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Re: Rocker Geometry Measurements
[Re: AndyF]
#1524398
10/31/13 08:42 PM
10/31/13 08:42 PM
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Joined: Oct 2003
Posts: 7,506
Az
Crizila
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master
Joined: Oct 2003
Posts: 7,506
Az
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Quote:
Quote:
Brad I would like to see an engine with one theory applied on one head and the other theory on the other. Then check the lift at the valve to see which achieves the most lift at the valve. One thing for sure the set up that has the rocker 90 degrees in relation to the valve at mid lift will have the least amount of scrub.
Mid lift provides the least amount of scrub. Low point (2/3 lift) gives you the least amount of scrub under load. That is, the scrub occurs while the load is low and then when the load is high there is very little scrubbing action.
I think most of the serious valve train designers migrated to the low pivot point design a number of years back. The math is fairly complicated but if you put the rocker arm perpendicular to the valve stem at 2/3 lift you're in the ballpark. The scrub pattern is larger than with the mid-lift design, but the sideways force applied to the valve goes down.
 - try reading the book "Valve Gear design" by Michael Turkish, 1946, Eaton corporation. Turkish was a mathematician who worked for Eaton - and Eaton was a tier one supplier to GM - and probably a lot of other automotive OEM's. Yes, the math is well over my head, but pretty much as you alluded to verses the common 50/50 rocker arm arrangement ( 90* at mid lift) that most use today. My brother ( much smarter than I ) has done extensive research in this area also. I was able to grasp about 75% of what he sent me on the subject. Yes, it is a complicated subject and unfortunately, a lot that has been written about it has been written by people working for magazines trying to sell you a product ( those pretty gold anodized aluminum roller tip rocker arms with your initials stamped on them  ). So, since this thread has turned in to "who's the smartest", Could I see a show of hands of those with the title of "Mathematician".  - I won't be raising mine  .
Fastest 300
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Re: Rocker Geometry Measurements
[Re: AndyF]
#1524399
10/31/13 09:11 PM
10/31/13 09:11 PM
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Joined: Jan 2005
Posts: 12,423
Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
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Posts: 12,423
Kalispell Mt.
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The only math class I ever did good in was geometry so I can follow along with all the geometric theory part very well but still have a couple questions about the real world.
So is the effect of scrub really more important than valve lift/timing effects on the power/reliability of normal street/strip engines with roller rockers? Seems scrub would not be very important with a roller tip as it would be with a sliding type rocker tip, within reason of course.
Maybe say in a lift limited class where your valve opens to max lift for more than just a degree or two, would you want to set it up so it is perpendicular to the valve at max lift where the ratio is the highest?
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Rocker Geometry Measurements
[Re: cudaman1969]
#1524402
10/31/13 11:34 PM
10/31/13 11:34 PM
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Joined: Feb 2011
Posts: 4,302
Nebraska
72Swinger
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master
Joined: Feb 2011
Posts: 4,302
Nebraska
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Keep talking about it now that you run off the guy willing to give this thing a remedy. Contempt prior to conviction....
Mopar to the bone!!!
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Re: Rocker Geometry Measurements
[Re: HotRodDave]
#1524403
10/31/13 11:38 PM
10/31/13 11:38 PM
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Joined: Oct 2005
Posts: 8,906
Ontario, Canada
Stanton
Don't question me!
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Don't question me!
Joined: Oct 2005
Posts: 8,906
Ontario, Canada
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Quote:
Seems scrub would not be very important with a roller tip as it would be with a sliding type rocker tip, within reason of course.
Actually I think it would be the opposite. With a roller rocker the roller is round (obviously) and the pivot is fixed so you will definitely have scrub.
On the other hand a sliding type rocker could have its tip ground in an eccentric so that although there is still the friction, the contact point could be maintained at the very center of the valve tip. Never seen one like it but definitely a possibility!
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Re: Rocker Geometry Measurements
[Re: HotRodDave]
#1524404
11/01/13 12:56 AM
11/01/13 12:56 AM
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Joined: Nov 2003
Posts: 5,160
Texas
dannysbee
master
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master
Joined: Nov 2003
Posts: 5,160
Texas
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Dave with the rocker position you are suggesting the scrub would be double what it is with the rocker perpendicular to the valve at mid lift.
Getting old just means you were smarter than some and luckier than others.
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Re: Rocker Geometry Measurements
[Re: cudaman1969]
#1524405
11/01/13 12:29 PM
11/01/13 12:29 PM
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Joined: Nov 2004
Posts: 3,544
Syracuse,NY
CompWedgeEngines
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master
Joined: Nov 2004
Posts: 3,544
Syracuse,NY
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Although I can only understand about 10% of the 20 different simulations going on here....I am shocked now after reading this that anyones engines even make it safely down the track three times.....I think we are being " theorized" to death on this one. In my world....there is idealology....and reality.....I often choose only one.....please carry on....  and for the record, I do realize what the OP was trying to do, unfortunately the presentation fell short. He was addressing an issue that can be a problem for sure. Now how you handle it, thats a different cat to skin. My question would be, what is the IMMEDIATE catastrophic result of setting up a valvetrain with well known principles that work, with a realistic degree of engineering and geometry, that would be considered adequate?
