More Power Through Improved Rocker Arm Geometry
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- Опубліковано 29 чер 2012
- Another of my old RaceScene TV Episodes. It was filmed at Crane Cams with Ralph Johnson who worked with them under the old ownership of Crane. Ralph shows how to maximize rocker ratio by using different length pushrods to produce more power. He also discusses correct valvetrain geometry.
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Ralph was my dad's best friend. When my dad passed after fighting cancer for months. Ralph was there for me. When I would get a break from carrying for my dad.I would head over to Crane Cams and Ralph would share stories and help me deal with my emotional times. Thank you Ralph.
0😊p
😅o.
Pll9
Holy cow that man was Smokey's right hand man.
GREAT JOB! RJ is one of the founders of American Speed! THE INVENTOR of the Holley 4150 racing carb! Thank you RJ! Thanks for getting him on video!
That old man has forgot more than I will ever know! well done sir what a resume you have.
My thoughts exactly.
It's amazing how you can learn from the old timers that have been around since the 40s. Awesome
Absolute genius! It makes perfect sense the way that this gentleman explains it! I am a master mechanic from the military I worked on jet engines and for a time I even taught physics. This gentleman no surprise with his experience is an absolute genius.! He even worked on the Chevy small block development! What an honor to have instruction from such a caliber of Man! Perfect explanation for me!
Wow.. that man helped design the 283 small block !!!!!
Outstanding! It's hard to find true, reliable, expert info like this.
Ralph, Thanks for passing along some of your years of information very helpful to many that will view. Mike Caruso
Now that’s some history to be proud of for sure
Thank you for sharing your knowledge. I get it. It's an honor sir.
Knowledge is power 👍love watching these video
This guy is a true legend 🇺🇸👍
wow, yes! Great info. Very interesting.
Wow, great info! Thanks.
this,man.is a genius
Very Informative. At CRANE CAMS Ralph was known as "The Big Johnson Bumpstick"
I got Johnson hi-lift rockers on my -54 Ford Six,when did they first apear?
I’ve learned to listen to these Wylie Veterans.
These guys are the salt of our earth in my views.
How does changing rocker ratio or shorter push rods alter valve spring pressure?
what is that little spring your using
Is rocker arm ratio the same as mechanical advantage? If no, how are they different?
Help me understand please. If I have an engine with a rocker arm ratio of 1.5 and a valve spring with an open pressure of 300lbs. Does this mean the pounds of pressure needed at the cam would be 450lbs since there is NO mechanical advantage when opening the valve?
This is a great series but why do we need the background music!
My question is. Why didnt they design the engine so that the rocker arms are longer on the push rod side to have more leverage to reduce the amount of power required to push the valves in? It should free up some horsepower. How many horse does it take to push them valves down?
great info
Thanks
Cut that darn music off when the man is talking!!!
Yes, it's like the distraction of a southern accent
I agree no music
I have a brand new 1914 motor I built all the goodies whistles and Bells the same rocker or elephant foot has broken twice once at 5:00 miles again now at a 1000 miles I haven't gone near 3000 rpms yet I'm doubting my mechecin I've got nearly 6000 dollars in the motor any advise
So colonel sanders built engines too?
I'm no expert but I do know that when the pushrod is the correct length for the application, the tip of the rocker arm will be centered on the tip of the valve stem when the cam is at 50 percent lift. If the pushrod is too long or too short, the tip of the rocker will be offset towards the outside or inside of the valve stem rather than centered over it. This can create side loads on the valve stem that increases friction, stem and guide wear. Catastrophic failure is next, just my opinion.
Yes, that's exactly what this does, it places the initial contact point of the valve to the rocker tip at the leading edge of the valve. It will increase wear but this is intended for race engines where you're looking for maximum power without regard to long term durability. I asked Ralph when we were filming this segment about the increased side loads and he said the gain in power outweighed the loss due to additional side loads.
+Pontiacman That was my first thought, Im curious even on a race motor if its worth the stress on the valve stem.
Danny Duplechian , Yeah I'm with you! I wouldn't even do it on a race motor, especially if you don't have deep pockets.
