Mr. Vizard, I used your cam choice information when building my 408 Ford. It idled about as smooth as a Toyota Camry at 800 rpm, and with 13.5 inches of vacuum. Power was 607 HP at 6500 rpm, and 546 TQ at 5200. A nice little 10.5 to 1 pump gas street engine I could drive every day.

@carlclark989

Ай бұрын

What heads did you run on that 408

@buildaboiworkshop

Ай бұрын

Vacuum at idle is low

@captainrawn

Ай бұрын

Very nice. What is the LCA, lift and duration for both intake and exhaust on this camshaft. In other words can you please provide the cam specs. I really like those results.

@Mustang_Chris

Ай бұрын

@@carlclark989 EDL 7721 2.125/1.625 with mild porting to keep velocity up. They flowed 355 @600 but the focus was on mid lift numbers

@Mustang_Chris

Ай бұрын

@@captainrawn it was a Comp 35-772-8. 286/292 248/254 .614/.621 110 LSA. Page 78 of the catalog. Slightly off, with a bit too much duration. It was during Covid and everyone seemed to be having cam core issues at the time. I felt it was close. Being a solid "street roller" I felt it gave good ramp acceleration rates and stability without having to check the lash every time I drove it. Knowing what I learned, I didn't need that much cam, but it's what I could find used at the time. Maybe 8-10 degrees less duration would've been ideal for what I wanted out of it, and I might've made roughly the same power. I had EDL 7721 heads on it since the cubes were so much higher. Big block sized cubes should have appropriately sized valves and flow. The 396 Chevy BB has 2.19/1.88, but we have better knowledge of port design these days, so I thought the 2.125/1.625 would be good. The more accurate the head choice for the combo, the less cam duration you need to compensate. Velocity, and port and valve size should be appropriately sized with the airflow demands off the cubic inches and stroke. Except for the Boss 351 engine, Ford has always struggled in this department until the Coyote engine.

David "the Cam" Wizard...I mean Vizard. He actually knows what most think they know.

I had a 1970 malibu with the 300 hp/350. As a young kid we did a dingleball rebuild, and we installed a Engle rv10 cam. It was 210/210 .440 lift and 108 lca. With just that mild cam, and headers. Turbo 350 and 3.31 gears, people couldnt believe how it pulled! That sold me on short timing for street driving, and 108 l.c.

@robertwest3093

Ай бұрын

A 210@.050 on a 108 is the perfect cam for an otherwise stock 350 engine in a street car.

@jondough4116

Ай бұрын

​@@robertwest3093Exactly what I have in my 350 astrovan pills like a team of mules...

@gorkzop

21 күн бұрын

Going to put an Rv10 cam with 106 in my 225 slant six. Similar specs to what you describe up here. It needs it even tighter..I can't wait how this little stroker will rub with it's headers and reworked head

I don’t know why the trolls are questioning this DV. It’s worked for me ever since I started using it and it has worked for many other people.

Mr. Vizard is on the know, I got one of the how to build books when I was 16, the first Chevy 350 I built I used the extreme amount of knowledge and did a lot of independent research asking engine builders their take. I had limited cams available to me being in Canada so I chose what worked closely to the Vizard formula. The engine pulled so hard it would keep pace with a motorcycle from a stop light. If I could I would love to sit in a class. Thanks for sharing Mr. Vizard.

So a few months ago, I decided to try some of David's theory, and I had a custom cam ground from Bullett for a SBF. It originally had a 5.0 HO roller cam, which has a wide LCA. I ground this cam on a 106, with similiar duration and better lift on a hyd flat tappet camshaft. It idled good, basically the same as the 5.0 HO roller cam, but had a crap ton more torque down low. Up higher in the RPMs I dont think it lost anything compared to the 5.0 HO cam. I really liked the way it acted, especially with taller gears etc. Before it wouldn't do a burn out. After the cam swap, it would light them up, same trans, same stall, same gears. Putting every cam on a 110 is a cop out. off the shelf strategy. I love tight LCA cams, and most people dont really get it. Thanks David V!

