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?
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?
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.
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!
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
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. > 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. > 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. > 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. > 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".
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
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
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?
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 ⏱
@@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.
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.
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.
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.
