Problems with Comp rockers on AFR 185 heads.

[Infected Mushroom]

Hi guys and girls.

I have a problem with setting up my valvetrain on my fresh Ford 347 stroker ('87 5.0 OEM roller block). I have brand new hydraulic Comp cam with .0598 lift, AFR-185 heads (#1388), Comp Cams Ultra Gold ARC roller rockers 1.6 ratio (19043-16). Using the studs (ARP 3/8") and guide plates (AFR) included in the heads kit. Valve springs should handle .600 lift.

What happens is that when trying to adjust the rockers to roll as close to the center of the valve tip as possible (starting at the intake side, rolling to the center, and back at full lift), the rocker body will hit the pushrod and start to bend it before it reaches full lift. If I lower the rocker on the stud by adjusting the pushrod checking tool, I can avoid rocker hitting the pushrod tool (but just barely), but the rocker roller tip will be very close to the intake side edge of the valve tip. It seems like the rocker is just too short for the heads geometry.

I've googled my a** off trying to find others experiencing this, but came up empty. I've communicated with a tech guy at Comp Cams, but he didn't have a clue. AFR haven't responded yet.

I made some photos with descriptions, hope this helps someone to come up with a solution. An option for me now is to try the Scorpion Race rockers which can handle up to .950 lift, and recommended by AFR.

[TheJDMan]

Looks to me like a call to Comp Cams may be in order. Rockers don't appear to be clearanced properly or push rods too long.

[Infected Mushroom]

I talked (emailed) to a technician at Comp Cams. He first suggested the heads weren't machined for guide plates. Heads are a complete kit, and I could not see how removing the GP would fix the problem. Then he said the pushrods are too long. So he obviously doesn't understand the problem here.

[rchaskin]

I think you do need a shorter pushrod length.
Remember, it is the full sweep across the valve stem you are looking for, not just exactly centered at mid lift.

See this
http://www.compcams.com/Technical/In...20Geometry.pdf

This combo similar to yours recommends 5.25" pushrods.
http://treperformance.com/i-9214805-...l-stage-2.html


...Also check the distance from the spring pocket to the top of the valve stem.
If the actual valve stem is short, that could cause these problems.

....and double check the rockers to make sure they are the ones you ordered as well.

Lots of places a gremlin could hide in this mix.....
Good Luck!!

[Infected Mushroom]

The Comp Cams instructions is a bit confusing because of the drawing they made, but what they actually are saying is that you want the roller tip roll from the intake side, across the center to the exhaust side at mid lift (at this point the rocker centerline and the valve stem would be near or at 90 degrees to eachother) and then back to where it started at full lift. What they should have included is that the sweep should be as narrow as possible, and not edge to edge which would be a disaster if it rolled off. So they are basically saying what I am trying to achieve.

My first post might have been confusing too for some; I don't want the roller tip to only stay at the center, but to roll near the center in a narrow sweep, like the instructions say.
But it is impossible to adjust the rocker anywhere near the center, because of the contact the pushrod and rocker body make when trying to do a full lift at this position.

I would rather swap the rockers for another type than having to alter the heads spring/valve/retainer setup, although I can see that a longer valve might correct the bad rocker geometry. I'm gonna try a set of Scorpions Endurance rockers, which can take on a .950 lift.

I have looked for any stampings on the rockers for identification, but they only have the Comp 1.6 printings on them, I have no idea how even Comp Cams can tell the SBF apart from the SBC rockers for instance.

The 19043 rockers are made to fit SBF 289, 302, 351W, but it doesn't say if they will fit AFR heads. I just figured they would fit as the AFR 185 heads are modeled after the OEM 5.0 heads.

https://www.lunatipower.com/Tech/Val...nGeometry.aspx

[ford396]

I believe I would try another brand rocker arm.

[Jetfixr320]

From my understanding you have the roller tip going across the valve stem as required.

What diameter pushrod are you using? Could you go to a smaller diameter to gain clearance from the rocker arm?

And this link posted in a previous post http://treperformance.com/i-9214805-...l-stage-2.html recommends 5/16" dia 6.250" length. But that kits cam also has less lift then yours.

So, I wouldn't base your pushrod from their recommendations. Stick with using a pushrod measuring tool.

[Infected Mushroom]

The roller tip would have been going across the valve stem properly if the rocker body hasn't crashed into the pushrod on its way down.

The diameter of the pushrod is 5/16 (AFR pushrod guide don't allow any larger).

Already tried a Trick Flow 5/16" dia 6.250 length pushrod, too short, roller tip will sit on the very edge (intake side) of the valve tip, too unsafe to run in this position. Can adjust the pushrod checking tool up to 6.4" at the most without rocker touching the pushrod, but roller tip is still far from the recommended sweep across the valve.

I have used a pushrod checking tool (Comp Cams 7701-1) from the beginning of setup.

Already ordered another set of rockers, Scorpion Endurance. I think the Comp rockers are not intended for any higher lift than .500.

[Infected Mushroom]

Just an update: Made a decision to buy another set of rockers, Scorpion Endurance. Fitment and geometry on these turned out to be perfect. I first set it up by adjusting the rocker to have a 90 degree angle to the valve stem at half lift. In this position the roller tip is perfectly centered over the valve tip, and there is more than enough clearance between the pushrod and roller body. I also ended up with the same pushrod lenght as on the comp rockers; 6.4".

So obviously the comp rocker can not be SBF rockers, or they are not intended for higher lift than .500.

Just gotta find some Chevy guys.

[MonzaRacer]

I just make clearance on rockers if can find sweet spot on PR length. Clearances a many of the old Crane gold race rockers till they redesigned them. When Comp became leader and Crane died, (S&S has revived them.) Just did same.
Used to hate Scorpion parts as all were cheap Chinese parts. Quality has came up, at least there is that and some of the parts are now not from cheap a$$ Chinese product lines.
Glad you found parts your happy with.

[1BADBET]

If this is a hydraulic cam and your not using a checking spring when setting pushrod length how are you keeping the lifter cup from bottoming out? That maybe a problem...

[maverickmk]

Those valve are set up for self-aligning rockers and those rockers are not self-aligning. When using self-aligning rockers you don't need push rod guide plates.