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FE Power Forums => FE Technical Forum => Topic started by: 6569fe on March 05, 2019, 08:09:58 PM

Title: rocker wear pattern
Post by: 6569fe on March 05, 2019, 08:09:58 PM

Howdy,
Really great info here, some sharp individuals.
I have checked numerous times trying to get a rocker wear pattern as small as possible, have seen here that guys have been able to get to .060 pattern width. I haven't been able to get that narrow, .120-.125 is approx where I seem to end up.
My question is,
Is there a starting point, as far as stem height, rocker shaft center line to head or?
And since heads warp and twist are you milling the pad mount on top side of head?
Appreciate the help,
Thanks, Larry

Title: Re: rocker wear pattern
Post by: Stangman on March 05, 2019, 10:22:11 PM

If you look up rocker geometry for shaft rocker systems on line there are a couple of good videos, even the video for stud geometry still gives you the basics of wear patterns and pushrod length.

Title: Re: rocker wear pattern
Post by: blykins on March 06, 2019, 05:47:41 AM

Is it a factory rocker? 

I can get down to about .040-.045" with my roller tipped stuff, but the shoe-style factory rocker makes it pretty hard to get a real narrow pattern. 

To adjust, you either shim the stands up, or mill the stands down, depending on which direction you need to go.  It's nice to have some short stands and shims on hand to play with.

Title: Re: rocker wear pattern
Post by: 6569fe on March 06, 2019, 11:58:09 AM

Howdy again,
Using Harland Sharp roller tip rockers.
Started out by using adjustable length push rod to get length.
Pattern is centered on valve tip but .120-.125 in width.
What a learning experience.
Larry

Title: Re: rocker wear pattern
Post by: blykins on March 06, 2019, 12:22:35 PM

Adjusting the pushrod length doesn't do anything on a shaft mounted rocker.  You have to either drop the stand height or raise it up, otherwise the rockers will stay in the same spot. 

Title: Re: rocker wear pattern
Post by: Thumperbird on March 06, 2019, 03:55:07 PM

Not sure what heads you have but I know first hand Harland Sharp rollers on Edelbrocks as is provide the sweep you describe, at least with a moderate cam.  Heads are designed to go to a lift of ~.625 so the pads are low to begin with I suppose to accommodate lots of setups.  I'm sitting with a .25" shim to get good geometry. 

Title: Re: rocker wear pattern
Post by: 6569fe on March 07, 2019, 11:34:50 AM

Howdy,
Looks like the next swap meet I'll be looking for some stands to cut down
so I can do this right.
Thanks for the replies,
Larry

Title: Re: rocker wear pattern
Post by: 67428GT500 on March 08, 2019, 08:42:42 PM

Are you running stock rocker shafts and stands?  That also factors in. Heavy springs, high lift cam you should use the Rockerstands and end supports with heavy duty shafts. My pattern is about .45 and dead centered.

                                                                                                    -Keith