Cam profile or cam event timing - which is most important?

In this, episode 15, of the rebooted PowerTec 10, we look at the importance of a cams profile design versus it's opening and closing events. Here DV, in conradiction with a number of pro cam designers sets out to show the evidence that strongly indicates they are wrong!

[@ChipsAndSparksGarage]

“I don’t have an opinion, I have a Dyno.” I love that quote!👍

[@billythebake]

Ha! Ya' beat me to it I literally chuckled out loud when I heard that

[@idontcare3013]

He tells them off so politely. Love it.

[@milojanis4901]

I must say as a guy who's been around awhile (10 years younger than you), I've seen your name in many articles in many, many publications over the last 50 years, or so. But this is the first time I've seen a face attached to the print! I greatly respect your knowledge. Only wish I had a way to contact you directly. Please keep the videos coming. I've subscribed, and shared......👍

[@terryheimerl8674]

Mr. Vizard, David, You give your expertise freely and in a very easy to follow manner. Anyone who has a basic understanding of engines can reliably follow your advice and obtain great results. Your videos teach listeners to lift their game and improve their results. Also, unlike others who only have knowledge on a couple of engine types and sizes, your knowledge is of many different different types and sizes from the Morris "B" block to the biggest car and diesel motors. I never get bored of your videos. There is a saying, "the day you stop learning is the day they screw the lid on".

[@user-hz4gw6no9w]

Your videos have made me think about engine preformance a little differently and in ways I never thought before THANKS FOR YOUR HELP AND TIME IN MAKING YOUR VIDEOS

[@johnelliott7375]

You are the man and God knows this, 64.years! Congratulations on this milestone!

[@jseal21]

Ha!!! Quotable quotes; FDR: The only thing we have to fear, is fear itself Churchill: A pessimist sees the difficulty in every opportunity, an optimist sees the opportunity in every difficulty DV: I don't have an opinion, I have a Dyno

[@tobbytownsend9968]

David Vizard - The man has undergone brain surgery & is STILL! the most intelligent engine builder on the interwebs.

[@billythebake]

I remember that thread on speed talk. Your formula got posted as a rule of thumb, for picking cams for small block Chevy engines. It was also stated that it would work reasonably well on similar engines, where the ports and combustion chambers were very much like the small Chevrolet (such as small block Ford, or MoPar wedge engines), but the 128 constant might change by a degree or so. There was also a caveat that the formula worked on the assumption that the engine had a 10.5:1 CR, and that the LSA should get spread about half a degree per point of compression above that I thought that was pretty cool. Something that would basically get me (as a 'shadetree' guy) in the ballpark If I was going to try and spec a cam It was never put forth as the 'end all and be all' of camshaft design formulas; just a quick way of getting a pretty good workable answer to a question. Nothing more, nothing less. Yeah, it became a typical internet forum deal; the discussion got way off in the weeds about hemi's, four valve cylinder heads, huge engines, tiny engines, canted valve engines... The ONLY problem I see here is that my 10:1, 489" stroked Plymouth with 2.14" intake valves should have a cam ground on a 102° LSA, which may until a significant upcharge over a "shelf" unit Looks like when I go to upgrade cams, it's going to downgrade my wallet a little extra, LOL

[@theshed8802]

Great video David. As usual. It doesn't matter what dyno numbers you get if you don't know how to interpret them. As they say, never argue with a stupid person, they are too dumb to realise that they have lost. Personally, I suspect that you know a lot more about interpreting dyno numbers than most. Would be good to see a video on it one day if you ever get time. Regards Greg

[@v8packard]

The only methods I have found for calculating a max performance cam that is more accurate than your approach involves expensive computer software and/or substantial dyno time. Your methods get damn close, time after time. Thanks for the video.

[@DavidVizard]

Hey V8 - thanks for the vote of confidence!

[@v8packard]

@@DavidVizard I thank you for everything you do

[@jimlathrop8603]

​@@DavidVizardthanks for all the years of info. Is the "lobe centerline...cart" based on the 128 chevy formula or visa versa? Ie.can chart be used for other engines? Also is the formula using flow #s available somewhere? Is the "great cam scam" out there somewhere?

