Rocker Arm Advice

simman77 · simman77's Garage

File this one under "while I'm in there" I guess. Long story short, my #5 rocker shaft came loose and walked out of the carrier. Here are some pictures of the shaft and rocker arm. I will be adding the RSR seals on reassembly. Does the rocker arm cam surface wear look within reason?

Flat6pac · 04-10-2011, 06:24 PM

Thats a forged rocker, you dont want it in the engine anyway. You jump time and loose the engine.
A lot of times the hole is too big from loading and reloading the rockers and there isnt enough housing left to get the rocker to expand and grab.
The rockers are 65 and 66 original equipment then they went away from forged to castings.
Bruce

tom1394racing · 04-11-2011, 01:45 AM

That rocker is badly worn and must be replaced.

The matching cam lobe will also likely be worn and the cam should also be replaced or repaired.

304065 · 04-11-2011, 05:45 AM

And that is a shorty rocker shaft from 64-66 only.

You can see how the center between the grooves is shorter.

Replace your rockers (the forged ones are worth $,$$$ so save them for a racer!) and shafts at the same time. Tom Butler (above) can help you out here.

Probably a good idea to send used rockers and shafts out for rebushing and polishing the shafts before they go in. And Tom's right, your cam lobe is probably flat. . .

simman77 · simman77's Garage

Wow. Thanks for the advice guys.

Flieger · Flieger's Garage

I think you should refurbish any of those rockers and shafts you can, and find replacements for the others. You have a 1966 911, after all. Those are the rockers it is meant to have. Porsche decided too expensive and race-oriented for normal drivers.

hcoles · 04-12-2011, 06:25 AM

I'm worried about the carrier - also you might consider installing a setup from cgarr using the new bushing material.

Walt Fricke · 04-12-2011, 05:05 PM

I can't tell just how much the rocker arm cam surface was worn by all this. Maybe not too badly (and cam maybe OK also) because this was not the result of an oiling problem. You can clean it up a bit like this: place a piece of fine grit (maybe 600 or higher) wet/dry sandpaper on a pane of glass on your workbench. Glass is usually pretty darn flat. Wet the sandpaper and work the rocker surface over the sandpaper. You can clean up the surface some that way without changing any angles or the like. The existing surface will keep it square.

I'd replace the one rocker shaft with a new (or good used) one of the longer variety. Yours is most likely toast. If you had a polishing wheel you could see how it polishes up, but shafts aren't awfully expensive, at least if you are buying just one. The longer kind will work fine, and are easier to install because one end is flush with the short side of the cam carrier. No fussing around with feeler gauges to get it positioned right. You'll need the longer hardware to go with this.

The RSR seals may help if the holes in the carrier got damaged some by this event. If it is really damaged they won't help at all. But the longer shaft should help with the sealing as well,

The rocker bushing looks well worn. But you can still use it.

This approach gets you back and running the fastest (and with the least expense), and things aren't worse than they were before.

Or you can send just that rocker to Craig Garrett for resurfacing and rebushing, get another shaft and hardware, and be back in business. Craig can turn things around rather quickly.

To me, many of the other suggestions are ones for you to consider when you decide to rebuild your engine, or at least the top end. Then you could change out the rockers for cast iron, rebushed, and reconditioned ones, and sell your forged rockers to a racer to pay for your replacement ones. And replace all of the rocker shafts. I don't think all that wear on the shaft came from it getting loose. I suspect it has been in there for rather a long time. You could pull a neighboring shaft and rocker to compare easily enough.

But you can pick a time convenient for a top end rebuild (and whatever more you might want to do "while I am at it.").

I had a rocker shaft get loose on me once (the result of not tightening the shaft when setting the cam timing on rebuild, and forgettiing this while installing all the other rockers and shafts later) at the track. This announced itself by a lot of oil escaping, which had to have happened here also for quite a while if you ran until the rocker came completely loose. It takes some time for the shaft to back completely out to the point that the rocker doesn't rock.

I just put it back into place and went on about my weekend. Worked fine thereafter. Of course, I might just have been lucky.

Steve@Rennsport · 04-12-2011, 05:37 PM

FWIW,.....the early forged steel rockers have a hard chrome surface and one should not sand those willy-nilly. Depending on the surface and if its is damaged, they can be re-chromed to like-new. Further, these can be bushed (some had no bushings) to recondition them.

When we rebuild them, we will usually have them re-chromed and then we regrind them with the proper surface finish to retain oil and restore the proper shape.