Tackling the twins soon. Want to avoid broke studs
 

Ok fellow fd owners I have some questions and need your suggestions. When removing the twins I don't want to strip or brake any studs. What do you guys suggest to remove all the nuts. Just plain old brute force or air impact gun and should I first heat every nut/stud before attempting to remove it? I will most like replace all nuts and studs with new ones. Also what is the torque for the nuts and the nuts on the oil lines? Tried checking the service manual but could not open it on my phone. Thanks guys

Liberal soaking in PB Blast, hand tools, a torch, and good judgment :)

Here are some options for studs (kinda pricey):

https://www.full-race.com/store/garr...-hardware-kit/

Good option for nuts:
M10-1.5 Exhaust Lock Nut Copper Plated Steel 14mm Hex

Is the engine out of the car?

It's probably better to plan for broken studs, as opposed to just hoping that you don't break any. Get a couple spare ones to have on hand just in case ;) That, and definitely have new copper-clad locking nuts on hand. Treat those guys as 1-time use items, they're cheap enough.

Replace with OEM hardware. It's inconel

I've also had good luck getting studs out with this

https://asttool.com/detail_page.php?...nd%20Extractor

^Yup, I got mine from Ray. It was forever and a day ago though, so I don't remember pricing..

I got all of my replacement studs from McMaster and Carr.

Not cheap. I paid like $14 for the studs and $5 for the nuts (ea). There's really no cheaper alterhnative that will withstand the exahust temps

It's a PITA to do it with the engine in the car, but chase the holes and any studs you might re-use with a tap and die.

OEM hardware is best but expensive and should not be reused. If you reuse it there is a very good chance it will seize and break.

A good alternative is here Cylinder Head And Manifold Studs

These copper plated steel nuts also work well for exhaust and turbo applications
Nuts, Copper Plated Steel

Spray everything down with pb blast the day before. If a fastener begins to get tight stop and heat it, then try again. Repeat until it comes out. Its a good idea to chase the threads with a tap.

Thanks a bunch for all your help guys. Will definitely take my time and use pb blaster and heat. Do any one know the torque spec for twins?

I found this a couple days on what exact sizes to get for replacements and where to get them.

https://www.rx7club.com/3rd-generati.../#post10669635

Although it's not the OEM inconel, I wonder how these would hold up in the long run with some antiseize or something. Maybe theorie will see the post and reply, it's been 6 years.

All torque specs are in the FSM, but for reference (from the 94 FSM)...
Values are for OEM hardware

https://cimg4.ibsrv.net/gimg/www.rx7...82b6894a8b.jpg

https://cimg9.ibsrv.net/gimg/www.rx7...5d4e418018.jpg

I'd have used McMaster and Carr studs like Theorie posted but saw that some people had reservations on not using Inconel studs like OEM due to the intense heat our engines put out warping regular studs. That's why I used the Full Race studs I linked up earlier, which are made of an Inconel alloy.

Thanks bud.

This and other related threads might be a good read too. Seems like it usually comes up....

https://www.rx7club.com/3rd-generati...skets-1080695/

FYI I've used the McMaster-Carr studs in a few FDs with no problems.

The big one here is using the copper locking nuts, the stock locknuts are WAY too aggressive and will almost always pull the stud out. The copper ones work great, aren't too expensive, fit nice, and will come off nice down the road when you want them to.

Dale

Just replaced my twins with another pair of lightly used stock twins. I did not take out the engine, but it was a real headache to get off all of the hoses, heat shields, and connectors etc. There are some tight spaces to get into.

To get to the twins, I removed intake, intake hoses, air pump, y-pipe, and turbo control arm.

I removed my DP and installed an HKS along with swapping the twins, so I removed a lot of components.

I got all new gaskets, seals, and bolts from Ray (he's the man!). Some of the gaskets are very pricey, especially DP to turbo sandwich gasket, but I wanted to sleep better knowing I got OEM. Don't skimp on gaskets. I would not advice re-using gaskets if at all possible. Many, if not all, of these gaskets have a slightly raised indentation which crushes and seals properly when tightened down. Not really designed for re-use. Many of my gaskets were hardened and brittle, so they would have been impossible to re-use anyhow. If you want the full list of hardware I got and the prices I can PM you or just post it here for later reference.

I didn't have any bolts that were seized up, but ones that were tougher to remove I hit with some PB blaster and let it sit for a while and then went to work. The best advice would be to get a second pair of helping hands. :)

Thanks for all the replies I am getting rx7 brothers. Can anyone tell me the stud sizes I need for housings to manifold, manifold to twins and down pipe studs. Thanks

Never mind looks like I found the sizes here in my own thread lol. Thanks bud

What about Titanium Exhaust Stud ?

Thank you guys I was able to remove the twins successfully without braking a stud. Most nuts came out with the studs but no problem removing them. Can or should you reuse the studs from engine housings turbo manifold?

Anyone?

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