RIP Monte Smith
Your work is a reflection of yourself, autograph it with quality.
WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.
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Re: Rocker Geometry Measurements
[Re: CompWedgeEngines]
#1524406
11/01/13 01:03 PM
11/01/13 01:03 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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... In my world....there is idealology....and reality.....I often choose only one...
I often get caught between the two (like an "Outer Limits" episode) and the end result is my junk never gets back together to see if I can even make those three passes down the track. 
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Re: Rocker Geometry Measurements
[Re: CompWedgeEngines]
#1524407
11/01/13 01:30 PM
11/01/13 01:30 PM
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Joined: Jan 2003
Posts: 5,875
communist bloc of new jersey
jamesc
master
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master
Joined: Jan 2003
Posts: 5,875
communist bloc of new jersey
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Quote:
Although I can only understand about 10% of the 20 different simulations going on here....I am shocked now after reading this that anyones engines even make it safely down the track three times.....I think we are being " theorized" to death on this one. In my world....there is idealology....and reality.....I often choose only one.....please carry on....
and for the record, I do realize what the OP was trying to do, unfortunately the presentation fell short. He was addressing an issue that can be a problem for sure. Now how you handle it, thats a different cat to skin.
My question would be, what is the IMMEDIATE catastrophic result of setting up a valvetrain with well known principles that work, with a realistic degree of engineering and geometry, that would be considered adequate?
agreed especially the last paragraph and was my basic point when i commented on another thread. does it make a difference, yes but unless something is out in left field there are bigger concerns. i've said it before personally i think people get carried away with the whole valve train geometry thing. unless it's completely wacked i would focus more effort on other aspects of the engine but that's just me
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Re: Rocker Geometry Measurements
[Re: BradH]
#1524408
11/01/13 01:37 PM
11/01/13 01:37 PM
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Joined: Jan 2004
Posts: 13,247
Mt. Vernon, Ohio
dartman366
I Live Here
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I Live Here
Joined: Jan 2004
Posts: 13,247
Mt. Vernon, Ohio
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I have been reading this post and remembering the day in which my engine builder explained all the rocker geometry stuff to me. thats why I have not gotten into the mix of opinions that seem's to have gotten a little out of hand at times, seems like some feel the op has some ulterior motive here, I see it as he has a service to offer and it isn't free as there is no free lunch,,he may of come off as a little defensive but after being on this site for the time I have, you learn to be a little thick skinned,it also seems to me that anyone that gets on this site that knows anything ends up getting critiqued to death and some just decide to leave so not to deal with it,,,I don't blame the OP but his presentation may of been a little brash for some, the rest of us just overlook that trait and move on. 
Light travels faster than the speed of sound,,,this is why some people seem bright untill you hear them speak.
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Re: Rocker Geometry Measurements
[Re: dannysbee]
#1524410
11/01/13 02:28 PM
11/01/13 02:28 PM
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Joined: Nov 2004
Posts: 3,544
Syracuse,NY
CompWedgeEngines
master
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master
Joined: Nov 2004
Posts: 3,544
Syracuse,NY
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Understand 100% Danny. Nothing wrong with that at all.
it really all comes downt o how much time and money someone is willing to spend to " fix" their issue. Everyone will accept a different level of " right". Thats why my last paragraph.
I just did a 500" BBC and it had ProComp heads. To do them right, I would have had to start all over, re-machine the pads, reset the angles, and techinically re-locate the rocker stud locations, if I wanted it to be " right".As it was I had to play around and get Dart psuhrod guides and change a few other things to get them useable. There is no way in he** a guy with Pro Comp heads is going to spend that money for his street car. A Pro Comp head is like a all out race head, in the fact that nothing fits....lol...so there we have it, a cheap offshore head, vs a high dollar aftermarket race head. At times, there is no difference.They both need work.Heck, most of the Chevy guys think valve train " geometry" is just selecting the proper length pushrod!~
Most guys are fine with what I stated at the end of my other post. Good mechanical skills and reference to accepted standards will work for most everyone.
I like to refer to the old W2 offset rocker stands and offset rocker shafts to remember, people have been trying to adress this in Mopar sfor a very very long time. Milling the rocker support pads and starting with a new square block of aluminum works pretty well.When you think of it, thats all very simple math. All of this changes based on the rocker centerline to roller tip. Then add the height of a taller valve...it goes on and on. Go back to the accepted prinicpals I spoke of , and they all work, and dont wear out parts at a alarming rate, at least that I have every expierenced.
RIP Monte Smith
Your work is a reflection of yourself, autograph it with quality.
WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.
