Need to replace the Thermactor exhaust plugs on with something like C6AZ-6052-A (old part#) but can't find them. Is there an alternative, like a regular 1/2-20 bolt? I assume a grade 5 or 8 steel bolt should work, about 2" long, but don't know for sure, is it exactly 1/2-20 thread? Any suggestions are much appreciated.
Hi,
I just had to figure this out myself, through trial and error. If you're talking about the EXHAUST MANIFOLD A.I.R. RAIL PLUGS (8 of them... 4 on each side), you can use 1/2"-20 THREAD 1/2" LONG SET SCREWS. I chose 1/2" long set screws because they sit just below flush so that my Patriot mid-length headers fit.
Good Luck!
I think these were used in later smog heads... read somewhere starting in about '74? I'm not completely sure. I guess I didn't need these two oddball plugs after all. I just needed the eight 1/2" 20 set screws.
Thank you, Semperfido, that is exactly what I was looking for. I am going to buy 8 pieces and install them this week. 1/2" length makes sense, but how did you find that it is the best length? They come in 9/16, 5/8, 3/4, etc. Like you, I also want a flat/flush surface so that the exhaust manifold (and its gasket), don't touch. As far as material, it can be steel or some kind of allow, it shouldn't really matter, correct?
BTW, on the other part (TFS-51400265) I did buy a set of plugs, problem is, I can't figure out whereabouts on the header they go? Apparently my air pump went into the intake manifold (and of course the top of that silly pair of Thermactor ducts). Does this go into the intake manifold?
Um... I'm not sure about the two TFS-51400265 plugs. I tossed my smog pump and I handed off those two plugs to the shop where they're fitting my dual exhaust. I didn't personally install them. I assumed that they thread into the intake manifold (but you know what they say about assumptions...) Maybe one of the experts can chime in?
As for the 1/2" length set screws, I arrived at that length by trial and error. First I tried 3/4" long set screws and they extended about 1/4" past the exhaust manifold... voila! I arrived at 1/2" and it worked. The C6AZ-6052-A plugs that you identified have a long, tapered, "dog" point like the original AIR rail fittings. The typical cup point set screws can't fill in that space past the thread but I figure that it can't hurt the flow significantly. Incidentally, I bought the phosphate coated (black) set screws for my engine (at my local ACE Hardware). I don't know the properties of an alloy material and I'm not sure if it could cause potential issues with expansion due to the heat.
I bought the 1/2-20 x1/2" and installed them, they worked like a charm, thank you, Semperfido!
Still working on the two plugs (TFS-51400265), just can't see anything else to plug, other than the old carburetor choke tubes comming off the passenger side manifold - but those need smaller plugs I think.
I want to say this forum is awesome! Very useful help and very timely - I wish I joined sooner when I started the restoration on my 66 18 months ago.
Yeah, me too (started 12 months ago and nearly finished). My only problem with the forum (and another one that I periodically check... probably worse on the other one) is that "some" folks (seems to be the same handles over and over again) just can't play nice all the time. It's juvenile but some people feel too free to be disrespectful and condescending from behind their keyboards. I hope that they wouldn't act that way face-to-face.
Thank you, 2nd66, but it's not. I found these so-called thermactor plugs on CJPony and SummitRacing and others, but the thread and size is different than a 65-67 289cci thermactor plug. I believe they are for 302 and bigger engines. What worked brilliantly well were the 1/2" long 1/2-20 socket head screws that "semperfido" mentioned.
I remember back in 1980 when my brother was complaining about all this Ford airpump stuff (thermactor) in California, that it was useless and just plain poor design (back at the time he had a Mercury Comet with a 302 engine) and now I get it. For some poor reason Ford made California Mustangs with these plugs right above the exhaust port of every cylinder to literally blow air in the exhaust, as if it would help... complete waste. But problem is solved now. Engine is running well, though I have to replace the exhaust gasket, apparently I have a small leak somewhere, because I had to cut each of the corners sligthly to bend around this so-called old "thermactor inlet plug". (First thing though, I should check the two choke ports that were used for the carburetor, that I no longer need on my new Holly 500cfm; I need to plug them somehow, and I don't thing they heave a threaded hole in the original exhaust manifold, any suggestions are much appreciated).
BTW, on another topic. You were totally right about the caster angle. Turns out my right wheel (the one that touches the fender after the 1+" drop), needs to go back in the wheel well which would be a very low (almost negative) caster. So basically I have two choices: try a Mikey-Mouse shim on the spring perch on the UCA (about 1/8") or just buy another spring since this was cut too much. I hate it because I just spent $95 for the new so-called high performance, 1" shorter 600lp/in Scott Drake springs, but I am not impressed with them at all.
I'd love to buy another quality spring if I could find something really stiff, like a 700+ lb/in kind, so I'll be looking, and if you know of any recommendations (1" shorter than standard) I really appreciate it.
The only problem I have with the SHCS is that heads are big and interfered with the valve covers. I spent the $ and got the correct plugs. Much better.
I agree, "bartl", I wish I could get the bice plugs, but the short SHCS'es (1/2" fit underneath the valve covers and we were able to drive them nicely with a 1/4" Allen wrench. Now the hole exhaust manifold "face" is nice and flat. BTW, did you actually use original C6AE thermactor plugs? I wander if they go all the way in nice an flush, or do they stick out a bit?
m66
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