High Temp thread sealant/thread locker

[Creekside]

I am removing the rotten AIR injection lines from the exhaust manifolds on my 86 Chevy K20. I was able to get all of them to come loose with the help of a 6 point socket, torch and welding tip, and Schaeffer Penetro. I'm plugging the holes with Dorman 090-055 drain plugs because the thread matches on these. I'll have to face all of the plugs off in the lathe to get the sealing surface of the plug to sit against the manifolds(the threaded portion bottoms out in the hole before the flange seats on the manifold). I want a thread sealant that will handle the manifold temperatures of the old 350 and also work as a thread locker if something exists. I don't want to rely solely on the flange of the plug to seal it off. Maybe I'm overthinking this and carbon will seal them when I start driving it? 🤷‍♂️

 

[joegreen]

I would just install them. Things like this always find a way to weld themselves into the manifold with time.

 

[RooflessVW]

Permatex® High Temperature Thread Sealant, 50 ML – Permatex

www.permatex.com

Could also use crush washers.

 

[doitmyself]

With a Google search I found this product that is medium/strong strength, lists engine exhaust bolts, and is good to 2000 F: https://www.vibra-tite.com/threadlo...t-lock-extreme-high-temperature-threadlocker/ But, its description does not mention "seals"........a call to the company is warranted.

Loctite 2422 states it is good to 650F

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[atikovi]

Just use hex pipe plugs,

 

[tasch72]

Can the plugs be welded in?

 

[atikovi]

Can the plugs be welded in?

Why would you in case you ever have to restore emissions function or at least appearance?

 

[tasch72]

Why would you in case you ever have to restore emissions function or at least appearance?

I can't imagine OP is planning to reinstall emissions equipment that has fallen apart. Plus, there is only one county in Missouri that requires emissions testing and it's in St. Louis.

 

[atikovi]

What if he sells it to someone out of state where emissions are checked?

 

[repairman54]

What if he sells it to someone out of state where emissions are checked?

It's an '86. Cavet Emptor. Here in the people's republic of NJ where CA standards are in effect the pre OBD2 vehicles are emissions testing exempt.

 

[atikovi]

It's an '86. Cavet Emptor. Here in the people's republic of NJ where CA standards are in effect the pre OBD2 vehicles are emissions testing exempt.

How many buyers check or even know about air injection systems and their components? Regardless of state regulations, it's still a federal offense to remove or disable emissions components and I don't think there is a cut off age.

 

[brianl703]

How many buyers check or even know about air injection systems and their components? Regardless of state regulations, it's still a federal offense to remove or disable emissions components and I don't think there is a cut off age.

Just make sure that neighbor you don't get along with doesn't work for the FBI or the EPA.

 

[atikovi]

 

[paulo57509]

Brings back memories of when the one-way valves or the tubes would corrode away; open the hood and you see eight of these jammed in the manifold:

 

[atikovi]

Brings back memories of when the one-way valves or the tubes would corrode away; open the hood and you see eight of these jammed in the manifold:
View attachment 124517

The hex plugs I used in post #5 look more factory and should fool most inspectors. No inspector Bob, that's how they came in 1986, only the California cars came with air injection, the others had the ports plugged instead of making two different manifold designs.

 

[Chris142]

I can't imagine OP is planning to reinstall emissions equipment that has fallen apart. Plus, there is only one county in Missouri that requires emissions testing and it's in St. Louis.

My state don't care. It must be there and operational to be registered. Here they emissions test 1976 and newer.

It's also a federal crime to remove emissions parts even if it's not enforced in some states.

 

[Creekside]

The threads are straight, not a taper like a pipe plug would be. I could possibly force something into the bungs but there's no reason when I've found the drain plugs that work. They'll be as close to factory looking as I could probably ask for once I shorten them in the lathe.

As far as the emissions concerns go, the chances of any inspection being done in my rural county is slim to none. I understand the legal issues. If they're upset about me removing the inoperable AIR system they'll really be upset when they see the Holley Sniper EFI system that I intend to install. How many LS engines have been swapped and highly altered? I think it's a far stretch to think I'll ever run into issues here.