all due respect you want to run some math on that theory and see what happens when you apply an overlap to ivc ratio. Then look at the effect on actual overlap area graphs when you have different lobe rates, then look at the actual overlap flow available as governed by cylinder head, bore diameter, piston crown shape , stroke etc etc etc. Maybe one specific combination likes a particular overlap to ivc 'ratio' and this is because you have the correct valve events, lift and lobe rate for that combo, change anything from air intake to tailpipe and you are no longer correct.

[@b_hall]

@@powellmachineinc i haven't been on a race track since i learned this and I've never been on a dyno. I get info, results and data from other people, including you, and put it all together. I see most street style sbc's getting the best performance with 36-40 ivc, 10-15 overlap and 6-10 more degrees duration on the exhaust side with stock or budget cylinder heads. This is all my opinion, no facts.

[@powellmachineinc]

@@b_hall I'd say that in line with what I see

[@b_hall]

@@craig8187 the stuff that i see the most and deal with the most, won't see and gains from going that in depth with it.

[@YourFriendlyHoodVampire]

Some people find an accident that is close enough, but there are a lot of over confident people that have no business "creating" formulas. Your approach is simplistic, non esoteric, and correct. That "128" formula is complete esoteric misunderstanding of multiple subjects.

[@YourFriendlyHoodVampire]

@ refer to the "esoteric" part of my comment. What you are saying makes no logical sense. A valve event is a valve event. Edit: dude deleted his comment. Username was @"b_hall"

[@powellmachineinc]

Yes

[@notsponsored103]

Let me write down my thoughts in real time. I've never designed a cam. I understand that a 4 stroke engine induces a vacuum on the first of the four strokes. I know that the timing of the induction is constrained to the timing of the piston motion. The piston motion is a constant relative to the cam lobe motion. I know when the induction stroke begins and ends. I also know that air has mass. I know that any mass is subject to Newton's First Law of motion. I know I can take advantage of the inertia of the mass flow of air into the cylinder to increase the duration of the induction cycle. Thus, I know I can open the intake valve earlier than TDC and close it later than BDC. I now know my duration could be greater than 180° of Crank movement. I need to calculate when to crack the intake valve off the seat. I need to consider optimising induction vacuum. I need to have the combustion gases from the previous cycle exhausted optimally so I can have the purest mixture of clean air and fuel ready for the compression stroke. I suspect I want to close the exhaust valve as late as possible to optimise the purging of inert combustion gases. I suspect I can use the wave front of the induction surge to push the last inert gases out of the way as it approaches the exhaust side of the chamber so I want both valves open simultaneously for just long enough to achieve this without losing any of the clean mixture into the exhaust port and without compromising induction vacuum. I estimate for the sake of the experiment that I may open the inlet valve a few degrees before TDC while the xhaust valve remains open for a few degrees patiently waiting for the rush of air from the inlet valve to reach it and consequently close it immediately there after at perhaps a few degrees past TDC. So I have calculated my Inlet Valve Opening and my Exhaust Valve Closing events. I need to calculate Inlet Valve closing. I know that air is rushing into the cylinder at speed. I know that Newton's First law of motion dictates that the air chasing through the Inlet runner has inertia, thus I know it wants to continue the chase despite the piston beginning its return to TDC so, I know I can wait to close the Inlet Valve After BDC to take advantage of this physical phenomenon to optimise cylinder filling. I estimate that I may be able to wait as much as 40° ABDC for the Inlet Valve Closing event without pushing air back into the Inlet runner. I need to calculate my Exhaust Valve Opening event. I know that the combustion cycle produces maximum cylinder pressure at about 18° ATDC and that almost all off the power has been delivered to the crank through the connecting rod well before piston reaches BDC. I know the expanding combustion gases are needlessly chasing the piston to BDC and might as well be allowed to escape the cylinder before BDC. I estimate that there are diminishing returns from the expanding combustion gases as the piston decelerates towards BDC so I estimate that I may open the exhaust valve at about 40° BBDC. I have calculated my Inlet Valve Closing and my Exhaust Valve Opening events. Let's say: IVO 5° BTDC IVC 40° ABDC EVC 5° ATDC EVO 40° ABCD DURATION 225/225 Let's give the Lobe 3/8 inch lift Rocker Ratio 1.1:1 I think the engine will run. How'd I do?

[@doomman700]

When you figure out how to get square lobes to work you will be fast.

[@trucksofspeed]

If i send you a cam can you make me the same cam...its a sbc hyd. Roller..

[@powellmachineinc]

@trucksofspeed normally yes, we can get very close

[@trucksofspeed]

Ill ship it out.

