Valvetrain noise

[70rrclone]

I have a noise in the valvetrain I can't find. I have the drivers side rockers off looking and noticed the exhaust valves have the roller markes a little below center and about .050 wide. The intake roller marks are all over the place. Looks like the intake valves are spinning. I'm running a comp xe285hl. .545lift 241 247. 1.6 mancini rockers (.581 lift). I have the correct comp springs for the cam. I have also checked the installed height. At about 2500 it has a higher pitched rattle.
What am I missing? Could the intake valves spinning cause a noise?

440
Trick flow 240 heads
Mancini rockers
Comp hyd cam and springs

 

[HEMI-ITIS]

That don't look kosher........

 

[69Bee]

The second pic shows what the valve tip looks like after it is ground and is normal. There are some lines and shadow which could be indicative of it spinning which also is normal. The first pic shows the roller valve tip contact position and could possibly use a 0.025" to 0.050" longer pushrod to bring the contact point closer to the center of the valve tip. This valve does not seem to be spinning as the roller/tip contact is making contact in one position. If the wear mark is a divot, it could create a clicking possibly.

 

[RemCharger]

The second pic shows what the valve tip looks like after it is ground and is normal. There are some lines and shadow which could be indicative of it spinning which also is normal. The first pic shows the roller valve tip contact position and could possibly use a 0.025" to 0.050" longer pushrod to bring the contact point closer to the center of the valve tip. This valve does not seem to be spinning as the roller/tip contact is making contact in one position. If the wear mark is a divot, it could create a clicking possibly.

How is a longer pushrod going to change the rocker to valve relationship. Without jacking up the rockershaft

 

[69Bee]

How is a longer pushrod going to change the rocker to valve relationship. Without jacking up the rockershaft

Being slightly longer, it will pull the contact point closer to the middle of the stem. If it is shorter, it will push it away from the center. If the contact point is too high, the pushrod needs to be shorter to push it closer to the center.

 

[RemCharger]

Being slightly longer, it will pull the contact point closer to the middle of the stem. If it is shorter, it will push it away from the center. If the contact point is too high, the pushrod needs to be shorter to push it closer to the center.

Ok. I can see the rockershaft going up/ down changing the relation. And if the valve side of the rocker was longer/ shorter changing the relation. But I'll have to take your word on how the rocker never moves, or changes, but the longer pushrod installed will change it.
I could understand that on a chevy

 

[dvw]

Puhrod length won't move the tip pattern on a fixed shaft rocker stem. The only way to do that is move the rocker pivot or find a rocker with a different shat to tio length. I'm not worried near about the tip being slightly inside. What does bother me is the pattern on the intake tip. The valve train isn't happy on the intake side.
Doug

 

[BSB67]

Puhrod length won't move the tip pattern on a fixed shaft rocker stem. The only way to do that is move the rocker pivot or find a rocker with a different shat to tio length. I'm not worried near about the tip being slightly inside. What does bother me is the pattern on the intake tip. The valve train isn't happy on the intake side.
Doug

This.

 

[69Bee]

I had it backwards, but the point I am making is that the contact point can be moved by lengthening or shortening the PR.​

​

ALIGNMENT​

Alignment of the rocker arm is extremely important, any deviation from the correct contact point of the valve stem can cause accelerated wear at best and component failure at worst. The contact point on the valve stem should begin toward the intake side of the cylinder head with the valve closed. As it starts to open, it should roll out past the center of the stem toward the exhaust side of the head at half lift and then from half lift to full lift it should return to it’s original starting point toward the intake side. The actual amount of tip travel across the valve stem in affected by the amount of lift at the valve but you want to make sure that all the travel is in the center of the valve stem and not biased to one side more than the other. An easy way to get a visual witness mark of the travel area is to color the valve stem tip with a sharpie, install the rocker with a checking spring in place, adjust it to zero lash and rotate the engine to completely cycle through an intake and exhaust event. When you remove the rocker, it will have rubbed the coloration off the tip and you will be able to see the travel distance and location. If the travel area is located too far toward the intake or exhaust side then you will need to adjust the push rod length accordingly. If it’s too far inboard, the push rod needs to be lengthened, if it is more to the outboard side it should be shortened. The other alignment location will be from the front to rear of the engine. The rocker contact point should be centered on the stem and this can be adjusted by locating the guide plate for proper alignment (adjustable plates are available if the standard guide doesn’t allow you to achieve correct alignment) and by using shims or offset rockers on shaft mount systems. On some shaft mount applications, an offset rocker must be used in order to get the correct location. This situation usually occurs when using cylinder heads with larger runner sizes or different valve spacing. Getting the alignments correct will provide better valve guide longevity and keep the rocker arms from damaging the valve tips.

