AMC Eagle Den Forum

The Mighty 258 => Exhaust System. => Topic started by: doc65 on March 25, 2012, 09:58:33 AM

Title: A.I.R Injection Plugs
Post by: doc65 on March 25, 2012, 09:58:33 AM
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.
Title: Re: A.I.R Injection Plugs
Post by: rohnk on March 25, 2012, 10:34:49 AM
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?
Title: Re: A.I.R Injection Plugs
Post by: carnuck on March 25, 2012, 01:25:49 PM
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.
Title: Re: A.I.R Injection Plugs
Post by: BenM on March 26, 2012, 11:29:51 AM
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.
Title: Re: A.I.R Injection Plugs
Post by: shaggimo on March 26, 2012, 12:16:02 PM
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.
Title: Re: A.I.R Injection Plugs
Post by: rohnk on March 26, 2012, 12:29:58 PM
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.
Title: Re: A.I.R Injection Plugs
Post by: doc65 on March 26, 2012, 02:15:08 PM
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
Title: Re: A.I.R Injection Plugs
Post by: rohnk on March 26, 2012, 02:50:13 PM
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.
Title: Re: A.I.R Injection Plugs
Post by: doc65 on March 26, 2012, 03:51:49 PM
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.
Title: Re: A.I.R Injection Plugs
Post by: rohnk on April 03, 2012, 07:53:43 AM
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.
Title: Re: A.I.R Injection Plugs
Post by: BenM on April 03, 2012, 09:11:45 AM
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.
Title: Re: A.I.R Injection Plugs
Post by: rohnk on April 03, 2012, 09:32:11 AM
Ah, good. Thanks for the info BenM.
Title: Re: A.I.R Injection Plugs
Post by: doc65 on April 03, 2012, 10:50:06 AM
Yes, brass, though steel are avail as well, either will work, I like the allen driven ones, but hex head works too.
Title: Re: A.I.R Injection Plugs
Post by: AMCKen on April 03, 2012, 08:46:50 PM
You're not worried about the brass melting?  : )
Title: Re: A.I.R Injection Plugs
Post by: doc65 on April 03, 2012, 09:03:53 PM
Not really, the melting temp on those brass plugs is 1700+ I don't expect the manifold temp to get beyond 1300 or so
Title: Re: A.I.R Injection Plugs
Post by: vangremlin on April 04, 2012, 09:27:38 PM
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.

I have the MC carb installed and left all the emissions equipment on but not functioning.  No belt to the smog pump, no vacuum line to the little doo-hickey canister on the passenger side of the engine, no vacuum to the EGR.  Engine runs fine.
Title: Re: A.I.R Injection Plugs
Post by: rohnk on April 04, 2012, 09:34:05 PM
I did the same thing Van. Although I am thinking about pulling the stuff off to clean up the engine bay.
Title: Re: A.I.R Injection Plugs
Post by: doc65 on April 04, 2012, 11:15:39 PM
My AIR injection ports/tubes were leaking something fierce, noisy!!!! Not to mention UGLY, and my 2150 is really just interim untill I TBI it, and further out drop in a stroker 4.6...
Title: Re: A.I.R Injection Plugs
Post by: vangremlin on April 04, 2012, 11:21:02 PM
I did the same thing Van. Although I am thinking about pulling the stuff off to clean up the engine bay.

While my Eagle is currently grandfathered in from emissions testing, I am leaving everything intact in case the rules change or a new owner (my son in 30 years???) has to pass emissions.  Not that the people working there really know what they are looking for.
Title: Re: A.I.R Injection Plugs
Post by: jspeez13 on June 14, 2012, 06:57:19 PM
does anyone know if you can elimate the downstream side of the smog pump system and keep the exhausst injection side functioning?  i would this set up keep my emmissions down.  i have to get an all new exhaust system but would like to simplify things.   
Title: Re: A.I.R Injection Plugs
Post by: ammachine390 on June 14, 2012, 09:52:06 PM
does anyone know if you can elimate the downstream side of the smog pump system and keep the exhausst injection side functioning?  i would this set up keep my emmissions down.  i have to get an all new exhaust system but would like to simplify things.   