My 1st experience on LCA. Was 39 years ago. A friend of mine worked for John lingenfelter and got me a cam for a street 383 SB CHEVY. It was circle track grind and had 108 LCA. For a street stock. My friend witch is the engine builder said we'll it's going to blow the tires off. I said great., I'll take care of hooking the car up. All of them knew I was going to tune the carburetor to get it to idle smoother

FINaLLY someone who knows what they are talking about! Been saying this since high school of course I read some of your books in highschool 😂👍👍 thank you Mr. Vizard

Hi David, your Mod’ Mini book is still my prize possession after all these years. Regards from Olde England 🏴󠁧󠁢󠁥󠁮󠁧󠁿🇺🇸🏴󠁧󠁢󠁥󠁮󠁧󠁿

How about giving us Pontiac guys some love!! Love to hear how your program works on 400 Pontiac!!

@hotrodray6802

Ай бұрын

I think there's a fudge factor in the 128... 126 ? I don't know. Even if you're off a couple it's better than the wide LSA the cam companies push to you

@mikemcnamara2943

Ай бұрын

I have been asking him for over a year to talk about Pontiacs, from what I read he worked on them back in the day. Come on David show us some love!!

@alfredvigilotti3709

7 күн бұрын

Probably not an interest in them blocks,,for David​@@mikemcnamara2943

My friends and I have been taking David Visard's advice for building performance, SUCCESSFULLY since the 1980's! He knows how to make power.

Thank you , david , you keep my wheels spinning and the Ideas flowing, you are on my Mount Rushmore right next to smokey.And just ahead of grumpy

Excellent video David. My minimal experience aligns with what you are saying. Most of my experience is with old Cleveland's and cast iron heads. Through trial and error, i ended up with much greater LSA's than the cam grinders were happy with. Interestingly enough, many years later i bought your How to Build Horsepower book and based on your recommended calculations, I was within 1° of where your recommendations said I should be. I got there on luck and money, wish I'd bought your book many years ago. One thing that I have worked out is that most of the people that you talk to at cam grinders are order collectors, and salespeople, not engineers or engine builders. Many thanks Greg

@psychoholicslag4801

Ай бұрын

Clevelands are a different animal. Most never realized that and caused them great confusion.

@theshed8802

Ай бұрын

@@psychoholicslag4801 agreed. I've always said that the greatest weakness of a Cleveland is Team Small Port engine builders

@psychoholicslag4801

Ай бұрын

@@theshed8802 😄😄 so true.

@stuartwall8212

Ай бұрын

I am building a roller 302 2v OC Clevor, and decided that the stock HO cam @ 115 LSA was close for a street engine. I am doing weird things to it to get 10.5:1 with flat top pistons. I think ideal was around 114 according to the 128 rule.

@theshed8802

Ай бұрын

@@stuartwall8212 you need to buy David's book and read it. Fords use 127° as the baseline

🔔😎 Street performance "sleeper"... DV cams have been kicking axe for many years. (It cant run that good, it idles too smooth 😁)

LSA=128-(CID/8/Valve Diameter X .91)

This is why I went for a 227@50 with just over 11 to 1 static comp instead of high 230s to 240 degrees @50. With a 109 LSA.

@DANTHETUBEMAN

Ай бұрын

sounds like a good street cam. 🤠

@lcxu1051

Ай бұрын

@DANTHETUBEMAN that was the whole point of it. With that cam and the calculated 11.15 static comp it works out to be 8.5 cranking compression. Perfect for E10 fuel here In Australia with a tight. 040 quench. The .006 cam duration is 277 289. Should run from around 2000rpm to about 64 6500rpm power curve with peak torque just under 5000rpm with the intake track being about 13" long and DV inspired exhaust system with street legal sound open header power.

