Why Roller Rockers....
#21
02-19-2019, 04:39 PM
Road Master
S&S rocker arms
S&S / Geo Smith has built a very successful business reengineering Moco's various design shortcomings. I won't say all of his
stuff is perfect but when I go aftermarket he's my first choice. An engine's valve train design and modification has been played
with for over a hundred years and it's still going on. Valve, lifter/follower, spring and pushrods / rocker arms when used been
designed over and over for various engine applications. Often aftermarket parts are actually inferior just using sales gimmicks to
pedal their product - something most of us have experienced. As for roller tip rocker arms they tend to bridge a geometric gap
between stock design parameters and those created using aftermarket camshafts etc. Racing engines designed from scratch
rarely use roller rockers as they don't offer any advantage. Observe the videos below of both a Chevy and a Toyota racing
engine on a Spintron machine used to analyze the valve at high rpm. The last video has a custom built engine using roller tip
rockers; keep in mind that the tip would not be turning if no side load was present.
Toyota -
Roller tip
stuff is perfect but when I go aftermarket he's my first choice. An engine's valve train design and modification has been played
with for over a hundred years and it's still going on. Valve, lifter/follower, spring and pushrods / rocker arms when used been
designed over and over for various engine applications. Often aftermarket parts are actually inferior just using sales gimmicks to
pedal their product - something most of us have experienced. As for roller tip rocker arms they tend to bridge a geometric gap
between stock design parameters and those created using aftermarket camshafts etc. Racing engines designed from scratch
rarely use roller rockers as they don't offer any advantage. Observe the videos below of both a Chevy and a Toyota racing
engine on a Spintron machine used to analyze the valve at high rpm. The last video has a custom built engine using roller tip
rockers; keep in mind that the tip would not be turning if no side load was present.
Toyota -
#22
02-19-2019, 05:47 PM
Seasoned HDF Member
ok I did not read this but will put my 2 cense in - at 1/2 cam lift and center of the roller has to be -- has to be in the center of the valve and this is done by adjusting the push rod length ( no special magic valve adjustment will do what the push rod length can do ) - a dial indicator is used to adjust the solid lifters - the engine benefits the most when using roller tips - and the cam valve adjustment comes into play - reason for the dial gauge to adjust the valve clearance - you need this part to be exact
motorcycle engines don't really have a benefit using a hydraulic roller camshaft - its an after sell to generate more things to sell - most guys are running way to hi valve spring pressure and the guides wear right out because of the incorrect way they the roller rockers are always installed
what happens is the center of the valve is the focal point @ 1/2 cam lift so the rockers roller tip is starting at the same spot on the top of the valve stem and ending on the other side of the valve stem in the exact spot other side of the valve stem - if this is not followed the valve stems roller will favor one side of the valve stem top and wear the valve guide out on the opposite side bottom in the port area and this wallows the valve seat out -- ect ect ect - its not a play for a street bike anyway
motorcycle engines don't really have a benefit using a hydraulic roller camshaft - its an after sell to generate more things to sell - most guys are running way to hi valve spring pressure and the guides wear right out because of the incorrect way they the roller rockers are always installed
what happens is the center of the valve is the focal point @ 1/2 cam lift so the rockers roller tip is starting at the same spot on the top of the valve stem and ending on the other side of the valve stem in the exact spot other side of the valve stem - if this is not followed the valve stems roller will favor one side of the valve stem top and wear the valve guide out on the opposite side bottom in the port area and this wallows the valve seat out -- ect ect ect - its not a play for a street bike anyway
#23
02-19-2019, 08:09 PM
S&S / Geo Smith has built a very successful business reengineering Moco's various design shortcomings. I won't say all of his
stuff is perfect but when I go aftermarket he's my first choice. An engine's valve train design and modification has been played
with for over a hundred years and it's still going on. Valve, lifter/follower, spring and pushrods / rocker arms when used been
designed over and over for various engine applications. Often aftermarket parts are actually inferior just using sales gimmicks to
pedal their product - something most of us have experienced. As for roller tip rocker arms they tend to bridge a geometric gap
between stock design parameters and those created using aftermarket camshafts etc. Racing engines designed from scratch
rarely use roller rockers as they don't offer any advantage. Observe the videos below of both a Chevy and a Toyota racing
engine on a Spintron machine used to analyze the valve at high rpm. The last video has a custom built engine using roller tip
rockers; keep in mind that the tip would not be turning if no side load was present.
https://www.youtube.com/watch?time_c...&v=dlkdCvnFwK0
Toyota - https://www.youtube.com/watch?v=a-fs8CFnZ_g
https://www.youtube.com/watch?v=WtqDHJDN79w Roller tip
stuff is perfect but when I go aftermarket he's my first choice. An engine's valve train design and modification has been played
with for over a hundred years and it's still going on. Valve, lifter/follower, spring and pushrods / rocker arms when used been
designed over and over for various engine applications. Often aftermarket parts are actually inferior just using sales gimmicks to
pedal their product - something most of us have experienced. As for roller tip rocker arms they tend to bridge a geometric gap
between stock design parameters and those created using aftermarket camshafts etc. Racing engines designed from scratch
rarely use roller rockers as they don't offer any advantage. Observe the videos below of both a Chevy and a Toyota racing
engine on a Spintron machine used to analyze the valve at high rpm. The last video has a custom built engine using roller tip
rockers; keep in mind that the tip would not be turning if no side load was present.
https://www.youtube.com/watch?time_c...&v=dlkdCvnFwK0
Toyota - https://www.youtube.com/watch?v=a-fs8CFnZ_g
https://www.youtube.com/watch?v=WtqDHJDN79w Roller tip
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tar_snake (02-20-2019)
#24
02-19-2019, 10:50 PM
Banned
The center of the valve is not Est by pushrod length.
