Shaft mount rockers
05-27-2007, 03:20 PM
#1
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Shaft mount rockers
Im trying to figure out if there is a quality difference between shaft mount rockers for us. Ive seen several brands all $800+ which Ive come to live with and expected. I know Jesell makes a good rocker, what about cranes and comp?. Is there a certain lift where shaft mounts are a must, the max lift on the cam is .615 lift.SR
Last edited by MEAN LT1; 05-27-2007 at 03:24 PM.
05-27-2007, 06:41 PM
#2
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I'm also interested in the new shaft rocker assemblies, but don’t have any knowledge about them. I was wondering if the heads (GM or aftermarket. i.e., ARFs) require any machine work to install the shaft assemblies?
WD
WD
05-27-2007, 07:27 PM
#3
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In my experience you would need a much more radical cam than is usally seen on LT1's to warrant shaft mounts. A good set of 7/16" rocker studs and high quality rocker arms is going to be fine in almost all cases with perhaps a stud girdle as the most logical upgrade. There are no hard and fast rules. I'd start thinking of shafts in the 0.700-0.750"+ lift range with seat pressures of 250+lbs. I run a cam with ~0.700" lift and 225lbs on the seat in my BBC race motor with a stud girdle and have no issues with valve train stability up to 7,500rpm.
Rich
Rich
05-27-2007, 07:39 PM
#4
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i thought the same exact thing Rich,till i saw the difference on the dyno,apparently the 3/8 and the 7/16 studs do flex a great deal it was enough for a 30hp gain when switched to the jesel shaft mounts.
they do cost alot (800.00 +/-) but when you figure how much a set of good rockers are,good studs you are already 1/2 way there(almost)i saw TD has a set of shaft mounts also but i saw no price.
600*of lift,solid roller i would buy shaft mounts
they do cost alot (800.00 +/-) but when you figure how much a set of good rockers are,good studs you are already 1/2 way there(almost)i saw TD has a set of shaft mounts also but i saw no price.
600*of lift,solid roller i would buy shaft mounts
05-27-2007, 08:31 PM
#5
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Location: Rich, Va.
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I found a set of the Jesel Sportsman Series on Ebay for right around 600, sold all my other stuff (Rockers, Gudies, Pushrods) for about 300
They bolt right on to my LT4 heads, I had to purchase new pushrods
A little overkill for what I have, but may be a benefit in the future if I decide to go with a larger cam (around 600 lift now)
The car is a bracket racer, so I was looking at the durability of a shaft sytem also
They bolt right on to my LT4 heads, I had to purchase new pushrods
A little overkill for what I have, but may be a benefit in the future if I decide to go with a larger cam (around 600 lift now)
The car is a bracket racer, so I was looking at the durability of a shaft sytem also
05-28-2007, 12:09 AM
#6
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I have Jessel SS shaft mounts on mine. TFS heads and a Cam motion SR with .686" lift. The rockers are pretty nice. I have no complaints about them so far but I havent fired the motor yet. Jessel gived you everything you need to install them. You can not run head studs in the center holes with them but the supplied bolts from Jesel are just fine. I run studs on the motor and just used the bolts under the rocker stands instead of studs.
05-28-2007, 08:41 PM
#7
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Interesting to look at what the LS7 uses, and doesn't use to achieve an unheard of level of rpm, hp, and hp/ci in a production OHV motor. One would assume that the choices were based on cost effectiveness. They include a "conventional" stud mount rocker system (with light roller rockers). A lot of effort obviously went into making the valvetrain stiff and light. In spite of some very exotic parts, no shaft rockers. One would do well to look closely at those choices and design philosophy.
One specific thing about the valvetrain intrigues me. Ti springs with steel retainers. Opposite of what is done and generally available in the aftermarket.
Hmmm.
Rich
One specific thing about the valvetrain intrigues me. Ti springs with steel retainers. Opposite of what is done and generally available in the aftermarket.
Hmmm.
Rich
05-29-2007, 02:41 AM
#8
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Location: Lexington Park, Maryland, USA
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Rich, the BBC has a geometry advantage over a SBC in the aspect of rockers. When you put shaft rockers on a SBC you then get the same leverage advantage as the BBC. That's the one big reason to go to a shaft system on a SBC.
I have no idea what the geometry is on the LSX motor but I'm sure it has geometry/leverage maximized toward the best available.
Probe makes a shaft system for the LT1 and it's good quality and life-time warranty and the least expensive. I have a set but have not found a motor to put them on. You might look into it.
I have T&D on one motor and the T&D is awesome quality and you can use studs under the stands.
I have Crane on another motor, (a mild 350LT1), and you can also use head studs under the stands. Awesome quality but not very well clearanced for valve covers.
I have used Jesel sportsman on all my customer motors and they are by far the easiest to fit and very good quality (and true, you cannot use head studs under the shaft stand). Jesel sportsman fit on GM LT1/LT4 heads with no mods. All the others require machining of the stud boss (for GM heads) or taller valves. Jesel's come out of the box with the best valve cover clearance, (but you still need to make slight modifications).