[@DANTHETUBEMAN]

​​@@DavidVizardHello Mr David V, The 128 on my 283 with 92 votec heads 9.5-1 compression comes up in to 112 degrees but looks like 110 on the chart? thnx. can a 107 thumper cam make torque in this engine combo? 🤔

[@darrelkinney9856]

A dyno machine brings you facts not here say . I like the videos that you have on building an engine top to bottom. A machinist Master and a wealth of knowledge.

[@brentscott364]

Thanks David! I've been using your cam tool program for awhile. Its been spot on with my 383 stroker motors. The Torque curve is quite explosive for being a street strip engine.💪🏻

[@danielmauter1737]

Dr. Vizard!!.. Excellent as ALWAYS!!.. I believe I have ALL your books... Learned a ton from each one!!..

[@jonoskowski5545]

Thank you for what you do. I’m learning a lot from your videos.

[@johnelliott7375]

These series are awesome stuff.

[@DavidVizard]

Thanks John - make sure you are telling everyone else that.

[@joesalazar770]

I think being a deisel or even a two stroke enthusiast answers the question but I still love the way David tells it like it is. The event is the real timing not the cam position.

[@wayneireland4802]

Some people just can't be told I no a few here in Australia still waiting for there book so I can get there signature.totally understand thanks mr vizard.peace

[@markmcmullen1371]

DV that would be interesting to see Jon show up with the perfect cam being the other cam manufacturers agree he'd be right, so he could test it against yours, he'll never show up no guts, my vote is for you DV. He (Jon) has spoiled more than one speed-talk post.

[@FizzaMC]

**Copied from an older video, just some constructive feedback mate** Hey David. I really loved your engine building books I borrowed from the school library when I was a young and inquisitive boy. Back then it was a great knowledge base to start my own building and learning as I go. But David I have to admit that while the earlier videos that you used to release have been great and for the most part pretty informative, however as time goes by you seem to get really affected by any feedback that differs, even slightly different, than your own opinion. I think that the internet can be a beast and unless you learn to tune out the noise and also to listen and consider to people's knowledge and opinions then it's not going to be the place in this huge public domain where people can actually challenge on the spot what you're saying, unlike writing articles for your books or other publications. This comment is coming from a place of respect for you so please remember that. Take care and I hope you start to get back on top again real soon mate. God bless and kind regards, Jim

[@salvatoregiovanni8967]

I think you’re confused when you quote the phrase “differing from his [Dave’s] ‘opinion.’” None of the info presented in his videos is opinion based. These are absolute facts backed up by thousands of dyno tests (as he often reiterates in his videos). The naysayers are stating opinions. DV spits facts.

[@FizzaMC]

@@salvatoregiovanni8967 nah, I'm not the only one who's getting confused Sal. I'm just a humble spectator of the Race engine challenges and don't understand why other builders are regularly finishing above DV when the way engines are built according to DV can't evolve past the research and thousands of dyno testing results he has done. I'm still saying this from a place of huge respect and admiration for DV too btw so don't get all salty when you go to reply. There are more builders and engineers using some fantastic new technology and procedures that are getting results that are obviously a cut above the rest. It's always good to understand that technology does continue to evolve and saying it won't get better than one particular way is just backwards thinking. Food for thought Sal

[@genemanno1533]

Well stated, the world is always moving forward and somebody alway comes up with better and faster than what previously was winning.

[@jonelford4513]

I 100% agree with you. Vizard is a smart guy, and has decades of experience. BUT, these videos are 5% information, and 95% him and that other dude railing against the rest of the industry.