 

[69Bee]

I digress, I am used to working with stud mounted rockers. ...On some shaft mount applications, an offset rocker must be used in order to get the correct location...

 

[snakeoil24]

Make life easy put lash caps on the stems

 

[dvw]

I had it backwards, but the point I am making is that the contact point can be moved by lengthening or shortening the PR.​

​

ALIGNMENT​

Alignment of the rocker arm is extremely important, any deviation from the correct contact point of the valve stem can cause accelerated wear at best and component failure at worst. The contact point on the valve stem should begin toward the intake side of the cylinder head with the valve closed. As it starts to open, it should roll out past the center of the stem toward the exhaust side of the head at half lift and then from half lift to full lift it should return to it’s original starting point toward the intake side. The actual amount of tip travel across the valve stem in affected by the amount of lift at the valve but you want to make sure that all the travel is in the center of the valve stem and not biased to one side more than the other. An easy way to get a visual witness mark of the travel area is to color the valve stem tip with a sharpie, install the rocker with a checking spring in place, adjust it to zero lash and rotate the engine to completely cycle through an intake and exhaust event. When you remove the rocker, it will have rubbed the coloration off the tip and you will be able to see the travel distance and location. If the travel area is located too far toward the intake or exhaust side then you will need to adjust the push rod length accordingly. If it’s too far inboard, the push rod needs to be lengthened, if it is more to the outboard side it should be shortened. The other alignment location will be from the front to rear of the engine. The rocker contact point should be centered on the stem and this can be adjusted by locating the guide plate for proper alignment (adjustable plates are available if the standard guide doesn’t allow you to achieve correct alignment) and by using shims or offset rockers on shaft mount systems. On some shaft mount applications, an offset rocker must be used in order to get the correct location. This situation usually occurs when using cylinder heads with larger runner sizes or different valve spacing. Getting the alignments correct will provide better valve guide longevity and keep the rocker arms from damaging the valve tips.

This is all a nice happy story written by someone who thinks they have a grasp on valvetrain reality. The first statement {quote] "any deviation from the correct contact point of the valve stem can cause accelerated wear at best and component failure at worst." is total BS. Tell me that moving the pressure point .050" or even .100" on a part that in no larger in diameter than .375" and 5"- 6" long is going to accelerate wear in the bore. Really? What kind of leverage do think that imparts in side load? The second statement [quote} The contact point on the valve stem should begin toward the intake side of the cylinder head with the valve closed. As it starts to open, it should roll out past the center of the stem toward the exhaust side of the head at half lift and then from half lift to full lift it should return to it’s original starting point toward the intake side. The actual amount of tip travel across the valve stem in affected by the amount of lift. This statement is what many adhere to. It is called mid lift geometry. It results in the smallest sweep across the tip. Many use it. It works pretty well. But is it gospel? No there are other things that come into play if the rocker arm geometry is varied from this statment Trust me, high end builders have ther own ideas what is best. As far as pushrod legth. Whoever wrote this is talking about rockers that are on a moveable pivot heigt, I.E. stud mounted rockers. Do this simple test. Bolt the rocker shaft and rocker to the head with no pushrod. Now show me how the rocker tip can be moved in relation to the valve stem. It can't. The position is a fixed length. Here is the bottom line with shaft rockers. To have mid lift geometry the centerline thru the rocker arm pivots has to be at 90 degrees to the valve stem. Lets take a stock head from Mopar. at the most factory cam lift was barely over .450". That means with the valve closed the rocker C/L and valve tip should be .225" higher than mid lift. This is basicaly how the head was designed. Now lets throw in a .600" lift cam. The rocker is still starting at the same point as with the .450" lift cam. But now at mid lift the valve is open to .300". This is way past the designed 90 degree height of .225". Is this geometry correct? Not if you follow the mid lift theroy. Will it function? Let me ask how many engines were built with .590 Purple shafts using ported 906 heads? Did they fail due to incorrect geometry, No. Could it be better, yes. The majority of shaft mounted rocker engines today are not anywhere near mid lift 90 degree geoetry. Yet there are thousands of them racing and running on the street. Where do you draw the line on perfection? Super Stock, Nascar, Formula 1? When you build and race your own stuff on a budget you learn whats important and whats not. And if you do it long enough you can build some pretty darn quick stuff that stays together for way less than others. My 2 cents.
Doug

