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Not quite on subject, but the last 2 T&D set ups were disappointing. AFR 357 and Dart Pro 1. These heads have been around for years but the rocker stands put the center of the rocker roller .040' toward the exhaust side and the left to right position off too. Sheldon was not very energetic to get to the solution even though I think he was aware the problem exists. He did take the original stands back and made new "custom" stands that corrected the issue, but had to pay $200 on top of the
$1350 original cost. I felt like they should have this fiqured out by now and he felt like it was both the head companies fault for changing thing around, which they did not do.

Once correct, they have been bullet proof.
One thing I’ve encountered with Jesel is nothing is ever their fault.
 

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One thing I’ve encountered with Jesel is nothing is ever their fault.
Just went through this on a set of 12* Profilers. Stands were .300 short! Lol
 
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Just went through this on a set of 12* Profilers. Stands were .300 short! Lol
Or how about the time the cam adapter for one of their SBF belt drives didn’t fit on a standard SBF cam core because the chamfer around the mounting bolt hole on the backside was not large enough? Did you know that over-torquing their lash adjusters by even a pound or two can stress their aluminum rocker bodies to the point of failure? That was news to me until they told me so.
 

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Not quite on subject, but the last 2 T&D set ups were disappointing. AFR 357 and Dart Pro 1. These heads have been around for years but the rocker stands put the center of the rocker roller .040' toward the exhaust side and the left to right position off too. Sheldon was not very energetic to get to the solution even though I think he was aware the problem exists. He did take the original stands back and made new "custom" stands that corrected the issue, but had to pay $200 on top of the
$1350 original cost. I felt like they should have this fiqured out by now and he felt like it was both the head companies fault for changing thing around, which they did not do.

Once correct, they have been bullet proof.
I've gone through the same with 2 pairs of AFR BBC heads. Were way off centre of pushrod slot. Sheldon just told me that there rockers are right and AFR must of changed there design again and for me to contact them. He did say he will make new stands at extra cost. Some people can never do wrong. I did notice that they have changed the rocker design over a period of time for the same heads.
 

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I've gone through the same with 2 pairs of AFR BBC heads. Were way off centre of pushrod slot. Sheldon just told me that there rockers are right and AFR must of changed there design again and for me to contact them. He did say he will make new stands at extra cost. Some people can never do wrong. I did notice that they have changed the rocker design over a period of time for the same heads.
There are three different designs from T&D for AFR BB Chev heads depending on what heads you have. Most people aren't aware of this and inadvertently order the wrong ones. I had to design some special stud mount rockers for the latest version AFR heads to get something that fit and had good geometry.
 

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Discussion Starter · #31 ·
One thing I’ve encountered with Jesel is nothing is ever their fault.
Just went through this on a set of 12* Profilers. Stands were .300 short! Lol

I'm having to run 3/16" shim stock to get a-b-a geometry on this setup, but age of components and all being used stuff I can't really complain. If I could set-up at ~2.0" spring height they would bolt on w/o shims; being I need 2.180 minimum....not so much - I have two sets of these heads, one set being very little use and sitting for many years, the other being only of value that they came with the rocker set-up(though 1.7's that I swapped for fresh 1.8's) and that I can run them through the bandsaw to know how much material I have in the ports to work with in the good set, lol.

Stands were all welded together nicely, prior to me cutting them apart to correct/suit the geometry of them on the better heads, lol.


Personally I like T&D for production stuff, but Pegasus Engineering has been knocking out some killer one-off custom stuff and will be sorting out our next heads and rocker system. That will be steel body shafts on billet heads. :devilish:
 

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Discussion Starter · #34 ·
Doing this, just make sure you check the pushrod side as well.

I was already going to have to clearance to fit the 1/2" pushrods, it just is what it is at this point. - 3/16 shims and stands shifted back .095. I drilled the shim stock to fit the bolts and the dowel pins, going to weld the shims to the stands and then weld new 4130 tiebars to everything to tie them all back together and even an additional from the end stands out to bolt through the ends of the heads.
 