[@FizzaMC]

@@jonelford4513 hey buddy thanks for the reply. I think you may be able to see that I'm not on a witch hunt but more to the point of clarifying my position and opinion that DV was and still in some areas a great source of information that can help heaps of people to get some massive gains and economic health in building some great combos. My few main concerns is that sometimes the most of us let out ego speak for us instead of hard analytical date instead of really focusing date and procedures that will give massive gains and reliability. When people tell me that this is the one and only way to produce a great race engine then I tend to just tune out and perhaps comment on a different process to improve. Problem is that when people get into the "one way is the only way" mentality then it's just plain to see that some people will never accept anything new because the ego won't allow the fact that sometimes and often a lot of times that we just can't get everything right. Still mad respect for DV from the building a development, but I don't tolerate the amount of slander and trolling to guys who tend to give him stress in his own profession. Just need to listen, read information and accept that not many things in life will always be the best. Take it easy Salvatore and it's great to chat with another person on the fringe Of what performance technicians are still improving on each and every day. Cheers Bud

[@shaneshane1379]

i am going to try this equation on a mild performance build for my pu truck. cmas are plentyful and now days are well advertised to help a builder choose what they desire. i would still rater have some sort of proven method to get the most out of a component. once again, thank you mr. vizard.

[@harryashe8093]

I barely know anything about cam angles but I understand the importance of valve timing as opposed to lift. Your formula works and that's not an opinion, that's a seat of the pants experience !

[@mikecondoluci53]

HI DAVID IVE BOUGHT AND READ ALL OF YOUR BOOKS, IVE WATCHED ALL OF YOUR VIDEOS, I DONT LISTEN TO THE REST CAUSE YOUR THE BEST, THANK YOU FOR SHARING ALL YOUR KNOWLEDGE WITH US AND I HOPE I CAN MEET YOU SOME DAY, THANKS AGAIN

[@brianbridgeman6877]

David, I'm curious as to how you built the lobe centerline angle chart we see at 7:16. Is this a plot of empirical data based on the best results achieved by altering solely the LCA with all other camshaft variables being unchanged? And, my next question is, were the best results based solely on max horsepower? I'm wondering if this chart would look differently if you favoured street manners, or average horsepower over effective RPM range, for example. To me, this plot is at the crux of your theory, since it seems to be what you based your formula on. I would love for you to do another video explaining your process in building the chart, including what variables you changed in testing, what assumptions you made, and what your initial hypothesis was. I think it would add a lot of meat in your arguments! Thanks, I really enjoy watching your videos and reading your work.

[@danielmauter1737]

Its in his cam and valve drivetrain book..

[@michaelgideon8944]

The SAE paper that deals with this topic is No. 820749. It agrees with Vizard generally that valve events are what you are interested in controlling. Specifically intake closing and exhaust opening. The others are less important. Vizard also makes some comments about the profile centerline. I think this is a result of the crank rod geometry setting the max piston velocity at around 70 ATDC. The SAE paper also deemphasized the importance of TDC overlap relative to the valve events themselves, particularly intake closing. The paper used street engines for the testing so it's probably not as applicable to the most radical race engines with extreme valve events and timing. I have also read comments from cam designers reflecting the same sentiment as in the study. I suspect there maybe some benefit in stability and long term durability in modifying the profile once you have nailed down the the significant valve events. Anyway I recommend reading it for yourself, it's not overladen with math jargon and very accessible to those without an engineering background.

[@michaelblacktree]

To be honest, I'm not a big fan of the internet drama. I understand where you're coming from, and agree with you. But the old saying "don't feed the troll" applies here.

[@terryenyart5838]

I can honestly say I've tried this & there is much truth in whst David is saying. I own my own dyno & the only exception to this rule is when engines have extensively modified cylinder heads that flow much more than a typical street car or mild drag race engine. Im talking Big $ heads that can use a wider LSA and produce power at high rpm. 7000-10,000 If your heads are Edelbrock or similar, even with porting, DV's chart works best.

[@prestonedmonds4128]

Thank you David for sharing your knowledge. I've bought many of your books over the years. I do have a suggestion though...would you be opposed to using a separate microphone 🎤? My old ears have trouble hearing the audio with the hissing noise and the echos.

[@gergatron7000]

I have a follow-up question regarding LSA. If the ideal for an SBC is 108, why do cam companies mostly offer grinds in the 112-114 range, even on the most modern LS designs? Are they hamstrung by emissions requirements in order to be sold as street legal cams? Is your approach to cam design purely race-oriented? I mean no malice in my line of questioning, I just want to know why so many can be wrong when we're possibly comparing qualities of cam design for two different criteria here.

