You gotta love Erics videos......cuz you ask him what time it is, and he explains how the clock works.....

🔔👍 One thing that needs a mention... all 1.6 ratio rockers are not the same coming off the seat. A plain 1.6 might be 1.6, but others check 1.83 off the seat. The valve is opening sooner and quicker.... That is worth a bunch of power. David Vizard explains this well. thanks 👍👍😎😎

Thank you. I now understand why stainless rockers become a choice in certain applications: aluminum suffers more deflection.

Most don't realize that incorrect pushrod length changes valve lift by changing the effective rocker arm ratio. For those of you that can do math, think of cosine of the rocker pivot with respect to the valve stem with a different length pushrod. For those of you not math experts, just use your dial indicator next time you degree a cam and substitute a longer/shorter pushrod. If you imagine the angle of the rocker with a REALLY long or short pushrod, the opening/closing parts result in a lot of side motion, not valve depressing.

Great videos!!! Keep me coming please! You seem very good at what you do! Thank you!

I use Crower Enduro stainless rockers, 7/16 studs with girdles to help reduce deflection and thick wall pushrods. You still lose .050 to .075 lift depending on rpms and engine temperature. Heat makes all metals pliable and deflect more.

Thank you for taking the time to do this. Excellent information!

This has been the most interesting comparison on deflection i have seen. Great stuff.

Never to much to digest, stay on it and chew it longer. Very excited excellent info, never stop learning thank you !

Awesome video. Now that I've watched every video on your page i wait for the new episodes just like waiting for a new favorite tv episode to drop.

I've always wondered about actual amounts of deflection, just never tested. Awesome video!

I find what you show us super interesting & I do watch your video’s far longer than I should! Some days I need to kick myself in the butt to get going or I miss half my day. Anyway,I did some engine building & street racing like 40 years ago & wish I had someone with your knowledge helping me out,make no mistake you are helping everyone who watches your video’s! I am now to old to put into practice what I learn from you but watching still trips my trigger. Thanks for that!

I have checked this before with stock ls pushrods and the 3/8 .080 and there was a bit of difference in lift values. Awesome video.

Lemons builds high quality stuff. Another excellent video.

You just made me feel better for going with stainless rockers. And A.R.P. studs. Thanks.

So much knowledge, thank you! I’m working to become a performance builder for small engines like atvs and dirt bikes. I know it’s not exactly the same but the fundamentals!

Exactly why the Ford Cleveland will work with a smaller cam bring than I would normally choose on a SBC. This video has a world of knowledge in it if the viewers are really paying attention to it. You did a great job of letting us see the real deal with this. Thanks

My new favorite youtube guy!!

Such a great video i had no idea it was that bad. Im looking into beefier pushrods today. Ive got a solid lift intake is 7.24 with 1.6 rockers and ive got small pushrods im losing some serious lift and im sure it gets much worse higher rpms thanks for this vid

Just putting the finishing touches on a 417 ls carburated build useing a BTR stage 4 na cam .I went with 1.8 ratio comp steel rockers to correct the loss from all of the verables you mentioned and also used 3/8 pushrods.its going to be a interesting dyno session

Nice Job Eric, I really would have stepped up to the 224/230 comp, they have a really nice idle & pull plenty of vacuum, & have a even nicer power curve! If you run a solid roller on the hydraulic cam, set to like 2 thou cold, they are still pretty quiet & pickup around 8 to 12hp! If I remember right, It made like 460/460 I forget what heads, they were brought to us, Might have been box stock Edelbrock? With the performer rpm intake, back when it was new! Basically the same bottom end, scat rotating assembly, & Keith Black pistons, but it was only 2 thousand in the hole. Went in a jacked up square body longbed, Every time I see it out, there’s 150ft long burnouts, from 36in tall tires, I think! Guy is a circle racer, & drives the truck harder than the modified! 😂😂😂😂

Excellent video. I've got a 331 SBF solid roller/shaft rocker going together as soon as the rods come in. Going to be paying WAY more attention to this stuff now. Thank you.

