At this time I am not putting the smog system back on, and would like to get some ideas on what plugs to use that wouldn’t be such and eyesore and easy to remove down the road.. Any suggestions??

Thanks, Dave

Dave, you'll need inverted flare plugs to fit the threads correctly, if you use pipe thread, you'll bugger the manifolds up & the AIR tubes won't thread back in.:eek:
If you consider a hex head pipe plug to be an eyesore, then I'd find some manifolds that aren't threaded or some that you could drill and install a 3/8" allen head plug into. JMHO.
BillL

The threads are regular bolt threads, not pipe threads. If you can find brass inverted flare plugs use them. They would be the easiest to remove later.

The threads are regular bolt threads, not pipe threads. If you can find brass inverted flare plugs use them. They would be the easiest to remove later.

I usually like to go to the Edelmann-Plews website to find part numbers... They also cross-reference several other brands (Weatherhead, Everco? Napa?) once you find the fittings...

Thanks for all your help... I was hoping to find a allen type plug I can sink into the manifolds so they are flush or close to it.. I guess I have to take one to a hardware store and start playing.. So would regular steel and or stainless be a bad idea, how about aluminum? Any one know off hand what the thread size is?

Thanks again,
Dave

Just send me your smog setup, and I will give you some manifolds without holes :)

It's a 5/16" inverted flare fitting. The thread size is 1/2"x 20. Don't use aluminum, use steel or stainless steel, liberally coated with antiseize.
http://midamerica.thomasnet.com/viewitems/a-45-degree-flare-fittings-inverted-flare-fittings/inverted-flare-fittings-inverted-steel-plug?&forward=1
Mark has a good idea, ya'll ought to work something out.:D:thumbsup:
BillL

The threads are regular bolt threads, not pipe threads. If you can find brass inverted flare plugs use them. They would be the easiest to remove later.

Brass, this has worked the best in my past experience. Easy to remove.

The threads are regular bolt threads, not pipe threads. If you can find brass inverted flare plugs use them. They would be the easiest to remove later.

It's a 5/16" inverted flare fitting. The thread size is 1/2"x 20. Don't use aluminum, use steel or stainless steel, liberally coated with antiseize.
http://midamerica.thomasnet.com/viewitems/a-45-degree-flare-fittings-inverted-flare-fittings/inverted-flare-fittings-inverted-steel-plug?&forward=1
Mark has a good idea, ya'll ought to work something out.:D:thumbsup:
BillL

Not exactly correct on either count.

These "smog tube" threads are 1/4"-18 NPS (National-Pipe-Straight). This IS a pipe thread but NOT an "NPT" (National-Pipe-Tapered) deal. It's been that way for years now.

If you want to "plug" the holes safely just fabricate a solid plug that fits the tube opening in the manifolds and make it the proper length to accept the original nuts on the tubes so the ass'y becomes tightened by those nuts.

We've done a number of these on 100% resto's where the outer tubes MUST be in place BUT the smog function is totally eliminated, "capped-off" so to speak!

Thanks, Gary in N.Y.

P.S. Your only other option is to use another set of manifolds and "save" the originals. Most of these are being remanufactured now.

Not exactly correct on either count.

These "smog tube" threads are 1/4"-18 NPS (National-Pipe-Straight). This IS a pipe thread but NOT an "NPT" (National-Pipe-Tapered) deal. It's been that way for years now.

FWIW, I went to get plugs for my manifolds. Definitely not regular fine threads 1/4 x 20 (too fine, but easily available and cheaper). I went to a local plumbing supply shop and asked for 1/4 straight plugs. They have the bin listed as 1/4 BLK plugs. Fit perfect! Thanks!

Hope this helps others, too.

Not exactly correct on either count.

These "smog tube" threads are 1/4"-18 NPS (National-Pipe-Straight). This IS a pipe thread but NOT an "NPT" (National-Pipe-Tapered) deal. It's been that way for years

Exactly right, and I found some Allen head Low profile Plugs at my local hardware store.

You can also install from the inside of the manifold so that the Flat end of the glug is showing to the out side.

I also did a "non functioning" Smog install.

Thanks for bringing this back up guys.. Great info, and I never thought of putting them in from the inside that's a great idea..

Thanks, Dave

Good info.:thumbsup:

Wouldn't installing std pip thread plugs (esp with hex heads)from the inside of the ex manifolds setup a small exhaust restiction?

The ex manifolds themselves are restrictive enough and dont need any help which is why i would not install the plugs from the inside.

To add,if later any of them are stuck (even if anti sieze is used) if/when you want to remove them you will not have nearly as good an access to them when installed from the backside of the ex manifolds and you may be forced to drill/re-tap from the outside in that's case.

I would opt for the hex head plugs with allen heads installed from the outside along with using anti sieze too.

Scott

Scott, do you still have enough room to install the air tubes after you install the hex heads from the outside?

Wouldn't installing std pip thread plugs (esp with hex heads)from the inside of the ex manifolds setup a small exhaust restiction?

The ex manifolds themselves are restrictive enough and dont need any help which is why i would not install the plugs from the inside.


Scott

I used Allen head Plugs that can be tighted "Flush" from the inside.

I used Allen head Plugs that can be tighted "Flush" from the inside.
Thats what I have installed from the outside now. I guess I could remove my exhaust manifolds and put them through the back side?
http://s193.photobucket.com/albums/z238/1badss396/Gardner%20Exhaust%20System/th_a997.jpg (http://s193.photobucket.com/albums/z238/1badss396/Gardner%20Exhaust%20System/?action=view&current=a997.jpg) (http://s193.photobucket.com/albums/z238/1badss396/Gardner%20Exhaust%20System/?action=view&current=a997.jpg)

Brad, you seriously need to finish that car so you can drive it a little and get some dirt on it.

Brad, you seriously need to finish that car so you can drive it a little and get some dirt on it.Its too hot down here to drive. I will have to wait till it gets cooler outside at least in the 80 degree range.

i agree with scott, if you ever have to remove them......good luck.

Just wanted to give an update. I ordered a set from McMaster-Carr for anyone interested. They are part number 4534K42 @ .51 cents each... Here is a pic of my manifolds with Eastwood Coating and the plugs. To lazy to get that anti-seize off right now, man that stuff is messy.

http://www.chevelles.com/forums/picture.php?albumid=25&pictureid=409

Dave