The Stovebolt Site Forums The Shop Area Engine Shop Dressing rocker arm tips.

First of all, my shop is the opposite of modern high tech. It has electricity, that’s it, no wifi, internet or phone. So in this low tech operation I finally got around to working on the lifter tick the 216 has had for 15 years. While chasing an oil leak I fell into the old “while I’m here” trap. Pulled the rocker arm assembly, disassembled and dressed the rocker arm tips.

With just under 60k miles and 75 years everything looked pretty good, except the valve stem wear on the rockers. Predictably all had wear, some noticeably more than others.

My first thought was too just use the grinder, nope, grinder wheel needs replacing. Dewalt angle grinder, maybe. Wait, under the work bench is a HF belt sander I haven’t seen in years.

Belt sander it is. Secured in the bench vice it was easy to match the factory face profile on the rocker tips.

Now that’s using your head for more than just a hat rack! You gotta love it when someone else thinks outside of the box. I too graduated from Low Tech!

Thanks for sharing!

I have an adapter device that fits my Black & Decker valve grinding machine that's used for refacing rocker arm tips. It has several different radius grooves to handle shaft-mounted rockers with different lengths and leverage ratios. Much more accurate than eyeball methods to put the same arc on all the rocker arms.
Jerry

Jerry, I can certainly see the advantage your setup has over the eyeball technique. I briefly considered building a simple jig to keep things square…nope. I did keep a close eye on the contact area while surfacing and will check and adjust often while things are wearing in. My moto of late has been to just try and make things better than they were.

We’ll see if this is better

Just about every time the subject of refacing rocker arm tips comes up, one of our resident pot-stirrers (No, not me!) starts pontificating about putting an exact radius on them. Of course, he never offers any constructive suggestions on how to do that. In my somewhat biased opinion, anything that is done to correct wear from running these old engines far beyond their projected "use by" date is a good thing. Press on!
Jerry

i have a 12" sanding disc that i can fit in my lathe cuck now all i need to do is make a stand to fit my tool post to hold the rocker. i searched my steel supply last night but couldn't find anything the right size to fit the rocker arm, i'll have to machine a piece of round stock. just by eyeballing it, i don't think you can get a full arc on the rocker tip from a stationary mount to a flat grinding or sanding disc it just doesn't fit one would have to use the edge of the disc, i could be wrong, it just looks like the rocker holder its self is going to need to pivot. i would like to lock the tool post then surface the rocker tip, more engineering today.
Jay D.

I eyeballed mine a few years back. Some of my first attempts were noticeably less-than-perfect.

But once installed, the whole valve train has been quiet and trouble-free.

If you turn a piece of round stock to be a close fit for the rocker arm pivot hole, mount it vertically on your tool post holder, and rock the carriage feed back and forth, you can follow the contour of the rocker tip by turning the rocker against the disc by hand, and moving the carriage back and forth with the hand wheel. Just try to follow the existing radius of the tip and smooth out any wear spots.
Jerry

When they get so bad that they tear up your feeler gauges and give readings 010 or 015 looser than you wanted, just use a dial indicator, if you have one and save a lot of trouble. You can also sue the 1/8/turn-off-tight-method (or whatever 0.008 works out to).

I have seen them that badly worn and still in service and the owner just wanted less noise not a major machine shop job. I think those days are gone. Few are in original condition and run as daily drivers. But, I fear somebody will pipe up who has some old shop pickup that's still shagging parts, maybe with an overhead oiler too.

That's not what I did on my engine though.

On the rockers that I'm converting to roller bearings, I'll also be refacing the tips, and polishing them to a mirror finish with a hard felt buffing wheel and jeweler's rouge.
Jerry

I dress mine on a Dunn's knife sharpening wheel on a high speed bench grinder. I load the wheel with jewelers rouge and work it with a steady hand, rolling it to match the contour of the tip.
I continuously check my progress by looking at the worn section of the tip and work it just until the damage is gone. It is a rather slow process given the super fine abrasive in the jewelers rouge. When I am done, I have a mirror-like surface.

Theres no need to resurface the whole tip, just remove the high spots. I've worked on a lot of stamped steel rocker arms just using a scotch-brite sanding disk mounted in a drill press. At high rpm, a couple quick passes can really smooth out the tip. NextI use a flap wheel with alternating flaps scotch-brite / smooth emery cloth. Not sure where I got the wheel from, but it really leaves a nice finish.

I used my floor model belt sander. I set the table 90° to the belt, then set the rocker on it’s machined side shoulder where the shaft goes thru. Being careful to keep the shoulder in contact with the table, I lightly touch the belt rocking it back and forth trying to match the existing contour. Checking often and only taking off enough metal until the groove was eliminated. I followed this up with progressive grits of sandpaper to polish it up.

Whatever the polishing method happens to be, make sure it's done in the same direction the rocker tip sweeps across the valve stem. Even microscopic grooves at right angles to the tip movement will exacerbate the rate of wear.
Jerry

BINGO, i'll try it, you always have good ideas!

Here are the instructions for the rocker attachment for my 70 year old Sioux valve machine. I haven't worked a head in a long time. But I am hoping to get back to doing a little of it since I auctioned off my trucking business and have the shop to myself now. Years ago I used it a lot because I saw a lot of rockers with a pretty deep grove knocked into them making it impossible to adjust the valves properly. It wouldn't surprise me if the engine manufacturers didn't use something similar when they built the engines. 75 years ago.