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Sheared Cam Cover Bolt - Nothing Nice

 
Old 05-23-2019, 03:37 PM
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JayPoorJay
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Default Sheared Cam Cover Bolt - Nothing Nice

1986 928 LHdrive

Question - what is the potential for oil leaking here?

I'd been doing some other work and decided, after reading on the forum, that I would remove as much of the smog/auxiliary air pump as possible. There is no belt to the appliance, the blue hose isn't needed and the "gizmo" the blue hose connects to is in the way. It just is. I intended to cap the tubing coming up the PS of the engine from the cats (?) with a rubberized chair leg cap,,, one used to protect the floor from the leg end of the chair... Got that advise here. Anyways,,,

I went to remove the LOWER bolt holding the bracket that carries the gizmo holding it to the CC, and bam, the bolt sheared off under the cover. Stupid me! I only learned of the very real issue with shearing on the 86 cam cover bolts (reading here) AFTER the happening. Damn!

There still seems to be a triangle (at least) of CC bolts in the surrounding area securing that area of the CC to the head... One deep in the back corner near the firewall on the bottom corner,,, one center bolt mid cover (holding the upper portion of the bracket) and another center edge perimeter bolt (the one nearest the front lower corner)... I cannot get what is left of the bolt out of the cover because of the shoulder left (I think)...? I have NO intention of removing the cover right now. In all you'z experience will this result in a impossible leak at the CC seal at the lower edge?

I was/am intending to cut away the rest of the bracket so I can remove the gizmo (I don't know what it's called),,, then get under the bolt and epoxy or JBweld what remains of the bolt to the top of the cover for sealing... Does this make ANY sense? This whole fiasco kept me awake last night.

Any and ALL suggestions are super welcomed. Deep bow and a thank you in advance
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Old 05-23-2019, 04:12 PM
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I think I understand what you are saying but a picture always helps avoid confusion when there is an issue.

The cam cover is held in place by about 10 shoulder bolts if my memory serves me correctly but these are small items with little in the way of torque holding them down and there is no sealant on the gasket to engine joint. There is only one realistic solution to this problem or so I would think and that will involve removing the cam cover- that can be a little tricky because of obstructions like the fuel rail cross over but quite doable nonetheless unless your model presents unique difficulties not present on my motor.

If the bolt is missing I reckon there is a fair chance a leak will spring either on the cover or on the sealing ring around cylinder No 4 spark plug [or both]. I could not live with that and would have to fix it but that is me.
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Old 05-23-2019, 04:41 PM
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Old 05-23-2019, 04:53 PM
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With me now,,, all I have is something I pulled from the net.

The recieving hole for the sheared bolt is the second in from the bottom left in the photo. The sheared bolt is kinda flopping around in the hole.

Yeah, it sucks... I think I'm in real trouble here.

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Old 05-23-2019, 05:12 PM
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It won't leak. Oil will shoot out.
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Old 05-23-2019, 05:16 PM
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If it is the one circled in red see above. It it is the one in yellow you dodged a bullet.
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Old 05-23-2019, 05:21 PM
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I had a top one missing and it only leaked when I revved the engine......I'm afraid that a bottom one will leak profusely all the time the engine is started and running.
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Old 05-23-2019, 05:22 PM
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SMH....
It's the one in Red!!! Damn!
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Old 05-23-2019, 05:41 PM
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From the seam where cover meets head, I mean...?
I'm confident in my ability to fully block the hole...

Desperate question from a desperate guy.
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Old 05-23-2019, 05:55 PM
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Originally Posted by JayPoorJay View Post
From the seam where cover meets head, I mean...?
I'm confident in my ability to fully block the hole...

Desperate question from a desperate guy.
Park the car until you can get the cam cover off and fix it properly. plugging the hole is the 1st step on how to end up with a parts car.
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Old 05-23-2019, 06:00 PM
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Originally Posted by 928sg View Post
It won't leak. Oil will shoot out.
Sterling,

I suspect that your good self [and John] did not read the original post the way the OP intended. It should be rather obvious that if the head of the bolt has sheared off there will be a hole through the cover. There is not much in the way of pressure there and if the bolt head were missing I think the best way of describing it would be "oil will **** out"- semantics!

