How Camshaft Timing Affects Engine Performance - Engine Power S8, E7

[@Carl_Jr]

As the great David Vizard says, if you have to change the cam timing that much to put the engine in the RPM range you want, you chose the wrong cam.

[@mikef-gi2dg]

That is exactly what the great DV says, you need to choose a different cam.

[@bunky8077]

Really shows just what an advantage variable valve timing is on a modern engine.

[@edwardmyers1746]

@@bigboreracing356 Ford has deffietly developed incredible VVT systems, the coyote being one great example in its capabilities and the 3.5L EcoBoost is another

[@crannyscustoms]

You can all thank Honda for all those technologies.

[@edwardmyers1746]

@@bigboreracing356 LOL the 2.7L is pretty decent but I'd much rather take the 3.5L. If I cant get the 5.0 I'd at least get the next biggest option 😆 and one that's been out and tested for much longer...

[@crannyscustoms]

@@bigboreracing356 I don’t see how that’s comparable to variable valve timing and electronic lift control also know as VTEC. And it’s newest variant IVTEC. I for Intelligent. Have a google on how it works it’s genius.

[@crannyscustoms]

@@bigboreracing356 your mistaken in what your saying but that’s ok. There was no variable valve timing or variant in the 40’s. sorry.

[@mtd610]

We want max power low to mid. Continues to tune 3500-7000...

[@michaelszczys8316]

We're looking to drive it mostly low rpm four- wheeling - - " okay, we'll set er up for quarter mile "

[@rayhope7957]

@@michaelszczys8316 and tell every body it's stock....

[@michaelszczys8316]

@@rayhope7957 in late 60s my brother in law had chevelle with 283 he built that had weird Duntov cam you could get from a dealer that made all kinds of horsepower over about 4000 rpm but not much at low rpm and at idle it sounded pure smooth stock. He would tach that thing up and pull the most ferocious tire boiling burnouts you ever saw in front of my house. As a young kid I loved it.

[@ryantexada9269]

@@michaelszczys8316 283s can rev to the moon and back when you build them right, there's a nova on KZbin that can go to 12000 rpm but every video its been rebuilt and bored a bit

[@michaelszczys8316]

I think I've seen it, thing just explodes off the line.

[@burtvincent1278]

Don't worry about the exhaust valve closing, the piston will help it along.😊

[@towgod3096]

Why the single plane manifold? And for a TORQUE motor, why so high in the powerband for that matter? What's the torque / hp numbers from 1,500rpm to 3,500rpm?

[@dbarr8261]

I agree, single plane makes more power up top but lower power in low to midrange.

[@towgod3096]

@@dbarr8261 yes, and they stated at the beginning of the video that this motor was going to be a bottom to mid - range motor. What was the point of the video?

[@Torquemonster440]

Yeah , I was scratching my head at the intake choice too. But , I think they ran with the single plane because it was the mate to the AFR heads. Still , a dual plane would have been a much better choice.

[@177SCmaro]

Some dynos can't load an engine effectively at low rpm.

[@dennisbelk3850]

That RPM range is for regular

[@ericabercrombie6780]

Owner: "This engine will spend its life at low rpms." Pat: "We'll be using a single plane intake for this build." 🤦‍♂️

[@blackopsrocks]

right? and a solid roller? got to be kidding me.

[@KingJT80]

@@blackopsrocks thats a really small solid roller. 236/242 at x lash is pretty small

[@b.c4066]

With 383 cubic inches and afr 220 race prepped heads.🤔

[@b.c4066]

And a really wide duration spread, that cam on a 108-106 would probably work out better for what they want it to do

[@blackopsrocks]

@@KingJT80 and its 100% unecessary. Its not appropriate to run a solid roller at all.

[@magellanstravels]

Bad engine combo for low rpms, but a great article on raising cranking compression with changing the intake valve closing timing ⏱ high compression = torque

[@craigstewart1532]

Yeah, I felt the same way. Single plane intake and a hot roller cam didn't seem like the right combo for a 4 x 4.

