Thanks Steve! I've been a professional mechanic for 30 years. I Thought I knew quite a bit about race engines until I ran into you! I realized real quick I'm just a hack. Thank you for sharing SIR!! We run a 11.5:1 psi d rotor @ 116-126% OD on a BBC. The more I watch the more I understand all of the issues we've had over the years.

13:19 - Steve defines small HP engines as those making 1000HP. Gotta love the truthful genius of it.

Great info!!! It is truly a shame that your videos don't get more views but total garbage videos get millions of views!! I guess few people know the difference between right and wrong and who they learn from.

Thank You Steve. Love your engines and your attitude. Always an inspiration.

Thankyou, for the great info and your time to show others your valuable info.Appreciate you making video on your personal time .

Great info as always ! You seem to b a very knowledgeable and humble person which turns into a winning combination !

I've taken a deep dive into SBC valve-train tech recently, but I still had questions concerning pushrods and their tendency to bend / flex. You spelled it out very clearly with: "You can never have too much pushrod" (sounds sort of... dirty), which confirmed the findings of my thought-experiments on the matter. Thanks, Steve! L/S

Cool video, excellent information from a pro. it takes a real man to admit you don’t know everything about something. 👍

I knew deflection was a bad thing but you made it easy to understand why. I need to re evaluate my big block bracket car!

Excellent information Steve, thank you!

Damn, that was thr deepest dive into any one subject that took only 15 minutes.....and at 14 minutes I was almost out of air and the lesson was over .... then WHAM BAM !! He hits me with a baseball bat. I mean .... Dang-O Man I have to ditch some worthless childhood memories so I can retain this for later when I need it. Thanks Steve Oh, and good to see ya over at Garrett's shop.

Right on Steve!! Just about to measure for push rods. This video couldn’t have came at a better time

It is great information as always.

More subs more views .... great channel , like your a delivery , and the entire package of info ... enjoyable viewing

Love these informative videos Steve.....

Thank you for the education this is really good

So much truth! Thank you

Would be great to have static deflection data comparing 5/16 .080" and .105", 11/32 and 3/8 .080" and .135" since that's what most folks would likely run. Using a typical 500psi open spring pressure and 1.7 rocker. This would prove your point. Better yet, if Spintron deflection data was available up to 8500rpm and compare to static. Just a thought. I know... one can dream!

Thank you for the information it really helped

Awesome stuff!! Big Thanks!!

Awesome info thank you!

Thank you Steve

Thank you Steve for the invaluable advice! Plus this one... Lol ".....that's just stupid" - Steve Morris

Thank you !

Material, wall thickness and taper, ends, rocker cups, lash caps, lifter weights, and a host of others things determine specifically whats desired in a pushrod. They found out a long time ago with lifter mounting rev kits. The pushrod plays just as much too valve train weight at a heavy lifter

Cant see how pushrod deflection causes loft. When there is clearance between the lifter and cam lobe at full lift, doesn't this give a chance for the pushrod to straighten rather than deflect? I can see agressive lobes and wrong springs cause this issue. Can someone explain what i'm missing

I'm going to add whiskey to the can't have too much of list. Nice explanation on an overlooked aspect.

great info !! thamks

Tanx Stevo, great info. I love that explanation on loft. I think you need a spintron with stacks of valve springs to get that variable valve timing feature in your pro stock lol. Such an awesome idea for increased duration at high rpm. Do the springs have to be frequently tested to maintain the perfect open pressure for loft?

Hey I do like this video. Good info. But what is perfect quench & how do you know when its perfect??

Steve, I think what you really mean is; for equal total weight(mass) pushrods, the tubular one will be stronger in bending than a solid pushrod. Material close to the pushrod centerline contributes very little to bending strength. Having the pushrod material concentrated away from the centerline(as in a tube) maximizes bending strength for any given total pushrod weight. It's my mechanical engineering Strength of Materials class training bubbling back up 40+ years later....

3/8 pushrod now thats what we use for door hinges ,weld verynice and the tip alines very easy when droping your doors on.