+Pontiacman It will definitely wear parts faster but some racers don't care especially in very limited classes where you're scraping for every edge you can get.
This doesnt apply to drag racing where there is no rule, but the benefits for rule classes would be there if you only have to hold it together for the duration of the race.
Great video, thanks a lot! I just have one question, did the lift at the valve increase with a a longer or shorter pushrod?
Tecnomec tecnologia e ensino de mecânica shortet
Increased ratio equals more lift.
He added a .150 thousand longer pushrod and increased the ratio. When you add ratio depending on cam lift at the lifter you can expect on avg anywhere from .30 to .40 thousand more lift depending on what your lift was at the cam was so more lift made into the cam originally the more lift you’ll get from the increase of the ratio. Either way your increasing the ratio just beware I’ve seen people running a .480 lift cam with a 1.5 ratio rocker and pressed in rocker studs go up to a 1.6 ratio and make the lift around .510 and end up yanking the studs right out the heads. If you have pressed in studs I’d recommend at least pinning the studs as a cheap way to avoid this before ya go starting to play with your rocker arm ratio.
@@85gbody97 I would add....Make sure you've got the clearance in your spring package and retainer-to-seal clearance!! I've seen plenty folks scratching their head trying to figure out why they were bending/breaking pushrods.
Also, the longer pushrod trick only works with the old school stamped rockers because their contact area on the nose is long enough to accommodate the added angularity and travel. A roller tipped rocker of any sort needs the correct length pushrod or the roller can easily roll off the tip of the valve or poor geometry can cause accelerated valve guide wear.
@@hotrodray6802 Yes, but lets sharpen that. Because the rocker travels in an arc, ratio is actually dynamic through its full range of motion. For the same cam lift, a pushrod change uses a different part of the arc.
this only works for the most part on stamped steel rockers Im assuming
He said roller tips.
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I've never understood why Ford used a lower profile cam with better rocker ratio than Chevy with higher profile and less ratio?
so colonel sanders worked for gm ?
Apparently, and he's got some more secret recipes, this video is one,,, ha
What did the lifter valley get painted with
Usually the coating for inside electric motors.
It's suppose to help drain back.
It's called Glyptol, made for industrial electric motors, common practice back in the day, now not so much.
You NEVER want to worry about where the wear pattern is at on the valve to set rocker geometry. The wear pattern has NOTHING to do with "geometry." Because none of the manufacturers have any "accurate" standards for stud and stand mount dimensions from the valve, and because the stud leans into the valve, and because engine builders use varying length valves, and lastly, because every custom engine has a different NET valve lift, no rocker arm is going to be able to have the exact length required (on a mass produced basis) to accommodate all these variables. That is why you shouldn't worry about where the witness mark on the valve tip is at. Just worry about the angles. The BEST way to assure you are measuring ANGLES correctly with HARD measurements, is to use the VALVE SPRING RETAINER, because it is perfectly mounted at a 90 degree angle to the valve, and that is the principle of MID-LIFT precision.
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You NEVER want to use "checking springs" to set rocker geometry. You need to check for NET valve lift with ACTUAL springs. Once you know what your NET valve lift is, then EVERYTHING after that is done with a CLOSED valve, no tension on the valve train; not even necessary to have an adjuster in place. Just an adjustable push-rod; dial calipers and KNOWLEDGE.
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With all the tools I've made; and all the engines I've built; and all the tricks I've learned (many from other creative engine builders), to this day when I still occasionally help an old friend out on setting up his rocker geometry, I do it in less than 5 minutes with the following technique. It's all done in the CLOSED VALVE position, because you don't need to worry about hydraulic lifter valve compression or flex. You don't even need to have the adjuster on the rocker arm; it is all laying loose. And obviously, unlike this video, you are not rotating the whole thing over under valve spring pressure. Once you know what your NET valve lift is, everything after that is math, and setup; and this can all be done with the rocker laying loose on the stud, and an adjustable push-rod lifting or lower it as needed.