[@montebradshaw128]

Decent size dual plane like a weiand, 216-220 @ .050 .470-.500 lift hyd roller cam 112 centerline, 190 cc alum heads (AFR, Brodix, or for the money I like blueprint heads) 1.6 rockers. Cam correct (Google it, variable valve timing) with chain they run on video @ 6 deg advance. 1 3/4 x 30 inch primaries headers... would come real close in hp to what these guys get with ton more tq below 2 grand. A Lil of both worlds YMMV

[@magellanstravels]

@@montebradshaw128 I don’t really have any faith in a sloppy timing chain that tightens up on acceleration. That cam movement will also move the distributor relative to the cam gear. Better just to have a tight lobe separation angle cam advanced 4 degrees with an advance limited distributor (10 total). Set he total at 36 by 2800 rpm, and dial in the idle adjustments. This valve/ignition timing has worked amazingly for me both on both small blocks and big blocks

[@billmelcher1794]

What is with the single plane intake manifold???

[@JerseyMikeP]

They should have also ran it once with the recommeneded 106* Icl. for comparison.

[@robertemmons2260]

This episode was perhaps one of the best ones that Pat has made to date. Finally an episode that covers torque for the stump pulling numbers that us off readers require. On a side note, I love having the VVT in my Gen IV 5.3. Not only do I have better and slower off road control, but also the better top end for highway speeds.

[@b.c4066]

Too bad they used the wrong intake and cam specs.

[@gentilejoshsaved1646]

This was great for my learning style. Thanks guys great intelligent, well done shows. I love your enthusiasm also. I would love to see a 2500 to 5000 pull. For this application especially.

[@swampcritterisbackbaby1740]

Yep. Highway rpm power levels would be nice.

[@HammerHeadGarage]

I wanna see how many pens he can actually fit in that pocket. lol

[@slabbusterrtr7690]

He every has one explode they all may go if they do hes a gonner 😂

[@eknaap8800]

You 'wanna'? You really 'wanna'?? REALLY? WANNA?? 😢 Grow up.

[@philmartin4863]

Tons of us wanna see the same thing

[@michaelszczys8316]

I'm wondering right now if there is ANYBODY on KZbin land that can still talk with their hands in their pockets.

[@Rick-O-Shay60]

What's comical is now Jr. has just as many in his pocket as his mentor.

[@tomnekuda3818]

Really great video guys. I did the same process with a Ford 460 years ago that I needed to tow a heavy camper. It is truly amazing how cam selection and timing help get the torque when you need it.

[@ceasar9456]

Thanks!

[@fastmonaro05]

Great Video as I have just put a new Dynotech Camshaft into my Aussie Holden 308CUI V8. It is 314/224 @ 050 plus .484 Ex & .512 Int. I have it advanced 2 Degrees at present. Enjoy this videos as they give you great tech info.

[@kishorejayaswal1500]

Does advancing typically add to low end torque and retarding would provide the opposite?

[@stevengawlik1282]

Love the show! I just wish some lower RPM pulls would be shown. I'm an off road guy and don't spend a whole lot of time at 4+k

[@Torquemonster440]

Most engine dyons dont accurately measure output below 2,500-3,000 RPM. They just have a difficult time accomplishing that from what I've been told.? Not 100% sure why exactly. It may have to do with the resistance that is measured with a dyno is applied via water.. so possibly the instability or inconsistency of the water at low RPM perhaps ? Still, just a guess

[@flinch622]

@@Torquemonster440 In the case of a carburetor, that's weird territory - most dyno tests would like to be on mains, and away from transition. Tuning would add focus on IFR, idle air bleed, PVCR sizing, and the accelerator pump shot being midrange. You are right about there being a floor - if engine dies upon loading up, test fails.

[@Christian-lf6iy]

My 385” with 11.1, 249/253 @ .050” hydraulic roller, howard 91163 (morel) lifters, Reher Morrison Reversion Plate on top of a ported victor jr. with AFR 195 street port heads with the 8019 springs shimmed a bit tighter, huge dyno headers and a 1200 cfm large mouth 4150 carb or something like that made 597 at 6600 and 515tq. I put it in a ‘92 s10- blazer with a tko... dyno was at Reher-Morrison Racing Engines in Arlington, TX.