[@1crazypj]

Strangest cam I've ever seen was in a 1965 Royal Enfield Continental GT. (first British 250 cc PRODUCTION motorcycle to do a genuine 100mph) It was kidney shaped so slammed the valve open really quick. I thought it was weird so ended up buying another 4 bikes and stripping motors. All about the same profile even though different years and models. 'Modern' (1999¬2000) port design plays a big part in having what car guys would consider highly radical cams (103¬104 LCA) which idle well and have a broad power band (often 1,500 to 12,500 rpm or more) although things don't generally 'come alive' until 6¬7,000rpm when power climbs steadily getting close to 180BHP/litre More modern designs from last 10 years or so are averaging 200bhp/litre on sport bikes (and over 220bhp/litre for production racers, without turbo's, nitrous or other add on's)

[@terryenyart5838]

I should also note: my comments are for naturally aspirated engines. Forced induction generally engines do not need the amount of valve overlap on a tight LSA camshaft.

[@dannoyes4493]

Piss & Vinegar! Well Done! Really Enjoyed This One.

[@jmflournoy386]

Dave, as you must know, they just want to sell "shelf" cams ground on production grinding machines. Crane did both after he bought a "Detroit" cam grinder. I would bet that Harvey's cam would run longer with less spring than Sigs I knew Sig when he was with Isky

[@braydencozby]

Start off with great video David love the content. What number do we use for things other than sbc, I need to know the number for big block ford when I use your bbc number of 137 I get 106 lsa is that right or is it different

[@Mr-Yan.]

Loving your videos DV, think of you every time I have a black Russian! Michael, Australia.

[@wardfrahler6779]

Hey Andy, help us Ford guys out. David doesn’t answer the Ford questions. Does books tell about the SBF’s? I have a 351W going in a street rod. I have ordered a cam for the 1000-4800 rpm range. I know it’s not a race engine but will DV’s method work on a street engine? I figured the LSA and I have the range of overlap, now how do I forgive lift and duration?

[@littlevman2997]

Hi David. I was wondering if the 128 rule applies to hemis, and 4 valve engines. I really think that's the most impressive formula when it comes to engine building and cam selection. For a .030 over 440 big block mopar depending on intake valve size the recomended lsa is between 101 and 103.... this blows my mind. I always considered anything less than 110 bad for idle quality. Never thought to lessen the duration with tighter lsa to give less overlap...perhaps it's because there are no cams that have those specs on the shelf!!! Next engine is getting custom grind.:)

[@chiappettamark]

The 128 equation seems pretty good for the Med Compr Pontiac V8 LSA-needs for Street down to low 10s, yet i do wonder what the fast (7-8 sec ET) High-Compr Pontiacs are using. Also, i too found LSA to be a consequence after cam design, but now agree the LSA should be the starting point! As for Duration My Overlap has always been too high for ping- mitigation for Street-Strip, but having the LSA correct has helped the cold start, idle thru hot idle. That extra overlap gets applied to enhanced EGR for improved Highway MPG.

[@dennisrobinson8008]

I had a question. A 350 cubic inch engine with inline valve heads, the intake is the equivilent of an RPM air gap and a 750 double pumper carb with 1 3/4" long tubes and 2.75" dual exhaust. The heads flow 210 cfm @ .400" lift and 260 cfm @ .500". The car is considering two different camshafts, the cams have the same duration and LSA and different lift numbers. Cam #1 220@.050", 112 lsa and .410" lift. Cam #2 220@.050", 112 lsa and .610" lift. What is the power difference? I know in the situation if was the same situation but the difference was the cyllinder heads. The first situation has all those parts and a set of heads that flow 210CFM peak flow, versus a set of heads that flow 260CFM peak flow in the same combination. The 260CFM head will pick up the power in that combination something around 40,50 or even 60HP. So what is the difference if the heads can flow, but the lift doesn't lift out to that point, and finally you swap in a cam that lifts out to where the head is flowing?

[@dougroope8040]

I’ve been building engines for about 40 years and have always relied on what most cam companies would recommend… I’m very interested in finally choosing my own cam profiles, How does one use this formula on a BBF? Or any BB for that matter…?

[@sethbarnes7608]

Wanting to build a performance 460 for my Lincoln MK4, I really hope we get an answer to this one.

