what would cause rocker arms to fail?
I havent pulled the cover off the engine yet but it sounds like the elephant feet adjusters have come apart again.
is there any site that explains in detail how to correctly install and adjust rockers for a performance engine?
the last ones were installed and the engine spun over to check for binding and/or hitting at valve or valve spring and rocker arms, but they keep coming apart.

There is a lot more to it then just sticking some spacers under the rockers and using swivels. You have to set the valve train geometery. If you don't those adjusters will fail and you'll have accelerated valve guide wear, and worst case...suck a valve. Took me 2 full days to get mine right.

http://forums.aircooledtechnology.com/s ... d.php?t=25

I don't know if you can go to that link, he's pretty secretive about his info but its by far the most detailed on the subject.

Who built your motor?????

Thanks man I will read it when I get home tonight,
this is the engine in Donnies chubby chic

What exact adjusters is Donnie using and how much actual lift?

So the deal is this..

He has Tims stage 2's with dual springs.

82x90.5 motor.. with 5.4s should of went to gether close to stock
width..?

with this cam and the first failing of elephant foot adjusters..
when they failed the PR's failed.. the PR's may not have been
up to the task and failed first causing the adjusters to be beat to death.

nevertheless..
This go round he has a new set of MELLING steel PR's and stock 1.1's
of solid shafts with a second set of Elephant feet..

All should be rather close normal with a W series cam and 1.1's with stock length
PR's.

the swival ball head adjusters were tried on assembly but hit the retainer from what I understand and possible
a lash cap would of been an answer for this.. but then again if the PR's failed this would
of not helped in the beginning..

Not sure what is actually going on..

I do think that if they are not set at a loose/tight zero that could take a real beating
with dual springs?

I run the elephant with single HD springs.. I mine are not always set nice and tight
and I have yet to have a problem..

knock on wood.. lots of it!

to answer your question

W125
w/1.25 522.5 lift
w/1.1's 459.8


The way the head his set up the springs should more than OK to handle the lift and
have plenty of room from coil bind..

so one other question is "is it not enough" and the springs are vibrating..

I hadn't thought of a spring vibration until I talked and read up on the Pauter
roller rockers failing.. I have a set of 1.4s and was worried about this..
so taking the time know your springs. know what kind of pressure they have and
what kind of coil bind(or lack of) would be key in setting this up..

I really think I have a grasp of the issue.. but have no real world experience with
actually addressing or even documenting setting spring height and pressure with any of my motor builds..

it seems very easy to understand.. but a few measuring tools are needed to go after
this knowledge of the spefic setup..

I do also think that 99.99 precent of the motors running out there have not even
cared or knew this was a area associated with motor building and those cars run
more than fine every day.

Hard to say with out looking at it....

What brand were the swivel feet? Try a different brand maybe, there's a lot of crap out there....

And yes, if the PRs go bad they will beat everything to death, so eliminate that problem first if its still hapening.

I don't know why Jake had to try to write a dissertation on how to set up valve geometry. Actually I do, he loves to hear himself yap. It's pretty simple though. The axis of the swivel foot should be parallel with the axis of the valve at half lift. It should also be in the center of the valve at that point. Ideally if it moves across the face of the lash cap during it's stroke it should start on one side, be in the middle at half life, and on the oposite side at full lift. That's it. You basically have shims and PR length to play with, and a little leway with the swivel foot.

Current sent picture
shows the adjuster failing at the drilled oil hole on the threaded shaft.

so the adjuster nut and tip of adjuster fell off and the elephant head with half
threaded shaft backed out.

I suggested to set the adjuster all the way back in the rocker arm then turned about 1.5/2 turns out
from seated.. giving room for out /in adjusting but keep the adjuster from being out to far with the pressure
out there and keep it close to the strength of the rocker..
good thing is the PR stayed in the cup even if realy realy loose..

It does look like the adjusters quality may be in question through out this ..

Here's how I did mine, btw no shims were harmed in the making of my motor

actual 911 adjusters(i'm type 4 so I had to find some 1.7l rockers and then machine .060" off the bottom face for clearance). There are a lot of crap swivel adjusters out there.
chromoly cut to length pushrods
adjustable PR(the exact same kind as the ones I'm running, PR's can have shapped ends then it would comprimise all my measurements).
Started in a ballpark with the adjustable PR, for type 4's thats 26.1cm
Started on the intakes and found the warm fuzz PR length that got me within +/- 5% of the cam's spec'd lift(tried to get as much as I could) while having a perfectly inline swivel adjuster/valve stem alignment at exactly half lift.
I did that for all the intakes, and did an average then determined my ideal intake PR length
Then did the same for the ex valves, turns out my exhaust valse are 1mm shorter then my intakes and the PR's need to be 1mm shorter as well.

Also I think its fitting to mention with chromoly PR's you want zero valve lash. the stock PR's are Al and need .006" lash for expansion. Chromoly PR's expand at the same rate as the cylinders/head studs so it all jives nicely.

Jake wrote that because type 4's last over 100,000 miles and you don't want to wear your guides out before your next rebuild. Valve geometery is a very critical step of engine building, and thats why I spent 2 full days on that to quadruple check everything and make sure it is as close to perfect as I can get. Lots of math and measuring involved.

Brian- I'm kinda surprised your not super anal about valve train geometery, your super anal about every other part in the motor.