Easy way to remove exhaust manifold studs?!

  • #1

    Easy way to remove exhaust manifold studs?!

    The dilemma:
    Recently, I got my 87 turbo running again and once I did immediately I noticed a severe exhaust leak coming from my passenger side manifold.

    Upon inspection I saw that the upper stud on the runner to cylinder 5 was the cause. Checked that nut& stud with my hand and noticed it was completely loose and in need of replacement.

    I then pulled the manifold and the lower stud going to cylinder 1 broke in the process. One of the studs where the crossover pipe connects to the passenger manifold also broke.

    The question:
    I am far from being the first person to do this and I was hoping that someone has a trick to drilling them out that they would care to share with me. I have the equipment but there is limited space in that area especially by the number one cylinder. I was thinking air ratchet (because it's more compact than other equipment) with a reverse drill bit and if i failed with that then drill all the way through and retap it. This method is traditional, at least to me, but it will be difficult. any ideas or suggestions?

    Car: 1987 Nissan 300ZX turbo 5 speed [original motor and trans not swapped]
  • #2
    This same dilemma is what introduced me into the world of the vg30 many moons ago. I boned it right out of the gate by cross drilling a cylinder #1 broken stud and snapping an ez-out in it.

    I've successfully done a few more since then and can say with certainty, if you can pull the head or motor…do it. It will be so much easier.

    However, in either case (in car or out) soak the stud remnant in PB-Blaster for a day or so to really penetrate the threads and help loosen it up. Make a flat spot on the top of the stud with a dremel and center punch a divot to keep the drill bit from wandering. I've not used a left handed drill bit but if it does the trick..woot! Otherwise, drill all the way thru and get some more PB-Blaster behind the stud. Heat up the surrounding metal with a torch, say a prayer and use an extractor. I chase the threads with an M6 tap afterwards.

    PB-Blaster is the sauce that makes it work..let'r soak. Also you can get a pretty inexpensive right angle drill attachment at Harbor Freight.


    84 AE/Shiro #683/Shiro #820/84 Turbo
  • #3
    Originally posted by Z_Karma
    This same dilemma is what introduced me into the world of the vg30 many moons ago. I boned it right out of the gate by cross drilling a cylinder #1 broken stud and snapping an ez-out in it.

    I've successfully done a few more since then and can say with certainty, if you can pull the head or motor…do it. It will be so much easier.

    However, in either case (in car or out) soak the stud remnant in PB-Blaster for a day or so to really penetrate the threads and help loosen it up. Make a flat spot on the top of the stud with a dremel and center punch a divot to keep the drill bit from wandering. I've not used a left handed drill bit but if it does the trick..woot! Otherwise, drill all the way thru and get some more PB-Blaster behind the stud. Heat up the surrounding metal with a torch, say a prayer and use an extractor. I chase the threads with an M6 tap afterwards.

    PB-Blaster is the sauce that makes it work..let'r soak. Also you can get a pretty inexpensive right angle drill attachment at Harbor Freight.
    thank you for your reply Z_Karma, funny you should mention the right angle drill I picked one up at harbor freight just before I saw your reply. I'm going to face this dilemma sometime next week. I already have the torch, right angle drill, PB-Blaster, and ez-out. I'm crossing my fingers that the harbor freight drill lasts until I'm done with this job. I am going to try and get them out with the engine still in the car, and I was thinking about drilling access holes through the strut tower/wheel well to make my center punch on the studs.
  • #4
    Stop!! dont pull the motor or heads and stop drilling. I just went through all of this recently just to replace the manifold gaskets. You will thank me after using this method if you can weld great, if not get a friend or take it to the local exhaust shop. Put a steel nut around the broken stud, if the broken stud is not sticking out just put a steel nut over the hole and weld inside of that nut until it fills the hole up and grabs the broken stud. It might take a few trys but it works!!! heres a link to help you out. http://youtu.be/aRrz-cphBY4
    THE ONE AND ONLY AE 2JZ Z31 IN THE WORLD
  • #5
    Ya ever tried to get the head of a MIG welder into the area of the studs of cyl #1?
    Because of the shock tower, it's a funky angle and a close fit. It's definitely worth a
    shot if you have a welder that'll get in there.
    Once i had a MIG welder, i tried the weld fill method on an turbo stud but steel rusted to steel is gonna be stronger than my cold welds i guess.
    http://z31performance.com/showthread…l=1#post302478

    I've had a few exhaust studs that come out pretty easily after a soaking in PB Blaster, it's usually just crud
    holding the dissimilar metals to each other. Once that's dissolved they could turn out by hand if there was something to grab ahold of.
    You might get lucky.


    84 AE/Shiro #683/Shiro #820/84 Turbo
  • #6
    Originally posted by 1bustedZ View Post
    and I was thinking about drilling access holes through the strut tower/wheel well to make my center punch on the studs.
    yeesh…if you do, i hope your a better shot than the blind mofo previous owner of my AE…they swiss cheesed the sheetmetal trying the same thing
    on cylinder #1, not only did they swiss cheese the sheetmetal, they penetrated the waterjacket of the head when they drilled out the stud.

    http://img70.imageshack.us/img70/5016/img1495sm.jpg

    I guess they said "fuck-it" because they just put another stud in there, sealing the leak…until i bought the car and tore it apart.


    84 AE/Shiro #683/Shiro #820/84 Turbo
  • #7
    All you do is unbolt the engine mount for whatever side of the motor your on, jack the motor up and the welder gets in there no problem. Its a good the thing the heads are aluminum because the mig wont stick to the head only the broken stud. Id say its the best way, I almost gave up until my friend told me about this method.
    THE ONE AND ONLY AE 2JZ Z31 IN THE WORLD
  • #8
    I prefer heat for removal… center punch and drill shallowly into the bolt, heat the piss outta it for a few/10 seconds then try your ez-out or lefty drill bit… pulled many broken studs this way.
    88T.... needs assembly
  • #9
    been down this road many times, tried all of the above methods. While I have gotten the nut welding trick to work, it would likely very difficult to do in-car. I just pull the head or the motor now. It will even out to the same amount of time and labor involved, I assure you. With the head out of the car you are now free to work like a gentleman quickly and efficiently.

    My .02
  • #10
    Originally posted by Gregmatic View Post
    With the head out of the car you are now free to work like a gentleman quickly and efficiently.

    My .02
    And for good measure I did the damn valve seals.
    Cha iro

    enjoy building it yourself.
    if it fails, fuck it.
    at least you gave it a whirl.