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I was already going to have to clearance to fit the 1/2" pushrods, it just is what it is at this point. - 3/16 shims and stands shifted back .095. I drilled the shim stock to fit the bolts and the dowel pins, going to weld the shims to the stands and then weld new 4130 tiebars to everything to tie them all back together and even an additional from the end stands out to bolt through the ends of the heads.
I was talking more about the geometry on the pushrod side. I've tried the 90* geometry on Jesel rockers before and at full lift, the pushrod was almost out of the cup because of the angle of the rocker on the pushrod side. That's when I learned that Jesel doesn't design their rockers around the 90* geometry and I went with their instructions. To be "correct" the pushrod side should have the same 90* geometry as the valve side.
Rectangle Slope Font Line Bird
 

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I was talking more about the geometry on the pushrod side. I've tried the 90* geometry on Jesel rockers before and at full lift, the pushrod was almost out of the cup because of the angle of the rocker on the pushrod side. That's when I learned that Jesel doesn't design their rockers around the 90* geometry and I went with their instructions. To be "correct" the pushrod side should have the same 90* geometry as the valve side. View attachment 277656
I noticed the pushrod side of my Crower stainless shaft rockers seem to get out of kilter at full lift. Looks like they are pushing the boundaries of the cup. Going to fire it up next weekend, but will give a closer look before I do. Will also be watching during priming to see if it's out bad enough to block off oiling.

Never really heard much about the pushrod side before. Geometry was a lot simpler with lower lifts and stud rockers. Lol
 

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Stock Chevy rocker pivot sweep versus Jesel rocker pivot sweep drawing I did a while ago after I designed and made my own stud spring install/removal tool. Apologies for the mix up in circle colors.

The smaller Blue circle in the center represents the stock Chevy pivot location and the Red Centerline circle is the contact sweeping arc the roller tip travels on the stock pivot center. You can see that 0.850” travel on the valve stem for a stock Chevy is really not ideal! Yes you can move the height up and down a little bit but you are making the best of a bad geometry for 0.800”+ lift. Lifts 0.600” and below are fine since this is what the stock valve train was designed for.

The Green smaller circle represents the Jesel sweep center location. I found in a Jesel interview where Dan stated he moved the pivot point rearward 0.100”(towards center of engine) and down 0.225”. From those dimensions I created the arcs/circles here. The Blue Centerline circle is the sweep a Jesel 1.7 rocker goes through. As you can see for 0.850” lift the Jesel motion across the tip of the valve through the lift is greatly improved. From the start of motion to middle and full motion the roller tip moves less than 0.020”.

For 24 Deg Chevy heads Jesel or T&D shaft rockers work much better than stud rockers simply because of where the pivots are placed and how those pivots optimize staying central to the valve stem over a given lift distance. Hope this gives a good visual what is happening. The height matters and so does the distance away from the valve stem center. The ultimate is to create your own for custom applications. Pretty easy if you have 3D design software and accurate measuring tools.


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Stock Chevy rocker pivot sweep versus Jesel rocker pivot sweep drawing I did a while ago after I designed and made my own stud spring install/removal tool. Apologies for the mix up in circle colors.

The smaller Blue circle in the center represents the stock Chevy pivot location and the Red Centerline circle is the contact sweeping arc the roller tip travels on the stock pivot center. You can see that 0.850” travel on the valve stem for a stock Chevy is really not ideal! Yes you can move the height up and down a little bit but you are making the best of a bad geometry for 0.800”+ lift. Lifts 0.600” and below are fine since this is what the stock valve train was designed for.

The Green smaller circle represents the Jesel sweep center location. I found in a Jesel interview where Dan stated he moved the pivot point rearward 0.100”(towards center of engine) and down 0.225”. From those dimensions I created the arcs/circles here. The Blue Centerline circle is the sweep a Jesel 1.7 rocker goes through. As you can see for 0.850” lift the Jesel motion across the tip of the valve through the lift is greatly improved. From the start of motion to middle and full motion the roller tip moves less than 0.020”.