You could, as thats how the 80 and 81 Eagles were set up. They ran air continuously to into the exhaust manifold. However, if you still are using the feedback carb with the ECM functioning, you cannot, as pumping air into the exhaust manifold would drastically throw off the O2 sensor reading. What year is your Eagle?
Title: Re: A.I.R Injection Plugs
Post by: jspeez13 on June 15, 2012, 11:34:31 AM
its an 81 sx4 with california emmissions.  it has the dual injection system.  i just got the mc upgrade from gronk and im trying to iron out a few things before i start dismantling everything.  so it will be non feedback.  i want to keep egr and the smog pump i just want to be sure it is all functioning.   i wanted to eliminate the vacuum crap that directs flow from the smog pump.  i am keeping a very strict rule of "anything that comes out of the car goes in the trash and is replaced with new"  ive learned the hard way to never reinstall old parts especiall when its so cheap to just get new ones. 
Title: Re: A.I.R Injection Plugs
Post by: ammachine390 on June 15, 2012, 04:07:13 PM
its an 81 sx4 with california emmissions.  it has the dual injection system.  i just got the mc upgrade from gronk and im trying to iron out a few things before i start dismantling everything.  so it will be non feedback.  i want to keep egr and the smog pump i just want to be sure it is all functioning.   i wanted to eliminate the vacuum crap that directs flow from the smog pump.  i am keeping a very strict rule of "anything that comes out of the car goes in the trash and is replaced with new"  ive learned the hard way to never reinstall old parts especiall when its so cheap to just get new ones. 

Ok, since you're going the non feedback way, you will be fine.

Out of curiosity, does it have a "thing" (its a set of vacuum switches) on the firewall across from the distributor that has 3 vacuum hoses going into it and some electrical wires? I've been looking for one of those, and there were only installed on 81 Concords, Spirits, and Eagles with California Emissions. If you have it, do not throw it out please.
Title: Re: A.I.R Injection Plugs
Post by: jspeez13 on June 15, 2012, 04:22:33 PM
yeah i got that in the trash pile ill pull it out.   i guess i need the plumbing from another year that doesnt have the dual injection to hook up smog pump.  any ideas on how to get that? i could ship that "thingy" to you if you pm me your addy.  do you have all that stuff hooked up and functioning?  if so, congrats on that.
Title: Re: A.I.R Injection Plugs
Post by: Jurjen on June 16, 2012, 07:23:25 AM
I put some 1/4" NPT - 18 plugs in.
1/4" NPT has about 1/2"OD.
You can probably get steel ones at your local plummer for $0.25/pc.
Title: Re: A.I.R Injection Plugs
Post by: ammachine390 on June 16, 2012, 12:46:12 PM
yeah i got that in the trash pile ill pull it out.   i guess i need the plumbing from another year that doesnt have the dual injection to hook up smog pump.

The good news is you shouldn't need all the other parts from a single air injection car. Because they both used the same parts.  To turn yours into single air injection, you have to remove the the air switch valve. Thats a little valve with 3 hoses attached to it, on the passenger side of the valve cover, toward the back. The air switch valve has a vacuum hose that connects to the solenoids on top of the valve cover. Once you take out the valve, just connect the hose that sources from the air pump, do the hose that goes to the air injection manifold.

Make sure you keep the diverter valve. Which is on the passenger side of the valve cover, more toward the front of the engine. It has 2 hoses, 1 from the air pump, and 1 that goes to the air switch valve. And it also has a vacuum hose that is connected to one of the 3 vacuum solenoids on top of the valve cover. Since you probably want to get rid of the 3 solenoids, just connect that vacuum hose to any manifold vacuum source.

You definitely need to keep the diverter valve, if you want to use the upstream air injection, as it prevents backfires in the exhaust manifold on deceleration.