@DANTHETUBEMAN

Ай бұрын

@@lcxu1051 vary smart build, vary fun to 😁

@lcxu1051

Ай бұрын

@DANTHETUBEMAN I know it is. Funny thing is the engine shops here in Australia disagree and say it won't work. I grew up around racing my whole life and never knew DV or any of his ideas. Only learned about him about a year ago. What he talks about and says is exactly what I learned from my dad growing up with motor racing.

@DANTHETUBEMAN

Ай бұрын

@@lcxu1051 DV is not selling car parts, so there is no salesmanship on this info, he is telling the information he learned out of flow bench testing and racing, he has a great software program now he sells, but that's a tool he developed out of years or testing.

Thanks DV. For sharing all your wisdom

David Vizard, man, you are the master, I really appreciate your time in helping us, your experience is very precious.

Long time subscriber. Currently waiting on the LS constants. I believe your system works. Keep up the good work.

Your videos are great and super in-depth. I really enjoy them!

Thank you Mr. Vizard. I think you've mentioned cam companies are under pressure to supply "too big" of cams for the application due to customers being greedy for power. So they spread the lsa to kill some overlap. But then the cam ends up being a little lazy, especially in low and midrange. Thank you for cutting through the bull!

As always your videos are doing us a great service...thank you very much for your hard work sir..

Well... if I ever seem to have some luck that's not "bad", and am able to get some money together again, I'll certainly be using DV's camshaft formula! Seems to have a pretty good reputation out there, and I have no "issue" with anything I've heard him say before. ...and his porting vids and such are GRRREAT! I've been messing around with "hot rodding" all different stuff for 30 years (my entire family is into it, too) and he shows some things that I certainly haven't thought of doing that I REALLY want to try now. Unfortunately, life turned pretty bad for me, and just getting out of the mess (hopefully) and back on my feet again... I'd LOVE to be able to pay him to port the head for my 2.3T '87 Mustang project that I started on forever ago, and can't afford now... ANYWAY... I truly appreciate the effort made by the "Powertec 10" crew, regardless. David has no obligation to share any of this with us, yet he chooses to take the time out to do it. I think that's AWESOME.

Agree completely, bit want to add one variable. That is cam design. Two identical cams on paper. One may do nicely on the idle quality, the other will chop at idle. The acceleration and deceleration ramps on the cam play a role too here.

Really enjoyed it as always thanks

30 years ago I built a 383. Chevy 10.5 compression 248 ' @ 50 duration 108 lca. Power brakes worked excellent. Don't know why people crying about vacume.

Thank you, DV, for your logical explanation of one of the most misunderstood camshaft parameters, LSA!

@blakeuhl8731

Ай бұрын

I think you're great, David!👍 Don't worry 'bout them other guys, too much

Hey David I remember Crane had a cam for small block Chevys, that was close to stock specs but on a 104 lobe center, made tons of torque for a 4×4, were you involved in that, probably the 90's, good video again David!!

Thank you David.

Wish I would have known, I just installed a nsr truck norris cam for the ease of it and the hype. 4th gen 6.0 ls with 823 rectangle port heads terminator x max and 4l80e in a street 1994 s10. Also, I’m building a 1st gen sbc 383 10.5:1 cr with TH400 and 4.11:1 gear in a 1989 rx7. I bought the Lunati voodoo 268 cam 110 lsa but I will not be using it and will be using your lsa method for the cam. Maybe I will compare on dyno and look at average power. I hate learning the hard way and wish there were more research and development in the right direction like this.

Up to the minute technology? Your how to build HP book is over 20yrs old! That’s antique in the motoring world!!!