Harland sharp bud.i have a set on my roller small block with .620 Valve travel.250 lbs closed and 650 lb open @ .620.run on the street and 15k miles before I lost a roller tappet @7800 rpm . On the rebuild I noticed I had finally cracked one rocker arm .but it was still working.it cracked at the stud side of the valve spring.

Very good explaining valve train physics! vs. theoretical Eric

Very interesting & informative

There are so many factors to include. You can give me any cam card and I'll prove the numbers are off. Everything from cam core, push rods, plungers, oil type and bleed down, rocker materials and rollers. Can alk effect actual lift. The longer and wall thickness will also effect the readings. HEAT will change everything.even with all those components the same! The numbers will change!!!!!! As the engine runs. Even RPM will change the lift numbers. Think about setting hot last on a solid. How much room is given for heat expansion! Steel rockers will grow more from heat then aluminum will from reflection. A running engine will also stack up more oil on parts at a specific rpm more then at other times. And lastly....Even head bolts and rocker studs will stretch causing even a different number. Your slow roll testing is only getting the mechanical readings without all the hydronic and deflection effects. Even the type of coolant used can change the cam card numbers. Water filled race cars will read different then a car with antifreeze. Just saying....Even top fuel guys will tell you. The car that runs longer before the launch will be slower!

Very informative, thanks.

I love all these tech videos

Very good video sir

Steve morris was talking about running thicker walled push rods in a video and i believe it was exactly because of the deflection as you are talking about.

Turn left to go right! Got it!

Great video

I read somewhere that retainer flex is most of the loss in lift when measured at the retainer. It would be interesting to take a mock up block without rods and pistons and measure lift at the head of the valve in the bore

Now I've got to look see if you have a collector length/ exhaust length video.

At .050", deflection is minimal compared to open deflection due to lower spring pressures, so durations at .050" aren't affected as greatly as the full lift values. Also, Valve radial clearance should be checked at TDC with piston fully biased (pushed) towards the valve... clay using a valve, or drop a centering tool through the guide, and make a pip in the piston then measure radial from your pip mark with a vernier. (Flat top pistons with small valve reliefs are a clay method candidate)

At higher RPM the spring pressure over nose will reduce.. valve may even loft and lift will be bigger than mechanical. Though this test applies for low speeds.

This video makes me question what max cam lift you can use regarding valve spring coil bind. I usually see recommended .050 to .060 as a safe buffer but if you don’t get the lift expected could you generally speaking reduce the coil bind buffer value to .040 ?

Hydraulic lifters are designed to pump up at certain rpms. Lots the time I've read they do it so you can put around and have it not run as rough at idle and low rpms, which is understandable. Which in some efi cars it helps to keep the computer from over adjusting

I like you work and videos I see the one head bolt on center , did you add bolts once you added additional spring pressure? especially the ones near the pivot area (rocker studs)

Stud mount rockers move around too much. Shaft mount steel are my go to. Alloy heads grow and studs stretch so I tend to tighten the lash a little more than spec. Its too hard to work out how much "actual lift" you have. So many variables. Pushrods act like po-go sticks lol.

Nice to see you finally pulled the trigger on some decent exahust manifolds for the S10. Steve Morris made a video about valve train deflection too but I think yours is more detailed tbh. Steve used to work in a Pro Stock team which probably why he only does boost engines now but boost is cheating imo.

How much worse does it get when you go to a reduced base circle sbc cam with heavy 1.550 double valve springs, like comp 943's?

Wow thanks foe the tips.

What rocker arm ratio options are available with the Federal Performance heads and who makes the rockers? Does it make sense to spend more on rockers for more lift or just get a bigger cam?

Im sharing the hell outta this vid great info

Wow, the amount of deflection was much greater than I would've thought!

