Roller rocker centered on the valve stem

[Cranky]

I did a ton of dyno testing with the TF240 heads when they first came out. We ran a bunch of different rocker arms and didn't see any difference in power. None of them had any real issues with rocker arm geometry. What you have is fine.

http://www.hotrod.com/articles/trying-find-extra-power-rocker-arm-testing/

Did you do any dyno testing between roller and non roller rockers? Over the years I haven't seen much if any real difference between them and am always interested in what others have done....

 

[BSB67]

Did you do any dyno testing between roller and non roller rockers? Over the years I haven't seen much if any real difference between them and am always interested in what others have done....

Track testing. 440 w/ hydraulic small cam - 400 hp-ish. Tested 1.5 ductile iron Cranes vs 1.6 Crane roller tip rockers. Controlling the track/weather/car variables the best I could, I could not find any difference. There might have been a few HP difference, you just could not find it with certainty in the time slip.

 

[Challenger340]

It is more a band aid solution to use lash caps, the position of the rocker shaft relative to the valve tip center and height is not correct.
Using a lash cap will cause the below angle between push rod and adjuster bolt to become worse, which is something you do not want as it increases side load.
More side load increases the chance of material failure.
Also you will loose valve lift as the side-movement increases and therefore the lift reduces.

That's the first time I have ever heard of a lash cap called a "band aid solution" ?
That's why they are available.... to correct Geometry and save V/Tips in extreme applications, we use them for both.
We use them all the time as insurance on Valve Tips with anything in excess of 550 Lb rate /Inch Roller Big Wedge/Hemi setups around 850-950 hp....
never had a problem ! nor with angularity/side loading or wear.
and most of our Engines we see back every 600-700 runs some going as far back as the early 1990's ?
NEVER had an Adjuster problem either using Lash caps.... because as we all know if you use the proper length pushrod there should only be MAX 1-1 1/2 threads showing below the Rocker anyway ? the thread pitch "root" being the weak point.

 

[Challenger340]

Well, perfectionist is a big statement..... I just went through all of it and its fresh at memory
I think it is $200 well spend on going with a B3 kit, if you change to roller tip rocker, you need to correct the rocker shaft position to the right place as the geometry changed a lot.

Adding a lash cap causes the rocker arm to face up more, and with that the angle between the adjuster and push rod becomes more "extreme".
The push rod starts to create a side load against the adjuster screw, there was a post not long ago here from someone who found a rocker cracked in half.
That was because the push rods were too short and had the adjuster screws sticking out too far, which causes the similar effect.[/QUOTE

Far too much Adjuster protruding out below the Rocker caused the Rocker failure..... NOTHING to do with anything "extreme" in Angularity.... that's just a bunch of nonsense same as your side-loading fantasy !
NOT the Lash Caps !
We probably already have at least 10 sets of PP240's with Harlands running on the street with lash caps.... NO PROBLEMS !
You can break any Adjuster and have all sorts of problems by having too much Adjuster sticking out below the Rocker.... MAX 1 to 1 1/2 threads and NO more, which is still plenty enough for Oil to get in the Cup and lubricate.

 

[Wietse]

Push rods. What I am finding is there is not an off the shelf push rod exactly what I need as it sits right now. There are some a touch short, leaving 3 threads showing under the arm. And some a bit long leaving almost no threads showing under the arm. Spec from HS is 0 to 2 threads showing. Am I better to get the longer ones or shorter ones or custom order?

If you are going to do something on the roller sweep you need to do that first before deciding what push rod length you require, push rods are the last piece to determine.
Get an adjustable pushrod and set it up that you can see only 1 thread showing of the adjuster screw and use the adjustable push rod to check what fits between.
If you have a dial gauge you can measure the valve lift at the spring retainer and try longer/shorter push rod setups and see what it does with your valve lift.
If the lift increases in a certain direction (longer/shorter push rod) keep adjusting in that way untill you find the spot where is max. lift. That point is best geometry.

Have a read:
http://www.hughesengines.com/Upload/productInstructions/HUG8220.pdf

@ Challenger340:

The reason you describe for using a lash cap is something i can understand, to protect the valve tip against wear.
And it can be used for that, fully agree on it.
But as long as the valve tip height, including lash cap is being used to setup the geometry that is not a problem.
But using a lash cap to compensate for a poor geometry setup i would call a band aid solution.
It only creates problems on the push rod side of the rocker arm.
When you step away from the OEM rockers and go for roller type the geometry is not what it should be, yes it will work in many cases but why take the risk not setting it right when building an expensive engine?
My engine ran for years without proper geometry, guess i was one of those lucky ones.