My problem with this theory is the best cam for a road car is the standard one it came with, if it's a race car with a 4k rpm rev. range from 4-8k if it's a 10k rpm motor that's 6-10, if it's a single seater 8-12k.all requiring very different profiles. In the case of the Nissan infinitely unit that used on ovals over there they had a 600 rpm difference between down the straight and around the corner. Experimentation was 1deg of cam duration at a time. At that level after 6 months of testing there is only one answer, for every thing else there seems to be many. Piper cams in the 80's had their HR2 range which had assymetric profiles on opening & closing ramps. Brilliant and logical idea which lasted 10 ish years before reverting back to conventional equal flanks

GREAT JOB DAVID THANK YOU

Thanks DV!

I can't wait for this video!

@joe-hp4nk

Ай бұрын

What video is that?

Spot on, David!

I wish I would have known this years ago. I called comp for my Dually Vortec 454. I asked for an aggressive towing cam and they gave me a 01-412-8 Xtreme energy. specs 264/270 duration .510 lift and 113 LSA. with mild ported head, headers, exhaust, intake, injectors my tuner couldn't get it to idle any lower than 950RPM. It ran ok but low end seemed to be lacking.

Thanks for sharing 👍

When you simulate your engine in DinoSIM 6 and run LCA optimization targeting maximum area under torque curve the results are usually within 1 degre from DVs formula. Just saying...

Nice, looking at getting rid of my superram intake and going to a carb on my C4 Corvette.

🙏Please do a focused video for the Cleveland on this topic. We are always neglected due to its not a pop topic for the big money makers, yet It is an incredible foundation for one of the greatest of all time Engines. Thanks David for all your time and sharing the no bs knowledge! It is greatly appreciated. 😎✌

@hankclingingsmith8707

Ай бұрын

Thevacuumed. Principals are the same that apply

Have a 355sbc. Edelbrock aluminum heads, Edelbrock h122 blower. 850 blower carb. 9.25 static comp. 8psi of boost. In a 3200lb car. Picked a dougherty cam. 228/234@50 535lift 114lsa. Idles very well, lots of vacuum 18 at idle. Pulls hard to 6500. Had a comp 230/230 @50 515 lift on a 110 lsa before did not work nearly as well.

@DANTHETUBEMAN

Ай бұрын

it's the smaller intake duration, bigger exhaust duration, you are forcing air/fuel in, you need more outflow, that's what the second cam is giving you. 😊 you can keep the same durations, and go down to a 108• lsa and get more Torque. 🤠

@David Vizard Will you be adding the Cleveland parts to your Program the future??

Looking forward to examination of what the LS likes as a constant. It deserves attention primarily on account of valve angle and its effect on scavenging? Unwinding many decades of Stroker McGurk theory seems to boil down to this: many of us in the past accepted wider LSA's... thinking bigger duration was the ticket. Better spring tech these days gives us a nice helping hand: with higher lift possibilities, a return from wide lsa is not a punishment at all.

I keep thinking of my Harley Sportster, it has four cams one lobe for each valve, one could change the lobe center line by shifting the intake and exhaust cams gears with each other. One would have to check the valve to piston clearance closey first. It would be a very interesting experament.

@trailerparkcryptoking5213

Ай бұрын

Yea bro....I wish he would derive a constant for Harley engines! It’s doable, but DV may not want to allocate the time needed to do it. It would be nice because Harley cams are marketed by totally different specs than hotrod car cams.

G'day David. Do you have a number for the 2V and 4V Cleveland to plug into your Cam formula? Or is 132 that you use for big blocks sufficient? Regards.

Can't wait until you can get Mopar engines in your program!

@jeremylastname873

Ай бұрын

Poly POWER! 🎉

Waiting on the Cleveland constants...please.

@williamherring5441

Ай бұрын

Read his book and how he adjusts the LCA for big block Chevys…. Canted valves need a slightly wider LCA compared to inline valves to keep parody. v/r wh

BTR would agree with you DV looking at their grinds for the Ls world.

Great tech DV

Can you provide a factor to use with a 10 degree canted valve head, specifically a viper engine?