Is this simply more common in SBC due to it's geometry ? Is this less of a problem where the rocker isn't suspended by the stud and instead solid mounted, such as a shaft mount, or even an OEM LS style with the trunnion mounted solid to the cylinder head, leaving the pushrod (and perhaps the valve tip if no roller) to take the brunt of the abuse and potential deflection ?

I always use a 3/8 pushrod on my LS motors regardless, now i want to test if there is actually a lift difference just by switching from a 5/16 to a 3/8 rod

My thinking on this is how much is comming from rockers and how much from pushrods. If you get a lot from pushrods. Then they will be like wet noodles vibrating in the engine. I dont think you can calculate in the loss of lift in the engine. Build ,because as rpms increase spring pressure would effectively decrease. Over revving causes valve float which is effectively zero to no spring pressure.

so how is it when you degree a cam you come up with what's on the cam card?

I would like to know are you running 3/8 or 7/16 studs? What push rods .080 or .105 wall, 5/16 or 3/8? I run a stud girdle and i will check to see how much difference i get. Great video.

Did you try a stamped steel 1:5 rocker to see if you exhibited the same results?

I was shocked to see that much lift gone with an .080” thick pushrod wall. Mostly this video made me happy with my SBC parts selection: .600” theoretical lift, .105” wall pushrods, 7/16” rocker studs, comp ultra pro magnum 1.6” rockers, jomar stud girdle, Johnson Short travel lifters, and beehive springs to cut down on open pressures and hopefully deflection. -Kinda regret not going with 3/8” pushrods but already done and the .105” wall should be fine with my 5,850 rpm peak.

There is some other geometry that goes into play, I did this with one Comp Cam solid roller I bought to do this and I found the solid roller cup is shorter and closer to the cam than the hydraulic. Also Eric placement of your gauge has to be in the exact spot, keep the dial indicator at the same degree of angle is critical for consistent measurements. I think deflection is not a issue just taking a measurement if that's what your saying!?

Can ı use 294hr camshaft with 1.6 rockers on 3973487X chevy old heads?

Have u ever tested the comp ultra pro magnum vs a shaft rocker in a deflection test?

My AFR 210 cylinder heads with 1.550 Solid Lift Roller Springs are supposed to be good up to a .710 lift. So my question is, can I actually run a bigger lift camshaft than .710 because I'm not actually getting .710 lift. I'm not going to run that big of lift probably around .650-.680 lift, but theoretically I could run bigger? My heads according to the flow sheet flow the best at .650 lift. Should I shoot for .650 of actual lift?

When measuring pushrod length, be careful switching between lifters. Push rod cup depth varies in lifters based on brands, and whether they’re mechanical or hydraulic. This is how people mis-measure pushrod length etc.switching for example between a solid flat tappet and hydraulic. For merely opening the valve the pushrod cup depth should have a minor insignificant effect on the results. JD

So while in motion is even more deflection losses due to valve train mases?

When i started building bbc 35 years ago i got laughed at for using huge 71/6 push rods, i said gm must of known something because they used them on the high performance big blocks. Now 35 years in the future people are running the biggest and heaviest push rods they can get lol. Maybe thats why the dyno guy couldn't figure out how my 461 bbc with merlin oval ports 12 .5 compression and a ultradyne roller made 744 hp and 676 torque. I had a holley dominator on a 4150 team g intake, used one of those adaptors. Engine had a gm forged crank and stock 3/8 rods that i polished and installed arp wave loc bolts. 2 bolt maon block with studs. It was in a 37 plymouth coupe i raced all over the Pacific northwest. Car was 3600 lbs with me and would run 10.10 @132 134. Had a th350 we built with all stock parts and just a manual valve body. Those were the good old days. I remember when i got those iron head merlin oval ports that thing were getting serious now lol.

Why don't 4V DOHC heads have options for different ratios on their roller rockers? I have a 96 Mustang Cobra and I'm thinking if that were available, I could avoid buying new cams.

