3.0 head question
 

Rebuilding my 3.0

What is the best way to get rid & plug of the air tubes in the exhaust port?

Use a fine thread 10mm bolt from a hardware store
Bruce

10mmx1.0 thread (I've found this to be hard to find off a shelf) , or a 1/8NPT pipe plug will work as well.

I have used set screws, mcmaster carr has them part #99642a154 10x1.0 10mm long

Tks cgar
Do you seal the threads in any way?

As I remember they tighten up in the hole but some high temp loctite wouldn't hurt


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Since the 1/8th NPT thread is not an exact match, I think using those plugs will distort the threads enough that they are not apt to come out again . Since it is likely you'll never need or want to pull these plugs, you don't have to worry about distorting the threads in the head as you keep screwing the plug in with more and more force. But I've always used the 10x1.0 stuff - it bottoms, and doesn't get in the way if something sticks out some. The set screws look a bit better in this application, though.

Walt
i don't think the thread is NP.
Looks like straight thread

It is straight thread, M10x1.0. I used a 1/8NPT for one head that had some thread damage and ejected a M10x1.0 plug. NPT worked like a charm and haven't had an issue since.

Er, I thought I said it was straight thread, not NPT. '76 put his finger on when using NPT might be useful - when the metric threads are buggered. The NPT might hold, as it just sort of cuts some of its own thread (worked for '76). Which would be fine if the threads are already bad. And even if it doesn't work, well you can just drill and tap for M12? Or for a thread insert to get back to M10 fine. But typically there is no reason to remove these plugs unless you are going to put the anti-smog air injection back on.

Some Loctite red isn't a bad idea either, though this area gets quite hot.

I've used 1/8 NPT set screws often without issues. Set it a bit below the surface and then stake them with a punch and they'll never give you a problem.

Pelican used to list a part in their catalog. It is actually a 914 brake plug.

Part #: 914-352-000-00-SIC