exhaust manifold stud
Thread Starter
Senior Member
Joined: 08-27-2019
Posts: 128
From: PA
exhaust manifold stud
Had a leaking exhaust manifold gasket and a flange gasket. Cleaned and replaced gaskets and torqued to spec but #7 manifold stud on the tightening sequence chart broke inside the head. The torque wrench was just about to click but the stud went instead. All the others are torqued to spec at 124 inch lbs. I'm currently running the car as it is and so far no leaks.
What is the likelihood this will start leaking? There is no part of the stud sticking out. It will likely have to be turned out with an extractor but I can't see doing that without taking off the head.
Looking for some brainstorming from the masterminds in the event it starts leaking.
Fingers crossed
What is the likelihood this will start leaking? There is no part of the stud sticking out. It will likely have to be turned out with an extractor but I can't see doing that without taking off the head.
Looking for some brainstorming from the masterminds in the event it starts leaking.
Fingers crossed
Senior Member
Joined: 05-09-2018
Posts: 260
From: NorCal
KM you're supposed to stop a quarter turn before it breaks! Run it as is and let the leak stay away imo
If money and time is no object get busy and tear it down.
I'd suppose the torque spec is engineered considering you're using brand new parts not ones that have aged for more than a decade of heating and cooling.
But I know that helps little for your dilemma.
The two master magicians on this forum have weighed in.
As a former shop foreman, I wouldn't be happy with you, just sayin'
If it leaks eventually you have to deal with it. Trying to drill a squared up hole in a broken stud without taking head off is near impossible.
Time will tell. It is a sinking feeling, when that happens and you second guess the process. Could have should have would have... Whats done is done.
Taking off the head then what? Freshen it up while it's off new timing belt and other related stuff blah blah.
If money and time is no object get busy and tear it down.
I'd suppose the torque spec is engineered considering you're using brand new parts not ones that have aged for more than a decade of heating and cooling.
But I know that helps little for your dilemma.
The two master magicians on this forum have weighed in.
As a former shop foreman, I wouldn't be happy with you, just sayin'
If it leaks eventually you have to deal with it. Trying to drill a squared up hole in a broken stud without taking head off is near impossible.
Time will tell. It is a sinking feeling, when that happens and you second guess the process. Could have should have would have... Whats done is done.
Taking off the head then what? Freshen it up while it's off new timing belt and other related stuff blah blah.
Thread Starter
Senior Member
Joined: 08-27-2019
Posts: 128
From: PA
The 124 inch pounds is mistyped, I meant 120 inch lbs. Yes, thank you Donbrew, 10 x 12 = 120 inch lbs
Woodysmobile, what do you mean stop a quarter turn before it breaks? I can't tell if this is just a joke or you're being serious. Either way, I appreciate your input. So you're not supposed to use torque specs on old parts? Should have replaced the studs??
I never expected the stud to snap when tightening. I was very nervous loosening them though because I know that's when they mostly break. But I did not have a problem loosening them.
I did put a little anti seize on the studs just in case there's a next time.
Timing chain already done last year. My question though is can I cheat and just remove the VVT sprockets but mark the chain and a sprocket tooth and be super careful that the chain doesn't slip off the bottom sprocket on the crank? This is if I decide to pull the head.
Oldblue, I am OCD as well and the mere thought of that nut not being on the manifold bugs me. Probably going to do this in the summer. Don't have extra cash right now.
How are the head bolts on these motors when loosening the first time? Tips or tricks to getting these out without them breaking as well? Better if engine hot/cold, etc??
Woodysmobile, what do you mean stop a quarter turn before it breaks? I can't tell if this is just a joke or you're being serious. Either way, I appreciate your input. So you're not supposed to use torque specs on old parts? Should have replaced the studs??
I never expected the stud to snap when tightening. I was very nervous loosening them though because I know that's when they mostly break. But I did not have a problem loosening them.
I did put a little anti seize on the studs just in case there's a next time.
Timing chain already done last year. My question though is can I cheat and just remove the VVT sprockets but mark the chain and a sprocket tooth and be super careful that the chain doesn't slip off the bottom sprocket on the crank? This is if I decide to pull the head.
Oldblue, I am OCD as well and the mere thought of that nut not being on the manifold bugs me. Probably going to do this in the summer. Don't have extra cash right now.
How are the head bolts on these motors when loosening the first time? Tips or tricks to getting these out without them breaking as well? Better if engine hot/cold, etc??
Administrator
Joined: 10-13-2011
Posts: 40,082
From: Welland,Ont Canada
No to the VVT sprocket idea! Do it right!
as for the comment about master magician, I have drilled out broken studs , I have a 90 degree angle drill .
I’ve also welded a nut on to a broken stud and removed the stud.
pulling the head on a 15 to 20 year old car isn’t cost effective if the new exhaust gasket isn’t leaking.
You can’t reuse the head gasket, the head bolts are not reusable!
May I suggest to future readers squirt penetrating oil in the night before you work on the exhaust studs.
as for the comment about master magician, I have drilled out broken studs , I have a 90 degree angle drill .
I’ve also welded a nut on to a broken stud and removed the stud.
pulling the head on a 15 to 20 year old car isn’t cost effective if the new exhaust gasket isn’t leaking.
You can’t reuse the head gasket, the head bolts are not reusable!
May I suggest to future readers squirt penetrating oil in the night before you work on the exhaust studs.
Moderator
Joined: 05-01-2014
Posts: 8,511
From: California
I agree, I tried to pull the camshafts out with a phaser holding tool. The tool was in the way of getting the phasers off. Long story short, the phaser slipped and I had to take the front stuff off and retime it.
Senior Member
Joined: 05-09-2018
Posts: 260
From: NorCal
A quarter turn before it breaks is a "joke" with seriousness to help provide relief when things like this go bad.
For example, replacing a y-pipe using the old manifold studs that are weak and fatigued. It is almost sealed but needs a bit more tightening. Use some heat and hope you get it sealed before the old stud breaks requiring the extra work to replace. Which you decided not to remove because experience taught us they ain't coming out with out a bigger battle like breaking off instead of backing out. Trying your best to do the job and minimize the labor cost expense to the customer.
The removal of a broken stud that's flush in awkward places requires skill, some luck and the magicians slight of hand touch. Half the job is getting the hole drilled in the middle square and straight. Then the hope it cooperates and the extractor is strong enough to finish the job. I've seen it all. It all goes well then the extractor breaks also. I've welded nuts on the small stub and gotten lucky. Failure is not an option!
Since you have time you need to run it for awhile and renew your mind that it's ok even if it's not perfect. What's the worse thing that can happen leaving it as is?
Only you (and us here!) know about it. Good day.
For example, replacing a y-pipe using the old manifold studs that are weak and fatigued. It is almost sealed but needs a bit more tightening. Use some heat and hope you get it sealed before the old stud breaks requiring the extra work to replace. Which you decided not to remove because experience taught us they ain't coming out with out a bigger battle like breaking off instead of backing out. Trying your best to do the job and minimize the labor cost expense to the customer.
The removal of a broken stud that's flush in awkward places requires skill, some luck and the magicians slight of hand touch. Half the job is getting the hole drilled in the middle square and straight. Then the hope it cooperates and the extractor is strong enough to finish the job. I've seen it all. It all goes well then the extractor breaks also. I've welded nuts on the small stub and gotten lucky. Failure is not an option!
Since you have time you need to run it for awhile and renew your mind that it's ok even if it's not perfect. What's the worse thing that can happen leaving it as is?
Only you (and us here!) know about it. Good day.