Rocker arm geometry and fitment issues.

Posted By: B3RE

Rocker arm geometry and fitment issues. - 09/09/13 02:16 AM

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
B� Racing Engines

Posted By: VernMotor

Re: Rocker arm geometry and fitment issues. - 09/09/13 02:29 AM

I do not have any at this time. But there are many post on this site about them ! Welcome

Posted By: STEFF

Re: Rocker arm geometry and fitment issues. - 09/09/13 02:29 AM

How about some roller rockers for the G3 Hemis? Other than the crazy expensive Jesel set up, there's nothing.

Posted By: B3RE

Re: Rocker arm geometry and fitment issues. - 09/09/13 02:33 AM

Thanks for the welcome. I'm sure the issues aren't over yet.

Posted By: B3RE

Re: Rocker arm geometry and fitment issues. - 09/09/13 02:40 AM

Sorry, I haven't gotten that far yet. That's usually the way it works though. It's like going to the movies, if you gotta see it this weekend, your gonna pay way more than watching it on DVD six months from now. Same thing with the latest greatest car parts.

Posted By: moparman89

Re: Rocker arm geometry and fitment issues. - 09/09/13 03:58 AM

Hey Mike

This is Pete from SAM. Hope all is well with you and your career. Here is a link to a issue brought up recently on another forum, check it out.

http://www.yellowbullet.com/forum/showthread.php?t=599123

Posted By: AndyF

Re: Rocker arm geometry and fitment issues. - 09/09/13 05:50 PM

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.

Posted By: Biginchmopar

Re: Rocker arm geometry and fitment issues. - 09/09/13 07:15 PM

Andy is right, you get what you pay for. I have went through the world of hard knocks on valve train parts for years.

Now I run nothing but T&D's and I don't have any issues.

Posted By: AndyF

Re: Rocker arm geometry and fitment issues. - 09/09/13 07:34 PM

Yep, the serious guys eventually end up with either Jesel or T&D rocker arms.

Posted By: B3RE

Re: Rocker arm geometry and fitment issues. - 09/09/13 10:40 PM

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.

Posted By: B3RE

Re: Rocker arm geometry and fitment issues. - 09/09/13 10:43 PM

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!

Posted By: B3RE

Re: Rocker arm geometry and fitment issues. - 09/09/13 10:55 PM

Quote:

Andy is right, you get what you pay for. I have went through the world of hard knocks on valve train parts for years.

Now I run nothing but T&D's and I don't have any issues.

Yes, you do get what you pay for in most cases. However, the geometry issues are not entirely from the rocker design. Again, it is the location of those points and lines and the relationships between them that dictate the geometry, whether right or wrong.

Posted By: B3RE

Re: Rocker arm geometry and fitment issues. - 09/09/13 11:37 PM

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.

Posted By: BigDog68Dart

Re: Rocker arm geometry and fitment issues. - 09/10/13 12:39 AM

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!

Posted By: B3RE

Re: Rocker arm geometry and fitment issues. - 09/10/13 02:39 AM

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.