[@craigstewart1532]

I thought this was a parody.

[@artysmotorsports]

Just when I thought I knew my way around an engine. You guys are like no you don't 👌👌

[@burtmoore2101]

Great episode you guys, you're making me want to switch timing chain kits, and definitely t/c cover! Good thing I'm early in the build process.

[@docstruthers]

probably one of the most valuable videos for anyone taking engine building serious.

[@kenlaursen6435]

Being a mechanic since 1977, I love seeing all the armchair quarterbacks on here, I just hand built myself a 383 stroker engine myself, using a old school Crane Fireball cam which was the go to cam back in my day, I watched this video to help me figure out the timing. I didn't get fancy with my build, but she just Dynoed out at 595 HP, using the stock Corvette checkerboard intake and a HolleyDouble Pumper spreadbore carburetor.

[@Randomgearhead]

Should sample lower rpm to show torque difference

[@GhostMerc86]

I make a similar comment on most of these videos. I want to see lower rpms measured. Tell me where it starts making 80% of its peak torque.

[@johnterpack3940]

Dynos don't work very well below a certain RPM. That's why you never see that.

[@beller5853]

Cool info! I learned Pat's pockets are both advanced to interference fit!

[@flinch622]

lol... made my day! His waistline might be headed there too, but shhhh.

[@firebird70]

Extremely well executed & demonstrated, well done ! I’ve been preaching this myself for a while since i learnt about it, Inlet closing valve angle, cyl cranking compression pressures and Dynamic compression ratio are the real thing to manipulate a motor’s behaviour one way or another. Great vid !

[@aaronburratwood.6957]

Engine nerds are awesome!

[@mickannickstraining9879]

Excellent presentation possibly the best I've seen on YT, thank you and keep up the great work!

[@Laserwurks]

So true 👍 I built a 2300 engine 1978 Ford Cour long bed . Fuel race blue printed balanced 30 over forged pistons. Full race crane cam , some interesting blue racer hydraulics value springs with. 75" bind. A cam timing adjustable sprocket. Stock valves race grind. Ported sock intake . Ported intake. 2 to 4 barrel adapted, 600 holley running on primaries, hooked headers. Cam straight up rpm 7800 with no missing. With cam advanced 4 degrees mid to topend power fell off just past 6000 rpm. It was my parts getting truck 3rd gear speedo hit highbeam indicator. 4th get still slammed you into the seat rails. Note I was going to turbo but there was no need for it.

[@MrAcuta73]

Interesting information and barks right up my tree...I'm supercharging a V6 for off-road/Overland use. Low-end torque is all I really want, massive speed on the Interstate is useless to me. All I need is 65mph, and anything more is icing. Caveat is, I'm running SOHC....which is probably going to change things up, but I know I absolutely CAN adjust my valve timing....just need a suitable grind. Kinda wish you could re-do this idea with forced air induction. Gonna be similar enough, but compression ratios need to be lower thanks to being force-fed.

[@wyoming4x431]

Great little tuning video! Excellent info comparison on the dyno! Stout little chevy!

[@edpetrocelli2633]

I liked this show for 2 reasons: I`ve always wanted to change cam timing like that but dyno time is expensive and so is that T/C cover. 2nd I just finished a build for a customer 3 weeks ago which was almost identical to your set-up. The only difference was we used a set of PROMAXX 200cc cnc ported heads on a 388. It pulled 491 ft-lbs at 3100rpm and 500hp at 6100rpm, thats close enough to be identical to me. The big surprise was the heads are over-seas castings and machined here plus they looked impressive too with small diameter LS beehive solid roller springs. I`ve enjoyed all the shows y`all showed for the last dozen years with the big chevelle guy and the blonde ford guy..........Thanks guys

[@craigstewart1532]

ft-lbs? Do you mean lb-ft?

[@edpetrocelli2633]

@@craigstewart1532 No I meant ft-lbs and I`ll explain. When I was a brand new Mr. Goodwrench in 1970 that`s the way it was in all the manuals from GM and thats where I learned it. Force at a distance, distance to a force....all the same.

