Rocker arm shaft leaks!

[Wil]

I've noticed during head dissasemby, that my rocker arm shafts were leaking out of the ends and dripping oil down on my cylinder heads. I wondered if it would be ok to use RV high temp silicone to seal the cones at the end of the shafts upon reassembly. It looks like that would be all you would need to solve the problem. any thoughts?

[sammyg2]

i say nope, no RTV. If it seals at all it will be a temporary fix.

Inspect the bores very carefully and make sure they are clean and not scored, then use the RS rubber seals on your shafts, they work very well. Clean the threads on the thru bolts and use a small amount of never sieze on them, that wil lhelp to get a good torque. You can go a little higher than the factory recommended torque also.

[88-diamondblue]

Use the RS seals and torque to 16-18lbs. JW recommends 18Lbs and I went with 16 on my rebuild with no leaks.

[YTNUKLR]

If the cam towers have been torqued up a few times before, 20-22 lb/ft + the RSR shaft seals will almost guarantee a leak-free motor, as long as the rocker shaft bores are in good shape..

[KobaltBlau]

if you're patient you can try without RSR seals first; only 2 of mine needed fixing and with a good clean-up and torque they sealed. no harm in the seals I guess, but my compulsive self didn't want them on just 2 shafts!

[YTNUKLR]

Originally posted by KobaltBlau
but my compulsive self didn't want them on just 2 shafts!

LOL...sounds like me...

[Henry Schmidt]

In over twenty five years of building these engines (400+) we have never seen a need for sealing rockers shafts with o-rings.
Polish the shafts, inspect them for cracks, inspect the cam towers for damage, clean the cam tower as well as possible and torque properly.
It should go without saying that proper location of the rocker shaft is primary.
We recently started plating the rocker shaft hardware and the additional thickness of the expansion sleeves may also help to seal the shafts.

Because of the butchers in the business who over tighten the rocker shafts (over thightening can damage cam towers), it is advised that you test the shaft after it is torqued to verify that it is tight.

[philippeF]

Hello M. Schmidt
what is your advice on the rocker shaft torque value ?
thanks
Philippe

[Henry Schmidt]

15-16ft / lbs 170 + in/lb Then check to insure that the shaft is secure.
We also measure the shafts after we polish them. The minimum size seems to be .7075 inches.
If you over torque them you run the risk of cracking the shaft and expanding the cam tower.

[Ken911]

put seals in mine and have been told several times since that they are REALLY hard to get back out in the future.

[hcoles]

I had the same issue...a couple of leaking shafts. I installed the seals during the rebuild but still had 2 that leaked. Recently I pulled the engine and removed the leaking shafts...inspected and reinstalled with the idea to not under torque. I did notice a few dings in the housing because of my being stupid during my first disassembly (butcher job). After a track day and normal driving I don't see any leaks down on the bottom but could still be leaking a bit but apparently not worse. I like what Henry S. says....if all things are proper then the seals are likely not needed.

Now that I know how all the hardware works and where to be careful I'll be better off in the future... one of the many ways to mess up when rebuilding these motors... IMHO.. very glad to have Henry S. to help with excellent proven advice.

[BReyes]

Yes it is really helpful when can learn best standard op proc.

Everywhere you read, the variables often involved are with workmanship.

Let us know if you merely retorque and how it turns out.

Regards,

[afterburn 549]

seals are cheap............

[Henry Schmidt]

Cheap or not, proper assembly of quality parts eliminates the need for half thought out accessories.

These seals were used on RSR because the rocker shafts on an RSR were different and fit more loosely than a production rocker shaft. They fit them that way so the shafts would slide in and out easily for valve adjustment purposes.
Remember that RSR rockers did not have an adjustable end. They were solid and used lash caps for adjusting the valves.

Chances are that if worn out , damaged parts are used or good parts are assembled improperly even o-rings won't eliminate leaks.
Patching a hole in a muffler might work but installing a quality part is always better.
When it comes to building a proper Porsche engine, one you can be proud of, don't just do it because it's cheap. Do it or use it because it's the best method you can find.

Fuzzy dice and bobble head dolls are cheap too. They have no place in a Porsche. Unless of course it's a WRD bobble head.

[Henry Schmidt]

Good used cam towers are cheap, oil leaks suck and the labor to replace a repaired cam tower that didn't work, priceless.

Not enough money to do it right but pleanty of money to do it over.

[sammyg2]

I have only built one 911 engine, not 400.
I used the RSR seals. They were cheap and do absolutely no harm.
After 2 years my engine does not leak. It wouldn't have leaked without the RS seals, but now for about $15 I have added insurance.
There is absolutely no reason not to use them other than the $15 or so you might save.

if I build another engine in the future, I will use the RS seals again.

[afterburn 549]

I know I would never put an other engine together w.o. them. Cheap insurance !

[Henry Schmidt]

An interesting PM I recently recieved

Jim Sims wrote on 07-08-2006 10:51 PM:
There was a 911 with a colorful engine (lot's of cad plating and powdercoat) in my garage last month but much to my suprise it was spotting the floor with oil. I slid under and looked up and several cad plated fasteners sported more oil drops ready to fall. I checked the engine top side and there was not a speck of oil to be seen. The owner is very proud of the engine so I didn't have the heart to bring it up and it really isn't a big deal. Engine makes good power though and looks great. Oh, by the way, the repaired cam towers with RSR seals on the rocker shafts do not leak a drop of oil after three years of operation and 8,000 miles. Cheers, Jim

Hi Jim
If your story is a thinly veiled attempt to tell me one of my engines is leaking in an attempt to make me feel bad and pat yourself on the back, wow, good one....
A fact you won't see in any book, in 1992 Porsche had a 4% dyno failure at the factory on new engine because of oil leaks. New parts, factory trained mechanics.
We use the best techniques and top quality parts to build the best engines we can. Sometimes they leak. No bodies perfect.
That is why we offer the best warranty in the business. If your customer has an engine that leaks, whether we built it or not you do your customer a disservice by not telling him.
If it is one of my engines we want it right and the customer that you have chosen to deceive, deserves better.
Thank you for bringing it to my attention, now bring it to his.

[Henry Schmidt]

It looks to me like this has become a challenge of some sort.

It's not a contest.
I post here to help DIY engine builders succeed. That's it.
When I post something here it is not an attempt to prove something.
We build a fairly large number of air cooled Porsche engines.
We have had some success with the techniques we use.
I'm passing that experience on.
Guess what, it's free. If you don't want it don't take it.
In this post I was trying to say that if you use quality parts and don't rely on gimmicks, you will have a better chance for success.
That's all, take it or leave it.

[afterburn 549]

Henry- I dont think there is a contest. For some of us $$$$ is a obstacle to overcome.....If I had enough of it I would send my stuff out , or better yet buy a new " whatever"....for most of us a rebuild is big $$ !!, Time consuming- endeavor,...no contest you have built more air cooled ic engines then I have looked at.... The pt is a couple dollars of insurance is far less $$ then going back in. I think you are upset over a accusation ?? sort of ?? No worries mate- we all know you do quality work and stand behind it. We all appreciate your deeper in sight....but "O" rings will never hurt