What the . . . ? Fattie adjusting screws!

Several months ago I bought a Gene Berg swivel screw ("elephant foot") valve adjuster kit for the Wonderbus. Didn't install the kit because that engine blew up. I purchased a replacement 1600 DP engine in Mexico and put it in the Wonderbus and it has been peachy ever since. Today I got around to pulling the rocker assemblies off the new engine with an eye toward installing the swivel foots and discovered that the newer rocker arms take M10 adjusting screws. But the GB kit is set up for rockers with M8 thread.

I stared and harrumphed for a while, then disconsolately put the rocker assembly back onto the engine with the factory adjusting screws. They are already becoming faceted so I want to sort out this little issue out promptly.

Berg's website makes no mention of the swivel set coming with anything other than M8 adjusters, so I reckon I need to install rockers with M8 threads (I have e-mailed them requesting advice). The old engine's rockers have a lot of fretting where the rocker bears against the rocker axle, so I don't want to use them.

So, sign me,

"Seeking a set of good-quality factory stock-ratio rocker arms that take the M8 adjusting screw that are either new or in wonderful condition."

This is a bus -- don't need ratio or fancy billet valve train bits.

Reply to
Mike Rocket J. Squirrel Elliot
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the rocker

Turn the axle shafts "upside down" to get the rocker to ride against a smooth, non-worn side of it. Note that you may need to drill the stud holes a little bigger (not all the way through!) to allow room for the thicker base of ths stud. Study the other end of the hole, you'll see a step cut.

Or just buy new shafts or whole assemblies and eliminate all your problems :)

Jan

Reply to
Jan

For a stock application, stock rockers and adjusting screws are fine. It is normal for the adjusting screws to become faceted. Anyway, either with the Berg adjusting screws you would have to check valve clearances on every oil change, to motitor exhaust valve stretching. In case you decide to install them, keep in mind that you should keep the stock valve geometry, and to do this you will have to grind the rocker arms. Do not put spacers under the rocker towers.

Bill, '67 Bug.

Reply to
Bill Spiliotopoulos

On 12/8/2004 1:10 AM Jan stood on a soap-box and preached to the unwashed masses:

the rocker

These /are/ new shafts/assemblies on the new engine and are in tip-top condition. I want to stick on the Berg swivel feet but they are set up for M8 threads, whereas these new rockers are threaded for M10. So how would buying new assemblies help? I may be overlooking something.

Reply to
Mike Rocket J. Squirrel Elliot

On 12/8/2004 3:50 AM Bill Spiliotopoulos stood on a soap-box and preached to the unwashed masses:

The advantage to the swivels is that the ends of the adjusting screws do not get faceted. As I understand it, once the tip is faceted, accurate valve adjustment is very hard to accomplish. So I'm either replacing adjusting screws (M10 ones? are they easily available?) or living with sloppy valve adjustment.

So the Berg setup -- shims under the towers -- is bogus? I know that the valve geometry must get disturbed by the shims, but this is a 1600DP on a bus with standard valves and non-ratio rockers, etc. I don't think that this slight change to the geometry will affect my performance.

Back to my question: where does a squirrel find new or really good condition stock rockers w/ the stock M8 thread?

Reply to
Mike Rocket J. Squirrel Elliot

"The advantage to the swivels is that the ends of the adjusting screws do not get faceted. As I understand it, once the tip is faceted, accurate valve adjustment is very hard to accomplish."

Agreed. Once the tip of the screw starts to flatten out a bit, you do the obvious..turn it in to reduce the clearance. But that also presents a new 'unworn' portion of the screw, so your lash adjustment becomes tedious. The clearance goes away very quickly; the new surface on the screw is higher than the worn spot, and the screw is moving towards the valve stem at the same time.

"So the Berg setup -- shims under the towers -- is bogus? "

No. I've used the berg shims. You don't want to use washers because that can cause the rocker tower to fracture, but using a berg shim which covers the entire surface is not a problem in my opinion. I don't like the fact that the berg shims are a press-fit on the studs, Berg says they need to be like that..I disagree. I usually drill them out just a tad so they slip on easily. I visually check to make sure they remain lined up as I tighten down the rocker shaft.

"Back to my question: where does a squirrel find new or really good condition stock rockers w/ the stock M8 thread?"

No idea. Have you confirmed that berg does not offer the swivel adjusters in the larger thread? If you haven't run the M8 sized ones yet maybe they will exchange them for you?

Chris

Reply to
Hal

against the rocker

OOps, I need to take a few reading comprehension classes myself. Disregard anything and everything I said :)

Jan

Reply to
Jan Andersson

Not very hard, just a bit less accurate, but nothing to worry about. You can replace or resurface the adjusting screws by wiping on sandpaper every

3-4 oil changes if you want.