Nice. I'm way back in the shallow end looking at 380ish horse at around 6k. Is that even enough to deflect the stock pushrods? (Mopar Magnum small block)

Awesome 😎

Is it possible to see any loft landing or bounce on the camshaft?

Not sure if you guys will see this. BUT...Im working on a weird engine. Its a diesel flat 6. Im reading the manual (its poorly written, and diagrams are xeroxed three times over from the original German ones). Im not seeing hollow pushrods. The say that oil comes up to the rocker arm shaft through the heads, then through the rod, then squirts out, goes AROUND the pushrod, down to the lifters, and back into the pan. Also, not much on the lifters themselves, if they are solid or hydraulic. I havent opened up the engine yet (mostly for fear of lack of parts, and because its huge..10.35 liter). Im just writing this manual in case I will have to, and rather than chase things down with a dismantled engine, I can have all the date at the ready. Also, changes are, it might be an engine shop doing this work (since Im already disabled and getting old). So I want somebody else to have all the info possible and this ancient Romanian engine. So, am I getting this right, that the lifters get their oil from AROUND the pushrod, and that the pushrods are hollow? Thanks. Also, great visualization of loft. An often forgotten metric when it comes to valve trains. (Hey, I know SOME stuff lol)

Wanna bet on the too much ignition? The resistance between the ignition rotor and the distributor cap button increases current and will burn up a cap in no time and I’ve seen rotors short out to the distributor shaft as well.

what do you think about titanium pushrods? Thank you!

Given certain dynamic loads a tube is stronger than a solid. This is due to total amount of surface area. Has nothing to do with heat treatment although that will significantly change the material properties.

Thanks

on the subject of fuel pumps. Ive always read if you are returning high amounts it heats up the fuel

I have a question for any and all mechanics. I need 5/16x5.475 pushrods but can't find them what can I substitute?

For the stuff you deal with I'm sure you can never have enough fuel pump BUT I've had one heat up the fuel a lot

I've a 4.2 v6 pushed bent can't pull out it moves about 2in is all?? How do I get it out??

what if the closing ramp was more porky,or rounded then the opening ramp,to eliminate loft?

Hey Steve what cubic inch on the BB Chevy do you think is best suited for boosted application using Conventional Style profiler or CNC ported type Cly heads ?

Steve, The reason that a hollow tube is stronger is that a hollow column's ultimate bearing capacity and lateral rigidity are inherently greater than a solid column's. Compared to solid shafts, hollow shafts of the same weight are superior at withstanding torsional and compressive forces. Multiple factors make tubes intrinsically stronger than solid bars of the same size. This indicates that steel tubes perform better in applications requiring durability and strength overall. Oh, and by the way, it is a common misconception that the weight of the pushrods does not matter; simple physics suggests otherwise (as you will see when you test our AWA pushrods).

Cool

Whatllushpush which push rod should I use the long one other show on for the

Always check pushrods for hardness with guide plates, A file won't scratch a hardened pushrod.

🔔😎🇺🇲 Doesnt the pushrod weight affect the total valve train weight that must be controlled by the spring? Heavier prods mean stronger springs. Guess it doesnt matter much on a short 5.7 pushrod 5.0 at 6,000 rpm. Thanks for the information.👍👍

I changed my rockers and pushrods and now when my motor is running you can hear a loud knocking. Somebody plz help me.

👍

This guy gets it..he is smart.. Knows his shit...what you said makes a lot of sense....and he is right.....I get it. Do you.....

To follow the cam on the closing ramp the valve spring has to overcome and accelerate the total of the Valve, Valve cap and collets, Half the spring mass, the second moment of the rocker, PUSHROD and cam follower. So the valve spring is not sized for the opening ramp of the cam it's sized for the closing as it has to overcome alot more mass, actually the spring could be deleted if the valve only had to open. So yes, a Big Pushrod can be detrimental and incur more cost for heavier springs, limit top RPM, poor VE when the valve float starts and excessive wear due to increased loading.

Man o man,.............SOO much information.. HEY, dude behind the camera,....he's talk'n to you. LOL

Church.....Good!

