Plugging Header Test Ports on 308

They are similar to injector ports in head...smaller, IIRC.

I've seen standard plugs used, or in my case welded closed.....HTH

I don't think "chirping' is an issue at this location...we sniff it at the tips anyway.....although cylinder by cylinder is better, I suppose.......

 

The test ports on the headers are threaded. If the threads are in good condition, or if you can chase them with a tap, you can insert a short bolt into the port. It would be a good idea to tack weld them in place so they don't work loose. Or simply have the hole welded shut. I agree with Big Tex that whistling is probably not a problem, the way it is with the injector port on the head if you don't fully fill the port hole.

 

Tom -- Do a search on "110860" (here and at the old site) for prior threads on this subject.

(PN 110860 is the short threaded "CO plug" that F supplies for this purpose.)
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T Rutlands stocks the plugs for those ports...

 

grind off flush and put a weld button across all four, IMO.

Harder on the front, unless you have header off......

 

Unwrapp cladding and inspect for cracks, may be calling Quicksilver!

 

I'm surprised that it's so few

The thread size is M12 x1.25P so the most usual repair would be:

1. Get an M12 x 1.25 tap and the corresponding tap drill;

2. cut the tube off flush with the top of the existing (rounded) nut, or the nut flush with the top of the bung (if the nut is already badly damaged);

3. using the ID of the old tubing as the pilot hole, enlarge the hole in a series of steps using slightly larger drill bits until you get up to the tap drill size (be careful to not go too deep -- you want to preserve the reverse flare feature at the bottom of the bung;

4. pick out as much of the remaining male thread crests as possible;

5. Grind most of the point off of the M12 x 1.25P tap if necessary (to convert it into a "bottoming" tap -- or if you can buy an M12 x 1.25P bottoming tap, do that ), and "chase" the threads to clean them up.

Good luck...