Top End Advice Needed - What is this thing?

tmaull · tmaull's Garage

OK guys, so today I decided to tackle my first (ever) valve adjustment on my new to me 911. Car was making some valve noise, didn't know when the last one was performed, so I got to it. Looked up a bunch of different write-ups, felt pretty confident. Drained the oil, got access to the valve covers, took all the valve covers off. While I'm pulling the old gasket off the left bank intake, a part rolls out of the number two cylinder intake. It's a sheared rod of some kind, with an allen adjuster threaded at the end of it. However, when I found it, the allen key was in the wrong orientation, facing away from threads as in picture.
Picture here.

So I tried to figure out where it came from. I can see three parts like it, but I cannot see anywhere obvious that this one came from. Picture here.

So my questions are these:
1) What is it that fell out?
2) Did this break, or did some prior mechanic leave it in there?
3) If it did break, what now? Did I just get myself into a rebuild situation?

Thanks so much for your responses!

gazzerr · 08-26-2015, 07:14 AM

Unfortunately I think that's the classic broken head stud. The real experts here will chime in on what you can get away with without a teardown and rebuild.

vascott01 · 08-26-2015, 07:29 AM

That looks like a snapped Head stud...Not sure what the object is at the end of it. (Cylinder Head Nut)..You will need to get a closer look to see if you are missing a head stud..I will put my money on it...

If it is indeed missing...you are looking at dropping the engine and replacing them... Welcome to a rebuild..

Pazuzu · 08-26-2015, 07:47 AM

Yes, headstud with the hex barrel nut riding along.
It's possible that you can drive with a broken stud indefinitely, don't think you need to rebuild right now. also, it's possible (but VERY unlikely) that it's a spare that the mechanic left floating around in there after replacing others.

Here's a good picture showing where the 12 headstuds are, I highlighted a structure that you can see in your picture so you know where to look (they are deep in there):

Get a flashlight and a mirror and start searching, account for all 12 of them. If you cannot see the hex barrel nut in the hole, then you have found your broken stud. If you can't find TWO nuts, then you have another broken stud as well

turbo owner · turbo owner's Garage

That is a head stud and nut, as long is it is, I'd say broken off at the case.

I had seven on my 79 turbo engine, about a $7000 in parts a machine work. I'm having the engine assembled by Hindson racing, I'm doing the rest.

No big ticket items were damaged helping keep cost down.

tmaull · tmaull's Garage

OK, heading out to do some counting. Just read this thread: I'm screwed...surprise during 1st valve job

Is the prevailing wisdom that with just one head stud broken, minimal oil loss, etc, that I can probably drive this thing for a good while longer before doing a rebuild? I don't have a garage or even a paved driveway right now. I'd like to get my garage built before I dive right into this, so if I can go another year, that would be great.

Pazuzu · 08-26-2015, 07:57 AM

Quote:

Originally Posted by tmaull

OK, heading out to do some counting. Just read this thread: I'm screwed...surprise during 1st valve job

Is the prevailing wisdom that with just one head stud broken, minimal oil loss, etc, that I can probably drive this thing for a good while longer before doing a rebuild? I don't have a garage or even a paved driveway right now. I'd like to get my garage built before I dive right into this, so if I can go another year, that would be great.

As long as it's only 1, then you can drive it. Heck, you were driving it yesterday, and it had a broken stud then, right?

Even 2 studs as long as they are not on the same cylinder.

I had 4 broken studs when I tore my engine apart, and I even drive it that way for another several months before I put everything together and took the time to do the rebuild.

Jerome74911S · 08-26-2015, 08:20 AM

What I don't get is that you say you also found an allen key when you took the valve cover off. I don't understand why anyone would intentionally leave that in there. Any pictures of it, or more info. Maybe it was simply forgotten, but in any case someone probably already knew about the broken stud.

T77911S · 08-26-2015, 08:26 AM

put a wrench on the rest to see if they are broken.
you dont need to torque them....you will know

tmaull · tmaull's Garage

Sorry, not the allen key, the allen key adjuster.

Jerome74911S · 08-26-2015, 09:39 AM

Quote:

Originally Posted by tmaull

Sorry, not the allen key, the allen key adjuster.

No problem.

Flat6pac · 08-26-2015, 10:00 AM

That's a deep broken stud, that long, probably broken at the threads. The half case will need to go to the machine shop. Tha nut on the end is the head nut. You're missing the thick washer that goes under the head nut.
I'll send you a Private Message on pelican. PM on the upper right oh the first page.
Biruce

CCM911 · 08-26-2015, 10:09 AM

Are you guys sure that is a head stud? It looks more like the pipe that sprays oil on the rockers.

tmaull · tmaull's Garage

Yeah I can see the washer up in there. In the picture it's in the upper right corner, in the mirror. It's misaligned with where the head stud should be. Pardon my ignorance, but does the depth of the break matter with regard to continuing to drive the car? I'm trying to figure out what my next move is:
1) Continue valve adjustment
2) Button it back up and park this thing until I can get my garage built
3) Cry myself to sleep

Thanks so much for everyone's help.

Walter_Middie · Walter_Middie's Garage

1.) Follow T77911S advice and put a wrench on the other head studs to see how many are broken or loose. You don't need to turn them, just see if they are really loose.

2.). Continue your valve adjustment if that is the only broken stud.

3.). Drive it as you were before.

4.). No crying. Look forward to getting very familiar with your car's engine.

Robey5 · 08-26-2015, 10:29 AM

Sorry for your misfortune.

What I am going to say may be poo-poo'ed by others in the forum, but --- I would finish the valve adjustment, and clean out the various debris left behind from the broken head-stud that you can find... ...then I would drive it for the time being until I was ready to tackle the head-stud job on your own. While you are driving it with broken head stud, I would start to save funds to do the job (head studs themselves are not all that expensive all things considered...) and because you have a Porsche as your 'fun' car, I would set the budget and save 2x to tackle the "while you're in there" stuff that you typically do with the engine out. Be prepared for a slippery slope, you will find lots of things that you may want to upgrade on your car when you're working on it (...CV joint re-pack, various suspension bits (ie: trailing arms and wheel bearings) that can be reached easier with the engine out, maybe a clutch, and all the seals...)

With this impending repair on your hands, I would not push the car super hard, and stay off the track for the time being.

Flat6pac · 08-27-2015, 08:41 AM

Is the broken stud actually magnetic? It looks black coated.
Bruce

tmaull · tmaull's Garage

I'll check when I get home. It came from the intake, so it should be steel?

simsalabim · simsalabim's Garage

Is it odd to anyone that the broken stud came from the intake side ?

I always thought that the differing expansion rates of the stud and case metals was more likely to cause stud failure on the exhaust side of things ...

tmaull · tmaull's Garage

Took a magnet to the stud this morning. Nothing, must be Dilavar. Which is odd considering it's on the intake side, so the heads must have been rebuilt with dilavar studs at some point in the car's history.