You Must CHECK the Rocker Shaft Bolts when you DIY Valve Adjust!

[DRACO A5OG]

Hey Fellas,

Well, sort of a good and a bad day.

Yesterday, after a normal freeway round trip up to the valley, a hot day in the 90's, almost home, I heard and uneven engine tone, not steady but almost ossillating, then I decided to get some gas and check the oil level. Weird how we know the sound of our engines

DARN Lucky I did, well I hope.

While filling up the gas, idling for the oil level check, I heard a sudden "Plunk" like ball pin hammer to aluminum sound, then idle suddenly skipped and miss-fired and plunk plunk plunk. Well here is a video to better describe it:



Shut down, immediately! Well, after the video.

Looked below, found this abnormal oil puddle, I usually get a drip or two, but never ever this much in this short of a time span (??? * )



Called AAA & towed her home, geez, even on the flatbed, she still looks good to me



DAY 2:

Drug myself out of bed, not really wanting to face the music. Then I dove right in, head first.

The dreaded probing surgery, cracked opened the lower driver side valve cover to allow the oil to leak out the bottom ( I noted something here * )

Here is the culprit "plunking" noise



and it's evil sister and the real culprit ( the oil leaker too * ):



So now I see where I was getting the valve cover leaks. I always thought it was the cam shaft o-rings. Now it makes sense if the rocker shafts are loose, it also will seep out oil, WARNING SIGN!

So for the benefit of you DIYer valve adjustment guys, CHECK the darn Rocker Shaft bolts while you are in there. 11ft lbs or SNUG (credit TRE).

[tkmoore]

Great advice and I hope she is back up and running great again? Tim

[356RS]

Good save. Glad you were not at speed on the freeway. Now you get to check them all!

[Wayne 962]

Don't overtighten them though - or you can damage the aluminum housing. Also a good idea to use the RSR seals in the little grooves there to prevent oil leaks. The grooves were not meant for seals - they are meant to help the metal compress into the aluminum and seal. If your shaft was floating around here for a while, then it's probably damaged the housing a bit, and you may have difficulty getting them to tighten up again. Hopefully not, but definitely use the RSR rocker arm shaft seals - we have them in the catalog of course - the car needs 24 of them.

-Wayne

[rusnak]

OMFG!

Don't worry J I know you'll have her up and purring like a kitten soon.

That last pic is crazy but I think you really got lucky.

[SoCalSK8r]

Crazy stuff, I hope you get her up and running soon!


Sent from my iPhone using Tapatalk

[scarceller]

Draco, Always something with these old cars. Very common issue, the walking rocker shaft!
Good news is they usually don't cause much damage if you shut the motor down as you did, wise choice! The only thing to be careful with is to be sure it did not damage the bore that the shaft slides into. Basically tighten it to spec and be sure you can't easily move it once tight.

The problem as Wayne pointed out is the bore on the RHS in the pic, because the shaft likely ran for miles slipped out of the LHS it can easily do damage to the RHS bore, the rocker puts significant pressure on the shaft when it opens the valve and the shaft was likely only held in place from that RHS, hope that makes sense.

[Pazuzu]

Did the crazy rocker shaft nut/washer/bolt combo at least stay together, or did you have little parts flopping around in there as well?

[DRACO A5OG]

Luckily it stayed together,



Checking Cam lobe for damage now and next piston using my video probe

Thanks Wayne, I was about to order a new rocker ( inner busing is mared/damaged ) and shaft seals, will order the RSR seals instead, Where is it by the way?

[cabmandone]

Who added the RSR seals? Mine is an 85 and didn't have them and I notice yours does.

[Baby]

Good catch, and I hope you are back on the road soon! On my '83, that bushing is separate from the rocker. You can probably take that rocker arm to your machinist/engine builder and get it re-bushed.

[manbridge 74]

My first 911 had this happen on the highway to the previous owner. He said it caused a loud bang. I bought it thinking the engine was trashed but I discovered the "walker" and put another rocker in it after a leak down test showed good numbers.

[sugarwood]

Can someone circle the rocker shaft bolt (and explain what is actually wrong) for those of us who have never seen the inside of an engine?

[Tippy]

One of the Achilles heels of the engine.

Hopefully the housing didn't suffer bore damage. Most of the time from my limited experience happening to me and reading here, they're usually ok.

[snbush67]

Originally Posted by sugarwood

Can someone circle the rocker shaft bolt (and explain what is actually wrong) for those of us who have never seen the inside of an engine?

The rocker shaft bolts are on both sides of the shaft, they have a hex head on each side, different sizes, I can't recall the sizes, perhaps 6 mm and 8 mm, when you tighten them they squeeze together expanding to seal tightly in the housing.

[Tippy]

5mm and 8mm

[DRACO A5OG]

Sugarwood, the bolt and nut are on side of the rocker shaft above.



8MM allen for the nut and 5MM allen for the bolt, they are shallow as poop so you have to make certain you are absolutely SQUARE to the two or you will fudge them up.

The two end are pretty easy to torque but the middle one that I blew up is going to be interesting. Will need to rig something up to torque that sucker.

So I looked at my CAM Lobe at #2, FUCH! I guess I am going to need a new one



or up to 964 Cams. Ah poop.

[Ronnie's.930]

^^^

That little bit of wear/scuffing would not bother me for a second with a street engine. I would re-assemble with a new rocker arm and not give it a second thought.

[DRACO A5OG]

But I need an excuse to up to 964 Cams. I have new Eibach valve springs just laying around too :-P

Yeah, but It will always bother me. Well, let me sleep on it. So now on the search for 964 cams.

[A horse with no name]

Whoa!...Jim, so sorry to hear the bad news. As the Aussies say, "Bugga!" Actually it's even more than a "Big Bugga" I've never heard of any rockers coming unloose on any engine, but when reading the posts, it appears that they do on 911's. Not good.