As I understand the query the issue the OP was asking was one of if he blocks the hole with two pack epoxy will the resulting loss of tension at that location cause a leak on the joint sealing surfaces- that or my brain is getting ahead of itself.

Regards

Fred
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Old 05-23-2019, 06:21 PM
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Originally Posted by FredR View Post
Sterling,

I suspect that your good self [and John] did not read the original post the way the OP intended. It should be rather obvious that if the head of the bolt has sheared off there will be a hole through the cover. There is not much in the way of pressure there and if the bolt head were missing I think the best way of describing it would be "oil will **** out"- semantics!

As I understand the query the issue the OP was asking was one of if he blocks the hole with two pack epoxy will the resulting loss of tension at that location cause a leak on the joint sealing surfaces- that or my brain is getting ahead of itself.

Regards

Fred
Hi Fred, yes thanks. It is what I'm asking.

Will I have an oil leak that seaps out of the area of less tension/pressure/seal where that bolt is missing OR,,,, well, I'm sure you know the next question. Will it gush or eventually gush. Will it blow the gasket out of that area eventually and just pour out? Ive been looking for pictures that will give me a close up of the underside and gasket channel to get a sense, but I haven't found that yet and am unfamiliar (sadly)...

I am already asking myself, self, what is in store for you and this car amd what will be the horrifying process, of removing the remainder of these bolts??? Before this I wasn't even aware this shearing was a problem. Talk about live and learn. OMG!!!

Haha,,, why didn't someone WARN me!?!?

I'll get her done. I usually do.
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Old 05-23-2019, 06:30 PM
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I read it and my recommendation stands. plugging the hole is the 1st step to owning a parts car.
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Old 05-23-2019, 06:58 PM
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Originally Posted by JayPoorJay View Post
Hi Fred, yes thanks. It is what I'm asking.

Will I have an oil leak that seaps out of the area of less tension/pressure/seal where that bolt is missing OR,,,, well, I'm sure you know the next question. Will it gush or eventually gush. Will it blow the gasket out of that area eventually and just pour out? Ive been looking for pictures that will give me a close up of the underside and gasket channel to get a sense, but I haven't found that yet and am unfamiliar (sadly)...

I am already asking myself, self, what is in store for you and this car amd what will be the horrifying process, of removing the remainder of these bolts??? Before this I wasn't even aware this shearing was a problem. Talk about live and learn. OMG!!!

Haha,,, why didn't someone WARN me!?!?

I'll get her done. I usually do.
The bolt probably sheared because someone over torqued the bolt previously and the resulting break torque required to get it undone being a bit higher after long term "stiction" causes the bolt to shear. The not so good conclusion is if one is like that how many others are. When I put these things in I tighten them until they start to pinch and holding the head of the wrench [not the shaft] I give it a little pinch- nothing more than that. I reckon the main reason these joints leak on the main seal face is because the oil finds a leak path round the back of the seal as its sits in the trough thus why I use a little sealant in there before fitting the cover- no leaks to date and no broken bolts.

Nowadays I have a small torque wrench but whether even that goes down low enough for these bolts remains to be seen.

As I suggested in my original post just do yourself a favour and sort it out correctly.
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Old 05-23-2019, 07:03 PM
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Originally Posted by FredR View Post
There is not much in the way of pressure there and if the bolt head were missing I think the best way of describing it would be "oil will **** out"- semantics

As I understand the query the issue the OP was asking was one of if he blocks the hole with two pack epoxy will the resulting loss of tension at that location cause a leak on the joint sealing surfaces-
Fred, If there was not much in the way of pressure there, then why would Porsche have secured the Cam Cover with so many bolts?

Best course of action is to replace the bolt.
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