I pulled off my twins yesterday and the studs look bad on both the manifold and downpipe. I found this thread making it easy to find replacement studs: https://www.rx7club.com/3rd-generati...dition-957371/

Has anyone tried using allen screws as studs, so that when you are installing them you can you and allen wrench to properly torque them without messing up the threads?
IE Metric set screws, Allen, Cup point, Class 14.9 steel black oil finish, 10mm x 1.5mm x 35mm - Bolt Depot

 

when pulling and putting the studs back in, I just used vice grips and thread locker. it's not really a matter of torqueing them down but making sure they won't pull out. I'd suffice to say that twisting them with my hands on a vice grip was more than enough to make sure they were not going to come out.

Along with that though, I used stock replacement ones because of the ungodly amount of heat that comes out of this little engine. There's some things you don't really want to gamble with when replacing it with something aftermarket. You want to make sure your replacement studs can handle the heat and won't warp.

However, I did replace the stock nuts with copper ones and anti-seize.

 

You need a good stud tool.


These things are amazing. They have round barrels inside that grab the stud and allow you to torque it in or torque one out without damaging the stud.

I've been using aftermarket studs for quite some time on my car and on other FD's with no issues. Definite must on the copper lock nuts, the OEM nuts are just a dumb design.

Dale

 

Dale....I honestly just post replies to peoples threads to what I have done to see what you'll say, lol

You seriously provide such good feedback

 

When I was looking at those stud remover/installers on Amazon one of them mentioned they will ruin the threads when installing the studs so I figured they all would operate the same. However since you're recommending it I can assume you've used it before.

The review on this item made me think they would not work for installing studs:

 

Well I've managed to remove all but one stud, and the last stud appears to be seized. I'm thinking I'll have to buy a torch and try heat.

 

one of my favorite tools....

Sears.com


no stud wreckage, put down that Channel Lock! i have never met the stud that my KD set couldn't remove.


hc

 

Have the same tool as Howard ( amazing how fast the tools add up)
Saved me a few times
Along with pb blaster and small propane torch

 

I've got the stud double-nutted, so I don't see what advantage that tool is going to give me?
I'm just unsure at what tq point this stud will snap if I use a breaker bar. So I'm curious if heat or a different detergent than PB blaster will help.

 

 

Get yourself a small plumbers propane torch or butane torch, hit it with heat, should crack loose
Not sure on torque breaking point tho.
I snapped one, bought stud easy outs also at sears (removes stripped or broken bolts and studs)

 

Hi - also strike it with a hammer as you turn it - don't just tap it, wack it. Worse outcome is you shear it off and need a stud extractor tool. Rusty.

 

Howard and I have the same idea on the stud extractor tool . Both are the same design, just different manufacturers.

Double nutting works fine, it's just a pain to do. The stud extractor tool is SO easy and works SO well you feel embarrassed you haven't had it before now.

That said, stuck exhaust studs are sometimes a REAL chore to get out. You will have to work it with heat. Heat it up good, let it cool, heat it up, let it cool, then hit it with PB Blaster and let it soak in.

Oh, the stud extractor tool - I've used it numerous times to install and remove studs. In some cases you might get a bit of a tool mark on the side, but the stud functions perfectly, nuts thread on and off easily, etc.

They make installing block off plates a SNAP, btw.

Dale

 

I bought a propane torch today, how long do I heat it up? Do I keep the flame focused on the stud or both the stud and manifold?

 

Both, mainly where the stud goes into manifold, heat it up, tap on it and try to crack her loose, repeat should come right out

 

Agree on the OEM studs. Corrosion is sometimes a big factor, too. Because of the high heat, corrosion happens very quickly. OEM exhaust fasteners are usually some form of stainless to resist this.

 

I still cannot get the stud out. I took off the manifold, taking it to a professional.

I took a video to peek into the housings:

 

if you have the engine on a stand, turn it so the manifold is upright. try hitting the stud with PB blaster or some equivalent soaking agent.

hit it healthy once every hour for like 5 hours. let it soak overnight. next day, hit that stud with some heat from the propane torch, the blue portion of the flame is the hottest, hit it for like a minute or two, it doesn't need to be glowing hot, just heated.

if you don't care about the stud, I'd say do my vice grips approach and tear that thing up and buy another one.

but if you want to reuse it, you should be able to break it after all that.

btw, what're you showing us in that vid? everything looks fine if that's what you want to hear.

a video of you attempting to break the studs would be more helpful so we can gauge how much difficulty you're having at getting it out.

 

I took the manifold to a shop this afternoon. I got a call about 4:30 saying the stud snapped after they heated it with an acetylene torch and used an impact on it. Tomorrow they will drill it out.

I posted the video (maybe should have been a separate thread) because I thought my primary rotor looked like it was caked in carbon and was concerned how bad it really was in the eyes of those who have seen more carbon buildup.