For 24 Deg Chevy heads Jesel or T&D shaft rockers work much better than stud rockers simply because of where the pivots are placed and how those pivots optimize staying central to the valve stem over a given lift distance. Hope this gives a good visual what is happening. The height matters and so does the distance away from the valve stem center. The ultimate is to create your own for custom applications. Pretty easy if you have 3D design software and accurate measuring tools.


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Well that's as clear as mud. I'm seeing circles. 🤪
Where are you coming up with a "Stock Chevy pivot location"? There is no such thing. Chevy never made a roller tip rocker for the BB Chev head...which is part of the problem in the industry. That, and no two aftermarket heads are the same.
I think you have some terms confused.
"Moving the pivot point" as you put it, is increasing the fulcrum length. If you simply move the pivot point without changing the fulcrum length, you won't change the sweep, you'll just change it's location on the valve tip which, sometimes, is necessary. Changing the fulcrum length is what changes the geometry and therefore, changes the amount of sweep on the valve tip (for the same amount of lift). That's the case with any rocker. That will also change the ratio if you don't make the needed adjustment on the pushrod side.
"Jesel or T&D shaft rockers work much better than stud rockers simply because of where the pivots are placed"
That is simply not true and one of the nice things about a stud mount rocker: it's ease of adjustability of the pivot point (fulcrum). There is no reason a stud mount rocker can't have perfect geometry and as far as working "better", the valve has NO idea whether the rocker is stud or shaft mount.
"Pretty easy if you have 3D design software and accurate measuring tools."
LOL... 3D might get you close, but if you don't have the heads on a block with cam, lifters, pushrods in place, and the rockers you're trying to use, you're just guessing. Way too many variables in play here. I've worked with Harland Sharp on designing quite a few rockers for different applications and never used a computer. Just math and some trial and error. Made lots of drawings by hand too. I did this years ago and I see it all over the internet;
Rectangle Slope Triangle Schematic Parallel
 

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Couple things, I measured and modeled my Comp 1.8 rocker to investigate the “fulcrum” sweep pivot- whatever technical term you wish to use and how it interacts with the valve stem.

For ease of confusion let us call it the “radius” created by the rocker arm trunion centerline and the tangent point of the roller wheel contacting the valve stem. Yes the 26 degree stock 781 head on my engine is different than 24 degree aftermarket head using studs but the stud location does not move relative to the valve stem, it is a fixed distance. The height of the rocker trunion is adjusted by push rod length to achieve best as possible sweep for a “radius” location that was never designed for more than maybe 0.600” lift tops. However the actual “arc” the “radius” rotates through causes the roller “tangent” contact to nearly come off the valve at higher lifts. The stock stud location IS NOT ideal for higher valve lifts. This is why Dan Jesel moved the pivot “back 0.100 and down 0.225” (his words).

I overlaid the Jesel shaft location (assumption here is for 26/24 degree heads) to see why he did that. The Jesel rockers have a longer “radius” contact tangent with the valve stem than a stud rocker does. The handy design feature of the shaft set up is being able to move the trunion centerline height up and down and fore aft if needed to achieve a “radius” contact tangent that minimizes the horizontal movement across the valve stem. That is what I am illustrating here. Apologies it is not clearer, I drew this in AutoDesk Inventor 5 or 6 years ago and haven’t cleaned it up. I am using Siemens Solid Edge now and there is a learning curve!

As far as creating parts from 3D modeling I do it very often, granted it is not usually “engine components” but metal is metal, it does not care what it’s in, Metallurgy aside. I have measured and studied prototype Dodge NASCAR rocker gear at length as I am fortunate enough to work at the Chrysler Tech Center in Auburn Hills MI. Funny thing, we make prototype parts all the time in this building and they seem to work out very well. I am not an engineer but do understand geometry, metallurgy, static and dynamic loading. I use 3D Modeling software to get me closer to my desired target in conjunction with accurate measuring of components I need to integrate with.


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