Hello,

I have a 1.6l miata engine that's getting prepared for turbo and bought some better Exhaust studs. So I was cleaning the threads on the Exhaust side of the head with a thread chaser and on the very last stud hole my thread chaser somehow fouled up and got stuck, I had to back it out with force and with it the threads were gone.

I've found this post: https://www.miataturbo.net/engine-pe...threads-81900/
and it's a fixable mistake...

My question: I noticed on 1.6l heads there are two unused exhaust stud holes (pic 1)


I messed up the threads on the upper left part of the head (pic 2)



Is it possible to set up the stud configuration like such (pic 3)


to provide adequate clamping of the manifold to the head?

Or do I need to repair that hole and go with how the studs were originally setup?

My reasoning is , to me the configuration in (pic 3) seems symmetrical and can provide a proper seal if I tighten the nuts evenly around. I also saw this miata head (pic 4) with a similar configuration .




Thank you for your help,

Drew

 

Just do a thread sert or a helicoil

 

Is there any downside on using the stud configuration in pic 3? Do you happen to know why mazda left two unused stud holes?

 

Does your header have provisions for that stud? I wouldn't see any reason that it wouldn't be adequate, but are there headers and gaskets that have holes for that unused hole?

 

It does.

Here are two gaskets I have, one mls and other is composite.


Here is my turbo manifold.


Also here is an 1.6 OEM manifold gasket set






Thoughts?

 

probably just fine

 

Plus 2 for above; and by the way, that is a beautiful header!

 

Thanks man, I will just have to test and see.

Surprisingly, it's cxracing turbo kit version 2. I know they don't have a good reputation with their old manifold , but I wanted to give it a test anyhow , and I based this off of several people getting this kit.

 

trubo not hit block. nice!

 

Just use heilcoil. Stripped threads in alumnium heads is pretty common, heil coils are steel and would provide a stronger thread anyhow. Some people preemptively heil coil their stud holes for this reason.

 

I much prefer the MLS gaskets over the composite ones. I only get a single use out of the composite ones as they really deform on me after the first torque.

 

EZ Loks are so easy I'm happy I did this:
https://www.miataturbo.net/build-thr...4/#post1540476

 

Will the helicoil work on the turbo flange as well? Threads are boogered up on one of mine. Have used it successfully on a caliper but kind of thought the high temp would make it fail.

 

I always use a keencert if room allows. King cert? I never remember the name.