Rocker to Retainer with Pictures

-
T

thomasfouraker

Well-Known Member
Joined
Feb 2, 2020
Messages
143
Reaction score
47
Location
Jacksonville
Through my research I haven't found an objective spec on what it should be but more less "exercise the rocker arm throughout its throw and check for interference. Provide clearance and adjust as necessary". Seems a bit generalized.

I am hoping to run these HS 1.7 on my Magnum Heads but I upgraded to a larger spring and retainer combo to work with the cam I have. It brings the arm pretty close as you can see. I know a Dremel could relieve that some if need be.

Wasn't sure if there was a spec for reference or something anecdotal.

Thanks!

BC29F583-EF82-43F2-A74B-862CEDDB456C.jpeg
 
anecdotal ~ a miss is as good as a mile... and, if it ain't broke, don't fix it. But I see your point, that is close!
 
Thanks for that reply! Its actually more the spring interfering than the retainer. My fear is that spring starts dancing around, plus heat expansion and then it begins to self clearance.

It seems like I have about .018-.020 like it is. Hard to get a wide feeler in there.
 
If you do grind any clearances, be sure all the grinding marks run lengthwise with the rocker and NOT ACROSS. Then polish it back as smooth as possible. Hopefully you could use a Dremel ball file and just dimple it in the center (not all the way across) still keeping the rotation lengthwise.
 
tinman2 said:
If you do grind any clearances, be sure all the grinding marks run lengthwise with the rocker and NOT ACROSS. Then polish it back as smooth as possible. Hopefully you could use a Dremel ball file and just dimple it in the center (not all the way across) still keeping the rotation lengthwise.
Click to expand...

Any particular reason for this? Just out of curiosity.
 
Any cross direction scratches from grinding or sanding is like a crack starting. Think about a piece of wood, like a 2x4. Cut a groove in the surface across the middle of the board. Support both ends and stand on the middle. Guess where it will break. Take another 2x4 and cut a groove lengthwise. Do the experiment again.
 
tinman2 said:
Any cross direction scratches from grinding or sanding is like a crack starting. Think about a piece of wood, like a 2x4. Cut a groove in the surface across the middle of the board. Support both ends and stand on the middle. Guess where it will break. Take another 2x4 and cut a groove lengthwise. Do the experiment again.
Click to expand...

I figured it had to do with grain/strength. I appreciate that explanation it makes complete sense.
 
I can't really tell from the angle at play, but what does the roller to valve tip contact area look like? The clearance should really be closer .050 with the stud rockers. Considering that the Magnum uses stud rockers, I would look into using a longer pushrod. Crower has a pile of various pushrods in their clearance items on their website for pennies on the dollar, you might could come up with some there.
Clearance
 
I bet the springs will move around a bit as they cycle at 6000 r's. You don't need a lot of clearance but you will need some. I don't recall seeing a spec. (I used the wrong springs but with the right shim they work)

100_5227.JPG
 
Last edited:
The Chevrolet people recommend .040 for their stud rockers. There are claims that longer pushrods will produce more power on the Dyno. In IMHO, that would more be a function of the rocker geometry needing help to begin with instead of “magic snake oil” happening.
 
I haven't set up my geometry yet but, have it "mocked up close" to where my rocker arm is 90 degrees at 1/2 the total cam lift. Its not an extreme cam, .316 so .506 with 1.6 and .537 with 1.7s.

I will know more about stem contact area once everything is mounted. I ordered a measuring pushrod that should let me dial in the right length for proper geometry and stem contact area.
 
For future consideration, one can look at beehive springs, if one can be found with similar specs as the recommended standard spring.
 
Adding a little extra clearance with the aforementioned method with a dremel or die grinder would be okay. It wouldn't be the first set of Harland Sharp rockers that have been likewise modified for a little extra safety. Hopefully, you may find a little extra clearance when you finalize your geometry, too.
 
