The Stovebolt Site Forums The Shop Area Engine Shop rocker arms

Is there any reason badly worn rocker arm tips can't or shouldn't be dressed down flat again? Makes them really hard to adjust properly with a regular feeler gauge.

Don't try to do it freehand. There are fixtures for the oldtime valve grinding machines that allow you to put a consistent radius on all the rockers. If you can't find a local machine shop that can do it, some of us old geezers on the bolt still have that equipment, and the US Mail still works- - - -sort of!
Jerry

I smoothed mine out on a knife sharpener wheel which is mounted on a bench grinder motor. It is a 10" diameter wheel made of compressed paper which is similar to wood in texture and hardness. It is loaded with jewelers rouge leaving a mirror finish.
The only reason that I even attempted doing this was twofold.
1) I had nothing to lose except useless rocker arms.
2) I could see that all that I had to do was look at the pattern of the grooves worn into the surface as a guide to maintain the correct arc on the surface.

I placed the rockers on the wheel and rocked them up and down to approximate what I felt was correct, checking it regularly to observe how the grooves were disappearing in an even pattern.
Jewelers rouge is super fine grit (if you can even call it grit), so it is slow going, but it gives you plenty of opportunity to do it right as you go along, constantly checking for the grooves to disappear evenly.

Among the Black & Decker, Kwik-Way®, Rottler®, Sioux®, and Snap-On® valve regrinding machines I've investigated, none of them have a pantograph function to contour the rocker pallet to a known radius, nor is the radius known.
The curvature of the new surface is entirely the product of operator skill.

"Operator skill" went belly-up sometime in the 1970's, never to return.
Jerry

52 Carl Sounds about right,a valve machine would be best but a careful hand with a smooth file,in the vice should be able to duplicate the curvature close enough.Have purchased a few 10 $ valve cover loads of shaft rockers for the future,stands and all. Could use those to go by.

My truck has hydraulics so getting them perfect is probably not as critical. I used my stand up belt sander. I checked to make sure that the table was at a perfect right angle to the belt, set the rocker on one side where the shaft goes thru, then sanded them by hand slowly, rocking them trying to match the contour, checking progress frequently. I finished them off with a stone to give them a finer finish. The the three pictures show the progress. I can’t say they will last forever but I do have 500 miles on them and so far there good.

Phak 1 Can't see anything wrong with your method,the valve refacers mostly followed the original contour,just had to keep moving to avoid a flat spot.

It's only important when you price "new" rockers at $54 each!

the valve refacers mostly followed the original contour,just had to keep moving to avoid a flat spot.

Exactly. The valve regrinding machine's fixture does help, in that the rocker is held on a shaft at right angles to the wheel to prevent incorrect motion. What you want is a 2-dimensional wave, not a dome with a curve in both axes. As long as the pressure is light and constant, and the sweep across the radius doesn't stop, a competent result can be achieved.
Experience is the master, but diligence is a good substitute.

Skooter Not gonna happen at 54$ each ,will file a set or make a jig to dress em.

I haven’t tried a contour gauge.
As you press it on to a multi-dimensional surface the needles are slowly pushed back into the tool, and you’re left with an inverse of the original shape.
The pallet is convex, so the tool shape becomes concave. Obviously, select a rocker arm model with no detectable wear or damage to the pallet.
It can be used as a test as the work progresses (shine a light behind it to detect where more work is needed), or to construct a pantograph (duplicator) to control tool movement.
I’m not sure it’s accurate on such a small (13∕32”, .406” long) surface, but it may tell us something.

My ancient Sioux has a rocker arm attachment with movable pin position to accommadate most rockers, a set up to radius worn lifter bottoms, also has the micrometer set up to grind flat head Ford valves to length. Just think, people used to REPAIR, now they just replace. For race engines only we have an even older Black and Decker dry grinder that leaves a perfect mirror finish but has to have a 10 minute cool down after each step so a three angle valve job takes almost a week. My Tobin-Arp grinder has the exact same stone speed from a brand new stone to a worn out one but along with brake shoe arching, riveting shoe and clutch facing, stick welding,---all just gather dust with resto/street rods having LS and Ford Modular engines with automatics and disc brakes. Need to load Jerry's trailer up on his next trip.

Can you load up a couple of apprentices who are willing to learn to use that stuff? If it can't be done with an app on a smart phone and no manual labor, nobody born in the 21st. Century will even consider doing anything! Lord forbid anyone might break a sweat!
Jerry

Went ahead and gave it a try and they turned out great. Did it SLOWLY with a bench sander, making sure to rock the rocker to match the original curve, verifying along the way by laying rocker on its side on a flat surface then using a small carpenter's square to make sure they ended up 90 degrees to table. Original grind on at least half of them actually wasn't 90 degrees to start with and the wear spot showed it (first pic below).

Looks good!

Skooter they do look good!!

Yep. keep that baby under 6,000 RPM and under 120 MPH and those rocker arms will last longer than the rest of the truck.

The stovebolt rocker arm length does make their weight a bit much, but it's a benefit as well.
For the same lift, the stovebolt rocker has far less side-thrust on the valve stem than a SBC rocker.

If the tips are that badly worn, what about the condition of the rocker shafts? They have a tendency to wear out on the bottom, especially if the lubrication gets compromised. There's also a fix for that without going to new shafts that are expensive and extremely hard to find.
Jerry

The shafts are good. My spare set had much better rocker tips that I'd planned on using...until removing a few from their shafts. Talk about wear! Both shaft and rocker bushing was so worn I could barely get them off. Rocker bushing on the bottom had a raised nub protruding into shaft oil hole. Shafts almost looked like they had crank throws worn into them.