I wore them rocker out with my solid roller cam in 6 months I went to comp golds

Interesting, I have checked lift with checking springs and have found a tiny bit more lift. And duration as well. Never done it with proper springs,, well some light ones for baby hydraulic using a solid lifter to check.. And that was very close to the correct numbers. A tin rocker would have been interesting, that style of cam many do use factory rockers. Comparing a 1.5 roller to a factory rocker gains both lift and duration. And yes those Scorpion rockers have more lift. Comparing 1.72 with a diecast Crane gave about 30 thou more lift. So I did not use them. As I knew piston to valve was ok, but that extra lift may well have made it less than ideal. I suspect the lift lost is more pushrod deflection than rocker flex. I also have found that cam cards are conservative on spring pressure. Crane specs decreed 125 on the seat. Engine was a little lazy over 6700. I was given a set of 140lb seat pressure and it gained power over 6000, revved smooth to 7500. And that was above my safe limit! That alone was half a second a lap. I checked the springs that came out and they were between 120 to 125psi. So were still in spec. Though probably started a little heavier. And it was no where near coilbind, the closer to coil bind means A You can lose a cam B have springs go soft quickly, or even break

HI ERIC WHAT DO YOU THINK OF CONICAL SPRINGS

Wil you lose lift with the actual strong spring resisting ?

The faster you can raise the valve, generally the more power you make.

Is 40/50 thou deflection common?

Hopefully there are still some brands of lifters out there that are fit for purpose, as Ive seen several engines making metal on the runin cycle lately and these were premium lifters from reputable brands! Its the same thing with the rockers too, I dont trust alloys in high stress / high shockload applications, I know a racecar fabricator and he REFUSES to make any braking or suspension related components out of alloy as their hardness values seem to be akin to european cheeses than anything else.

Wondering about the push rod lengths here, with different rockers the angle matters, if you start with it too flat your loosing a lot of potential lift, same with it sharp it’s the same. Ideally you’d want the rocker flat- 90 deg to valve at full lift- maximum operating pressure. I’m not saying your wrong here and maybe you considered this and didn’t mention. The card just does the basic math- built “correctly” it’s a lot closer to cam card, by that I mean build it how they did- good video tho.

I have found .024 thou. Difference between 2 different companys 1.6 rockers !!

Hey. Watch you on you all the time. Thanks for your experience and sharing with us. My question is when the engine is running let's say at 5000 rpm, will you possibly regain some lift from the momentum of the valve at speed rather than at idle?. Thanks and have a great day. James

Ok can you tell me what you think about porting so much that you open the port AND the seat 3-4.5mm wider going from a 35° multiple angle to a 45° single angle (same size valve) larger deeper seats to accommodate the portwork. On the exhaust side. And reducing the lip on the intake back cutting it to the sealing angle. Leaving the lip on back side on the exhaust valves. But over all same size valves. I've posted a short hyperlaps of shaping a bowl. I plan to make a bunch of videos on the next head (about 54 hours into porting alone! ) cast heads are a bear to port

Great video. I have a 427 CSB with all the good stuff. It has 220 AFR heads. On the dyno it made 650 Hp and 598 lbs torque. It has a hyd roller cam. Intake .400 lift and 251 degree duration at .050. Exhaust is .387 and 255 duration. 33 degree overlap at TDC. Cam card .600 and 304 duration on intake and .581 and 308 duration on exhaust with 1.5 ratio rockers. 110 lobe center. It makes max hp at 6200. Do you think I would be better going to a 1.6 ratio rocker. I'm running steel rockers on it now. Thanks for any input you may have.

Thx again

Eric, also wanted to add, the higher the ratio, the more deflection the pushrod will see.. Higher spring rates will always show a decrease in net lift as well.