[@sethbarnes7608]

But I think I heard him say that the formula would be damn close in anything up to a 4 1/8 bore, and I think a 460 is 4.18, so maybe it'd work, or be at least close enough to work, or play around with an adjustable cam gear on the dyno, and find out. Because as David puts it so eloquently, we don't have opinions, we have a dyno!😂😂 love it David!!

[@brainward2611]

Love watching and learning I would really like to know how I can get some more of your knowledge directly pertaining to my setup

[@havebenthere]

DV Thanks for the video. I'm always comparing cams in catalogs for the SBC. There's many that seem very close or perhaps copied from one cam company to another, but show a different rpm range. Sometimes the same company cam is the same except offered in a 106 108 and 110 lsa but many times their post rpm is the same. Shouldn't the wider Lsa have a slightly higher rpm range?

[@bretts408]

Hi DV, do you have data on how LSA calculation applies for individual runner V8s? ie; quad Webers or 8-stack EFI on the typical SBC. PS: Love the channel, regards, Brett from Australia

[@ryanm1983]

Anyone see the latest episode of engine masters? If not, here's the cliffsnotes: 3 different cam profiles, but all with the same event timing and lift... result? Power curves showed almost no difference at all.

[@utahcountypicazospage5412]

Does boost change this equation

[@eberalves7163]

Acompanhando a série aqui do brasil, estou aprendendo muito...

[@styleracingshop]

Hi .. DV… I have a question about that formula. .. do you have a formula for BBC too? And Thanks for sharing your knowledge with us… I really appreciate it

[@robertbriggs4176]

I'm with you, trying to pick a solid roller for my 454. I thought I heard something about a 132 formula in another video. David? Anyone?

[@infinityinnovationdesign2i301]

Maybe I have missed a video :), I presume the 128 factor works with Turbo diesel engines as well? such as a 4 valve head.

[@joesalazar770]

Ok as a research person I compare lots of info. But as a real tinkerer., I like to build small two stroke engines just from scrap parts exc whatever I have on hand. And it's amazing the things u can learn from hands on. It can be very interesting to say the least remember the valves on a two stroke do not exist from a standpoint of a valve plus most loose the exhaust stroke so every stroke is a power stroke and a two stroke is mostly a degree standpoint. It's measured in angles and degrees. Not timing. Have fun sorry if it's not explained well .

[@shane-222]

Ridiculous you have to put up with this bullcrap. I'm planning to re-cam a Gen V L83, your LSA formula easily bests every commercial camshaft available..... I tested this in Desktop Dyno 2000! Will be upgrading software simulation technology 20+ yrs modernized with the Performance Trends software. My point being your methods can be proved or disproved without looking at a real dyno or buying one litre of gasoline. I have most of your books including how to build HP Vol.2, somehow I don't have the original HTBHP that contains your LSA formula. I guess I figured it was edition 2 not volume 2. In any event, I'll have to get that HTBHP book soon. Thanks for everything!

[@t.g.5832]

I love this guy.

[@538nate]

DV when you say lobe centerline are you talking about the same thing as the lobe separation angle (LSA) or are you talking about the intake lobe centerline?

[@DavidVizard]

LCA =LSA

[@538nate]

@@DavidVizard thanks that's what I thought

[@538nate]

@@DavidVizard DV while I have your attention a lot of your older videos only had audio on one side, I haven't watched with headphones in a while so I don't know if you fixed it but I thought I would let you know

[@lukesimeon5756]

Hey David thanks for all you do... if you don’t mind would you please remind everyone how many cam shootouts you’ve lost in the past 30-40 years

[@landonthompson5604]

David you done a mic drop on EVERY naysayer with the "I don't have an opinion, I have a dyno". These people who fail to understand the simple and effective method you choose your cams then the naysayers should go find new professions.

[@dalewarriorofthesea3998]

" In Dyno we Trust "

[@t.g.5832]

DV. Thank You!

[@JeffKopis]

Disagree with the Wizard Mr. Vizard at your peril! 😆

[@darrellsomers5427]

Cloyes builds edelbrock's timing chains and TRW builds the EDELbrock lifter ,the edelbrock rolling thunder series cams are selicted by pat musi and those cams are a 112 center line you always say 108 ?