I have a book on tuning Weber carburettors and it gives suggested idle speeds depending on cam duration, lower duration suggest lower idle speed and higher speeds for longer duration cams.does that align with the information in this video?

id love for DV to spec a ls 5.3 cam specs with standard heads 7g rpm limit. i would think it end up in the 108-106 LSA area the duration would be intresting.. and say just go dyno headers, and 750 DP on a vic jnr

Many years ago when I was first learning about cams, the rule of thumb was more overlap, rougher idle. Maybe what changed is all of the programs out there to compare and design cams for max HP making people focus on LCA.

I have seen cars that run good have cams that fit near the DV profile recommendations. Read the book!

Way back in either 81 or 82 when Competition Cams introduced the High Energy 268 for small Chevy's they ran a huge ad campaign so I bought one and believe me they were high back then, paid 125 bucks which was a lot! Installed it in my 78 Z28 that I bought new which by this time had headers ,dual plane intake, "legendary" 350 hp 327 copy cam , still stock 8.5 compression and stock converter and would run 15.0's with that combo. The original 268 H.E. had a LS of 108 with 218 duration and was pretty choppy but worked fine and it knocked a full second off my E.T. down to 14.0's with no other change. It lived up to it's hype and i was ecstatic but I guess they felt the need to smooth it out and it wasn't but about a year and the LS was moved to 110 which is the Comp Cams norm now.

Great explanation David. What do you recommend for overlap. How do you determine how much overlap to run?

I love your 128 formula! Is there formulas for choosing the correct duration & overlap? I'm struggling to choose the correct cams & really really want to be able to get it correct. How exactly do I get your program & how much? Chevy gas & Cummins diesels are my prefered builds. I was so looking forward to watching & learning from Jacque & her point of view. Must have been amazing to have a father with so much love, knowledge & wisdom to teach & share daily! My grampa raised me, male pecking order was God, Grampa, & John Wayne.

In a way, we almost can't really blame the cam makers for not selling the best possible cam, most of the cams are going into stock head and bottom end engines, most even with a stock intake and usually generic a long tube header. The manufacturers never designed those engines to make power, they were designed with emissions and fuel economy first and the power was just a side effect. I always took it as them selling a less than optimal cam on purpose, they want to give just enough of a power gain to get $200-500 out of a customer and I feel that they leave the extra power on the table so there is something they can sell someone who wants to pay more and get as much as possible. I always felt like they didn't want to get beaten on the street or strip by the average jackstand jimmy who didn't have to drop all the money on creating an optimized program. Maybe I'm wrong and these dudes really think they are selling the best they have but, I doubt it. It's the same as GM selling so many 4.8 and 5.3 engines that were designed to squeak through the fuel economy and emissions testing yet in the real world you could probably get the same fuel economy out of a 5.7 or 6.0L, it wouldn't have cost GM any extra to just build 5.7 or 6.0 engines as the base and put them in everything with a 6.2/6.6/7.0L as the upgrade engine/HD truck/supercar engine, who knows why they did it all these years and didn't give the customers the best they possibly could have. That seems to be the way everything is, the world is full of bean counters, greedy executives, non-enthusiasts and non-scientists. I blame DEI programs that promote and hire based upon immutable differences rather than intelligence, capability, experience, work ethic, passion and qualifications. Diversity never existed before and was considered dangerous to societies of the past. You will not do the best work you can to improve the future for people you don't care about who are dissimilar to you.