[@craigstewart1532]

@@edpetrocelli2633 www.macsmotorcitygarage.com/foot-pounds-and-pound-feet-the-difference/

[@fd797]

I am curious why, for a low rpm engine, two things. 1) Why using such big ports and valves, and a single plane manifold. 2) Why dyno running from 3600 rpm up. An off road rig should seldom see those rpm's. But, fascinating learning about the cam timing - thank you.

[@macthemec]

I have a audi with a 2.7TT and i adjusted the timing about 1° on the crank to shift the power curve down in the RPM range and it made a huge difference in off the line

[@62-62]

Pat the PEN man is in the house! He’s an awesome top hand motor man and a great guy too!

[@marsv7777]

Great comparison video, well done, I thought it would of made more power though with a 220 head, I have built a 383 with 195 head, slightly bigger cam, made 542HP, 400 with 195 head, 552HP. Both mid 11 CR. Vic Jnr manifold. 106CL, Again Great video.

[@JohnSmith-ok9sn]

Anything BUT the advertised topic. I came here to find out about camshaft timing, but all I've got was a quick glance an some ad placement.

[@thelol1759]

Really liked the format of this episode!

[@raymondwelsh6028]

I’d love to see a similar episode comparing a flat plane crank shaft to just a standard crankshaft.🇦🇺

[@johncoyle707]

if u want hp at high rpm go flat plane crank if u want a real engine that runs good even at low rpm get a crossplane and btw flat plane crankshafts have major 2ndary imbalance at high rpm where they make power btw a flat plane v8 sounds like a 4 cylinder

[@alirezaeskandari2287]

I feel like I'm back in 2006 by watching your videos 😂 It's like a tv show but i love it

[@nexgencarguyscraig331]

It is a TV show, or at least used to be

[@Rebar77_real]

We're the side ho. But we get "Hi youtube!" bits now and then(which we love, thank you!), so feel better about it. Heh heh.

[@Roboticgladiator]

Not sure why they used a single plane manifold for a low to mid rpm mule motor.

[@OldGriz708]

It was what they already had and was a set with the heads.

[@popwarner8029]

Because they aren't building a mellow street engine.

[@baby-sharkgto4902]

Excellent video; guys.

[@SophiaAphrodite]

You would think running a dual plane would improve low end even more than a single plane so the pulse resonates at a lower RPM.

[@towgod3096]

I agree, why the single plane manifold?

[@tomjones5860]

They kept stating single plane and other bits were from a different build that was scrapped. But it’s a fair point. $10,000 engine with wrong $250 intake manifold. Oh well. Still made great numbers.

[@KingJT80]

A dual plane is way too small for an AFR 220

[@josephmancini4400]

@@KingJT80 a standard one would be, but a better sized head and an RPM intake that had a little work done would have been a better combo. torque numbers up, and don't miss they're spinning this thing to almost 7000 rpm! thought it was "..going to live at low/medium rpm" :)

[@KingJT80]

@@josephmancini4400 well yeah it needs a 180 head and a 230 cam in a stroker application Would make 420-430 or so all day with a flat toque curve

[@ShawnGilbert1967]

I liked the concept but a solid roller in a daily and ive tried every variety even dissimilar metal bushed pressure fed lifters...they all eventually fail.... I've had real good success with a hybrid roller lobe and dual pressure oil pressure fed solid rollers with a street ram base converted to sequential MPI on my BBC.....500 smashes and years of duty....

[@b.c4066]

Especially when they'll be lugging it up steep inclines. Looks good on a chassis dyno with super cool water temps, but in a suburban, with mild converter, loaded up and yanking a fellow trail rider out of the mud... Detonation city. Agreed, it's a recipe for disaster.

[@futuresonex]

If you're after low-end torque why use a solid-roller cam and a single-plane intake? Aren't those far better suited for high-end applications?

[@mikef-gi2dg]

That was a good display on how cam phasing controls where the power is and when. I question a solid roller cam, big single plane intake, on a huge off road vehicle, with giant off road times and 4-wd, and shorty headers? But hey I got a 78 malibu that would run real good with that engine.

[@THROTTLEPOWER]

Always enjoy Powernation!!!!!!!!!!!