You can adjust just a bit tighter (so that the feeler gauge slides tightly) to compensate for the wearing in in the new position. Anyway, don't worry so much about extra accurate settings, even the feeler gauges don't have

100% accurate thicknesses. They usually are 10-20% off their nominal thickness. Try to measure one with a micrometer and you'll see. Try not to have less than about 0.15mm valve lash the engine will be happy. With more valve lash the valve noise increases and if exesive you might lose a bit of power.

It doesn't have to do as much with performance, as with valve guide wear. Maybe sims or spacers don't alter the geometry too much, but why go worse than stock? The idea is to do modifications the right way in order to improve things. If you find that spacers are needed, the entire valve geometry must be rechecked. Otherwise, it is better to stay with the stock adjusters.

Bill, '67 Bug.

Reply to
Bill Spiliotopoulos

I don't know where you can find, I live in Greece so I won't be able to help on this one. But I believe that most probably you wouldn't have a problem using your old rockers on the new shafts. It is normal for the rockers to get polished at the load side (bottom) but this is not to worry, expept if they are really really worn and they have noticeable sideways when fited on the shafts.

Bill, '67 Bug.

Reply to
Bill Spiliotopoulos

On 12/8/2004 9:22 AM Hal stood on a soap-box and preached to the unwashed masses:

They don't list anything but the M8 on their site, and they've not yet responded to my e-mailed inquiry of yesterday. We await patiently.

Reply to
Mike Rocket J. Squirrel Elliot

On 12/8/2004 11:57 AM Bill Spiliotopoulos stood on a soap-box and preached to the unwashed masses:

This makes sense. I memory has it that the bearing surfaces were more than polished, they showed signs of fretting. Certainly the shafts showed fretting. I'll take another look at the rockers ...I might very well be able to use them! Thanks Bill.

Reply to
Mike Rocket J. Squirrel Elliot

I thought the newer rockers were 9mm

RT

Reply to
Raymond Lowe

Update: Berg Co. replies that Brazilian rockers use M9 thread, and they don't make their swivel footsies in anything other than M8. I was mistaken about these being M10, mis-read the tap.

Reply to
Mike Rocket J. Squirrel Elliot

Reply to
ilambert

I have 473,000 miles on my original cylinder heads, rockers and shafts. The word you seek to describe the wear is not "fretting" but rather "galling." I have plenty of galling that is now 180º away from the wear surfaces on my original rocker arm bushings. Having deleted the cylinder head gaskets as required by VW's Type 4 engine technical service bulletin, spacers were required to maintain optimal valve train geometry. Rocker support shims are not rocket science and are no big deal, your shims just need sufficient surface area to keep the stands happy. The 8mm rocker arms can be ground down .060" under the threaded area that accepts the swivelfoot adjusters to help you achieve sufficient clearance. I use the 911 elephant feet, accept no crapola subsitutes from China. They have allowed me extended high rpm operation for well over 25,000 miles of easy valve adjustments and ridiculously decreased guide wear. Wish I had done this 25 years ago. Colin

Reply to
Colin

Nope, nope, not a juicer; just good old-school aluminum and steel. No fluids involved.

Reply to
Mike Rocket J. Squirrel Elliot

Fretting, galling -- I don't know enough about metallurgy and machines to know how to tell the difference. The online glossaries aren't much help for me:

Fretting Action that results in surface damage, especially in a corrosive environment, when there is relative motion between solid surfaces in contact under pressure.

Galling The damaging of one or both metallic surfaces by removal of particles from localized areas due to seizure during sliding friction. ALSO Developing a condition on the rubbing surface of one or both mating parts where excessive friction between high spots results in localized welding with substantial spalling and a further roughening of the surface.

The Gene Berg kit comes with useful shims.

How did you grind them? John Connolly sez to grind them lengthwise, not crosswise, or the rockers will be weakened.

Sign me,

Hoping to do this now.

Reply to
Mike Rocket J. Squirrel Elliot

...........I have the 911 adjuster screws from Aircooled.Net and when I learned that I had ground the rockers in the wrong direction, I used a bastard file to remove the wrong direction grinding marks on the rockers. The only way that I could ever grind them in the correct direction woud be with a small dremel bit instead of my bench grinder. I too would like to know how grind them properly and what type of tool to use.

BTW..........I have about 6 or 7 thousand miles on them now without having any problems.

Reply to
Tim Rogers

I use a grinding stone tool for a drill, for coarse grinding. I suppose a bench grinder is even better. Then when I am about where I want, I polish the grinded area with a 80 grit flap-wheel attached on the drill, on the correct direction (lengthwise). I also remove all sharp edges around the cut. Be carefull, the flap-wheel removes material pretty fast, so do not overdo it.

Bill, '67 Bug.

Reply to
Bill Spiliotopoulos

..........Thanks Bill!

Reply to
Tim Rogers

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