A.I.R Injection Plugs

[doc65]

I'm looking for plugs for the holes left my removal of the AIR injection tubes.  these were leaking like a seive, and they are a problem for the TBI injection I'm working on, so they came out, they seem to be a 1/2" x 18 thread based on my dial caliper & a thread pitch guage, of course that is not a standard size(that'd be TOO easy).  Anyone know of a source for them?  I know I could replace the exhaust manifold, or do the 4.0- head swap etc, I'm trying to avoid putting TOO uch into it till I do a 4.5 Stroker install, but it'd be nice to be able to drive it till that's done.

[rohnk]

I'm at this point too. Just reading up in the service manual as to what the air injection manifold does. It's just there to inject air to help convert the emissions. The 6 cyl systems also inject air into the cat converter. If you remove the air injection manifold, you may need to plug off the air to the cat.

I don't know where to get plugs though. Do you think it is something that could be made easily?

[carnuck]

Take one of the old line fittings to an autoparts store (NAPA usually has them in stock) You want the line plugs (like for brake lines, etc) section. Sorry I don't recall the number, but they are commonly used with fuel line tees to add pressure gauges then cap off afterwards.

[BenM]

I was able to get them at the parts store nearby. I think AMC used them on old stock manifolds when a car didn't get AIR and until they changed the casting.

You can get stock style plugs with a hex head or pipe thread plugs with a square head. The hex heads look much better. Put a dab of exhaust system sealer on the threads.

[shaggimo]

If your pipes break as mine did, you can make your own plugs from their remains, just weld them (fittings with pipe remains) closed and put them back in.

[rohnk]

Has anyone installed a Motorcraft carb with the AIR injection manifold intact? I want to remove the air pump and all the emissions stuff eventually but for now I just want to get the carb plumbed with the correct vac lines and I am having a bit of trouble figuring out where all the vac lines go.

[doc65]

Ok, so after I asked that I looked further and found that the diameter and thread pitch were right for a 1/4" PIPE plug.  I got some Allen drive pipe plugs from ACE and installed those with anti-seize(I know the anti-seize doesn't really help long term in exhaust, but it allowed my to put them in really tight with out it's galling and binding up).  Those plugged it up nicely and it sounds SO much better without all those little exhaust leaks.  I have also had a new exhaust installed (prior to this) which included a new cat that I had leftover from an old Jeep project, so no side tube for additional AIR to need plugged up.  I then installed the 2150 I rebuilt on the manifold adapter that I milled Friday eve and fired it up. can't actually drive it yet as I still need to get the throttle hooked up, but it starts & sounds SO much better.  I still need to deal with ignition.  I do have the TFI/MUI pieces that were surplus from the wagon when I converted it to HEI, so those are going to get re-used until I'm ready to go ti EFI.

After all this I found that the engine cleans up pretty well, BUT that dang valve cover leaks(imagine that), gotta get rid of the plastic POS

[rohnk]

Can you tell me where you tied into manifold and ported vac? I'm still trying to decide which is which with all the spaghetti in the engine compartment.

[doc65]

My manifold vac is in 4 places, a fitting in the intake manifold runner that feeds #5/6, the drivers side surface of the manifold itself(large -> powerbrakes & small plugged ), the back bottom of the carb has a large tube for manifold vac to PCV, the ported vac fittings on mine are front edge of the carb base toward the drivers side, and the passenger side of the base, if you look at the carb upside down you can see that these two fittings go so a very fine slot in main barrel of the carb which is above(or at least mostly above) the level of the throttle butterfly when it is closed, I used the one on the right side of the carb just because it made the vac line a little less obtrusive: on my wagon that second/side ported vac fitting was not there so I used the one on the front.  Like most of the kits I've seen others install mine had permanent marker writing that said "Dist." above that front one, and more that said PVC on the back large port and bowl vent near that one.   This second one(current install) was a wrecking yard pull that I wasn't even really looking for, just ran across it while looking for other parts.

[rohnk]

The pipe plugs that you picked up, are they brass? I looked up on the Lowe's website to see what they are and I'm not sure what I'm looking for here I guess. Do the bolts that go into the AIR monifold actually hold the ehaust manifold on to the block? If not, then it is just a hole to be lugged then?

Hope I don't sound soft headed on this, just trying to understand. Thanks.

[BenM]

They're just extra holes. They had a hollow bolt about an inch long with a piece of tubing pressed in so that the air was blown directly onto the exhaust valves. But they have nothing to do with attaching the manifold to the head.

[rohnk]

Ah, good. Thanks for the info BenM.

[doc65]

Yes, brass, though steel are avail as well, either will work, I like the allen driven ones, but hex head works too.

[AMCKen]

You're not worried about the brass melting?  : )

[doc65]

Not really, the melting temp on those brass plugs is 1700+ I don't expect the manifold temp to get beyond 1300 or so