Jimmykash

I am finishing rebuilding the top end of my brother's motor and i have a question i cant seem to find an answer too:

I'm not sure what to call them, but the "tips" of the rocker arms that actually touch the valve tip.....are loose. Are they suppose to be that way?

Some have actually fallen off but attach easily, it seems like this would a normal thing but i dont know the motor enough. Can someone here help me out?

by the way, they do not look worn out at all on the side where they contact the valve. The "tips" have a nice wear pattern as well

thanks

jimmy

PorschePhD

They should not fall off. We call them elephant's feet. They should rock and have some play, but not come off. Also if you look at the center and it is discolored compared to the rest of the head you will want to replace them. When they get to this point they are no longer flat. They can cause excessive valve train noise.

Jimmykash

ok, do you have to replace the entire rocker arm or just the feet?

thanks

Steve Weiner-Rennsport Systems

Just the feet, as long as the rocker arm bushing is not worn.

an6drew

Is it possible to replace these w/ out taking the engine apart? I'm asking because I have valve noise even when the clearances are set correctly. The valves sound fine when cold, but get v. noisy hot & I'm wondering if the elephant's feet are the culprit? Oh, the top end was rebuilt w/ new valve guides 30 000 miles ago.
thanks
Andrew (82SC)

Steve Weiner-Rennsport Systems

Yessir, its quite possible but kinda tricky for those who have never done it before.

Worn rocker arm bushings and shafts will generate more valve train noise when hot, but I'd make certain that your valve adjustments are spot-on before you start replacing parts.

Lastly, worn valve guides will also contribute to noisy valves. I hope your rebuilder did NOT use Factory guides when the heads were redone.

an6drew

Thanks for the input Steve.
I'm not sure what guides were used for the rebuild- I've put a question in w/ the mechanic who did it for the P.O. I was assuming that the valve guides are ok, as the car consumes little oil (1/3 quart per 1000 miles). I think that a couple of valves are considerably noisier than the others so will probably have another go at those 2 (so far I've tried twice & a mechanic once). Can worn rocker arm bushings/shafts be discerned by checking play w/ the valve covers off? Lastly, other than noise are there any other problems that could come about if the bushings are indeed worn?
Andrew

PorschePhD

One of the issues you will find that worn rockers will cause is an inconstant adjustment. The feeler gauge is not really measuring a flat surface and will normally mean that the adjustment will be loose and not in spec. In time the improper adjustment will cause the stems on the valve to wear. Not a problem normally because you can touch them up by machining them, but if that goes below specs then they will have to be replaced. I see a lot of motors that have not had adjustments regularly or done improperly and the stems are shot. Of course too tight will burn a valve You can replace just the feet with the threaded part. They are one piece. You can reuse the nut. When you remove the rocker if the bushing looks to have a streak or burn mark then the bushing will need replacement. The rocker will as well if it shows the same sign. While you are in there do your self a favor and install the 40.00 Orings in the rocker shaft grooves. This will prevent oil leaks for years to come. Steve W is right that excessive wear is a BIG culprit of a chatty valve train. Easy to fix.

You can do this in the car....I would remove all of the side tin and anything else in the way. If you are still uncomfortable with the angle of view then undo the rear mount bolts and let the motor come down a hair on a jack. Support it with jack stands and watch the fuel and oil lines...Invest in a 5mm 1/4 socket for a ratchet and a cut down allen for the other rocker end. This will make life much easier. Make sure you have plenty of feeler blades and a stubby screw driver and go to town. It is time consuming, but not hard...Just watch the end of the shafts. When looking at the cam housing where the rocker shaft goes through you will see a thicker side and a thinner side. The thinner side will always have the rocker flush with this. The fat side should have a gap on the back side. Also watch the orientation. As a rule of thumb have the small allen side of the shaft on the thinner side of the cam housing except in cases on the end where you wouldn't be able to get to them. This will leave not only fix the issues you have but make it look factory and complete a job well done...

Hopefully this doesn't confuse more than it helps..

PorschePhD

Here is what you will be dealing with

Russ L.

Stephen...while you're on the subject of valve trains...I'd like to ask how I can tell if my 3.2 has had the turbo cover upgrade. There's no leaks that I've found but like Jimmy , the valve train does sound a bit noisy to me. This is my first 911 so I'm not really sure what has been done to her.
Thanks , RUSS

PorschePhD

The old covers are thin and have a series of ribs going vertically on the cover. The turbo versions look like this.

Russ L.

OOOOH BABY THAT'S PURRRTY!!! Are those covers aluminum and powder coated or just painted ? I'm dieing to pull the drivetrain out and detail her! Do you have any thoughts on anodizing parts? I've heard it makes the aluminum brittle?

PorschePhD

I like powdercoating or painting. The powdercoating is much more durable. The anodizing is not really an issue. It does weaken the metal a bit, but not enough to cause issue.

Jimmykash

Thanks a lot fellas, you've always been really nice to me when i need some help here

Just some info:

heads were re-done by a porsche expert. I gave them to my local porter/head guy and he had a friend that does mainly just european/high end stuff: Ferrair, Porsceh, Lamborgini, etc. So i am totally sure everything was replaced correctly. We (my brother and i) were lucky they we took it apart when we did, the exhaust valves were all shot and the guides had EXTREMELY EXCESSIVE play. My head guy told me another season of having fun and it would've dropped a valve

Also, i will buy all new feet to be safe and i'll get the o-rings too. Lastly, none of the bushings seemed burnt are had excessive play in them

thanks again for all the help

jimmy

PorschePhD

I personally would ask for all the sheets and measurements. The way I do things is generalizations are not good enough...Make sure you get all the info for your files in the future.