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It's not complicated:
A. Know your NET valve lift; divide in two; that is your MID-LIFT "motion" (MLM).
B. Measure the height of your valve tip above the retainer.
C. Measure the diameter of the roller; divide in half (this precisely gets you from the bottom of the roller to the AXIS).
D. ADD "B" and "C" together, to get the STACK HEIGHT. An illustration can be found at: www.mid-lift.com/TECH/TECH-Installed-G1.htm
E. Now, use a straight edge like the little machinist square shown in this video, and lay it across the valve spring retainer and alongside the trunnion.
F. SUBTRACT or ADD (as needed) the STACK HEIGHT to or from your MID-LIFT MOTION, by raising or lowering the rocker arm on the stud.
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EXAMPLE:
* NET VALVE LIFT IS .700", so MID-LIFT MOTION is .350". That's cut in stone, now forget it for the moment (you've written it down).
* Valve tip is .050" above the top of the retainer; and the .500" rocker arm roller diameter tells you its radius is .250", so the STACK HEIGHT is .300".
Kids today have no idea what in the hell he is talking about, or the patience for it.
Don Rutter and that old man probably forgotten more than I and others will ever know. I got excited when I see an old hands on fart that’s built more combos of stuff to make your head explode. I wonder what Brian tooley would think about this?
Jason Rogers: Brian Tooley is a GENIUS! I was watching some videos he did about cams and heads. Amazing content to say the least. So it's nice to watch someone who knows what they are talking about. I keep coming across videos of guys running Windsor 5.0L engines with huge cams and stock heads with stock rocker arms! It is completely insane how wrong some people can build an engine.
Kids today: Push rods? What are push rods?
Colonel Sanders does engines! Cool!
But incorrect loading of the valve creates more problems and guide where, so isn't it better to change the rocker arm and stick with the correct valve geometry?
Race engines get refreshed fairly often.
Street cars are a different animal.
This is targeted for the racer that is limited by rules. For instance, a 1.5 or 1.6 ratio are very typical rule limitations.
So stamped rockers are bullet proof. Thanks
For stock can, stock head, stock hydraulic lifters, stock pushrods, stock lift, and stock rpm limit of 4500-5000 rpm yep, they'll usually last 150,000+ miles. Any deviance from stock and your theory goes out the window
wow I never knew Ernest Hemingway was an engine builder, I always thought he wrote WW1 novels.
My favorite Hemingway quote, There is nothing noble in being superior to your fellow man; true nobility is having superior valve train geometry.
Ok, so it's been adapted,,,, lol
or Colonel Sanders
Great info! Too bad about the music
350 small block on gass re sserch
Whatstje best bildfor it
Very Basic and Misleading information , if you shorten your pushrods , you also increase your rocker angle that increases load in the stud and valve stem.
Try to listen
Monotone
The music is to keep u from falling asleep. 💤
cant hear you..... my comp sucks
good video but I can hardly here the man talking over that dam music turn off the music
Great info but that music sucks!
This is smoke and mirrors..... just get a 1.65 rocker and the correct length push rod to center the rub mark on the valve stem tip , in other words this guy is simply making a 1.6 of a rocker act like a 1.65 rocker at the cost of off centering the rub mark on the tip of the valve... this is very bad for valve guide to valve stem wear ! ( I bet if you call Crane cams and talk to a tech guy he will tell you the correct length pushrod will center the rub mark on valve tip )
ahhh i think the point here is how to bend the rules folks,clever old man,grey hair,but i bet he could make a "stock production motor go better than most of us.within in the rules.get it?
Engine Durability in a Race doesn’t matter if your in it to (win it )with making the engine have the horses 💥 power.... end of the day that’s what matter here according to the old timer ⏱
This is an engineering lesson.
Do you hear him tell us who he worked for ?
He doesn't get his info from Hot Rod Magazine.
Watch again.
And try to listen.
@@hotrodray6802 no, he's right. if this is for a racing engine then you won't be pushing stamped steel production rockers beyond their limits, you'll use the appropriate parts. for mild street use you can push stock parts a little, but it will stress the valve train more. simple fact.