Roller rockers
Safety Car
Joined: Aug 2011
Posts: 4,447
Likes: 409
From: Portland OR
I was, correct.
I've had the stands and rockers off my turbo motor several times of late. I had to replace the head gaskets then do a retorque.
The stands are nice, but at the same time don't grab the trunion until you nearly have the bolt tight. You have to make sure the rocker is aligned before the final torque.
Thought I read once that Lingenfelter made precision steel stands.
Anyway, that Jessel rocker is to nice to put in an engine. :-) looks like artwork to me.
I've had the stands and rockers off my turbo motor several times of late. I had to replace the head gaskets then do a retorque.
The stands are nice, but at the same time don't grab the trunion until you nearly have the bolt tight. You have to make sure the rocker is aligned before the final torque.
Thought I read once that Lingenfelter made precision steel stands.
Anyway, that Jessel rocker is to nice to put in an engine. :-) looks like artwork to me.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Sorry about the rocker ****. 
LPE does make machined steel stands. And they can be milled to adjust rocker geometry if necessary. I looked into them when I was trying to get a good wipe out of my stock rockers, but I just couldn't come up with anything I was happy with so I went to the YT's. The wipe I achieved with them is 0.045" wide.
LPE does make machined steel stands. And they can be milled to adjust rocker geometry if necessary. I looked into them when I was trying to get a good wipe out of my stock rockers, but I just couldn't come up with anything I was happy with so I went to the YT's. The wipe I achieved with them is 0.045" wide.
Burning Brakes
Joined: Oct 2004
Posts: 984
Likes: 23
From: Florence SC
Not needed. The roller tips slide, they don't roll. The stock heads also have powder metal guides which won't wear like a bronze guide so the wipe pattern is less critical. The stock rockers are also very light requiring less valve spring to maintain valve control. Only time I would switch to a roller tip rocker is high valve lift from an aftermarket cam or aftermarket heads with bronze guides.
Well hundreds anyway...
Burning Brakes
Joined: Jun 2012
Posts: 803
Likes: 42
From: Destin Florida
In a recent issue of Hot rod magazine , they help out a C5 owner with long term problems on his boosted engine .
One of his problems was the added mass of roller rockers was limiting rev's high in his power band. They go through the guys valve train , you might find the article entertaining, I did. It restates what has been posted here, but with pictures and more story.
.
One of his problems was the added mass of roller rockers was limiting rev's high in his power band. They go through the guys valve train , you might find the article entertaining, I did. It restates what has been posted here, but with pictures and more story.
.
I had the same issue on an 02 SS with Harland Sharp roller rockers. Alan Futral was tuning it back in the day and actually asked me did I have roller rockers on it because of the way it fell off over 6K. Because it was a group dyno tune day I had time to replace with stock rockers and it picked up hp at a higher peak rpm.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Really? Where did you get this information? I've seen thousands of roller rockers (off of drag cars and round track), I've never seen one that showed signs of the roller tip sliding. Not being critical here just looking for some conclusive evidence. Please show some documentation.
Well hundreds anyway...
Well hundreds anyway...
Roller tips become a necessity when you have an aluminum rocker to provide a hardened contact point to transfer the rocker motion to the valve stem motion. Not truly required with a steel rocker, although it can aid in obtaining a more optimized wipe pattern.
Burning Brakes
Joined: Oct 2004
Posts: 984
Likes: 23
From: Florence SC
David Vizard discusses this in some of his writings and I have read similar findings in other places as well, but John Lingenfelter states in one of his books: "Roller rockers have become more affordable and popular but there are few misconceptions about roller rockers that should be addressed. Perhaps the most misunderstood point is that the roller tip actually rolls across the valve stem tip. This is not true. Even though the roller will spin easily between your fingers, once loaded against the valve spring pressure the roller merely slide across the valve stem."
Roller tips become a necessity when you have an aluminum rocker to provide a hardened contact point to transfer the rocker motion to the valve stem motion. Not truly required with a steel rocker, although it can aid in obtaining a more optimized wipe pattern.
Roller tips become a necessity when you have an aluminum rocker to provide a hardened contact point to transfer the rocker motion to the valve stem motion. Not truly required with a steel rocker, although it can aid in obtaining a more optimized wipe pattern.
Believe it or not, even to this day, people think that the roller tip is for rolling on the valve. It is NOT. The roller tip is for one reason only, and that is to convert the shifting length of the rocker’s arc (that moves across the valve on a shoe design), to a fixed length that moves far less in its effect, because it is always point down in line with the valve’s motion, just as a roller tappet of a cam is always aiming its contact tangent line with the axis of the camshaft.