Hi DV, thanks for clarifying - great topic!! For IR intakes on your typical sbc ie; quad Webers or 8-stack EFI - does your 128 LSA calc change? (I’m assuming the 128 constant was developed for single plenum intake data) regards, Brett from Australia

40+ years ago I changed rocker ratio to aluminum 1.6 with better springs and mildly ported heads on my 69 Z28 which pick up .2 in the the 1/4 with a 4:88. Did even better when lunach was work out. My point is that the factory cam was dam good and rockers gave more flow ,old Indy engine builder show me this when I was in high school and all he stressed was port velocity at points that impeded flow

Hello mr Vizard, i would like to say thank you for youre educational videos. Ive learned quite a bit all thanks to you sir. On that note id like to ask you a question. I have a 91 mustang gt 5.0 5spd. Im looking to do a complete top end kit on it. Im looking to get the most i can out of it as well as still be able to drive it on the street. My issue lies in cam and head selection. Do you have any cam recommendations along w rockers and heads? It will be street driven w a few red light races lol. If i need to get ahold of you thats ok too. I wish you would do 3 builds on a 5.0. A budget, a mid tier, and a high end. I also wish you showed us how to port a set of aftermarket heads for it as well. I know its a tall ask as im sure youre a busy man. I wish i knew how to build engines let alone build as good as you do. This is my first project car that im having fun with. I know you said the lca is critical along w other cam specs. After seeing youre cam designs i prefer what you do. Does a good off the shelf cam even exist for these engines? Any help is appreciated and i look forward to seeing you build a high hp and tq 5.0l sbf engine. Budget friendly would be super awesome. I still have the original 5.0ho engine in mine ill be working with. From what i understand my engine is the roller engine. Again any help is appreciated and thanks in advance.

Where can i buy your cam software

What changes would you recommend on middle sized Cleveland engine. BB Chevy is also canted valve. Same changes to cam?

DV, I would love to hear your input on the Gen 3 Hemi platform, specifically the 5.7 "Eagle" 10.5:1 engine with stock heads. Several companies have flowed the stock Eagle heads so I won't go into that here. They flow pretty good, for a stock cylinder head. I want to change the cam in my 5.7 and am leaning towards (one of very few) a 108* LCA, offered under the "El Chapo" label from Scoggin Dickey Performance. 215*/221* on a 108* LSA, with .587" lift I & E. Application is a street-driven, daily driven Challenger with a 6-spd Tremec (unlimited stall 🙂) and 3.92 gears, which gets it rolling in short order. I don't chase horsepower numbers. I know that it's torque that does all of the work, so I'm more interested in power under the curve. There will be a HP increase, just by getting the stock camshaft out of there. :)

I’m a big fan David but I’m confused by your comment that said the cam vid was for BBC/SBC , and Ford Windsor but not Cleveland engines due to their canted valves , how do they differ from BBC’s canted valves ?

Hello David, will your 128 cam program formula need to be modified in order to calculate the proper LSA, to be used in a 1969 Pontiac 400 Ram Air III automatic Firebird, that will otherwise be completely stock except, +.060 Bore (4.180 X 3.750) ported heads, and 11:2 compression? I intend to use only 98 Oct leaded gas. Thank you...👍🏻

@fastekibeast9486

Ай бұрын

I used 128 formula in my Pontiac 400 and bought a camshaft with 106*LSA with proper overlap and duration, like DV has been suggested.

What about the BB Chevy with long and short ports? Different cam timing for short vs long? Different diameter exhaust pipes? Different ratio rockers?

How do we get a hold of the DV’d cam choice program? I’ve searched and searched.

Have ya produced any of the powertech 10 T shirts?

I'm no genius, but I agree with this presentation 100%

It all seemed so simple to me, and perfectly logical! We've always known that LESS DURATION = MORE TORQUE. LESS OVERLAP = SMOOTHER IDLE AND DRIVEABILITY. So where is the disconnect. The overlap determines the idle quality, not the LSA!

@____MC____

Ай бұрын

I think everyone wants solid roller high lift numbers in a hydraulic lifter engine.

@DANTHETUBEMAN

Ай бұрын

in the 60's people thought Chevy was going to wider lobe angles for better idle,

@baims8367

11 күн бұрын

LESS IS MORE allot of the time..

How does your cam program work for Big Block Mopar (383/440)??

DV would love to see some of your knowledge working with gen III HEMI. Huge community that could use expertise.

