King size gas tank problem

I am hoping some KZ veterans will have some answers to this king-size problem. I got my bodywork back from the painter and all looked great.Decals from Reproduction Decals and bang-on color match for my '74 Z1 project that is nearing completion. I had previously rebuilt my petcock and wanted to install it into the tank and found that the threads on the "bung" were almost non-existing. A nut by itself would thread on fairly well but with the rubber gasket in place I could not get it to seat without starting to slip off the threads. Teflon tape was tried in an attempt to get things to bite better but to no avail. I would bet money that the prep for paint (sandblasting) was the cause but don't remember seeing the problem months ago when dropping the parts off. Jeff at Z1 said he has seen "bungs" with the base plate for sale on E-Bay which I have not, but I guess my question would be this; does the "bung" thread into the base plate that is then spot-welded to the tank and if I make a series of fine hack saw cuts vertically into it could I break it away in pieces and then have a new "bung" machined, threaded in and sealed with some form of epoxy. Any kind of heat would surely mean paint repair which I am hoping to avoid.Will try to send pics tomorrow evening.
Any thoughts would be greatly appreciated.
David

Hi Dave,

here's one of the bung options - these are from Pingel:
www.pingelonline.com/tank_bungs.htm

Your thought on the blasting causing the problem is a likely one. Much depends on the media the paint shop used to clean the tank. If they used a very coarse aluminum oxide at high pressure it'll rip through paint (and anything else) in seconds.

wow bummer......jb weld it on...if nothing else .... hope you dont need to but be ready to re-paint...

the blasting away to much happened to me on a decent header i wanted to have ceramic coated the guys gave me back a pretty pipe the second time and damn near blasted/sanded through a few spots

Thanks to all so far for the input. I have taken some pics to show the dilemma. I found out today that a relative just purchased a telescopic camera that I will be able to use going through the cap to inspect the inner area of the bung. Thanks Jeff for the thought on the bung adapter, it is very close to what a machinist friend came up with today as an option. I don't mind permanently attaching a smallish adapter, but don't really want a big eyesore under the tank and that part from Pingle looks slick! I believe JB Weld is gas resistant as are a couple of other epoxy types so the homework begins. Thanks Tri for the input, I'll do my best to stay away from repainting!
David

Just a thought - Could you cut the old bung shorter and tap threads inside it? Then you could screw a nipple (pipe) inside the old bung, tap threads into a new bung, and screw the new bung onto the nipple. It would reduce the inside diameter (ID) somewhat, but I would suspect the ID of the nipple would still be greater than that of the fuel line, so it wouldn't reduce the rate of flow. That way you wouldn't run the risk of epoxy leaking or burning the paint. Ed

sure that is the best or like he was thinking getting bung on there clean...i was implying the jb weld with the same parts but in place of the teflon thread...it would set up and not spin again maybe but, be able to be spun off again i bet,once or twice...before iot would finaly be a leak....the first time though..i bet it would never leak if done right..cleaned and prepped......a thread filler in the existing parts....stupid i know but the more i thought about it

oh that tank is purty

Thanks for the input Ed, but by doing that I would not be able to insert the supply tube and reserve filter into that small a diameter. I thought of something similar to this already as I have one of the old gas cap gauges that would give me some notice before running out of gas. Think I like Jeff's idea about the Pingle adapter as it would be the most attractive option leaving it look and function as original.
Thanks David

Thanks Tri, the paint is awesome and jumps at you in the sunlight like you wouldn't believe! I got the side cover emblems on (original)the other day and the tailpiece is mounted to the frame. I have been taking some pics along the way so one day soon I will post them as it is finally starting to look like something.
David

you and tybolt and the other guys doing these early Z's is making my eyes water....i got one hanging below my feet on the floor joist down stairs....and on a pallet and in drawers and boxes and in mayonaise jars...it a 11/73 # 30,xxx something...wonder what color ...i like yours and would dig that..but think mine was yellow...anyhow..nice,,,nice nice..pics pics pics

It's been three years in the making as funds and time allow! You seem to go on and on for a long time thinking you've accomplished a lot (especially spending) with no real visual progress and then you start to see it come together which makes it all worth while. Would I be best to show a bunch of pics in a project section as a new thread?
Thanks David

Bummer Kawboy....650 Ed's idea of using the threade nipple sounds the best to me

ummmmmmm..should i show pics of my beautiful early Z that i am getting forward on...by all means