Broken Head stud, 2 weeks before DE!!!

Otis · 04-06-2009, 04:09 AM

I just started to adjust the valves in my '88 911 and found a broken head stud in #3 exhaust side. Question is it looks like it has been that way for a while, can I run in a DE on the 26th with the stud broken or is it adidios until I can afford a total rebuild.

JeremyD · JeremyD's Garage

I personally would not run a DE with a known broken head stud. It's easy to make things much worse

stormmaster · stormmaster's Garage

+1...I wouldnt do it.....but its your money....how important is a DE to you...

JohnJL · 04-06-2009, 06:11 AM

A reputable shop can do it in a day, though you need to be first in line. Its an engine drop, so thats 1.5 hours. Then its .5 hour to retract the old stud if there's any meat left. If not its 3 hours to drill out, recoil and install a new stud. Plus 1.5 hours to reinstall. Can be done in a day or so, so get her booked in and you can still make your DE.

John Brandt · 04-06-2009, 07:30 AM

Otis,
How about a different opinion?
I've been through this myself, and I ran for a while at the track, prbably almost a year, with one broken, #3 exhaust just like yours, before I pulled the motor for the teardown /fix. there was no sign of blowby, and no damage from it.

It is highly unlikely that anyone can fix it without a teardown; These studs are locktited in place and there is a trmendous amount of torque (with Heat ) required to get them moving. If they could do this, lots of us would have gone that route. Heck I don't think you would even need to drop to motor to get to it.

I would say to go do your track event , start collecting the bits and tools and information and fix it afterwards, maybe even in the fall. if it starts making the fart noise then park it. If you are reasonably skilled, can folllow written directions and detail oriented, you can do it. It's a bear of a job but possibe to do in the garage. I worked like an absolute madman for 29 days and was at the track again 2 days after that.

Otis · 04-07-2009, 03:40 PM

Thanks for all the great input. The car has 157K miles on it and has just gotten a great new paint job. I was planning to rebuild the engine when I bought the car 5 years ago. I would love to try the DE and then also do the Parade this year. Just so happens my son is getting married in Breckenridge the same week as the Parade. sounds like I can just finish up my valve adjustment and a few other race preps and give'er a try. This fall would be the perfect time to drop the engine and get going on the rebuild. I am worried that if I tried to do a repair right now I would get into the chain reaction of damage and have to rebuild on the cars terms not mine.
Now I should start a thread on what I should do for the rebuild!

Bmxrams80sc · 04-07-2009, 04:30 PM

If it helps any, I have about 8 known broken studs and it has been running fine for about a year. Still pulls really strong! I autocrossed it this weekend too. I know it will break loose sooner or later but for now im gonna wait for the flutter noise. My guess is the heads have somewhat welded theirselves to the block. 30 years will do that. Just an exteme example. rebuild is on the list, just dont have the time right now

jtratza · 04-07-2009, 05:03 PM

I had one broken stud and ran it for about 3 years including DE. Finally had the engine rebuilt at 140,000 miles (head stud plus cam seals leaking enough to attract attention from Exxon) and there was no sign of any damage. I don't think I've ever read about someone doing damage to the heads by running the engine for even a few years.

theiceman · 04-07-2009, 07:01 PM

I guess I am confused. it is a head stud or an exhaust stud.

If it's a head stud there is no way it is coming out in half an hour.

drewtiss · 04-07-2009, 07:29 PM

Quote:

Originally Posted by Otis

Thanks for all the great input. The car has 157K miles on it and has just gotten a great new paint job. I was planning to rebuild the engine when I bought the car 5 years ago. I would love to try the DE and then also do the Parade this year. Just so happens my son is getting married in Breckenridge the same week as the Parade. sounds like I can just finish up my valve adjustment and a few other race preps and give'er a try. This fall would be the perfect time to drop the engine and get going on the rebuild. I am worried that if I tried to do a repair right now I would get into the chain reaction of damage and have to rebuild on the cars terms not mine.
Now I should start a thread on what I should do for the rebuild!

Like you I'm still in the middle of my garage project. I need to finish this before the season ends.

sailchef · sailchef's Garage

Quote:

Originally Posted by theiceman

I guess I am confused. it is a head stud or an exhaust stud.

If it's a head stud there is no way it is coming out in half an hour.

I was wondering the same thing. Is it possible to replace a head stud without pulling the cam tower and cylinder heads?

Otis · 04-08-2009, 04:22 AM

Just to clarify, the broken head stud is on #3 exhaust side of the head. I really don't know how long it has been that way but based on some of these examples it have been at most 10,000 miles(last time the valves were adjusted). I have heard that there is a slight chance that you can pull the one cylinder and replace the stud. Almost everyone says that it would be pure luck if the stud came out without doing something to the rest of the engine. I think I will stick with the "drive til it drops" approach at least for this summer.

sc_rufctr · 04-08-2009, 05:18 AM

Quote:

Originally Posted by sailchef

I was wondering the same thing. Is it possible to replace a head stud without pulling the cam tower and cylinder heads?

I've been trying to imagine how you would be able to do this... I'm not saying it's impossible but very difficult to say the least.

stevemfr · 04-08-2009, 07:22 AM

I've not heard of a method to do this w/o at least a top-end teardown either, but I've been out of the scene for nearly 15 years.
If the stud is broken, then the threads should be good and I'd want to keep them that way. And def no heli-coils in this app!

I've seen cars that have run for quite a while on 3 studs - including autobahn km's (2.7's and 3.0's - no 3.2's). At some point the head/cyl become junk. It's often very hard to tell how long because the owners know nosink, see nosink, hear nosink... For the parade I'd say go for it and take it easy. The DE - you pays your money, you takes your chances.

But maybe someone like John Walker with more experience can chime in.

theiceman · 04-08-2009, 05:35 PM

I think the person who posted the half an hour thought it was an exhaust stud. The cam tower and head have to come off. The case has be heated up to melt the epoxy so the stud will come out. At that point since the cam tower is off do you replace ALL the studs on that side ,,, if one broke .....

Otis · 04-09-2009, 04:44 AM

That is consistant with what I understand would be required. Also almost everyone else I have consulted says to replace not only the other three but also the stud on the whole bank