Some of us gearheads have our Harleys and love cam upgrades, any way we could get a formula constant for Harley Twin Cam engines?!?

So how might I get my hands on this program to get some specs? I know the more simple equation but I'd like to play around with the program if I could

where can i find the complete formula for a high compressing race application?

Me vizard I have a cleveland v8 just wondering how you would pick the correct camshaft for this type of engine?

Years ago, I swapped cams from an Isky Mega 270 (221/221-108) to a Crane 216/224-112 due to the hype about Fords needing the duration split. Couldn't believe how much slower the truck was with the 112 cam.

@baims8367

11 күн бұрын

Advance it. Or put more gear ⚙️ to it!

With 230 @ 0.50" intake duration engines will idle smooth at 600 RPM on a 110 LSA if your compression is correct. It may only have 7" hg vacuum but it will idle.

Thanks David. Could I use the big block Chevy constants for the 351 Cleveland ,for approximation?

@hotrodray6802

Ай бұрын

107* Thumper works great in our 351C... But it is lumpy... But gut busting torque.

@lautburns4829

Ай бұрын

@@hotrodray6802 hi Ray, I’m using 108 right now 530 lift. I don’t remember the duration. (No cam card in my office it’s in the garage)

David does your cam software work with other types of engines? Vw flat 4 for example. Another great video!! Would love to see video on valve seat cutting and angles and seat dimensions. Thanks DV!!

@callahansmachine

Ай бұрын

Yes it works for vw motors, i used this in my cam decision to get what i needed... put me right around 230@0.050 duration which was smack on... from there pick the total lift for your heads and compression to give you what you need

@mathewboyd3746

Ай бұрын

I'm keen to know if this works for VW Flat4 aircooled engines too. I've read cover to cover DV's books and applied the LCA formula. But I think a piece of the info I in put was not quite accurate because I came up with a LCA exactly as the general production cams which never change (108). But one VW engine builder is often using tighter LCA.

@callahansmachine

Ай бұрын

@@mathewboyd3746 yes essentially its going to be 108 for most, the overlap is going to be the main difference in setting duration; CB makes theirs on a 107; you can always advance or retard the intake centerline to get it where you think it should be.

sbf 347 healty 250 hit of nitrous good cam ?

The way I see it is way too often a cam with too much duration is selected. The customer is thinking more is better and too much is just right. They have no idea of the many processes going on in a running engine to effectively the cylinder and then cap it off before the charge is lost. That to me is the major if not sole purpose of the cam.

@pete540Z

Ай бұрын

Agreed. And as David points out, for a given LSA (LCA), too much duration results in too much overlap, and poor idle, low speed torque. The big cam companies know you'll pick too much duration, so they broaden the LSA to lower the overlap. Wrong way to pick a cam. The TMC program will calculate the LSA, you pick the overlap, and the duration, and that specifies the valve timing fully. Only thing to spec out is the max lift after that, and the aggressiveness of the lobes.

@rayowens4355

Ай бұрын

@@pete540Z exactly

exactly why im using a ramjet cam in my 350 vortec build, with 1.6 rockers. 196/206, 109 lsa, 105 ICL. with 1.6 rockers, lift is .460/.480. -17 degrees overlap

Who would you recommend to make a cam according to your teaching

Then what benefit does having a wide LSA? Maybe it has to do with cylinder bank angle on a type of engine. The actual LCA on the shaft of the cam has to match the engine bank angle ?? I think some emgines like Pontiac low rpm high torque engines do better with a wider LSA?? while a Ford 302 high revving engine likes shorter LSA??

How much angle is needed to run correct for hp I know there is 360°.crank rotation. It's for a small block mopar

@billlittle4285

Ай бұрын

Look in the Mopar small block manual, it's all there, worth the money!!