 

[Challenger340]

If you are going to do something on the roller sweep you need to do that first before deciding what push rod length you require, push rods are the last piece to determine.
Get an adjustable pushrod and set it up that you can see only 1 thread showing of the adjuster screw and use the adjustable push rod to check what fits between.
If you have a dial gauge you can measure the valve lift at the spring retainer and try longer/shorter push rod setups and see what it does with your valve lift.
If the lift increases in a certain direction (longer/shorter push rod) keep adjusting in that way untill you find the spot where is max. lift. That point is best geometry.

Have a read:
http://www.hughesengines.com/Upload/productInstructions/HUG8220.pdf

@ Challenger340:

The reason you describe for using a lash cap is something i can understand, to protect the valve tip against wear.
And it can be used for that, fully agree on it.
But as long as the valve tip height, including lash cap is being used to setup the geometry that is not a problem.
But using a lash cap to compensate for a poor geometry setup i would call a band aid solution.
It only creates problems on the push rod side of the rocker arm.
When you step away from the OEM rockers and go for roller type the geometry is not what it should be, yes it will work in many cases but why take the risk not setting it right when building an expensive engine?
My engine ran for years without proper geometry, guess i was one of those lucky ones.

Here is the problem with what's "out there" for common knowledge by DIY guys around Rocker Geometry.... NOT MUCH !
The race to the bottom as I call it knowledge-wise.... has digressed to the point that for simplicity for Manu's and DIY guys alike... the most common instructions are to:
* Take Felt Pen
* Paint Valve Tips with Felt Pen
* Install Rocker/Pushrod, etc
* roll over Valvetrain a few times
* remove Rockers/etc
* Inspect V/Tip for contact pattern in middle of V/Tip
That's IT.... THAT's ALL !
and it don't matter a Hill 'O beans if it's NOT quite "centered" and it ends up a little towards the Intake or the exhaust on the V/Tip.

And you know what ?
That's just all fine and dandy for the average dork running a Hyd F.T. Cam, a Solid F.T. Cam... even a mushy Hyd Roller Cam... NO PROBLEM, because the chances of that stuff hurting itself sub 350-400# V/Spring Pressures let be actually making any REAL Power and RPM's is pretty much NIL !

But just say'in....
there is a BIG difference between the above..... and REAL Rocker Geometry..... where Job #1 is to insure that the Rocker Trunion is never allowed to change direction mid-lift.... because if it does ? Under REAL V/Spring pressures and RPM's ?
THAT is a destructive Harmonic that busts Rockers/Lifters/you name it.... and causes V/Springs to GO AWAY as the slew rate gets frigged with !

 

[Challenger340]

If you are going to do something on the roller sweep you need to do that first before deciding what push rod length you require, push rods are the last piece to determine.
Get an adjustable pushrod and set it up that you can see only 1 thread showing of the adjuster screw and use the adjustable push rod to check what fits between.
If you have a dial gauge you can measure the valve lift at the spring retainer and try longer/shorter push rod setups and see what it does with your valve lift.
If the lift increases in a certain direction (longer/shorter push rod) keep adjusting in that way untill you find the spot where is max. lift. That point is best geometry.

Have a read:
http://www.hughesengines.com/Upload/productInstructions/HUG8220.pdf

@ Challenger340:

The reason you describe for using a lash cap is something i can understand, to protect the valve tip against wear.
And it can be used for that, fully agree on it.
But as long as the valve tip height, including lash cap is being used to setup the geometry that is not a problem.
But using a lash cap to compensate for a poor geometry setup i would call a band aid solution.
It only creates problems on the push rod side of the rocker arm.
When you step away from the OEM rockers and go for roller type the geometry is not what it should be, yes it will work in many cases but why take the risk not setting it right when building an expensive engine?
My engine ran for years without proper geometry, guess i was one of those lucky ones.

Here is the problem with what's "out there" for common knowledge by DIY guys around Rocker Geometry.... NOT MUCH !
The race to the bottom as I call it knowledge-wise.... has digressed to the point that for simplicity for Manu's and DIY guys alike... the most common instructions are to:
* Take Felt Pen
* Paint Valve Tips with Felt Pen
* Install Rocker/Pushrod, etc
* roll over Valvetrain a few times
* remove Rockers/etc
* Inspect V/Tip for contact pattern in middle of V/Tip
That's IT.... THAT's ALL !
and it don't matter a Hill 'O beans if it's NOT quite "centered" and it ends up a little towards the Intake or the exhaust on the V/Tip.

