Need some opinions from people that have actually repaired stripped exhaust/header stud holes on these L-series heads. I’ve got the classic blown gasket/exhaust leak situation and at least one stud hole is stripped.

What are you guys trusting more long term on exhaust studs — Helicoil or Time-Sert? Especially with all the heat cycles these engines see.

Also looking for advice on drilling/tapping angle. Since the stud hole is close to the runners and access sucks, what’s the best way to make sure the tap stays perfectly straight and the stud doesn’t end up crooked causing sealing issues again?

Did you guys freehand it with a right angle drill, make a guide/jig, use the manifold/header as a guide, etc?

And honestly… are these headers even worth saving at this point or once they warp/blow out around the flange is it game over?

Trying to fix it once and not deal with another ticking/blown gasket a month later. Don’t mind the Xmas tree rug beneath I have a leak 🤫 wife don’t know where it is!

Scrap the headers in my opinion and drill out the stud with a smaller diameter bit. Soak the stud after it’s drilled with Kano Kroil. It’s a penetrating oil available on AMZ. Works fantastic. Keep soaking it for a day or two. Get an easy out and remove the rest of the stud. Retap and be done. That stud tends to break more often than any other on these engines. Spray ever bolt on that exhaust at the same time before you attempt to remove anything IMO.

Edited May 12May 12 by Yarb

1 minute ago, Yarb said:

Scrap the headers in my opinion and drill out the stud with a smaller diameter bit. Soak the stud after it’s drilled with Kano Kroil. It’s a penetrating oil available on AMZ. Works fantastic. Keep soaking it for a day or two. Get an easy out and remove the rest of the stud. Retap and be done. That stud tends to break more often than any other on these engines.

I didn't think about at the rest of the stud being in there!! Doesn't seem like it..

Pretty sure that I saw that @siteunseen went one size up on all of those studs. Could be wrong (my memory) but it seems like an option.

If you decide to use an insert use one of the solid ones, not the Helicoil. Timesert is popular.

https://www.timesert.com/index.html

If it was mine I think I'd just retap to the next size up and see how it fits. If there's a problem use an insert and go back down to regular size.

p.s. I don't think that a locking nut is supposed to be used there. A PO probably had a problem with the stud loosening and tried to fix it.

Edited May 12May 12 by Zed Head

Have you tried to run a tap in there yet. I apologize if you mentioned it earlier?

I went up a size from 8s to 10 I believe on a wallered out N42 head. It was pretty easy from what I remember but my motor was still on a stand out of the car.

A bunch of threads here...

https://www.google.com/search?q=using+bigger+cylinder+head+bolts+siteunseen+classiczcars.com&rlz=1C1VDKB_enUS1121US1121&oq=using+bigger+cylinder+head+bolts+siteunseen+classiczcars.com&gs_lcrp=EgZjaHJvbWUyBggAEEUYOTIHCAEQIRigATIHCAIQIRigATIHCAMQIRigATIHCAQQIRigAdIBCTMwMDIzajBqN6gCALACAA&sourceid=chrome&ie=UTF-8

Edited May 12May 12 by siteunseen

I tend to write a lot.

11 minutes ago, Zed Head said:

I tend to write a lot.

Me too! My brain rarely makes it to the writings though. 🤣

15 hours ago, Yarb said:

Have you tried to run a tap in there yet. I apologize if you mentioned it earlier?

Nope I haven't really poked around at it.

Not gonna lie I’m pretty nervous about this one here. I’ve never tapped threads, installed inserts, helicoils, any of that before. Not sure I wanna start learning on the head of a running Z… my Z lol

Head up to Ace hardware. They have a multitude of taps & dies. Grab the factory size tap and try to start it by hand and if it starts to bite that’s a good sign. From there use the tap handle to continue on. I originally thought the stud had snapped which is happens in that position most of the time. It’s very common. After looking at the pics again I see a complete stud.The threads maybe just buggered up. Search on you tube it’s not difficult to do.

To add to Yarb's great suggestion HarborFreight has that stuff to. Much shittier but whatever is close by.