Air rail plug pics

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yotamotive said:
Why not just use an oem plug? I did, works great, a little more expensive but built specific for those holes. The right length and shape at the bottom to plug the hole. Check out the pic:
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Great information.

I just spent an hour in Home Depot trying to match up a plug. It did not work. I had previously just capped off the tubes with a plumbing cap.

I did not know Toyota made a plug. I am going to try to get some of these.
 
Match up the thread pitch !!!!!

You must use a metic threaded plug or grub screw, what ever fastener you choose. use Indian Head gasket stuff on the threads. Hey, they use on mack truck engines! can't beat it. NPT thread will work with enough sealant and a lot of luck!!!
 
Mace said:
Tellin ya, NPT plugs work just fine ;)
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X2

1/4" NPT pipe plugs work great. I read about it years ago in TT and mine haven't leaked since.

The metric ones are great... but the NPT are cheap and readily available.

The only thing I would add is use HIGH TEMP silicone to seal them up, that head gets HOT!

Rezarf <><
 
I would alsoe recommend the brass plugs if you use NTP. Less chance of damaging the head.

Mine have worked fine for several years, not leaks.
 
FYI the threads are not tapered in the head. NPT (National Pipe Taper thread) may work fine, but you are essentially wedging a tapered pipe plug into a none tapered hole. Not saying it doesnt work, but that is what is going on and probably why brass works best as it is the most forgiving. The OEM plugs and original air rail seal with a compression type seal at the bottom of the hole much like natural gas fittings used in homes, or brake fittings. Hope this helps.
 
True Value here in Fredericksburg, VA doesn't have the 14mmx1.5 plugs... but we do! In fact, the ones we stock come with thread sealant too. Exact fit, hex head, just like OEM.

NPT plugs in metric threads... you should be ashamed! I hereby condemn you all to "P.O." status!!

:-)

HTH

Lance
www.ironpigoffroad.com
 
Stock air rail plugs are tapered ;)


If you think I should be ashamed for using plugs in my truck you really don't want to know what else I have in mine :flipoff2:
 
Pskhaat said:
Air rail is for the air injection system into the exhaust to inhibit backfire and complete the burning process with introduction of new oxygen, especially on compression braking situations, etc.

Anyway, you shouldn't have holes in there, it would cause an exhaust leak in the engine compartment and decrease (slightly I'm sure) your torque, not to mention I would assume being quite loud.
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sorry.. but can someone explain this more. I do not understand what this Air Rail deal is? Seems to me, by reading the above, you need the "air rail".... so why are they being removed?
 
wantatlc said:
sorry.. but can someone explain this more. I do not understand what this Air Rail deal is? Seems to me, by reading the above, you need the "air rail".... so why are they being removed?
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Wantatic - the "Air Injection Rail" is a part of the original emissions equipment. The rail is situated between the valve cover and the carb. If one decides to "desmog" or remove the emissions equipment - then the air rail can be another component that gets tossed. Upon removal - one needs to plug the holes that are left in the head. They are threaded already - so in goes the plug and you're good to go. Hope that helps.
 
thanks. 100% clear now. :cheers:

As I purposefuly went for a rig that was pre the smog ban in CA, and that had a V8... I was not aware of this item.
 
yotamotive said:
FYI the threads are not tapered in the head...The OEM plugs and original air rail seal with a compression type seal at the bottom of the hole much like natural gas fittings used in homes, or brake fittings..
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Mace said:
Stock air rail plugs are tapered...QUOTE]

As it seems there is not concensus out there, I am curious what the right answer is.

I just got off the phone with CDan about ordering the stock plugs, and he said the holes are tapered, but in looking at the air rail connection itself (see pic) it would appear to me that yotamotive is correct. See the little bevel edge that looks like a sealing surface??

Probably foolish of me to question the Shaman, but can anyone definatively confirm/refute?

thanks
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projektdotnet said:
erics it was already confirmed that OEM ones are tapered at the bottom
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where?

maybe I'm slow, but it doesn't appear to me that there is a clear answer in the thread. I was trying to illustrate this by quoting yotamotive saying the threads ARE NOT tapered and Mace saying that they ARE tapered. That doesn't lead me to understand it to be confirmed.

I would think that they're either M14 tapered thread and seal by the threads wedging tigherter and tighter into the taper, or they're M14 straight thread and seal by the contact of the bottom beveled edge against a flared surface at the bottom of the hole. Am I thinking about this correctly? If so, which is it?

In any case, I'm sure metric or SAE, tapered or straight thread all can be made to work, but particularly if they're designed to seal at the bottom, I'm more likely to want to go with the OEM plugs.

thanks
 
Post #17 shows the OEM plugs, judge the threads for yourself. I thought you meant the bottom of the plug (not the threads) were tapered.

I used the method from post #1 (he was even kind enough to send me a set of plugs that worked great :cheers:) and I will be doing the same to the left-over rail of my 69 :D
 
erics said:
where?

maybe I'm slow, but it doesn't appear to me that there is a clear answer in the thread. I was trying to illustrate this by quoting yotamotive saying the threads ARE NOT tapered and Mace saying that they ARE tapered. That doesn't lead me to understand it to be confirmed.

I would think that they're either M14 tapered thread and seal by the threads wedging tigherter and tighter into the taper, or they're M14 straight thread and seal by the contact of the bottom beveled edge against a flared surface at the bottom of the hole. Am I thinking about this correctly? If so, which is it?

In any case, I'm sure metric or SAE, tapered or straight thread all can be made to work, but particularly if they're designed to seal at the bottom, I'm more likely to want to go with the OEM plugs.

thanks
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Erics - Like I said before the OEM plugs are NOT TAPERED. I know the difference between tapered and strait threads and the OEM are most definitely strait with the sealing surface at the bottom just as your photo above shows. The only thing I can think of that may have started the confusion is that a fair number of people use English size tapered plugs to fill those holes which apparently works fine but is not the original method. Or possibly some earlier years came with tapered and later did not. I know for a fact my 78 fj40 was not tapered. I think your photo says it all. Also the threads are Metric not English. If I still had my 78 I would pull one out and take some photos of it with a metric thread gauge attached and next to a english tapered plug of similar size for comparison. Then maybe we could finally lay this to rest. Good Luck:)
 
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