FILLING A TUBE WITH PRESSURIZED FLUID OF ANY KIND MAKES IT STRONGER. A PVC PIPE IS WEAK BY ITSELF. ADD 100PSI OF AIR PRESSURE OR OIL PRESSURE INSIDE IT AND IT INCREASES IN STRENGTH GREATLY. THE SAME THING CAN BE APPLIED TO PUSH RODS. ADDING 100+ PSI OF HYDRAULIC OIL PRESSURE WILL MAKE IT WAY STRONGER THAN A SOLID PUSH ROD.

You cool, man 😎 👨

weight of push rods does matter. the closer your valve train gets to floating, the more energy is lost to inertia; and the less of the energy, that goes into the valve spring, gets re-directed back into the engine. ( like a car going fast over a hill pushes down less on the other side ) and yeah, the rocker ratio plays into the mass x velocity^2, but it is still the mass creating the loss at whatever velocity. something to be said for overhead cams when you figure how much energy your valve train is chewing up.

When a pushrod flexes, it "pole vaults" the rocker arm over the hump of the cam lobe. The ramp rates of the lobe are completely turned the other way.

Can never have too much pushrod... Thats what she said Steve.

A tube is stronger because there are 2 walls sections that have t o bend verses a solid shaft of the same diameter.

Never too much cowbell

My non-expert opinion: Larger pushrods will deflect less and limit loft for that exact reason. But, a heavier pushrod will slow the spring's ability to quickly return the pushrod, causing loft for another reason. That is, for the same spring. Using a larger/heavier pushrod would then require a stronger spring to reduce the delay (loft). I also suspect (for a given pushrod/spring combination), loft begins at a particular rpm and amplifies as engine rpm increases.

Steve, for us street guys, wouldn't hydraulic roller lifters solve the pushrod difflection??Just saying, with 500hp??

Never too much....Wow, have you overlooked a lot .....

Just a little information. This is the most common mistake that almost everyone that is not a trained engineer makes. You said that the tube is stronger than a solid rod, but this is not accurate. A tube is stronger than a solid rod of the SAME WEIGHT. That means the solid rod would be much smaller in diameter than the tube. A tube with the same outside diameter of a rod would be much weaker than the solid rod. This is why top fuel dragsters have all moved to solid pushrods. Since they have a different path for the oil, they can now go to a much stronger pushrod that is solid.

Real engineer here. A lot of things wrong with this video. I won't address them all but I want to make a couple of points. First. Tubes arent "stronger" than solid rod. For a given shape (round, square, etc) a structure with a hollow cross section will be more resistant to bending in compression forces when compared "pound for pound" This is due in part to the fact that a solid round bar has a “neutral axis” that, when the bar is bent, is not in compression or tension and so does not contribute to the resistance to bending. The material in the rod that is further from the center of the solid rod contributes exponentially more to the rigidity (not so much strength) of the rod increasing its bending moment. So why not remove the material from the center of that rod that contributes the least structurally to reduce weight? Well now you have a tube. If you had a 3/8" solid rod and a 3/8" .080 wall tube made from the same material Between the two the solid rod would be stronger and more rigid. However the tube will have it beat by weight. Which brings me to my next point. While I agree that Pushrod rigidity is of utmost importance for the stability of a valve train... ever hear the phrase bigger is not always better? Well here it is actually true. What you said is very misleading, a larger pushrod is not always better. There is a point of diminishing returns where once you have met the rigidity requirements for your system for a given rpm range (cam, lifters, pushrods, rockers, springs, retainers and valves make up your valve train system) and the entire system needs to work together to obtain the performance an longevity. Any real engine builder knows and will tell you that valve train design is a careful ballance of weight and strength, granted on the lifter side of the rocker "strength" ends up being of more importance than weight, but engineers still understand the concept of comprise and diminishing return. Serious engine builders are putting their engines on spintrons and spinning their engines to 10k before pistons are ever fitted, just to pinpoint valvetrain issues and solve them before the engine ever goes on a dyno. Haphazardly throwing bigger more expensive parts at the problem might have "Worked" in the past but with today's competitiveness in the racing sports that just doesnt work like it used to. We are going faster and getting there quicker, and the tenth second you used to be able to shave by removing the spare tire and adjusting your carb is costing many thousands of dollars today.