Do NOT grind the rocker. Your springs aren’t big enough to warrant that, and it should NEVER be done.

Figure out why the geometry is off and fix that.

If you need help talk to Mike at B3racingengines.com and let him help you.

The rocker arm is no place to use a grinder.
 
yellow rose said:
Do NOT grind the rocker. Your springs aren’t big enough to warrant that, and it should NEVER be done.

Figure out why the geometry is off and fix that.

If you need help talk to Mike at B3racingengines.com and let him help you.

The rocker arm is no place to use a grinder.
Click to expand...

Thanks for that reply. I think this is a result of having a part that was designed for a much smaller diameter spring/retainer combo and using it with a larger diameter spring and retainer.

I know there are rocker arms that have pushrod and retainer clearances machined into them depending on the application. I am definitely not going to spin the grinder unless no other reasonable option is available.
 
Check full sweep clearance.

If your springs are dancing around, spinning or doing anything other than compressing and controlling the valves...you dont have enough spring.
 
MOPAROFFICIAL said:
Check full sweep clearance.

If your springs are dancing around, spinning or doing anything other than compressing and controlling the valves...you dont have enough spring.
Click to expand...

I am running Hughes 1110 Spring and their retainer as well. Supposedly good to .550 lift with 120 on the seat at 1.65 installed height and should be seeing about 305-310 at my full lift. I don' anticipate problems but I do try to exercise my due diligence in preventing possible or potential problems. Videos like this don't make me feel warm and fuzzy about tight fits!

 
I ran across that issue on a couple of engines using the 273 adjustable rockers. On one I was able to grind a real small amount off the cast iron rocker. The other, I had to use beehive springs with smaller retainers to get enough clearance. Neither engine had cam lift as high as 1/2" and neither was going to see 6 grand, so, I was not worried about a little grinding on the rocker. I've got over 75k on that one at this point with no problems.
 
thomasfouraker said:
I am running Hughes 1110 Spring and their retainer as well. Supposedly good to .550 lift with 120 on the seat at 1.65 installed height and should be seeing about 305-310 at my full lift. I don' anticipate problems but I do try to exercise my due diligence in preventing possible or potential problems. Videos like this don't make me feel warm and fuzzy about tight fits!

Click to expand...

Spring bounce.
Once they start spinning too.. power goes away and stuff starts braking.
 
MOPAROFFICIAL said:
Spring bounce.
Once they start spinning too.. power goes away and stuff starts braking.
Click to expand...

How much clearance would you be comfortable with? The clearance actually grows at greater lift for me.

Not sure if I could shim the pedestal some, I think that would provide some clearance as well.
 
yellow rose said:
Do NOT grind the rocker. Your springs aren’t big enough to warrant that, and it should NEVER be done.

Figure out why the geometry is off and fix that.

If you need help talk to Mike at B3racingengines.com and let him help you.

The rocker arm is no place to use a grinder.
Click to expand...

Exactly this^^^^^ If you grind something, you're doin it WRONG. The rocker shaft needs to be relocated. As mentioned, Mike at B3 can help make that happen.
 
thomasfouraker said:
How much clearance would you be comfortable with? The clearance actually grows at greater lift for me.

Not sure if I could shim the pedestal some, I think that would provide some clearance as well.
Click to expand...
The pic shows about .050 clearance, im guessing. Those rockers have a cup recess for the spring, so you probably have a little more than shown in the pic.
 
thomasfouraker said:
Thanks for that reply. I think this is a result of having a part that was designed for a much smaller diameter spring/retainer combo and using it with a larger diameter spring and retainer.

I know there are rocker arms that have pushrod and retainer clearances machined into them depending on the application. I am definitely not going to spin the grinder unless no other reasonable option is available.
Click to expand...


Unless your springs are 1.625 or bigger the notch isn’t too small, the geometry is wrong.
 
You must log in or register to reply here.
-

Back
Top