[@BulkInnovations]

Hu$$$h$$h$h$$

[@BulkInnovations]

,😍

[@BulkInnovations]

zz

[@aaronwallace8397]

10:04 Y’all put RTV around the outside of the screw holes, then immediately follow it up with a condescending remark about correct balancer installation. Nice. 😎

[@willy_larry]

I did the same snorkel as that suburban, the same way, a few years ago. The flex hose only lasted a few months and I was never confident of putting it in water and wish there were a better way.

[@ronniemaeker9102]

A request. This is for your (always new) viewers that are not sure how the spark plug gets its electricity and in what form (AC vs DC). The way ya'll explain things would make it clear as to the process...battery to spark.

[@bornfree3124]

Awesome build, I knew they would want the high torque for their application, I learned something new with cam advancement, great motor, i am very envious. 👍😎👍

[@lorddragonus8748]

Why are you putting the pistol and rod assembly in the block at a 45 degree angle, sliding the rod on the bore? Proper install is 90 degrees straight down, vertical to the floor.

[@permafrost2064]

I would KILL to have these guys dyno tune my motor. Pat would probably want to disassemble the whole thing and start over, but I would be really interested to see what my 383 makes. Awesome stuff!

[@elainestamper3873]

Good video! I do wonder why you didn’t run the engine with the cam in the straight up timing? And why a single plane intake?

[@CamaroRick]

Love the technical detail in this one! Very cool to see the movement of the curve. Thats big gains down low and all the way up to 5500rpm. Plenty to make the axles sweat.

[@clintxxx2875]

AMEN!

[@TonyPret]

Love your show. I have a question, If you have a very good power to ratio how would you tune the engine to go through its revs quicker so as to get better on the road performance rather than big power?

[@jessesyfie7244]

Id like to see 2000 to 3500 rpm on this intake centerline test and what its showing for engine vacuum at idle with it at straight up them 10 degrees advanced to weather it picked up vacuum or lost it?

[@whitewaterdave9683]

Poor Frankie, having to endure Pat's Dad jokes...

[@edwardmyers1746]

@@bigboreracing356 Bahah

[@ripper-wrench]

Look at the torque at 4800-5000 rpm, that's your stall for a drag car. You'd want the cam in straight up. Shift it 6200 rpm's and cross finish line 6600-6700.

[@sepg5084]

If the engine will be living primarily at low to mid rpm range, why are they starting the pull at 3500rpm? Why not 2000 so that we can actually see the torque at low rpm range?

[@mr.know_it_all]

Why would you put a single plane intake on a street/off-road engine 🤯

[@MeteCanKarahasan]

Hi, how does the fuel/hr change between supercharged SBC and same output air aspirated BBC?

[@Torquemonster440]

I know the intake was the matching AFR unit, but I'm really shocked they didn't go dual plane to bump the TQ even further.. probably would have boosted it 15-25 points across the power band.

[@samcharles1166]

What is dual plane?

[@Torquemonster440]

@@samcharles1166 it's an intake manifold that's built more for power production below 5,000 rpm , where 99.9% of off road trucks operate. "Single plane" intakes are generally engineered to produce higher power levels above 5,000 rpm at the expense less low rpm power production. Single plane intake manifolds are generally used for drag racing applications.

[@AG10CH17]

Love the knowledge and enthusiasm you guys bring! Watching all of your videos has helped me out so much!

[@knowyuhgrow420]

Thanks for sharing

[@dodgeguyz]

I would love to see someone develop an add on VVT system for the old school motors!

[@johnkraft7461]

Agreed ! Like the variable sprocket system they fitted but with a viscous clutch hub that responds to increasing oil pressure and retards cam as revs build 💪

[@clintxxx2875]

Just buy and instal a MSD Digital 7 and put some electronics on your ride, program-what you want to do and don’t ever touch a wrench! Lol

[@oldscratch3535]

It really is a great technology. I drive a newer Tacoma with the 2.7L 4 banger and it has dual VVT. You can definitely tell when it engages. The engine is still only 160hp, but you can tell there is a difference in performance above 4K rpm when VVT engages.

