Head stud nut fell off!

[jtfreels]

Well I finally came to the conclusion that my odd noises were more than the hole in the muffler.

This morning I guessed that the noise was coming from the right hand side.

So I took off the valve cover, trying to wriggle it out of the way I hear an ominous noise, metal on metal, "hmm that dosn't sound good".

Then out falls one head stud nut! Looks like it just backed out, no apparent damage, all was OK last year when I did my last valve adjustment.

What the heck, has any one had this before?

What do I do now, just put the thing back on?

The rest look ok, I'm going to go back and carefully check. I'm guessing this is much better than a broken head stud.

I've got my first DE in a couple of weeks, don't want to miss that.

So if any one has any advice please let me know.

Jay

[BrokeMyCar]

That happened to me once! Whew, talk about a loose valve. I just put it back on, adjusted that valve and made sure it was a little extra snug.

Babak

[Bill Verburg]

They normally break

[BrokeMyCar]

oop, sorry, I was thinking of the valve-adjusting retainer nut.

[yelcab1]

Put it back on, torque it and then check in 1000 miles.

[kneedragger302]

I guess this may be a continuation to this question. Could this be caused by a pulled head stud or streched stud? Just wondering.

[jtfreels]

Yes my big fear was a broken stud, so I have a bit of relief.

I've checked the others (lower) on that side and all seem to be tight, and they are Divilar.

I put the nut back on and tightened it a bit, the stud hasn't moved so far, so it doesn't appear to be broken (yet). Can't comment on stretched just doesn't seem to be loose.

Looking at some docs, it appears I should have a washer, that I've not found yet. It could have fallen out the back. So I need to get a washer.
Then I'll just torque it back down and see what happens.

Should I be using anti-seize on the nut? I am cross checking in Wayne's rebuild book

Jay

[euro911sc]

I'd rather have a broken stud than a pulled/stretched one. Be very aware when you re-torqe.

What do you mean the washer fell out the back? Are you sure? I guess it is possible, just unlikely IMHO... er... what cyl? Its probably still rattleing around somewhere... I just bought all new ones... they're cheap. Your local wrench might even give you one from the parts bin.

Best regards,

Michael

[jtfreels]

This is on cylinder 6 , on the second bottom stud from the front of the car.
Below is a photo, the top arrow points at the stud with the bolt off, can't find a washer here.
The bottom arrow points to the "gap" that the washer could have gone through. Still looking
on the garage floor, but I only heard one thing hit the floor.
Hopefully I can get one washer here locally.

[DaddyGlenn]

Originally Posted by jtfreels

Well I finally came to the conclusion that my odd noises were more than the hole in the muffler....{snip}

There are warning bells going off in my head.

Did you have a sound like a single cylinder exhaust leak? If so, I would think you have more problems that just ONE loose nut. I am guessing that even if one nut came off the other three would be tight enough to seal the head to the cylinder, right?

Personally, I would check the torque on all of them.

[SCWDP911]

Man, hate to hear it Jay. Let me know if you need an extra set of hands.

[jtfreels]

Well I guess this has been my lucky day!

Thanks to the nice folks at Pat Williams Racing I was able to quickly get the proper washer.

I checked the torque on the remaining nuts, all checked fine at 23ft/lbs. Torqued the missing one to 23 ft/lbs as well.
Got the valve cover back on.
Started her up and everything sounds fine.......
I still want to check the other side to reassure my self.

Jay

[Wayne 962]

They are special washers, you can't just get one at a hardware store. They are a specific thickness for this application. A loose nut just doesn't happen in a vacuum - there are other issues around that you need to investigate...

-Wayne

[JackMan]

Hmmmm

A loose nut doesn't happen in a vacuum?

How do explain our current political misgivings in Washington. Ooops. Sorry. Wrong forum.

wj

[dtw]

One possible explanation is that the washer was already missing, causing that nut to loosen and fall off. The washers are hardened steel and are critical to obtaining (and retaining) proper torque on the head studs. I had a 'rebuilt' engine with zero miles that I ran for 500 miles before I decided to take the engine apart again myself - - too many 'little things' going wrong for me to believe the engine was rebuilt properly. Among the things I found was one mild steel washer among 23 other correct head stud washers. Guess which nut was loose? Yes in 500 miles.

I would park the car and remove the nut for now, as it will not hold torque and can damage the surface of the head. Get the correct washer and then torque it up. Those washers can do a great job of hiding out in the head casting, sometimes hiding out between fins. Take a closer look under the car if you have a line of sight, shine a bright flashlight all around in there.

[jtfreels]

To clarify, I got a new proper washer and replaced it, torquing that one properly (the "missing" one), the others all checked ok.
Difficult to explain the nut being off... they were all ok when I checked the valves last February, as far as I know the engine has never been apart and they are still Dilivar studs. I'm still checking to see if anything else is wrong.

Thanks

Jay

[Porsche-O-Phile]

Job for locktite?

[hcoles]

check in Wayne's book but I think it says to use an anti seize - if correct this gives the proper final tension in the stud and reduces the twist force on the stud.... hopefully the cause is just that a past mechanic didn't install correctly - otherwise I sort of agree with Wayne. that's my 1 cent.

[SCWDP911]

Jay,

I have access to a borescope. If you really want to get in there and look around for that washer, let me know and we can get together. You know how to reach me.

Shane

[al lkosmal]

The washer may have slipped in between the cylinder cooling fins.