show and tell?

BobS · 09-18-2003, 05:12 PM

At the risk of making an idiot of myself on my very first post (and highly likely) .... My '77 has a leak that I cannot identify. I've been stalking this bb forever and I've looked at every (I think) post and diagram (and read about all the common 911 leaks and looked in a bunch of manuals) but I just cannot figure out what this is and why it is leaking. Is this a shaft on my chain tensioner that is weeping oil? The pic was taken from just behind the right rear wheel looking up and back toward the engine. This "thing" is on the front side (facing the front of the car) and is on the front side of the cam housing (I think). I do not have the updated chain tensioners (they are on my list). After driving for a few days the shaft will slide out about two inches and I can lever it back into place with a pry-bar (not very delicate, I know). Regardless, it weeps almost constantly. Please don't make me change my username and start over because of the shame I experience....

I hope the pic is attached.... Even more shame. If anyone knows can they suggest a fix? Thanx....

Tim Walsh · Tim Walsh's Garage

hmm.. I'm not sure exactly what I'm looking at either. I'm assuming the large object to the right is the muffler or a thermal reactor. THen that would make the nut an exhaust nut but I still don't recognize it. Sorry I can't help.

BTW there are no dumb questions here. If anyone's proved that it would be me. Welcome to the board!

Chuck Moreland · 09-18-2003, 11:19 PM

It kinda looks like the creature from Alien.

Really hard to tell what it is. A few more pics might help, maybe pull back a little to give some perspective.

lateapex911 · 09-18-2003, 11:37 PM

Well, I was going to guess that it was an issue with an oil line or the oil cooler itself, but after you mentioned a shaft sliding out 2 inches, I am totally confused. Weird!

I can't, off the top of my head, think of what that shaft could be, but I don't think it's movement can be considered a good thing. And as the area you speak of is full of oil related items, I would watch it closely, and attend to it promptly, as an oil loss can be sticky!

smestas · smestas's Garage

That’s the backside of the "Timing Chain Housing".

There are pressed in studs there that support the chain tensioner. On the outsides the factory used some sort of epoxy to seal them up. It looks like all of your sealant/epoxy has come off. This is one of a few areas (chain housing & engine case) that they used this sealing technique for pressed in studs and it is wise to reseal them when doing a rebuild. The consensus says to use JB-WELD for this purpose.

Here is a link to a somewhat similar topic.
Timing Chain Housing & JB Weld

smestas · smestas's Garage

Quote:

Originally posted by BobS
After driving for a few days the shaft will slide out about two inches and I can lever it back into place with a pry-bar

Bob,

If this is what I think it is (chain tensioner stud) you had better not run the motor. Any skip or failure of the chain tensioner can cause EXTREEM DAMAGE!

I hope I'm wrong.

Silveresrty911S · Silveresrty911S's Garage

JB weld it, remove as much oil dirt from the area as possible and then (with small wire brush) brush it. I've used JB on my truck, boat great stuff.
Or your car's excited once you drive her (shaft coming out, weeping)

BobS · 09-19-2003, 05:45 AM

Thanks everybody for the insights!! Simon, thanks, too, for the link. Part of the discussion there was exactly what I've been experiencing. This stud comes out far enough to get wedged by the cooling fins on #4. From parts diagrams it does seem to be on the same plane as the chain tensioner -- but none of the diagrams showed this piece coming through the other side (because, duh, it's not supposed to...). I'll run out and find some JB Weld. This bb is such an excellent resource. This engine was rebuilt about 20,000 ago by PO. Seems like maybe they forgot something.... Thanks again!

rcwaldo · 09-19-2003, 06:19 AM

This very pin worked its way loose inside the chain box of a 911 I used to own. Ironically, it happened to me on the way home, the day I bought it. Oil was POURING out of the left side of the car. Later, when I got home, I suddenly figured out why cars wouldn't stay behind me for any length of time.....

Turns out, the idler wheel pivot pin had come loose and worked its way aft, and just fell to the bottom of the chain box! Got lucky it didn't go further into the engine causing more damage. Also lucky that I didnt bend valves, because I didnt have much chain tensioning at that point.

I would be careful with driving your car without removing the chain box cover and have a look at whats going on in there...

Chris

BobS · 09-19-2003, 06:49 AM

Chris,

What did you do to repair/remedy the problem? How did the story end? I'm still heading out to get some JB Weld.... Thanks.

smestas · smestas's Garage

Bob,

The JB-Weld acts as more of a sealant then a bond to hold the stud in place. These studs are pressed in and shouldn't have any movement. I'd invest into some new Timing Chain Housings or take it to a machine shop. For me it wouldnt be worth taking the risk (engine failure) with just the JB-WELD on there.

My 2 cents.

BobS · 09-19-2003, 07:56 AM

Simon,

Excellent advice. Any idea whether I can I replace the timing chain housing without pulling the engine? I'm ready to do the new tensioners but wasn't anticipating the chain housing until this surfaced.

lateapex911 · 09-19-2003, 07:49 PM

As I remember, you can get this done with out a complete removal. But I am glad to hear that you are giving this your utmost attention. Problems here are total disasters. Ask me how I know!

Good luck, and let us know how it works out!

BobS · 09-20-2003, 03:29 PM

Okay, so I found a pic (borrowed it from PP) of the stud from the inside of the case. The stud protruding from the center of the case (the piece that everyone seems to identify) has lost its mooring and is sliding forward (toward the front of the car) out of the case approx. 1.5 inches jamming itself against the cooling fins of #4 and leaking oil. From what I've read, this stud also has its own oil supply. Can anyone confirm? Seems like a disaster waiting to happen as others here seem to have experienced (sliding forward or aft). How common is this problem? I hope to order the parts, chain box and new tensioners, and get started in the near term (still hoping not to have to remove the engine). Car's going to be sitting for a while.... I guess it's time to replace that broken radio antenna.... Thanks again for everyone's help.