Exhaust Manifold Stud Replacement

[Blurred Talon]

I've got one of the outer (bigger) studs missing on my exhaust manifold and I'd like to replace it.
I believe the threads may be buggered, it's been a while since I've looked at it.

How does one go about fixing this?

 

[schalk35]

This has been covered numerous times. Just look around it will pop up

 

[BogusSVO]

Heli-coil, timesert, or a ;home made bushing. Depending on how bad the stud hole is damaged.

Click the link in my sig line, and you will find the info you need

 

[T is for TURBO]

I ran a heli-coiled in mine. Just take your time and try to make sure you drill and tap as perpendicular to the flange face as possible. One of mine was slightly crooked so I wasn't able to put my manifold on. I ended up having to enlarge the hole in the manifold flange just a bit.

 

[Blurred Talon]

Can a heli-coil be done with the head still on the car or do I have to pull it off and do it?

 

[99gst_racer]

I Heli-coiled all of the manifold studs on my last cylinder head with it installed. You just have to be careful with the one stud that passed through the oil return area. I believe it's the bottom center stud. Avoid drilling all the way through on that one and grease up the tap to try to catch all of the chips. Aside from that, it's a piece of cake.

 

[serviceguy]

The only hole that actually taps into an oil galley is the center/lower one, if you need to fix one of the bigger stud threads y=that should be fine to be done while on the car. I've time-serted all my exhaust stud threads (with the exception of the center/lower one) with the head on the car.

 

[taz4432]

For almost all it can easily be done whilst on the car. Some of the ones closer to the driver/timing side may be difficult to get at.

As for drilling, as mentioned, one hole does run perpendicular to an oil galley, but it's pretty obvious when you've started drilling into solid aluminum versus just opening up the hole - just be smart about it and be gentle. With the bigger studs there's no issue of running into an oil galley, but again, just be gentle, drill, helicoil and enjoy. Just try and keep the drill as centred and straight as possible.

Another thing you can do is measure the depth of the hole with a caliper and then measure that height on the drill bit. Wrap the drill bit in plenty of tape above that height so that you know exactly where to stop drilling. Exceptionally useful when drilling with stuff you can't damage beneath (like a gas tank or oil galley!).

 

[Petergeralis]

Try to run a tap in there first, should be 10-1.25 if no luck before fighting with an extraction get yourself a1/4 or 5/16 left handed drill bit. If you get it centered it should spin it right out.