And you know what ?
That's just all fine and dandy for the average dork running a Hyd F.T. Cam, a Solid F.T. Cam... even a mushy Hyd Roller Cam or a wannabe "Street" Mech Roller Cam profile... NO PROBLEM, because the chances of that stuff hurting itself sub 350-400# V/Spring Pressures let be actually making any REAL Power and RPM's is pretty much NIL !

But just say'in....
there is a BIG difference between the above..... and REAL Rocker Geometry used on Race/REAL Roller Profiles..... where Job #1 is to insure that the Rocker Trunion is never allowed to change direction mid-lift.... because if it does ? Under REAL V/Spring pressures and RPM's ?
THAT is a destructive Harmonic that busts Rockers/Lifters/you name it.... and causes V/Springs to GO AWAY as the slew rate gets frigged with !
The REAL Geometry also works fine on the mushy Cams as well... but alas too much time/difficulty for the average DIY guy to pursue, and has been dropped like a lead fart off the knowledge base.

PS: The Adjuster/Pushrod angularity under the Rocker is NOT an issue when a Lash Cap is used to correct a V/Tip contact closer to the Exhaust side on the V/Tip, and as long as Adjuster threads exposed below the Rocker are 1 to 1 1/2 Threads only.

 

[dvw]

I laugh when I hear the the rocker not setting in the middle of the valve stem will wear the guide. Look at the guide length vs the rocker contact offset. How much leverage do you think that exerts? You know street/strip engines have been being built for years with little thought to valve tip contact. Amazing they actually ran fine. Now agreed when you get radical in cam and rpm there's a difference. As an example my race engine has paired T&D 1.7 rockers. The stands have been milled flat and moved slightly to the valve C/L. The mid lift geometry was spot on. But wait, my expensive Trend pushrods are too long. What to do? I shimmed the rocker bed plate .060" raising the rocker pivot. Before doing this a drawing was done in CAD showing the sweep across the valve. With the spacers the increase in sweep was .011". Its been running to 7200 for over 600 passes. Same guides and valve job. Doesnt hurt parts. So now we go back to a .550 cam in a street motor. Does it need to be perfect, nope.
Doug

 

[BSB67]

The Kool-aid drinking regarding what level of perfection is needed in rocker arm geometry, and the components of that geometry that are important is almost mind boggling. Never mind the billion miles traveled using roller tip rockers for the last 50 years. Never mind the race proven experience like Doug's.

Then you get the kool-aid drinkers with no experience telling people what they should or should not be doing.

If you want to spend money chasing after rocker arm geometry perfection that has no measurable value for 99% of the applications, go for it. But often times these same people are cutting corners in places that maybe they should not. Seems like very skewed priorities at times.

Ya gotta love the internet.

 

[Wietse]

I am not telling anyone what to do, that is all up to yourself bro's.
The OP is asking, i can tell what i did from my experience after asking people who know more than me.
If others have run engines as is for the last 50 years, be my guest and carry on.
It is either being stuck in stone age, or unwilling to admit they did not find room for improvement over the last 50 years themselves.
It is easy to stand on the side line and keep quiet and critisize what others are saying, no other solution or idea was mentioned and saying running a valve train as pictured below is normal for them...ok then.

For the OP, some reading material about the valve train geometry.
http://www.b3racingengines.com/techcorner.asp

 

[dvw]

What improvement would changing the geometry in the pictures make? Any power?Maybe the wallet of someone selling parts? The guy at the machine shop? A picture on a website? The people who have done things for years have a great advantage to learn from, experience with what works, and what doesn't. There are plenty of new ideas and products out there. The trick is which one is a good bang for the buck. Face it this is a hobby for most of us. And an expensive one for the average person. Read, learn, talk to others. Then make a decision. There's never been more available information than there is now. The trouble is decifering useful from not.
Doug

 

[Wietse]

Everyone shares their experience, and that is where forums like this are for.
I have just rectified the same finding on my engine, did the research and picked a side.
Being right, wrong or wasting money, who knows.
But to come around and start talking how people (like me) with no experience make issues out of things that are not a problem is IMO not a fair game.
I'll be quiet now and let the people with more experience do the talking here.

