I pulled a head stud...need some advice on what to do (kinda long)
03-14-2002, 10:46 PM
#16
Rennlist Member
Zamirz,
Jkline is right, if you have a pulled or broken stud and you drive the car for an extended amount of time, the leaking combustion will eventually work like a blowtorch and notch the head and the cylinder. The added stress of only three studs around a cylinder can cause an additonal stud to break or pull. This could lead to you replacing a perfectly good head and jug.
I didn't mean for you to get the idea that this would be like changing a plug, this is a good bit of work, but if you are mechanically inclined and are willing to commit the time and energy, this is a do-able job. As long as you have room and the car is just going to sit, does it make any difference where the engine is?
As long as it was maintained properly, 97K on an SC is no problem. And given your limited resources, I would fix whats wrong, the broken stud. I think you will find everything within servicable limits. Taking the heads & cam housing off as a unit will save quite a bit of work, stripping down a cylinder bank for a valve job adds a considerable amount of work and cost that I'll bet you just don't need. At a minimum you are going to need an upper gasket/seal set, new stud, time cert, dial guage etc... The stud is pulled so you won't have to drill out a broken stud, pull just the one jug and drag the motor down to the machine shop for the timecert. (if you get it crooked you won't get the head back on) Get the manual and look at what is required to do the job. Sure if you've got the cash rebuild as much as you want, but then the $4500 is going to go real fast...
I was about the same age as you when I rebuilt my first 911 motor, 2.7 with pulled studs. (I did have experience with 912/VW and american iron...) You will learn a bundle about the car, and have the satisfaction of doing the job yourself. If you get in over your head you still have the option of taking the whole thing over to your mechanic in a box and say fix it. Only you know your limitations, a porsche motor is fairly complicated and not a forgiving as other motors high school seinors mess with, but then, you're a high school seinor driving a 911...
Before you do anything, retorque the head or ask your mechanic if he did. This could all be academic if it takes a torque.
Anyway good luck, let us know which way you go...
Jkline is right, if you have a pulled or broken stud and you drive the car for an extended amount of time, the leaking combustion will eventually work like a blowtorch and notch the head and the cylinder. The added stress of only three studs around a cylinder can cause an additonal stud to break or pull. This could lead to you replacing a perfectly good head and jug.
I didn't mean for you to get the idea that this would be like changing a plug, this is a good bit of work, but if you are mechanically inclined and are willing to commit the time and energy, this is a do-able job. As long as you have room and the car is just going to sit, does it make any difference where the engine is?
As long as it was maintained properly, 97K on an SC is no problem. And given your limited resources, I would fix whats wrong, the broken stud. I think you will find everything within servicable limits. Taking the heads & cam housing off as a unit will save quite a bit of work, stripping down a cylinder bank for a valve job adds a considerable amount of work and cost that I'll bet you just don't need. At a minimum you are going to need an upper gasket/seal set, new stud, time cert, dial guage etc... The stud is pulled so you won't have to drill out a broken stud, pull just the one jug and drag the motor down to the machine shop for the timecert. (if you get it crooked you won't get the head back on) Get the manual and look at what is required to do the job. Sure if you've got the cash rebuild as much as you want, but then the $4500 is going to go real fast...
I was about the same age as you when I rebuilt my first 911 motor, 2.7 with pulled studs. (I did have experience with 912/VW and american iron...) You will learn a bundle about the car, and have the satisfaction of doing the job yourself. If you get in over your head you still have the option of taking the whole thing over to your mechanic in a box and say fix it. Only you know your limitations, a porsche motor is fairly complicated and not a forgiving as other motors high school seinors mess with, but then, you're a high school seinor driving a 911...
Before you do anything, retorque the head or ask your mechanic if he did. This could all be academic if it takes a torque.
Anyway good luck, let us know which way you go...
03-15-2002, 12:01 AM
#17
Addict
Rennlist Member
Rennlist Member
Was it a pulled stud, or a broken stud, and how did he determine this?
Good thread on the topic here, including a post by a guy who drove his SC with a broken stud for almost 50K miles with no ill effects.
<a href="http://www.pelicanparts.com/cgi-bin/vb/showthread.php?threadid=62617" target="_blank">http://www.pelicanparts.com/cgi-bin/vb/showthread.php?threadid=62617</a>
Tom
Good thread on the topic here, including a post by a guy who drove his SC with a broken stud for almost 50K miles with no ill effects.