 

[dvw]

Make life easy put lash caps on the stems

And that will help with what?
Doug

 

[BSB67]

This is all a nice happy story written by someone who thinks they have a grasp on valvetrain reality. The first statement {quote] "any deviation from the correct contact point of the valve stem can cause accelerated wear at best and component failure at worst." is total BS. Tell me that moving the pressure point .050" or even .100" on a part that in no larger in diameter than .375" and 5"- 6" long is going to accelerate wear in the bore. Really? What kind of leverage do think that imparts in side load? The second statement [quote} The contact point on the valve stem should begin toward the intake side of the cylinder head with the valve closed. As it starts to open, it should roll out past the center of the stem toward the exhaust side of the head at half lift and then from half lift to full lift it should return to it’s original starting point toward the intake side. The actual amount of tip travel across the valve stem in affected by the amount of lift. This statement is what many adhere to. It is called mid lift geometry. It results in the smallest sweep across the tip. Many use it. It works pretty well. But is it gospel? No there are other things that come into play if the rocker arm geometry is varied from this statment Trust me, high end builders have ther own ideas what is best. As far as pushrod legth. Whoever wrote this is talking about rockers that are on a moveable pivot heigt, I.E. stud mounted rockers. Do this simple test. Bolt the rocker shaft and rocker to the head with no pushrod. Now show me how the rocker tip can be moved in relation to the valve stem. It can't. The position is a fixed length. Here is the bottom line with shaft rockers. To have mid lift geometry the centerline thru the rocker arm pivots has to be at 90 degrees to the valve stem. Lets take a stock head from Mopar. at the most factory cam lift was barely over .450". That means with the valve closed the rocker C/L and valve tip should be .225" higher than mid lift. This is basicaly how the head was designed. Now lets throw in a .600" lift cam. The rocker is still starting at the same point as with the .450" lift cam. But now at mid lift the valve is open to .300". This is way past the designed 90 degree height of .225". Is this geometry correct? Not if you follow the mid lift theroy. Will it function? Let me ask how many engines were built with .590 Purple shafts using ported 906 heads? Did they fail due to incorrect geometry, No. Could it be better, yes. The majority of shaft mounted rocker engines today are not anywhere near mid lift 90 degree geoetry. Yet there are thousands of them racing and running on the street. Where do you draw the line on perfection? Super Stock, Nascar, Formula 1? When you build and race your own stuff on a budget you learn whats important and whats not. And if you do it long enough you can build some pretty darn quick stuff that stays together for way less than others. My 2 cents.
Doug

Thank you Doug.

The “perfect” rocker arm geometry and perfectly located contact patch has become an obsession completely disproportionate to its importance.

 

[RemCharger]

Thank you Doug.

The “perfect” rocker arm geometry and perfectly located contact patch has become an obsession completely disproportionate to its importance.

The theory is neat, at least about the valve acceleration curve. I went as far as mocking up the max wedge heads to see what it would look like but ,meh. The big deal is the diameter of the wheel changes the factory dimensions

 

[69Bee]