That doesn't mean the roller slides across the valve stem, it articulates, at least the way I read it. I'm not smart enough to debate any of these rocker arm issues, I just read and wish I could be involved in the testing these smart guys have done. John Lingenfelter is a smart guy also I expect he got some education from Jim Miller somewhere along the line.
Read some of this when you have time and keep a open mind.
http://www.aera.org/engine-professio...cker-geometry/
Rocker arms always open a can of worms with me, I used one of those little Moroso plastic jobs to set pushrod length on my 408 bracket motor years ago. I feel so stupid after reading Jim's articals. I've read his stuff so many times its starting to make since.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The roller tip contains a roller, needle bearings and a shaft. All I can think of is,, If the roller doesnt roll, the shaft inside the roller has to rotate in the bearing.
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Team Owner
Joined: May 2001
Posts: 87,334
Likes: 1,589
From: Western NY
I'll take a SWAG (scientific, wild-azzed guess) and say that the point load of the roller against the valve tip fatigued the axle, and it snapped.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
OK, Well Jim Miller explains it this way:
Read some of this when you have time and keep a open mind.
http://www.aera.org/engine-professio...cker-geometry/
Rocker arms always open a can of worms with me, I used one of those little Moroso plastic jobs to set pushrod length on my 408 bracket motor years ago. I feel so stupid after reading Jim's articals. I've read his stuff so many times its starting to make since.
Read some of this when you have time and keep a open mind.
http://www.aera.org/engine-professio...cker-geometry/
Rocker arms always open a can of worms with me, I used one of those little Moroso plastic jobs to set pushrod length on my 408 bracket motor years ago. I feel so stupid after reading Jim's articals. I've read his stuff so many times its starting to make since.
Safety Car
Joined: Aug 2011
Posts: 4,447
Likes: 409
From: Portland OR
Le Mans Master
Joined: Dec 2005
Posts: 8,475
Likes: 332
From: Port Arthur, Texas 77642
Comp makes a steel rocker that has been "lightened" up a bit with roller tip. With that said, I removed my YT-6645's in favor of new factory rockers with trunion upgrade installed from Texas Speed...$145.00/set of 16 I believe.
Below are the Comp "Ultra Pro Magnum" in 8650 chromemoly steel, very nice looking pieces. The roller tips do not have bearings of any kind.
http://www.compcams.com/Products/CC-...rs'-0.aspx
Below are the Comp "Ultra Pro Magnum" in 8650 chromemoly steel, very nice looking pieces. The roller tips do not have bearings of any kind.
http://www.compcams.com/Products/CC-...rs'-0.aspx
Le Mans Master
Joined: Dec 2005
Posts: 8,475
Likes: 332
From: Port Arthur, Texas 77642
Merely pointing out a lightweight chromemoly steel unit with good "arm design" as compared to the aluminum offerings. Surprised that Comp does not make these in 1.7's......yet
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I think if they made a similar design that mounts like stock in the 1.7 stock ratio that they would be a big seller. Not sure why they went 1.8 since most LSx owners shy away from the higher ratio rocker arms. Just doesn't seem like a brilliant business move.
Melting Slicks
Joined: Jul 2004
Posts: 3,092
Likes: 120
From: orlando florida
St. Jude Donor '15
love the 1.8 ratio. Still have to use stock stands.
Maybe they are following gm with their move to 1.8 in the ls7 motors.
Maybe they are following gm with their move to 1.8 in the ls7 motors.
Last edited by mrr23; Aug 19, 2014 at 08:53 AM.
Safety Car
Joined: Aug 2011
Posts: 4,447
Likes: 409
From: Portland OR
It would be a good question to ask Comp.
Cams are pretty much designed around the rocker ratio. So if you knew you were using 1.8 rockers up front, you would pick the cam accordingly.
For most of us who already have a cam installed, the extra lift just might run the valves into the peestons.
Cams are pretty much designed around the rocker ratio. So if you knew you were using 1.8 rockers up front, you would pick the cam accordingly.
For most of us who already have a cam installed, the extra lift just might run the valves into the peestons.
Melting Slicks
Joined: Jul 2004
Posts: 3,092
Likes: 120
From: orlando florida
St. Jude Donor '15
When going to a higher ratio rocker, it also slightly changes the duration as well. This is because it opens the valve sooner and closes later. How much it changes depends on rocker design.
It is best to check your piston to valve clearance when going to a higher ratio rocker if you have an aftermarket cam. Talk with your cam manufacturer and/or engine builder.
It is best to check your piston to valve clearance when going to a higher ratio rocker if you have an aftermarket cam. Talk with your cam manufacturer and/or engine builder.