6th, I’ll take it. Still a top 10.

up until recently there were lots of cam grinder worldwide , how many actually did dyno tests or had their own engines & workshops? what cam grind works for one engine doesn't work for other engines. yet if looking at catalogs it appears that one came grind is just adapted to other similar engines.

@DaveMcLain

Ай бұрын

I was talking about this just the other day with a friend of mine who also grinds cams. He used to grind for Reed and they used to grind the 290/296ULX or a 296/306ULX either on 106 or 108 a lot. These solid roller combinations seemed to work very well in a small block Chevy, Big Chevy, Ford etc, all kinds of applications. I think that the reason is because in a reasonably well coordinated racing engine the pressure and velocity conditions are going to be somewhat similar in the ports. Enough so that their camshaft requirements end up being about the same. This is why cams can seem somewhat generic. They can be and still work very well.

Can you specify how much overlap is needed for reaching certain RPM limits? (Say for 5,000, 6,000, and 7,000 rpm). Also, how much overlap do you recommend and for what parameters? Thank you, Mr. Vizard.

@nobodyspecial5026

Ай бұрын

just do a Google image search for vizard cam overlap estimator chart I’d post the link but youboob will delete it

@nobodyspecial5026

Ай бұрын

it’s in his book, which you really should biy for all the finer details, but basically 10* - 40*….towing 30* - 60*….ordinary street 50* - 75*….street performance 70* - 90*….street/strip 85* - 100*...race 95* - 115*...Pro race

@adm66gal

Ай бұрын

@@nobodyspecial5026are those overlap figures @.050?

@trailerparkcryptoking5213

Ай бұрын

@@nobodyspecial5026 these numbers look like they’re at full duration, say 0.006” lift, not @0.050” lift. Correct?

i feel same way wider LSA meant dropping cranking compression. only thing was Ma Mopar cams lacked enough lift hehe.

I ran a Comp 284xe with a 110 degree lobe separation and 240 degrees duratio in my big block Chrysler. I wiped out a lobe after about 5000 miles. I replaced It with a mopar purple cam with 114 degrees lobe seperation and 248 degrees duration. Both Cams pulled the same vacuum at idle. The Comp cam was way more responsive, but the Mopar cam pulled harder in the upper rpm range.

@cedricwilson2055

Ай бұрын

It was bigger, it should have

@brydkw

Ай бұрын

@cedricwilson2055 I'm not sure if I understand.

@baims8367

11 күн бұрын

Bigger the LSA 114 the Longer pull

Can you please do some stuff on turbo diesels?

for HD use you need to keep the valves on their seats, to cool, to live as you said it's valve events seat to seat. duration lca is a by product, whatever it is.(IMHO)

Quedó atento de la información revolucionaria.que se viene

Cant wait for LS info. Using your 128 rule I come up with a cam that no one makes (223 on a 108). The gospel in the LS world is manuals want 112deg of overlap and autos want 114. Other than that it's all about what stage cam makes the most chop *face-palm*

@Staypuff777

Ай бұрын

Most likely your favorite cam manufacturer will make it for you if you give them a call (and probably a few bucks more for a custom cam). Well worth it.

@383mazda

Ай бұрын

@@Staypuff777 I'll have to give that a try. With Dave's formula I can get LSA and intake duration. Ive heard him say lift is valve diameter × 1.3, but still haven't nailed down exhaust duration or what intake centerline should be? (How do I know where to degree the cam?)

David Vizard....more like Davud Wizard, for the power thus man produces with his knowledge

Your right David. Example would be Diesel engines. Turbo and non turbo. Have different cam specs than gasoline engines in today's cars and trucks. A good example of a good cam would be your turbo mustang. It has an adequate cam. It can be better yes. Yet what are the specs of that cam?!

Jim Leineweber of Harley camshaft fame told me probably forty years ago now that he had never found a intake opening that was too soon. I'd never heard that before or since. This has nothing to do with what David is saying about intake lobe centerline. David is the leading authority on all of this as far as I'm concerned.