Two arch's instead of one?

Why aren’t pushrods made from w-1 steel and heat treated

hole in the center gives you another circle or wall. like eggs. one shell. think of an egg with 2 shells.

Thin wall I=mr^2 vs solid bar l=1/2mr^2....higher moment of inertia

Pump pump pump .

Missed one. Number 4, you can't have too much money. I have had people.wanting 5 figure engines, but they only had 4 figure money. In the circle jerk world, that the difference between a claimer engine VS. The engine that ran off way out front.

Tube is better than a solid because of surface area!

i dont think you emphasized enough that you should REDESIGN the cam profile to better follow the loft/float... you shouldnt operate with float because youre not going to prevent bouncing at all speeds. LOFT/FLOAT IS NOT a great thing... its a phenomenon caused by high inertia caused by beefier pushrods (in your example). So i understand what youre getting at, but you only once mentioned the fact that you should redesign to match the loft (if you made a power gain) or otherwise change something to rid the loft (if its detrimental), but you shouldn't leave that feature in place just because you increased the mass of your system. Its not different than float.

That loft thing.....not good for roller lifers...at least on bbc. We run springs...lots of pressure...better way to much than just exactly what you think you need.. A vid about pushrods and no instructions on how the establish the correct length?? You sound like you have worked on some "stuff" What you think of the valve guides in these heads? NO, they dont have the wrong size stems for the guides....They are worn that bad and yes the motor ran fine...it did idle a little rough...Motor is a closed chamber 427 in a v-drive hydro With a .710 x 260 *.050 cam, 300 on the seat, 650 open. I would spin it 7800 and spin it 7k several miles at a time...i did not pull the heads off to fix the guides, motor spun a main after fram oil filter shit the bed...No damage to the seats, the cleaned up with a minor kiss on my bosses sunnen...one of those single angle deals...reused the exhaust valves, could have reused the intakes but i found a set of 2.310 valves and we cut the seats to match....Cause of the bad guides? Bad springs...sitting on the bench the ends were kinda crooked. People think guide wear is all about getting the roller down the middle of the stem. it aint so. Dont believe me? Get a head with a loose guide, figure out a way to open the valve with a pushrod...open the valve..the valve does not get pushed to one side...it just hangs there...if it goes to one side the spring is crooked. If the roller had any kind off a chance to push the stem sideways and wear out the guide the stock rockers would wreck guides faster than you could replace them kzfaq.info/get/bejne/Z5eVi8930MDJm4E.html

Nothin' bout Carbon Fiber ? How's Noel?

Can’t have too much head either 😉

Actually you can have to big/to heavy pushrod. Especislly in top fuel where The inertia from The pushrod actually makes cracks in the billet block and top. Thats why they are smaller and from Titanium. And its common in higher reving engines. Thats why its mostly eliminated in higher reving engines to eliminate vibration and overall complexity by using overhead cam design instead. But its common for alot of american engine builders to be biased.

Pushrod goes up and down, not around the camshaft!

to much fuel pump = too much heat in the fuel... if we are talking about street cars, not to mention noise rather run 4 smaller pumps than a A1000... cant carry on a conversation in the car with one of those going... BAAAAAAAAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHHHHHHHH

Church, GOOD FOR YOU Steve! After all, all knowledge comes from above. That's why there's a lot of dumb people running around now days! Lol.

2:04 Tubes are not inherently stronger than solid rods of same outer diameter, I have no idea where this false notion is coming from, but I have heard it other places as well and it perplexed me then as well. The pushrods you are showing are all limited in their outer diameter, so there is no benefit to strength of them being hollow, on the contrary, the hole makes them weaker. Not by a lot, so it's not a problem and the obvious problem of needing to deliver oil to the top end outweighs the small loss of ultimate strength.

Church Steve??? He probably prays faster than most, no big deal.

lol push rods

Funny when someone says "dont hold me to it!" actually means :i dont know

Yoy know, a female horse is faster than a male horse.... Naturally, female horse is 2 horsepower.

This dude dont know what he's talking about.