Anyone out there remove the smog pump system from their SBB? Looking to see what you used to plug the smog tube holes that connect to the head exhaust port. Thanks in advance for your help.
I would expect that 3/8 NPT plugs can be forced into place, and easier if they're brass rather than steel. I bet what you actually need is INVERTED FLARE plugs. You'll know when you remove the AIR injection tubes from the exhaust. If the holes and tubes are set up as inverted flares...
Are you plugging the bottom side of the intake or the top where the air pump connects? I was just going to make a plate to go over the top of the air inlet
I've tried 1/4 NPT pipe plugs which start to go in but stop a thread or two in. I also tried a 1/2-20 socket set screw which did the same... Is there something thats an iverted flare plug designed specifically for this?
The 1/4 pipe plug wouldn't fit so I'm assuming the 3/8 would be too big...not too familiar with pipe thread vs. imperial national coarse but I know they are completely different. Were these somthing you got from a hardware store?
I got the motor minus the smog equipment so I have nothing to check thread size on the male tube ends to.
Shine a light into the AIR ports, see if there's an inverted flare seat machined into the iron. Any automotive parts store should have a rack or cabinet of brass fittings, although they're probably not going to have eight inverted-flare plugs. They might have two, and they'll be expensive. Or order them from Amazon. Pack of ten, $8.02. These are 1/4" (7/16-24 thread) https://www.amazon.com/Eaton-Weathe...462&sr=8-2&keywords=Brass+inverted+flare+plug Or 3/8 inverted flare pack of ten, $17.33 (5/8-18 thread) https://www.amazon.com/Eaton-Weathe...462&sr=8-8&keywords=Brass+inverted+flare+plug These are examples, you'll want to verify which size you need.
Just get a 1/4" pipe tap and make a 1/4" pipe plugs fit! You will be in control of how far it will go in by how far you thread the hole with the tap. Use grease on the tap to make the chips stick to the grease that is stuck on the tap for chip removal. Another option, rather than trying to find the "correct" threaded plugs. GL
Thanks @300sbb_overkill I've all efforts trying to find the right size plug....Going to pick up a 1/4 NPT tap and do as you suggested.
If you look into the head and see a tapered seat that looks like a brake fitting, they will accept a 5/16" inverted flare plug, which are common as dirt at parts stores. The factory A.I.R. fittings were 5/16" inverted flare, for the tubing.
If they are 5/16" these Dorman 785-452 plugs might do the trick: https://www.summitracing.com/parts/...se1-_-dorman&gclid=CM3S0sXX5dICFUpNfgodK8wCAw I have the smog setup on my 67 Skylark 340 and would like to remove it. Any tricks on getting those off since you can't really get a standard wrench on it easily? There was a similar thread on this a while back as well: http://www.v8buick.com/index.php?threads/a-i-r-plugs.319747/
It's odd that your valve covers only have 4 bolt holes and not six? I haven't seen that before and they have built in spark plug wire guides. Very cool!
I'm not sure on the removal of the smog pump as my 300 didn't come with one, but the 340 that I have has the smog pump ports in the heads tht I'm trying to plug.
Thank you, I realy appreciate any and all suggestions, tips, & recommendations. This is my first Buick and a first time for me to work on and restore a classic car so everything is new to me.
Unfortunately I don't have the smog pump sustem and tubes to compre the thread diameter & thread pitch.