[@stevenbean9706]

theres a whole lot of forgotten technology that could be revived today if a cam manufacturer wanted to apply it . i laugh every time someone tells me ohh cams today are nothing like they used to be with the durations and lobe separation technology they are so superior . im thinking to myself yeah if you only knew they are just pounding pooey to you making you think your getting a better cam . theres so many pie in the sky numbers out there its almost senseless. Ed Smith showed a cam a while back id love to see someone make , opens super fast the ramp looks like a witches hat has a lot of lift opens and closes super fast and when you ask why ? he said exactly what I was thinking it actually allows the motor time to build more cylinder pressure ! in a motor with low compression like a lot of mopars it would be like turning a 7:1 compression motor to a 10:1 motor .

[@powellmachineinc]

@@stevenbean9706 you have a link to this cam you are referring to with Ed Smith?

[@stevenbean9706]

@ Ill try and find it , Ed treats those cams like gold cause he said he knows of nobody that makes them anymore its something that worked really well but fell off the face of the earth for no real explanation. it makes perfect sense when he explained why it was built and how it worked soon as he started explaining how it works it immediately got me thinking about the low compression mopars and smog days . ill look through his site hes got some really interesting stuff but that cam got me thinking and I wish I still had the shop to make one of those type profiles cause id definitely love to try one after his explination cause it made perfect sense cause a lot of people dont really realize where the valves are in comparison to where the piston is and busting the door wide open then immediately closing it so your cylinder can start building pressure immediately got me literally seeing how the air would move and where it opens so fast it pulls a lot of extra in with it as well.

[@TheJohndeere466]

I cant see where rockers can add total duration. I realize different lashes will change duration. Lets assume zero lash and the cam has 250 degrees duration. The rocker arms multiply the lift but they will not change when the valve starts to open. Lets say you have 1.5 rockers so when the cam raises the lifter .001, the valve would be open .0015 but it didnt start opening any sooner than when the lifter did. The valve should still have 250 total degrees duration. Now if your cam doctor has a different diameter wheel than your lifter then yes the cam would show more duration in the engine. The rocker will add more duration at say .050" than at the cam but not total duration.

[@powellmachineinc]

You don't understand velocity, that's the problem

[@TheJohndeere466]

@@powellmachineinc what does velocity have to do with total duration. There is no velocity at the point of total duration.

[@bencrisp9776]

😊

[@powellmachineinc]

Ty

[@PeggyParrow]

Im sure David understands this, but he is only giving generalitys knowing the general public will not begin to understand it as you explain it, so dont be too hard on people who try to just give the general public Something to go by ? What he says is ok for street motors.

[@powellmachineinc]

I'm not hard on anyone....

[@DutchKC9UOD]

Valves don’t like a drop off the cliff close

[@samstewart4807]

hi, you are producing very high tec videos.Suppose I am building an engine. I am using performance trends software to help me.At some point this software will give me cam and rocker specs.I call you. I say perf. trends says I want blah blah.What is your first response? OR will you say "ok I am going to give a xyz spec cam"."Put this cam in your software". "See if it matches your torque/hp. specs". Is that not what I should be concerned with?

[@powellmachineinc]

My first response is ok, let me take ur order.

[@samstewart4807]

@@powellmachineinc hi and lol what is your 2nd response? As I understand it ( is that correct) you are designing camshaft lobes to fit my order? OR are you saying the software you have does a better job than a perf trends type program.Last, will software like perf trends show the difference in power between your 245 degree lobe and your 250 degree lobe? ( I thought it did)

[@RussellCompton-fh3gr]

yep yep good job,,,,,im getting it,,,but ,,,,,,,,,,,,i think i heard sumpin POP inside my head ,,,,,,,,,,,,,,lol

[@powellmachineinc]

@@RussellCompton-fh3gr lol, give it time

[@Basketofdeplorables173]

I'm 46 seconds in, and the comment section is already worn out.

[@zacharymorris9917]

The easiest way to sort out a bad cam designer is to ask them what LSA you need. If they answer, RUN!!!

[@powellmachineinc]

@@zacharymorris9917 definitely

[@joe-hp4nk]

Clear as mud. To me cams are a black art. I just start with the factory cams the engineers came up with on the muscle cars and go from there.

[@markbogle8062]

There is formula to find the LAS yo start with it depends on the size of the piston to the size of the valve it's work on any American V8

[@powellmachineinc]

@@markbogle8062 no....

[@markbogle8062]

@powellmachineinc it the 128 formula its a Daivd viszard video

[@markbogle8062]

@powellmachineinc the 128 will work on aby motor except a Ford or a Mopar you minus 127 and Ford has the se number big block chevy you minus 132 that will give you a starting point then for valve work you all 2 and port the head you add a nother 2 and then if tye compression any over 11.8 you all a nother too .I did te 128 formula with the ls and got 109

[@joshiek7839]

@@markbogle8062lol.

[@ChristmasCrustacean1]

how much wear can the comment section take before it requires a boring and honing.

[@powellmachineinc]

Lol 😂

[@largesfc]

You kinda like triggering with facts. I just placed a little order.

[@powellmachineinc]

We appreciate that 🙏

[@largesfc]

@powellmachineinc I appreciate that it shipped same day! Thank you!