Rocker arm geometry and fitment issues.
#1498583
09/08/13 10:16 PM
09/08/13 10:16 PM
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Joined: Jul 2013
Posts: 561
USA
B3RE
OP
mopar
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OP
mopar
Joined: Jul 2013
Posts: 561
USA
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Hello everyone!
I wanted to start a discussion on rocker arm geometry as it seems this particular issue has plagued many, and shows no sign of letting up anytime soon.
I am a business owner, engine builder, and manufacturer and I make custom valvetrain parts to correct the specific problems related to Mopar engines. I am usually too busy to spend much time on the web, but Herb Reynolds from Herb's Parts, who many of you know well, encouraged me join this forum and talk about valvetrain issues.
Let me know of any issues/questions you may have or have had in the past. I'm looking forward to a good discussion.
Mike Beachel
Bł Racing Engines
Mike Beachel
I didn't write the rules of math nor create the laws of physics, I am just bound by them.
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Re: Rocker arm geometry and fitment issues.
[Re: VernMotor]
#1498586
09/08/13 10:33 PM
09/08/13 10:33 PM
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Joined: Jul 2013
Posts: 561
USA
B3RE
OP
mopar
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OP
mopar
Joined: Jul 2013
Posts: 561
USA
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Thanks for the welcome. I'm sure the issues aren't over yet.
Mike Beachel
I didn't write the rules of math nor create the laws of physics, I am just bound by them.
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Re: Rocker arm geometry and fitment issues.
[Re: AndyF]
#1498592
09/09/13 06:40 PM
09/09/13 06:40 PM
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Joined: Jul 2013
Posts: 561
USA
B3RE
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mopar
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mopar
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Quote:
Rocker arm geometry on Mopar engines is mostly a problem for "Bolt on Joe" who buys rocker arms based on price on the assumption that rocker arms are a commodity item. It is always a painful eduction as "Bolt on Joe" gradually figures out that aftermarket rocker arms come in a variety of different lengths and that those different lengths either work or don't work depending on valve lift and installed height.
I covered the topic in my big block book complete with pictures and examples so the answers are out there if people are willing to look.
Hi Andy,
Yes I have your book and it is filled with great information. The reason I wanted to discuss this topic is because, as you know, every engine is different, from the cam profile, right down to the valve job and resulting stem height. The thing that bothers me the most is when I look at the very definition of geometry, it is a branch of mathmatics that deals with points, lines, angles and relationships of those criteria, yet no one talks about the math involved, they worry about whether the roller is centered on the valve. I correct geometry by doing the math and making the custom parts needed to make it right, usually as a bolt on deal. I like giving "Bolt-on Joe" options too because they don't like getting their butt kicked by a chevy or ford any more than the all out racer.
Mike Beachel
I didn't write the rules of math nor create the laws of physics, I am just bound by them.
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Re: Rocker arm geometry and fitment issues.
[Re: moparman89]
#1498593
09/09/13 06:43 PM
09/09/13 06:43 PM
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Joined: Jul 2013
Posts: 561
USA
B3RE
OP
mopar
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OP
mopar
Joined: Jul 2013
Posts: 561
USA
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Hey Pete!
Great to hear from you buddy. How have you been? I am working hard at making big power up here. Thanks for the well wishes. I'll check out the link. Thanks!
Mike Beachel
I didn't write the rules of math nor create the laws of physics, I am just bound by them.
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Re: Rocker arm geometry and fitment issues.
[Re: moparman89]
#1498595
09/09/13 07:37 PM
09/09/13 07:37 PM
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Joined: Jul 2013
Posts: 561
USA
B3RE
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mopar
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Pete
I checked out that link. It looks like the stands are on the same angle as the valve on that head (unlike factory type stands) so just raising the shaft the proper amount would correct the shafts being too low . Unfortunately, he is simply looking at the roller location on the valve and not taking into account that his rockers may not have the correct fulcrum length to center the roller when the geometry is correct.
Mike Beachel
I didn't write the rules of math nor create the laws of physics, I am just bound by them.
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Re: Rocker arm geometry and fitment issues.
[Re: B3RE]
#1498596
09/09/13 08:39 PM
09/09/13 08:39 PM
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Joined: Nov 2006
Posts: 892
Caledonia, Ohio
BigDog68Dart
super stock
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super stock
Joined: Nov 2006
Posts: 892
Caledonia, Ohio
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how many passes would you expect to put on a set of jesel rockers (alum) before fatigue failure typ? just curiuos,I just Had exhaust rock er fail, approx.950 passes, Thanks for information Big Dog  new set on car!
Last edited by BigDog68Dart; 09/09/13 08:41 PM.
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Re: Rocker arm geometry and fitment issues.
[Re: BigDog68Dart]
#1498597
09/09/13 10:39 PM
09/09/13 10:39 PM
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Joined: Jul 2013
Posts: 561
USA
B3RE
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mopar
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OP
mopar
Joined: Jul 2013
Posts: 561
USA
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Oh man,
There are so many variables involved I couldn't begin to give an accurate answer. Things like spring load, rpm, geometry, and even the quality of the material. Now before anyone starts yelling at me, I am not questioning the quality of Jesels rockers. Simply put, not every piece of aluminum is the same, even from the same stock. I'm no metallurgist, but I do know that molecular composition varies throughout the material so maybe it was weaker in that rocker, if only slightly. At 950 passes it sounds like you got quite a bit of life from them. 95 passes would be a different story.
Mike Beachel
I didn't write the rules of math nor create the laws of physics, I am just bound by them.
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