Beware that Yella-Terra sell "Shaft" rockers for the LT1 or SBC 23 deg heads and yes they are shaft rockers but they do not offer the relocated fulcrum point leverage advantage that the other brands offer. Yella-Terra pivot at the same place as the stud mount rockers, (on the stud).
Karl
I have no idea what the geometry is on the LSX motor but I'm sure it has geometry/leverage maximized toward the best available.
Probe makes a shaft system for the LT1 and it's good quality and life-time warranty and the least expensive. I have a set but have not found a motor to put them on. You might look into it.
I have T&D on one motor and the T&D is awesome quality and you can use studs under the stands.
I have Crane on another motor, (a mild 350LT1), and you can also use head studs under the stands. Awesome quality but not very well clearanced for valve covers.
I have used Jesel sportsman on all my customer motors and they are by far the easiest to fit and very good quality (and true, you cannot use head studs under the shaft stand). Jesel sportsman fit on GM LT1/LT4 heads with no mods. All the others require machining of the stud boss (for GM heads) or taller valves. Jesel's come out of the box with the best valve cover clearance, (but you still need to make slight modifications).
Beware that Yella-Terra sell "Shaft" rockers for the LT1 or SBC 23 deg heads and yes they are shaft rockers but they do not offer the relocated fulcrum point leverage advantage that the other brands offer. Yella-Terra pivot at the same place as the stud mount rockers, (on the stud).
Karl
05-29-2007, 11:35 AM
#9
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Location: Montville, NJ, U.S.A.
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I run Jesel SS shafts on my AFR 210 headed 396, with a hydraulic roller 242/252 .576/.576 cam. I upgraded from Comp 3/8 stud rockers and guide plates. I can actually feel a SOTP difference, especially on the upper RPM range. For $800 it was the best investment I made in the valve train. Oh, and I was able to fit the head studs under the Jesel stands on the AFR's. They are worth it, and I will NEVER use a stud mounted rocker again.
Nick
Nick
03-29-2008, 01:57 PM
#10
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Location: RED OAK, TEXAS, USA
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I run Jesel SS shafts on my AFR 210 headed 396, with a hydraulic roller 242/252 .576/.576 cam. I upgraded from Comp 3/8 stud rockers and guide plates. I can actually feel a SOTP difference, especially on the upper RPM range. For $800 it was the best investment I made in the valve train. Oh, and I was able to fit the head studs under the Jesel stands on the AFR's. They are worth it, and I will NEVER use a stud mounted rocker again.
Nick
Nick
03-31-2008, 01:14 PM
#14
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Join Date: Jan 2001
Location: RED OAK, TEXAS, USA
Posts: 39
Rich, the BBC has a geometry advantage over a SBC in the aspect of rockers. When you put shaft rockers on a SBC you then get the same leverage advantage as the BBC. That's the one big reason to go to a shaft system on a SBC.
I have no idea what the geometry is on the LSX motor but I'm sure it has geometry/leverage maximized toward the best available.
Probe makes a shaft system for the LT1 and it's good quality and life-time warranty and the least expensive. I have a set but have not found a motor to put them on. You might look into it.
I have T&D on one motor and the T&D is awesome quality and you can use studs under the stands.
I have Crane on another motor, (a mild 350LT1), and you can also use head studs under the stands. Awesome quality but not very well clearanced for valve covers.
I have used Jesel sportsman on all my customer motors and they are by far the easiest to fit and very good quality (and true, you cannot use head studs under the shaft stand). Jesel sportsman fit on GM LT1/LT4 heads with no mods. All the others require machining of the stud boss (for GM heads) or taller valves. Jesel's come out of the box with the best valve cover clearance, (but you still need to make slight modifications).
Beware that Yella-Terra sell "Shaft" rockers for the LT1 or SBC 23 deg heads and yes they are shaft rockers but they do not offer the relocated fulcrum point leverage advantage that the other brands offer. Yella-Terra pivot at the same place as the stud mount rockers, (on the stud).
Karl
I have no idea what the geometry is on the LSX motor but I'm sure it has geometry/leverage maximized toward the best available.
Probe makes a shaft system for the LT1 and it's good quality and life-time warranty and the least expensive. I have a set but have not found a motor to put them on. You might look into it.
I have T&D on one motor and the T&D is awesome quality and you can use studs under the stands.
I have Crane on another motor, (a mild 350LT1), and you can also use head studs under the stands. Awesome quality but not very well clearanced for valve covers.
I have used Jesel sportsman on all my customer motors and they are by far the easiest to fit and very good quality (and true, you cannot use head studs under the shaft stand). Jesel sportsman fit on GM LT1/LT4 heads with no mods. All the others require machining of the stud boss (for GM heads) or taller valves. Jesel's come out of the box with the best valve cover clearance, (but you still need to make slight modifications).
Beware that Yella-Terra sell "Shaft" rockers for the LT1 or SBC 23 deg heads and yes they are shaft rockers but they do not offer the relocated fulcrum point leverage advantage that the other brands offer. Yella-Terra pivot at the same place as the stud mount rockers, (on the stud).
Karl
03-31-2008, 06:25 PM
#15
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