[@AdamOpheim]

Wasn't that 128 formula for the LSA? Not the LCA? or are those interchangeable? -thanks!

[@darrinstone49]

I understand the 128 rule, & how to calculate lift using math, how do I choose the duration? Is it seat of the pants feel or do you happen to have a formula I can use? Will your sbc math get me close for bbc LS? These are where we seem to be heading request wise. Thanks

[@funkiwikid6106]

Hi David, Recently helped out a guy who'd bought a scatter cam for his 1800 B series MG which didn't sound right at low revs but really sings at high revs. Kent says developed by DV. Any chance you could do a story on the scatter cams ? And while we're at it, I've heard you say a 4cyl should use 4 into 1 exhaust. But so many 4cyls get 2 into 1 then 2 into 1 supposedly in the name of torque, can you please clarify the 4cyl exhaust best requirements ?

[@boosthit811]

Hi David, does your running tighter lobe separation (106) also work well on turbocharged engines or does that create charge contamination?

[@pmd7771969]

David, Make a cam with high lift, moderate duration and a very wide powerband. How about. 750 lift, 278 dur, lsa 125 to 130. They say it can't be made. Bloodviking

[@jamessharp9790]

How about when some companies claimed something like 35 hp by changing to their needle bearing rocker arms on a mild SBC ? Or that by using their breaker less electronic distributor you’d gain 15 hp ? Guess those are old claims . Now, I used needle bearing rockers on my SBC because I liked the way they adjusted and I’m sure the friction loss didn’t hurt but I didn’t think any power gain ( haven’t seen any posted either ).

[@johnfairchild3421]

The Proof is in the Numbers

[@robertoguerrero1174]

Congratulaciones for you works. I have the cuestión..... Your formula(128-.........) Is valid for motor Suzuki gsxr1000 16v? Regards Roberto Guerrero Galicia, Spain.👌💯

[@barrymorris3679]

Talk is cheap. Numbers don’t lie. Opinions don’t move the needle. Horsepower does.

[@DavidVizard]

Right on Barry!!

[@GriffonGrowl]

@@DavidVizard would you like to help design a cam for my Rolls-Royce Griffon, v12, 2239ci, 6in piston x 6.6 stroke. Or if you want to look at heads, I believe theyd be a hit on the videos...

[@mitchm275]

want to know if it works, how well it works? for over 30 years ive used cams based on this and always find SBC Gen1 behaves exactly as stated! doubt it? get some cams made to same specs. 106 108 110 112 114 lsa swap them out and change nothing more and see what you end up with for HP tq , throttle response yourself . his math is spot on. wider lsa calms down engines, changes the entire behavior of it. the smoother OE'S needed an engine to idle, create more vacuum, create less emissions the wider they made the LSA. when they did that they created another issue, hence VVT to change the inake center lines. they can not change lSA on the fly but they use VVT to change the intake centerline. 108 lsa set to 108 106 intake centerline or 110 lsa set to 108 for most not all gen1 sbc works for me. countess cams over the years ive bought, 112 114 lsa yet ground advanced by 4 from most cam co;s which most dont disclose is setting the intake centerline there any way. they want you to enjoy the seat of your pants experience and love their cam and buy more. if it was not so true why are most ground and pinned to set the ICL close to the 108?

[@pmd7771969]

The lsa for a racing engine vs a street engine need to be quite different. One engine you want peak hp at a limited rpm range. While a street car needs a wider range of rpm for good drive ability.

[@gizmothewytchdoktor]

mr dyno speaks through you. i will not argue with either. thanks for the info. the 6 litre v12 will thank you too...or at least my right foot and seat of the pants will. 🙂

[@terrysmith8133]

a videos explaining three arc and poly would be interesting

[@kimberlysteller2556]

I wonder your opinions of cranking compression pressure used to optimize IO,IC,EC,EO. And if so would the data not be applicable at higher rpm

[@user-ic7zh5ng5j]

I don't have a channel anymore?

[@broke_dongle]

LSA or LCA. Same thing like when they say lambda or O2 sensor or MAF meter or MAF sensor. Linguistics ?

