Help! My rocker arm shaft is falling out.

[RickKlem]

I removed my valve covers to adjust my valves for the first time since the motor was rebuilt. When I removed the lower left cover , I noticed that the rocker arm shaft on the number one cylinder (exhaust) was pushed toward the front of the car. When I reached up to check it, the rocker dropped into my hands. "Oh my god , was that close or what" .

IF , this would have happen while the engine was running ,what could have happened?

Anyways, I have looked at it , and I can't figure out what holds it in. What do I need to do to repair the situation and How do I insure that the rest wont come out?

Also , is there some kind of seal or O-ring that should be on this shaft? If not , how does the oil NOT leak out the end of the case ,where the shaft protrudes out?

Thanks
Rick

[Jim Sims]

Broken rocker shaft and a bent valve could have resulted or other worse problems. The rocker pivots on a hollow rocker shaft. The rocker shaft is retained in bores in the cam tower by elastically flaring the ends of the hollow rocker shaft out against the bores. This is done by an axial pinch boltwith bushing and nut which expand the ends of the hollow rocker shaft radially outward. You need to find the rocker shaft, the pinch bolt, bushing and nut and check the bores of the cam tower for damage. You may need a new cam tower on that side. Likely the pinch bolt was tightened insufficently; if one uses the recommended torque found in at least one of the popular aftermarket references the bolts will be too loose. There is also the possibility that the rocker shaft wasn't correctly positioned side to side in the cam tower bores. The orginal design depends on very good metal to metal contact (shaft to cam tower bore) to effect the seal; however there are square cross section rubber seals sometimes called RSR racing seals that are put in the grooves in the outside of the rocker shafts to effect additional sealing. This is highly recommended to do. All the rocker shaft positions in the bores and pinch bolt torques should be checked. If the pinch bolt head orientation was not done properly the engine may need to be dropped to obtain access to all the bolts. Good luck. Jim

[Jim Sims]

From a previous thread on the topic:

The link is here... http://www.competitioneng.com/WaltsPage.htm

and a quick excerpt:

It is my opinion that rocker arm/shaft installation is responsible for more 911 rebuild oil leaks than anything else.

Step 1: "Dry installation"

When you install your rockers you naturally put engine assembly lube on the rocker arm and shaft for break in.........right? Wrong!

Install each rocker and shaft dry, then after torqueing the shaft, then oil the rocker through the oil holes and either side of the rocker. You can still put cam lube on the cam and rocker face.

Step 2: "The torque"

I'm a fanatic about torque specs. I follow the factory bible to the letter 99% of the time. But this is one of the exceptions. The factory manual says the rocker shaft torque should be 1.8 kpm. Multiply that x 7.23 and it converts to 13 ft lbs. This spec is fine if you have the luxury of new cam towers and new rocker shafts, but that is a very rare occurrence. Usually the cam towers have been used at least once or twice before. So........you torque your shaft to 1.8 kpm and less than a thousand miles later it looks like your new engine was built by a hack. On used rocker assemblies increase the torque to 2.5 > 2.8 kpm and the rockers won't come loose and the engine stays dry!

I have been using this installation method since 1980 and it's always worked.

[RickKlem]

Great response Jim, Thanks

I looked at the shaft and I see the grove that you mentioned but there is no seal or o ring installed in the grove. Does our host supply the "RSR racing seals" ? I guess I could " do a search " and find out.

When I mentioned in my first post that the rocker fail into my hand , that was a figure of speach. My apologes (SPl) but the rocker was extremly loose. I will be removing it and checking it for any wear.
Thanks for your quick reply .

Rick

[RickKlem]

I don't see how I'm going to get a torque wrench with a allen head socket into the tight space to get it to spec ,which is around 20 ft lbs . If I do it with right angle allen wrench , is there any way that I could over tighten it?

Any ideas on how to get close to torque with out a torque wrench?

[Jim Sims]

1/4" drive torque wrench which is expensive. I have used an adapter tool made by a friend to permit the use of a bulkier 3/8" drive torque wrench. I recall we tightened to the equivalent of 18 ft-lbs. The adapter was made by welding a 10mm 3/8" drive socket onto the end of the handle of a Sears Craftsman 1/4 drive ratchet. A Snap-On 1/4" drive 5mm hex key bit (Snap-On part number TMAMXS5E) was mounted on the 1/4" drive ratchet. The Sears 1/4" drive ratchet with the 5mm hex key bit fits down in the available space. The torque required of the 3/8" drive torque wrench (which is outside of the tight space) is reduced by the lever arm produced by the adapter tool. A trimmed back right angle 8mm hex key is used to hold the other side while tightening. Pelican should have the RSR seals. Jim

[widebody911]

Originally posted by Jim Sims
It is my opinion that rocker arm/shaft installation is responsible for more 911 rebuild oil leaks than anything else.

Can I get an "Amen?"

[Jim Sims]

"It is my opinion that rocker arm/shaft installation is responsible for more 911 rebuild oil leaks than anything else"

I think you're quoting Walt at CE not me, but I may possibly agree, although there are plenty of other places to cause leaks due to poor assembly practices/materials.

The RSR seal part number is 911.099.103.52 or Pelican C-099-103-52; they are $1.50 each and 24 are required to do all the rocker arm shafts. Jim