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Re: Rocker Geometry Measurements
[Re: AndyF]
#1524411
11/01/13 02:32 PM
11/01/13 02:32 PM
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Joined: Nov 2003
Posts: 1,664
North Sweden
RT540
top fuel
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top fuel
Joined: Nov 2003
Posts: 1,664
North Sweden
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Quote:
Quote:
Maybe some of you guys should look at that guys kit, it moves the shaft up to correct geometry and back to center the contact patch, the only compromise I see is the PR geometry will get worse, not a big deal on a BB but a SB is already bad. Of course a W2 is worstest yet and they can rev good so 
The CAD drawings I've done say the shaft has to move down to correct geometry with a high lift cam. Moving the shaft up makes things worse on every simulation that I've run.
If you have a perfect sweep with a .600 lift cam, and then change to a .800 lift cam, the wheel will move closer to the rocker shaft at full lift.
I agree, the shaft needs to go down. I moved my T&D 1.8 sep. shaft setup down 1.2mm and still got more scrub after the wheel starts to roll back( against the rockers shafts).
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Re: Rocker Geometry Measurements
[Re: RT540]
#1524412
11/01/13 02:55 PM
11/01/13 02:55 PM
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Joined: Jan 2004
Posts: 13,247
Mt. Vernon, Ohio
dartman366
I Live Here
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I Live Here
Joined: Jan 2004
Posts: 13,247
Mt. Vernon, Ohio
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Quote:
Quote:
Quote:
Maybe some of you guys should look at that guys kit, it moves the shaft up to correct geometry and back to center the contact patch, the only compromise I see is the PR geometry will get worse, not a big deal on a BB but a SB is already bad. Of course a W2 is worstest yet and they can rev good so
The CAD drawings I've done say the shaft has to move down to correct geometry with a high lift cam. Moving the shaft up makes things worse on every simulation that I've run.
If you have a perfect sweep with a .600 lift cam, and then change to a .800 lift cam, the wheel will move closer to the rocker shaft at full lift.
I agree, the shaft needs to go down. I moved my T&D 1.8 sep. shaft setup down 1.2mm and still got more scrub after the wheel starts to roll back( against the rockers shafts).
I know when I went to the TD rockers they sent a gage to set my rocker stand height, they will also tell you that X amount lower or higher lift then you correct height by a determined amount, my machinist went by this system and the geometry was spot on, now this is on the paired rocker system that uses the mounting bar that is bolted to the head's 
Light travels faster than the speed of sound,,,this is why some people seem bright untill you hear them speak.
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Re: Rocker Geometry Measurements
[Re: dartman366]
#1524413
11/01/13 07:13 PM
11/01/13 07:13 PM
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Joined: Jul 2013
Posts: 561
USA
B3RE
OP
mopar
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OP
mopar
Joined: Jul 2013
Posts: 561
USA
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I'm Baaaaaack! Hoohooaahaahaah! Ok, now I'm serious again. First, I would like to apologize to anyone who thought I came across with an attitude. I certainly didn't want to anger anyone, although I admit, when the name calling started, my dander started to "get up". I'll try not to let it get to me anymore.  I don't have a lot of time to spend on the forum, so unfortunately I don't know all of the rules for posting. This post was meant to provide information requested by members from other threads I posted on, discussing valvetrain geometry. It was NOT meant to be a sales pitch to anyone. I did ask a moderator how to post on New Products, once the "pup" (as my daughter says it) hit the fan, but I have yet to get a response. I was thinking the post wouldn't get any responses and some members might miss it so I contacted each one personally to let them know I posted the info. Whew, I never expected it to turn into a roast, 'specially since I'm no celebrity.  I will go through the thread post by post and try to answer evryone's questions and concerns as best I can. If I start getting a 'tude, somebody give me an emoticon backhand.  Thanks,
Mike Beachel
I didn't write the rules of math nor create the laws of physics, I am just bound by them.
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Re: Rocker Geometry Measurements
[Re: B3RE]
#1524414
11/01/13 07:22 PM
11/01/13 07:22 PM
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Joined: Nov 2004
Posts: 3,544
Syracuse,NY
CompWedgeEngines
master
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master
Joined: Nov 2004
Posts: 3,544
Syracuse,NY
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Mike, Just one thing....if you and Quicktree DO go on a date, make sure he pays.Last time , he did the old, " must have left my wallet in my other pants" thing to me, and then proceeded to " run out of gas" on the way home.....after a long night, he left me cold, shaken , and emotionally tattered.... .....he screamed something to me as he drove away....all I could make out was something about some pinhead angle or something like that....maybe it was pinion...I dunno.. Disclaimer: This is a valid attempt to inject some mild humor into a thread that has gone horribly awry. These are not the comments nor an official statement from the site, the owner or any of its affiliates. While reading this, or any other thread on Moparts' Unlawful Racing section, please remember to drink responsibly.
RIP Monte Smith
Your work is a reflection of yourself, autograph it with quality.
WD for Diamond Pistons,Sidewinder cylinder heads, Wiseco, K1 rods and cranks,BAM lifters, Morel lifters, Molnar Technologies, Harland Sharp, Pro Gear, Cometic, King Engine Bearings and many others.
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