It is dictated by the fulcrum or axis location, and the rocker ratio (roller to CL of the axis.)
We can't randomly start installing longer and shorter pushrods.
The Hyd lifter will compensate some but in the end we are at the same spot as the valve has to be closed for some of the duration.
It is dictated by the fulcrum or axis location, and the rocker ratio (roller to CL of the axis.)
We can't randomly start installing longer and shorter pushrods.
The Hyd lifter will compensate some but in the end we are at the same spot as the valve has to be closed for some of the duration.
Last edited by Kingglide549; 02-19-2019 at 10:54 PM.
#25
02-20-2019, 06:58 AM
Seasoned HDF Member
The center of the valve is not Est by pushrod length.
It is dictated by the fulcrum or axis location, and the rocker ratio (roller to CL of the axis.)
We can't randomly start installing longer and shorter pushrods.
The Hyd lifter will compensate some but in the end we are at the same spot as the valve has to be closed for some of the duration.
It is dictated by the fulcrum or axis location, and the rocker ratio (roller to CL of the axis.)
We can't randomly start installing longer and shorter pushrods.
The Hyd lifter will compensate some but in the end we are at the same spot as the valve has to be closed for some of the duration.
my guess you have not been involved in blueprinting a real race engine and that's ok - or you would have seen what I posted as correct as the engineering in location of the rocker to valve center geometry - the rocker axis is the offset in its ratio like 1.625 evo 1.43 shovel - 1.5 - SBC and a ratio change - changes the start and end point location on the valve tip - How do you propose you would correct that with out changing the pushrod length @ 1/2 cam lift and I was talking solid lifter you did not see that part ???
#26
02-20-2019, 07:08 AM
The center of the valve is not Est by pushrod length.
It is dictated by the fulcrum or axis location, and the rocker ratio (roller to CL of the axis.)
We can't randomly start installing longer and shorter pushrods.
The Hyd lifter will compensate some but in the end we are at the same spot as the valve has to be closed for some of the duration.
It is dictated by the fulcrum or axis location, and the rocker ratio (roller to CL of the axis.)
We can't randomly start installing longer and shorter pushrods.
The Hyd lifter will compensate some but in the end we are at the same spot as the valve has to be closed for some of the duration.
In theory he’s exactly correct. If you cross section a valve and rocker horizontally and watch the angle of incidence on the valve stem as the rocker actuates thru it’s stroke, the middle of the cam lift should put the rocker pressure vector on the valve stem exactly in line with the direction the valve is going. On cars, yea you can adjust the “effective stroke” of a rocker by simply elevating the rocker away from the head. It’s all based on the pivot point and of the rocker. That’s fixed on Harleys by a big 1/2” pin holding the damn thing in place.
I dont know that that anyone’s actually measured it on a Harley either.
#27
02-20-2019, 07:09 AM
Banned
perhaps you should have googled the concept and correct assembly of correctly establishing the location of the relationship of the camshaft @ 1/2 lift and valves rocker tip location ie pushrod length adjusting - and maybe you missed what I said about selling the idea not the function - hydraulic lifters only compensate for noise and maintenance nothing else
my guess you have not been involved in blueprinting a real race engine and that's ok - or you would have seen what I posted as correct as the engineering in location of the rocker to valve center geometry - the rocker axis is the offset in its ratio like 1.625 evo 1.43 shovel - 1.5 - SBC and a ratio change - changes the start and end point location on the valve tip - How do you propose you would correct that with out changing the pushrod length @ 1/2 cam lift and I was talking solid lifter you did not see that part ???
my guess you have not been involved in blueprinting a real race engine and that's ok - or you would have seen what I posted as correct as the engineering in location of the rocker to valve center geometry - the rocker axis is the offset in its ratio like 1.625 evo 1.43 shovel - 1.5 - SBC and a ratio change - changes the start and end point location on the valve tip - How do you propose you would correct that with out changing the pushrod length @ 1/2 cam lift and I was talking solid lifter you did not see that part ???
Speed reading again -
I missed that part in the thread somewhere -It looked like you inferred the
the geometry could be changed to the "correct point at 1/2, just by Pushrod length.
Beers.
Let me introduce to my 911 flat 6 sometime. (as for blueprinting )
Thanx for the insult, now you feel better?
#29
02-20-2019, 05:31 PM
Seasoned HDF Member
Sorry
Speed reading again -
I missed that part in the thread somewhere -It looked like you inferred the
the geometry could be changed to the "correct point at 1/2, just by Pushrod length.
Beers.
Let me introduce to my 911 flat 6 sometime. (as for blueprinting )
Thanx for the insult, now you feel better?
Speed reading again -
I missed that part in the thread somewhere -It looked like you inferred the
the geometry could be changed to the "correct point at 1/2, just by Pushrod length.
Beers.
Let me introduce to my 911 flat 6 sometime. (as for blueprinting )
Thanx for the insult, now you feel better?
BUT I guess you schooled me and I matters well throw the info I have saved and used for 50 years away --
quote -- I missed that part in the thread somewhere -It looked like you inferred the
the geometry could be changed to the "correct point at 1/2, just by Pushrod length.
and I got blamed for your speed reading as if I insulted you will know if I do and I don't think I did
