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Exhaust Manifold Studs


andreus009
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I've seen numerous posts on replacing the exhaust manifold studs, but haven't seen much about how to deal with the one's that have broken off and with nothing sticking out. Is this an engine out operation only? Currently I only have one broken one. The top one at the rear of the engine on the passenger side. Personally, I'm consider make a precision incision in the fender well with a sawzall, and see if can't drill it for an easy out with bit extension. Anyone else have any ideas?

 

:blink:

Edited by andreus009
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It can be done without taking the engine out, but be very VERY careful. The water jacket comes really close to the exhaust stud holes. One slip and you're done.

 

You might want to get some shop quotes before you start. I had new studs and headers put on for $400 labor and if I remember correctly, two of the studs were broken.

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I'd say yes, you could do it, if you have some experience... Either going through the fender wall, or maybe you could get in there with an air drill, etc ? I'll have to look at the clearance and I don't know what tools you have access to...

If you do it, tricks I advise is to try to grind the broken stud flat or concave, use a center drill to start the process and be patient (the start is critical), then use a left handed drill to core the drill the stud; sometimes they will back the remainder out eventually. Go slow and straight.... I can make carbide spade drills if you need one and feel confident...

 

B

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Broken exhaust studs in these engines are a _ _ _ _ _. It can be done. I did one on mine when I did the header install. Soak the stud as best you can with the penetrating oil of your choice. Kroil, PB Blaster and Deep Creep are good choices. I'm sure others wil chime in with their favorite weapon of choice. Anyway as the Precise1 said the start is mission critical. If you slide the drill bit off the stud and into the water jacket you are toast.

 

Start with a good center punch and cup out the stud if you can with a rotary tool (e.g. dremel etc.) From there it's slow and steady that gets the prize. Depending upon which stud is broke off this may be a two person job. My bro and I had to do mine. One below with variable speed right angle drill and a titanium left twist bit and one person on top holding the drill head and a small spotting mirror. Slow, slow, slow. Once you get a pilot hole started stop before you go too deep. Measure and mark your drill bit a lenght short of what is left of your stud. Don't drill to China! From there it's a screw extractor if the drill bit hasn't backed the stud out. I would suggest a handfull of drill bits you'll probably break a few.

 

Good luck if you decide to do it. :D

 

Mike

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Be careful using an easy-out. they CAN break. I used a reverse drill bit, and believe me... I had 4 broken studs... but I took the motor out. As stated above.. be careful of the water jackets. Take your time and use caution, and everything will be ok. GOOD LUCK!!!!!!! :aok:

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Just a word of advice from a tool and die maker (fancy machinist), dont use "easy-out's"... They suck... I have snapped more than have ever worked. Use the carbon steel square ones... They are much less prone to break, and if they slip, you can either tap them back in or still have a hole to work with... Just my 2c...

 

B

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So, would it not be easier to remove the heads vs. the motor to remove the broken studs? Just thought and would like your input. I need to do mine as well and am going back with the thorleys when I do, be nice if I could afford cams at the same time but we will see...

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that's how I did my second engine. It costs more 'cause you need to replace your head gaskets but I thought it was much easier than pulling the entire engine.

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So, would it not be easier to remove the heads vs. the motor to remove the broken studs? Just thought and would like your input. I need to do mine as well and am going back with the thorleys when I do, be nice if I could afford cams at the same time but we will see...

Get the Perma Cool oil filter relocation kit if yer gunna install the Thorley's.. I installed both and am REALLY REALLY glad I did the perma cool.....

And, you'll be fine if you just remove the motor. ;)

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I had the exact same one break about 3 years ago. Here's how I fixed it. Since then I have had exhaust manifolds off and replaced them all.

 

Did not remove the exhaust manifold.

 

Cut the head and about 1/2" of shank off a bolt the same size as the stud. Just long enough to fit trought the maniford and down inside the stud hole. Took a couple of tries and a grinder to get the length right. It was not broken deep enough to thread into the stud hole.

 

Trickest part: centerdrill the head and shank of the bolt the you just cut-off. I think it was about a 3/32" or 1/8". You will need to do this on a drill press. I would start with a small a hole as possible. You can always make the hole larger.

 

Used the head and and shank as a drill bushing to centerdrill the remaining stud embedded in the block. Had to use an angle drill but there was plenty of room for that particular stud. Drilled into it about 1/4 to 3/8". Just deep enough to get the ez-out to bite. Use a sharp drill, only about 30 seconds of drilling is needed.

 

Used the recommend square ez-out for the size of hole that you drilled. Let me stress the concepts: square ez-out and recommended size. Might want to use penetrating oil if stubborn. Do not break off the ezout in the stud. That is disaster. If you feel you are putting a lot of torque on it, soak it in penetrating oil and/or go to the next size ezout. Maybe even run the engine to get the aluminum head to expand and give the bitch up. Aluminum has 3 times the expansion rate of steel. If you break the ezout it may be there forever.

 

Mine came out without any hard twisting. Finger tight plus a little. As a matter of fact, when I removed (at a much later date) the remaining studs they all came out pretty eazy. None were bound. All were pretty clean. I don't think I live right. But I do think Nissan installs with antiseize.

 

Install new stud. Torqued stud, the existing gasket was still good enough to seal.

 

This method is a lot less risky than trying to do it free hand and you do not have to take the manifold off. Even if I removed the manifold I would still use a bushing, it would just be much shorter. Total time was about an hour. I heard the dealer wants $700. I laugh out loud in their faces. If I had the bushing pre-made it would have be a 15min job.

 

By the way, I looked for the bushing and could not find it. Will take another look later on. I am sure it was put away safely.

 

 

Tacoman

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Very nice tacoman !! :clap: While I have used many drill pilots, I have never used a bolt as a pilot like that; I'm remembering it :P I usually go at it free hand, but then I've done that many times so I guess I'm practiced at it. Very good write up; I recommend it to be pinned in the garage section. only thing I will add, and HIGHLY stress, is use a left handed drill and go slow speed... Coring the stud like that, heat, vibration and torque will often back the stud out, aleviating the need for the SQUARE type easy out. :D Good job.

 

Bernard

 

P.S. High speed drills are preferable as they flex more than cobalt and are less likely to break; just buy 2 because they will dull faster...

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