<a href="http://www.pelicanparts.com/cgi-bin/vb/showthread.php?threadid=62617" target="_blank">http://www.pelicanparts.com/cgi-bin/vb/showthread.php?threadid=62617</a>
Tom
03-15-2002, 04:22 PM
#18
Three Wheelin'
Thread Starter
Alright guys, thanks a lot for the advice.
erkj79, i'll be emailing you if i have any questions.
J Richard, thanks a lot for the vote of confidence......seems like you've been down this road yourself and didn't find it too difficult.
emcon5, not sure if it was "broken" or "pulled", but my mechanic showed me a stud that had broken in the center and he said to me "this is what yours looks like inside", so i'm assuming the stud is broken......any way possible for me to back the broken piece out and save myself from the machine shop?
My plan:
Well, I've decided to do the work myself and will probably try to pull the motor out and get it apart this weekend (I had the flu all this week, sorry i didn't respond to your messages sooner guys). I'm not sure exactly what i'm going to do once in there, but the plan is to replace the broken stud on the left bank with an OEM piece and put it back together. Other than that, I think I'll order a new Sachs clutch and 2nd gear is becoming increasingly hard to go into so I'll check that out. Other than that, can anyone recommend a good machine shop in greater l.a. area? preferrably in the valley.
regards,
amir
erkj79, i'll be emailing you if i have any questions.
J Richard, thanks a lot for the vote of confidence......seems like you've been down this road yourself and didn't find it too difficult.
emcon5, not sure if it was "broken" or "pulled", but my mechanic showed me a stud that had broken in the center and he said to me "this is what yours looks like inside", so i'm assuming the stud is broken......any way possible for me to back the broken piece out and save myself from the machine shop?
My plan:
Well, I've decided to do the work myself and will probably try to pull the motor out and get it apart this weekend (I had the flu all this week, sorry i didn't respond to your messages sooner guys). I'm not sure exactly what i'm going to do once in there, but the plan is to replace the broken stud on the left bank with an OEM piece and put it back together. Other than that, I think I'll order a new Sachs clutch and 2nd gear is becoming increasingly hard to go into so I'll check that out. Other than that, can anyone recommend a good machine shop in greater l.a. area? preferrably in the valley.
regards,
amir
03-17-2002, 01:17 AM
#19
Rennlist Member
Zamirz,
If the stud is indeed broken and there is enough of it left to get to with a solid bite from a large vice grip or stud extractor (prefered-the cam lock kind that goes on a breaker bar) you may get lucky and be able to remove the stud and thread in a new one without having to do any machine work at all. As I stated in my first post, it is not common for the aluminum cases (SC's) to have a stud pulling problem, this is usually the 2.7 magnesium cases. If the stud comes out clean, without bits of alum. threads on it you should be in good shape.
If the stud broke on the head side threads you may be able to get a grip on it with an extractor without having to removing the cylinder. (Better not to mess with removing the piston from the bore and messing up the seated ring IMHO). If it is on the other side at the case, I strongly recommend taking it down to the shop and having the remaining stud piece removed professionally. An errant drill and you are in a bad place, and they are REALLY in tight, you could easily snap off an easy-out.
Anyway get a manual and do your research on what you need to do. Also get Bruce Andersons handbook, and the little technical specifications booklet. Use it as a guide as you inspect the parts you remove. If they are within the specificatons, don't replace them.
Good luck, Keep us posted
If the stud is indeed broken and there is enough of it left to get to with a solid bite from a large vice grip or stud extractor (prefered-the cam lock kind that goes on a breaker bar) you may get lucky and be able to remove the stud and thread in a new one without having to do any machine work at all. As I stated in my first post, it is not common for the aluminum cases (SC's) to have a stud pulling problem, this is usually the 2.7 magnesium cases. If the stud comes out clean, without bits of alum. threads on it you should be in good shape.
If the stud broke on the head side threads you may be able to get a grip on it with an extractor without having to removing the cylinder. (Better not to mess with removing the piston from the bore and messing up the seated ring IMHO). If it is on the other side at the case, I strongly recommend taking it down to the shop and having the remaining stud piece removed professionally. An errant drill and you are in a bad place, and they are REALLY in tight, you could easily snap off an easy-out.
Anyway get a manual and do your research on what you need to do. Also get Bruce Andersons handbook, and the little technical specifications booklet. Use it as a guide as you inspect the parts you remove. If they are within the specificatons, don't replace them.
Good luck, Keep us posted