[@ericliles]

Concerning BAD products. I do know that the PRW's Stainless rockers are junk with anything over flat tappet spring pressure. Mine didn't last long on 250/600 lbs. They warrantied them but I wont use them on anything but a flat tappet cam.

[@davekulman8195]

Hell yeah 👍 call it how it is and thank you for your time and knowledge I can't get enough

[@jonathanschmidt6507]

Of course the capability of the valvetrain to handle acceleration is most important. You even stated as much when you said that you had Billy Goldbold choose a lobe for you. That is the work he is doing. It is the foundation of cam design. If you knew how to design a cam, you would know that.

[@pmd7771969]

Limited power bands are clearly for race cams only.

[@mackenziehutchison4838]

Hi David, I'm 21 and working on a 6.0 LQ4 with 243 heads, and with the 128 formula 107.3 is the best LSA/LCA. But I can't find any 107 LSA cams that are performace street / street strip frendly. So my question is, if I advance a cam with a 112LSA to 107LCA will I get the same benefits of tourqe and power a 107LSA cam would have?

[@witnesszer0]

yes

[@flinch622]

Um.... no. Reading most of DV's books, note he uses 'LCA' when talking about lobe separation angle. I have to admit I was confused at first: seems like icl and lsa got blended? No, and he is consistent. Lobe separation is per the grind, and regardless of advance or retard it stays the same. I might suggest discovering a profile near what you want, and calculate overlap if it was custom ground per the your 107 lsa. You may find lobes on a standard 110 offering deserve a little less advertised duration to keep overlap in the same ballpark.

[@matthewmiller2268]

The LCA (Lobe Centerline Angle) is ground into the cam. So you would have to regrind the cam for the 107 LCA.

[@markmcmullen1371]

You guys are using this on a LS engine not a SBC Chevy for what it was intended for, be careful.

[@troymecey]

The 128 was made for the SBC valve angle, not the LS valve angle.

[@boduke2299]

With the 128 camshaft formula how is the camshaft duration calculated, also what if engine compression is say 1 or 2 points higher like around 12:1 thanks.

[@patrickduncan9656]

G'day David. You mentioned 3.5 inch bores. I will be building a 221 inch Windsor next year which has 3.5 inch bores, can i still use the 127 ford formula or can you change it to suit. Also how big could i go with the valves before the cylinder shrouds them? Cheers mate

[@thomasward4505]

Your videos are entertaining but I'm not sure if I got any useful information from this one. I think a 108 Center Line is the outcome of this video?

[@chevyluv7216]

Mr David I have a 565 bbc , dart 355 cnc heads 12:1 compression sniper jr intake. All forged bottom end (Callies). What cam would you recommend? Running on E85. Thank you sir

[@pmd7771969]

How about a cam that makes equal hp and tork throughout the entire rpm range Bloodviking:,

[@scrotiemcboogerballs1981]

Thanks for sharing

[@darrellsomers5427]

Both

[@NorCalDA9]

I have a 351c with 302c 2v heads with 2.07" valve would I use 132-133 for the formula?

[@MrJosephfunk]

Anyone know what's happened to David's website? Was hoping to find more there but it seems it's not been in use or updated in a while.

[@N1gel]

Ive followed Davids tutorials from HotRod and Car & car convertions magazines back in the 60s head porting minis. But theres something I have Never seen. Perhaps because it is crazy? NON-Symetrical cam lobes. IF a perfect engine was designed & every inlet port was identical in shape, size & volume & smoothness etc then it seems reasonable that IF every port or trumpet can breath from equally identical airflow, density, velocity, swirl etc. Then using a full set of Identical cam loab profiles & timings does sound perfectly reasonable. But inlet ports are not often Identical. And ports or trumpets dont often breath from a homogenous air supply. So with enforced undesirable variables to work around, I find it strange that people havent produced Non symetrical loabed cams. At the point of ignition, the engine doesnt have a care in the world about how the fuel+air got into the combustion chamber. It only enthusrs that all cylinders are obstensibly the same. Obviously varying the throttle will cause these varients. So: if we accept that its having a Given volume of air or air+fuel at a given time, temp, compressikn etc thats impdritive, then we can deliver that volume by quickly flowing for a short period all the way to slowly flowing for a long period (obviously within limits of rpm etc). So: i envisage somebody taking a good cam for a bad engine and being able to adjust the breathing on an offending cylinder port by reprofiling just that 1 lobe to stop other ports from stealing its power. I realise that such a lobe profile imbalance would make the engine peaky. But I dont know how the benefits compare to the losses. The exhaust cam loabtrain has the same contentions to deal with, but I suspect to a lesser lurking benefit. Thanks David for a lifes great friendship, and you didnt know it, much respect.