[@ch3no2killz]

On the torque wrench it's ft. lbs., torque output is lb. ft.. Your not the only ones, there are many, just drives me nuts, don't know why? Like you vids! )

[@EXTRA---LARGE---FARVA]

"It's going to live in the low to mid range rpm range" Ok, we'll build it for a drag car.

[@PeggyParrow]

I saw a .060 over piston,? What is the stroke ? .030 is 383 ?

[@rtprecisionmachine6210]

I can almost guarantee that engine will ping itself to death under load at part throttle in that heavy suburban on pump gas with the camshaft being advanced that far. 10.9:1 static comp and 200psi cranking pressure. Wrong combination for that vehicle. Also take the single plane off and use a rpm air gap dual plane.

[@zackpowerusa]

Maybe just me, i hear noisy valve train @12:18? Sweet video!!!!

[@k.c.williams3385]

Great episode

[@bjr2379]

Why not use a dual plane intake for more low end torque?

[@89StarquestTSi]

Do you want better dynamic compression ratio in the lower rpms or upper rpms? Your modern variable valve timing systems do what mechanical adjustable gears do, but change by so many degrees with oil pressure and solenoids

[@Scubasteve22]

I know the cam was a little small , but ive seen that same 383 with afr 195 heads and a good size hyd roller make 500 and 500. That thing should have made 550 ish. Course i dont always agree with pats idea of optimum timing. He tends to be conservative instead of giving it what it wants.

[@RestorationObsession]

If I had a shop like that I would never leave it

[@frankkeener4755]

BEAUTIFUL ENGINE GREAT JOB!!!

[@oscarlandag1831]

What type of adjustment tool was that? Looks better than box end wrench and stand alone hex

[@KhanIlkara]

Nothing wrong with being stuck in the 80's. It's better than being stuck in the 90's or 2020. Dark times those 90's! I wouldn't knock that 350 though. A fresh start is nice, sure, but a solid 350 is tough to kill.

[@donniesullivan2700]

Great video

[@ChoatesCoatsandCustoms]

This combo doesn't make much sense to me for a low to mid rpm torque engine.. afr 220s, single plane, and a solid roller.. hmm..🧐

[@montebradshaw128]

I agree,, Straight up..

[@mrelectron6220]

Thinking same thing at least loose the single plane for a high rise dual plane.

[@darnellgrays4396]

Reason why it don’t make sense is because they didn’t tell u they used a hydraulic roller cam and solid roller lifters,look at the cam specs,that is an Extreme Energy XR288HR,u can use solid lifters on a hydraulic cam

[@ChoatesCoatsandCustoms]

@@darnellgrays4396 ok that makes a little more sense, but what about the big heads and single plane on a low rpm "torque" engine?

[@darnellgrays4396]

The heads are too big for the camshaft,they should’ve used AFR 195,more torque and hp,heads that flow 250 cfm supposed to make 500 hp

[@billruss6704]

If the adjustable cam had a set of holes on a Vernier scale you could adjust it more precisely and lock it in. For example, the base could have threaded holes 1 degree apart and the top could have through holes 1.1 degrees apart. This way a set of holes would line up every tenth of a degree and could be locked in with a bolt. This would also give you more exact adjustment.

[@fordilac]

Their idea of low to mid range is a little different from mine.

[@mikethompson2816]

Question for pat I built the black and blue 347 from y’all’s parts list what balance flywheel should I run TKO 600 transmission

[@haralddavis706]

Hey Pat, in your estimation how much power loss would there be with one half compression point less and 195cc heads ?

[@vin605]

Awesome guys very informative

[@theguy9234]

Why a single plane hi rise ?

[@andrewtreloar7389]

High-rise single plane intake for an engine that will spend most of its life at the low to mid RPM range.....ummm, no!!

[@ronbaker7501]

All these clowns pretend to know everything. You can tell they read off cue cards and are intended only to sell products and commercials. How stupid do you have to be to listen to this crap!

[@ryantexada9269]

There were a few things wrong with this build 1. He used a post 86 roller block but used retrofit SOLID lifters designed for pre 86 flat tappet blocks. He shouldve went with stock style hyd roller lifters with the spider that screws into the threaded parts of the lifter valley, also that way he could've had zero valve lash instead of having to set valve lash from time to time 2. Shouldve used a dual plane intake instead of a single plane for a low-mid rpm trail monster

[@ragingbull3406]

A single plane intake for a low rpm engine?