 

[dvw]

That far off-center will cause more wear on the valve guides.
The rocker shaft needs to move up and away from the valves.[/QUOTE

You made these statements. Have you seen or experienced measurable guide wear? How would adding valve lift want to make the rocker pivot go up? The rocker arm starts in the same relationship to the stem tip with with the valve closed. The stock cylinder head was designed around .400" valve lift. Though not exact for sake of math clarity I will use the .400" lift figure to illustrate. If the factory was concerned with geometry, the rocker C/L should be 90 degrees to the valve stem at .200" valve lift (50%) Now let's switch to .800" valve lift. Where does the rocker arm pivot move to maintain a 90 degree angle to the valve stem? It needs to go down, not up, as it is still 90 degrees to the stem a .200" lift. (25%).There is no mud slinging here, just information. What is your take on my math?
Doug

 

[Wietse]

To me it is quite clear that a rocker pushing on 1 side of a valve stem will cause (more) side load to the valve stem...which is retained by the valve guide...no science....just thinking.
The amount of increased wear and when this effect becomes a problem i don't know indeed.

It is not the valve lift that wants to make the rocker pivot point go up, it's because changing from stock stamped rockers to roller type rockers that causes the rocker pivot point to be raised.
The pivot point that once sat where the stamped rocker touches the valve stem tip has moved up to the shaft center of the roller.
Like my rocker roller is 0.500" diameter, so the pivot point went up 0.250" and that is what i compensated for when building it up again with the B3 kit.
The swap to roller rockers causes the sweep to increase and off center, that is what the OP questions.
Using the B3 kit is what the OP could do to get a reduced sweep pattern and be able to bring the sweep more centered.
Regarding increasing valve lift, the more lift the wider the sweep will become as the rocker arm is going to travel more along its radius.
And yes with the extreme lift of 0.800" the rocker shaft needs to be lowered, fully agree on that.

It's not the valve lift i am on about, just saying to people that change to roller rockers to use a B3 kit to get that sweep pattern more centered and narrowed.
It's up to everyone themselves, i can only tell i have seen a huge improvement after doing mine.

No mud slinging indeed Doug, but i wonder what other people think when start calling out names as average dorks that are not running high powered HP monsters and saying these people do not have the knowledge.
Just because saying a lash cap is a band aid for geometry, can someone then explain that when the angle between adjuster and push rod when becoming more extreme is not a waste of geometry?
Instead of just moving up and down with a small amount of side movement it needs to move much more side ways which is a loss of motion, thus poor geometry.
Just an explanation is all it takes.....

 

[wyrmrider]

roller tip rockers are a tremendous waste of money for most builds
I've repaired lots of motors where the needles got loose
just think about it
a .700 roller cocks the roller up .350 from where it should be when the valves closed
when the trunnion to roller center is perpendicular to the valve the tip is down .350 from where the cam designer designed his lobe for
and you are trying to go over the nose
give me a break

 

[Wietse]

I guess when they came out with roller rockers it was a **** hot item and everyone had to have them.
Maybe because of the claimed hp gain due to reduced friction between rocker tip and valve stem.

But seriously, if i had to rebuild an engine i am not sure now if i picked them over a set of new stock style.
I am just dealing with what the car came with.

Did any of these other head manufacturers (Edelbrock, Trick Flow, etc) ever changed anything on the rocker shaft location relative to the valves or something?
Or are they all a copy of original in that matter? Just curious.

 

[BSB67]

Ugh.

 

[dvw]

And here are many more theory's.

https://www.speed-talk.com/forum/vi...sid=9ed0ca112a6705c558db2992e02c1bd5&start=15

Read and enjoy.
Doug

 

[BSB67]

Nice to see pushrod side geometry included in a discussion. No small change in cup/ball load and angularity at max lift when spring pressure is the highest when you raise the shaft up 0.300".

Thanks for posting.

 

[66Satellite47]

I am not telling anyone what to do, that is all up to yourself bro's.
The OP is asking, i can tell what i did from my experience after asking people who know more than me.
If others have run engines as is for the last 50 years, be my guest and carry on.
It is either being stuck in stone age, or unwilling to admit they did not find room for improvement over the last 50 years themselves.
It is easy to stand on the side line and keep quiet and critisize what others are saying, no other solution or idea was mentioned and saying running a valve train as pictured below is normal for them...ok then.
View attachment 910863


For the OP, some reading material about the valve train geometry.
http://www.b3racingengines.com/techcorner.asp

As a "back yard" guy with a fair amount of experience, I found the B3 tech articles extremely informative. They in total, addressed the whole valve train picture. I have been guilty of looking at valvetrain only in slices. Much great information to process.