[@thomasleclair7418]

,,,It's impossible to assume and design a camshaft for a combustion engine ,,,,lobe for lobe.......Maybe if it lived in a dyno room under extreme inputs of airflow and temperature and constant fuel quality ; but how could any such animal be cataloged and sold to a thousand different racers and builds.....................

[@N1gel]

@@thomasleclair7418 No. I don't believe it's impossible. I accept its difficult for many reasons. Impossible is for the brainless. I am quietly confident that somewhere in the world there are sparks of imagination that will achieve non-regular cam loab profiles to address the port breathing issues IF the WEF NWO RESET wankers don't ban all ice engines beforehand.

[@janpieterse4175]

Hi guys what will be the best option be to put into n 1200liter 4cyl enjin for street use deg and lope angle

[@markblue1966]

Where do I find my custom grind ? Nobody even close . lSA 112 all I can find

[@cecilandrews7479]

Videos like this drive me insane. Do Tessa and talks about his self constantly. And apparently can't take criticism or today I'm either.

[@johnshackelford6965]

Texas Road house Veterans day Landry Joe's crab shack.

[@rogerpatton]

I think John had a jealous spirit.

[@1magnit]

What about the majority of cams that don't have symmetrical lobes? They don't and can't have a centreline, just peak lift. So when you talk about lobe centreline, you really mean the point at which it's at peak lift.

[@kimberlysteller2556]

They still have a centerline. I used ultradyne custom cams and if i remember correctly there was seperate intake and exhaust centerlines which were then equalled.

[@1magnit]

@@kimberlysteller2556 With a non symmetrical lobe, the centreline being mid way between opening and closing, it moves depending on what lift point you're measuring from. If you measure 0.010 inch either side of peak lift than it's at peak lift.

[@ChadBIsRacing]

Hey David, question about this equation. Let me see if I'm following correctly. I'm building a GM LT Gen 5 engine with a stroked crank. I'm using a 4" stroke and a 4.065 bore So I should be starting with a cam that uses a lca of 116? That matches the cams available.

[@Cowboy.underwater]

116 is way to wide, you should be able to find something around 110-112. Still not perfect, but much better. Richard Hold has a video on LSA you might find useful.

[@danielmauter1737]

You'll need 108*, 107*.. Its in David's book over last 40 years..

[@ChadBIsRacing]

@@danielmauter1737 Thanks.. I'm still doing a lot of research this helps.

[@baconunteggs]

Hello, I love your program! I have used your 128 method to find my 108LSA for my 327 SBC. Is there a method to find the correct duration's I should use for my engine? I'm not sure what my overlap should be. Much Appreciated!

[@DANTHETUBEMAN]

The classic 327/350hp cam has 222 duration @50 😊

[@baconunteggs]

I ended up going with a 224/230 duration @50 thank you for your reply.@@DANTHETUBEMAN

[@alexlandsberger1423]

I have had problems with speed master/procomp distributors and the ugliest ports I have ever seen was on a dual plain weiand for 360 la they where so misshapen/different sized that they look like that one goonies character.

[@gavindowell8239]

David did you do any books on just cam shafts

[@firstrespondergarage]

LSA is a base starting point for the cam its not a product of anything. Any builder that doesn't understand that shouldn't be in the cam business. If they are, then they are the ones that also say the cam is selected first and engine should be built around a cam. < is BS!

[@lawrencecarlson2425]

I'm out out the hobby now but, DV had I been exposed, could have saved me money on buying the wrong parts.

[@antaresanthony8205]

How do get the your torque master cam program?