What you are seeing is not even with it running! Lol. Most don't realize, huge difference between gross lift and net lift. Between deflection and rockers that are not a true ratio, you lose a ton. Not all rockers with the same ratio are created equal. Years ago I did testing for an up and coming rocker company, and tested MANY different brands. Same ratio, big names, and MOST fell short of actual ratio. Some were 1.6 that measured 1.4! SCORPION was the first to catch on and were much bigger than advertised ratio. Now, a lot have caught on. Aluminum is worse than steel, they also grow more than steel, which gains lash when hot vrs. cold. Shafts are always better, as they don't scrub the stud when it takes up lash on a solid roller, and are much more stable. When it comes to pushrods, the bigger and thicker, the better.

Any cam profile suggestions for getting 600hp from a Stealth headed, shaft rocker, 10:1 452 cid Dodge to run the Silver State Classic ?

Excellent video Eric, thank you. Am I correct in assuming 90%+ of the deflection shown here is due to the Pushrod and Rocker stud deflecting ? I'm sure very little is due to the actual rocker body. An interesting test would be to check the same dimensions on a shaft rocker application with sufficient pushrods for the spring pressure being used. I hypothesize we would see much less defelection. Thanks again for this excellent demonstration to illustrate your point. Time for a pushrod upgrade.

So a BSR shaft mount rockers and 3/8”.135 min wall pushrods helps a little????

STREET daily driver blueprint plan for 2nd gen camaro. Blueprinted Perfect 9.025" finished deck '010' 015 025 block350, 0.002" above deck pistons. Forged crank offset ground to 362 c.i. SBC 4.040" bore. PromaXX Project X215 heads, 2.08" intake valve unshrouded, .150" dome with relief. XR288HR on 108 LSA, PRW 1.65 roller rockers = 1.83:01 Off seat exaggerating ramp rate. Victor JR , 850cfm- VRS. Switching to 400 style bore block in tall deck block and Dominator 1050cfm.

Can u do those same tests with a stud girdle on there?

👍👍👍👍👍

I like to see if shaft mount rockers make that much difference. i run t&d chromoly

But won't RPM's and heat from a running engine make those numbers fall closer in line to where they're supposed to be?

Still need to put you the correct converter in that thing.

why do some cylinder heads say the are for flat tappet only? is it the pushrod guide setup or spring package? Thanks

what do you think about the assault heads? are they good quality? can you run them out of the box?

Eric, does a stud girdle help with deflection and lift loss?

Think this is why my friend said he was able to use Crane roller (BBC) advertised lift int. 587/Exh. 610 in crate 502 with the GM Hyd. lifters. Others said no due to link arm bind, but was no issue.

Lash closes up significantly at operating temperature.

You'd have to wonder if at least some of this isn't taken into account when you ask a cam grinder for their recommendations. I'm sure that good cam grinders will be recommending based on how the cam works in a typical engine. I noticed that the LSA on the cam was 112 degrees. David Vizard has some videos where he says that LSA is the most important spec and that for a SBC it should be 108, and even less for a stroker. David is very adamant about this saying that he doesn't have an opinion, he has a dyno and more testing than almost everybody else.

First your cam have .366875 of lobe lift. Second thing you can not multiplie rocker ratio to have lift because the cam lift straight the lifter and pushrod but the rocker change a vertical lift by by a radius liftso you always lost from the calcul. And you last test with 1.900 install probly you have the wrong patern on the valve too long pushrod.

Why is there so much duration split between the intake and exhaust ? Also is the engine going to the dyno ?

Hey Eric would to big of a carburetor lose a lot of low end torque like say going from a 1050 to a 1250

You missed a good point to make... flow reduction with and without deflection.

Have you ever port Promaxx 200 heads and if so what do think about them and flow rates?

Let's not forget beehive or conical springs.

A Flowbench is NOT a Dynomometer.... just say'in, lots of times the Engine doesn't care about 'extra' Flow.

I wonder if only having one head bolt in is letting it lift the head a bit causing some of the lift loss.

Hive you done any work with DOHC engines? I presume there would still be some deflection in the cam, but not to the extent of what you showed here. Love the content, keep it up 👍🏻