[@Hungry_Hippie227]

Soo question if my timing light is showing 800rpm at idle but my tach is showing 600 rpm. Which would i go off of the light i assume? And get a new tach...

[@colekitten1367]

The way Frankie looked at Pat when he said are those guys stuck in the 80s

[@Adan79Cheto]

I have an 87 k5 blazer TBI 350 5.7l v8 and I want to put a bigger cam in it. I’ve had several mechanics tell me this is not possible because of the MAP sensor. Is this true or do they not know how to do it? I’m not a me mechanic by any means so I’m searching for some answers.

[@lewisdeclouette6342]

Man I love this show

[@nigeleleven2172]

I’d really like a to see a dive into cam timing to include advance. Vacuum, mechanical, both, neither, switched, and how you can improve the response by lightening, or even removing advance springs. What do you think?

[@michaelszczys8316]

In my youth in 70s I was always tweaking distributor timing in effort to get better mileage as well as performance, especially since most 70s cars had distributors set to go nowhere, like a lawn mower. I had one motor that I had a super high power HEI ignition distributor that could arc 2 inches but it ran way better with old fashion points distributor as the advance mechanisms worked much better.

[@aussiesupersnake6642]

I was wondering why never tested the cam straight up where it was supposed to run,i still think it wouldnt made 500 hp,

[@krusher74]

they just wanted to show the most extreme differences, it would have just given a graph in the middle of the 2 shown

[@davidreed6070]

I would like to see what happens when you leave the 1.6 rockers on the intake side and put 1.5s on the exhaust.

[@jonathanlawson4667]

Nothing you'd lose torque and that's it

[@michaelvrooman5681]

Probably be better to go the other way. Most Chevy heads need help on the exhaust side

[@jasonlessard2373]

Can you start a pull at 2000 rpm?

[@doubletee4391]

i know some of the old school folks don't want to mess with variable valve timing but who wouldn't want to have the low end off the second run with the top end of the first? Science is rad

[@JerseyMikeP]

I would like to see how the cam time change would affect " boosted" power.. especially turbocharged.

[@lonnien.clifton1113]

GOOD WORK YALL

[@BigWood3131]

We just used the same set of AFR 220s, Comp cam solid roller 570 lift, 105* 10-1 comp callies 6" rod, 4" stroke TDS shaft rocker 670hp, 590 torq in a Dart 4.1/8 for street and strip use that needed way more air & cam total 427ci sbc and I know I could have did alot better

[@theguy9234]

2000-3500 rpm range is what we want to see.

[@krusher74]

yeah, feel cheated!

[@kunu98]

A True truck range

[@clintxxx2875]

Shit, are you out of the converter yet by that RPM? If so, probably a stock as a rock truck that it wouldn’t make a difference if it was at 1,000 or 5,000 RPM! Lol. You’re wanting to see torque/ HP ranges for what most performance vehicles idle at! Lol! Go back to being a keyboard racer!

[@kunu98]

@@clintxxx2875 with gas at 4$ a gal, I’m Gettn those revs as low as possible lmao

[@f14tomcat30]

How does retarding or advancing the cam change the distance from the valve to the piston? The max height of the lobe is constant (disregarding wear) and at some point during the rotation of the camshaft will always be reached. It would be at that point where the height of the valve would be closest to the piston and never change.

[@stevenhoitz9260]

You're right, the max valve lift does not change, but when it reaches that point in relation to the pistons location is what is affected. The piston is constantly moving up and down in the bore, but is never close to the valves when they are at full lift. Most PTV clearance issues happen during overlap, usually around 10 degrees before the piston reaches TDC for the exhaust, and 10 degrees after TDC for the intake. That is why the clearances for each change when they move the camshaft.

[@f14tomcat30]

@@stevenhoitz9260 OK. Now it makes sense. Thanks for explaining it.

[@craigcontofalsky4387]

Excellent video!! Keep up the fantastic work!😀