This is all a nice happy story written by someone who thinks they have a grasp on valvetrain reality. The first statement {quote] "any deviation from the correct contact point of the valve stem can cause accelerated wear at best and component failure at worst." is total BS. Tell me that moving the pressure point .050" or even .100" on a part that in no larger in diameter than .375" and 5"- 6" long is going to accelerate wear in the bore. Really? What kind of leverage do think that imparts in side load? The second statement [quote} The contact point on the valve stem should begin toward the intake side of the cylinder head with the valve closed. As it starts to open, it should roll out past the center of the stem toward the exhaust side of the head at half lift and then from half lift to full lift it should return to it’s original starting point toward the intake side. The actual amount of tip travel across the valve stem in affected by the amount of lift. This statement is what many adhere to. It is called mid lift geometry. It results in the smallest sweep across the tip. Many use it. It works pretty well. But is it gospel? No there are other things that come into play if the rocker arm geometry is varied from this statment Trust me, high end builders have ther own ideas what is best. As far as pushrod legth. Whoever wrote this is talking about rockers that are on a moveable pivot heigt, I.E. stud mounted rockers. Do this simple test. Bolt the rocker shaft and rocker to the head with no pushrod. Now show me how the rocker tip can be moved in relation to the valve stem. It can't. The position is a fixed length. Here is the bottom line with shaft rockers. To have mid lift geometry the centerline thru the rocker arm pivots has to be at 90 degrees to the valve stem. Lets take a stock head from Mopar. at the most factory cam lift was barely over .450". That means with the valve closed the rocker C/L and valve tip should be .225" higher than mid lift. This is basicaly how the head was designed. Now lets throw in a .600" lift cam. The rocker is still starting at the same point as with the .450" lift cam. But now at mid lift the valve is open to .300". This is way past the designed 90 degree height of .225". Is this geometry correct? Not if you follow the mid lift theroy. Will it function? Let me ask how many engines were built with .590 Purple shafts using ported 906 heads? Did they fail due to incorrect geometry, No. Could it be better, yes. The majority of shaft mounted rocker engines today are not anywhere near mid lift 90 degree geoetry. Yet there are thousands of them racing and running on the street. Where do you draw the line on perfection? Super Stock, Nascar, Formula 1? When you build and race your own stuff on a budget you learn whats important and whats not. And if you do it long enough you can build some pretty darn quick stuff that stays together for way less than others. My 2 cents.
Doug

Yes, it does cause accelerated wear, and if I had a nickel for every head with bronze guides that had too much clearance due to this problem... If you look at a service manual, they want you to use a toll to hold the valve off of the seat a certain distance and measure the axial play in the valve with a max of 0.017" movement. That measurement due to the moment arm of the valve is representative of approximately 0.003" of valve guide clearance. The same mechanical moment arm applies to the valve/rocker tip placement on the stem. The further away it is, the larger the moment are distance is and just like pistons and the thrust side of the cylinder, there will be accelerated wear in that guide. The best case is when the contact point is as close as possible, BUT there is a point of diminishing returns. You get it close with either 0.025" step PR's, or lower cost 0.050" step PR's. Also, in my post just after I posted this you quoted above, I cut and pasted the statement about the rocker shaft setup and said that I mostly deal with rocker stud setups.

 

[RemCharger]

Let me ask how many engines were built with .590 Purple shafts using ported 906 heads? Did they fail due to incorrect geometry, No. Could it be better, yes.

Have to remember a lot of the way back guys had iron rockers, which were designed to factory specs. But that's neither here nor there, the OP has heads on it designed for rollers, and an accepted rocker combo. Not alot to get excited over

 

[dvw]

Yes, it does cause accelerated wear, and if I had a nickel for every head with bronze guides that had too much clearance due to this problem... If you look at a service manual, they want you to use a toll to hold the valve off of the seat a certain distance and measure the axial play in the valve with a max of 0.017" movement. That measurement due to the moment arm of the valve is representative of approximately 0.003" of valve guide clearance. The same mechanical moment arm applies to the valve/rocker tip placement on the stem. The further away it is, the larger the moment are distance is and just like pistons and the thrust side of the cylinder, there will be accelerated wear in that guide. The best case is when the contact point is as close as possible, BUT there is a point of diminishing returns. You get it close with either 0.025" step PR's, or lower cost 0.050" step PR's. Also, in my post just after I posted this you quoted above, I cut and pasted the statement about the rocker shaft setup and said that I mostly deal with rocker stud setups.

By what criteria was the the guide wear determained to be caused by the pattern not being centered?. I've dialed bored more than a few that were finished poorly right off the bat. No way a bronze guide will provide the service life of an iron guide either.
Doug

 

[70rrclone]

So what I'm getting from all of this is.
My valvetrain is not happy and the geometry while not perfect is not the cause.

Any ideas on what it could be? Could it be an issue with the rockers?

 

[PRHeads]

Fast rate Hyd cams are often fairly noisy……nature of the beast.
The recommended spring for that cam(in a BB) is a Comp 924, which has a lower rate than any springs that come on TF heads.
Plus, Increasing the rocker ratio places higher demands on the springs.
The intake lobes on that cam are a fair amount more aggressive than the exhaust lobes.
Couple that with the fact that the intake valve is heavier than the exhaust, and it’s not surprising to me that the pattern shows some movement going on with the intake valves.

It also wouldn’t surprise me if that combo of parts starts getting unhappy before it got to 6k.

There is a recent youtoob video on the Powell machine website where they test a few cams in an LS.
Same everything except the cam.
There are several comments about how much mechanically noisier some of the cams were.