what cap will fit a moon tank?

I recently picked up a moon tank sans gas cap. Where can I get a cap that would fit it other than paying $100 through mooneyes to get one? The threads are on the inside which is opposite of any cap I have seen.

 

Look at a military surplus place

 

What exactly should I be looking for it in?

 

Fork up the $$$ for the tri bar spinner from Moon. It's very cool and worth it IMO.

 

What Kerry said x2!!!

 

Will it fit? Its an original 60's 8 inch tank. Are all the sizes standard? I would hate to spend the money and have it not fit.

 

They did make an early tri bar in 2 versions 1 was for the built in hand pump,,other was a regular. You would have to check to see if the still mke the inner thread ones

 

They do.

http://www.mooneyesusa.com/Store/product_info.php?cPath=188_128&products_id=550

 

Before you order that spinner style cap, call Moon and make sure the cap will fit an inside threaded tank. The new ones are for outside threaded tanks.

I don't believe they still make one that fits an early tank.

Mick

 

I called Moon. They are not sure if it will work and told me some would call me back. So while I am waiting does anyone have one of these caps that could maybe let me know?

 

Well Mooneyes called me back and I am out of luck.. They stopped making caps that would fit that in 1969. I need some ideas here boys. What could I use???

 

My early Moon cap does not fit the later Mooneyes tanks. (male/female threads difference)

I don't know for sure when they started to make the different threaded tanks. Possibly when the company was sold and became "Mooneyes"

Mick

 

I cut mine out on the lathe. Single pointed the threads. made it out of br***. Maybe aluminum would have been better. Lighter anyway

 

Scroll down here to Fuel tank fill bung and cap
http://www.kenlowe.com.au/tanks.htm

Cut the bung off your tank, contour the new bung to the tank and heliarc it on. Done.

 

If you find a cap that will work Let me know. I'm in the same boat.
94

 

Wow, The tank I got had some pretty significant road rash but it did have the spinner cap. I'm really glad now.

 

Lads I made a spinner using a Cragar spinner cap & the bung from a 44 gallon drum.

 

I live down the road from Moon. Sell me your tanks and I will walk them into the shop to get caps.

 

moon does not have caps to fit the 60's tanks. I am going to try a marine store. It looks like a marine cap may work.

 

Fwiw, my Moon cap, circa late 50's has a double eared cap much like a factory gas tank cap.

 

60s International big truck caps will fit. Mase of br***.

 

I just found a 60's international one on Ebay with a buy it now that looked like it should work. Ill let you all know once I get it. It was only $20 shipped and it doesnt look like it would look out of place on the tank.

 

International cap does not work, at least not the one I got. Back to the drawing board.

 

Have you seen the caps with internal threads that come with aftermarket tanks for hot rods?

I'm not sure of the size, but it appears to be 2" with fine threads.

Measure the OD of your tank filler tube/bung.

Get yourself a thread gauge - not too expensive, a little bit more than a good quality feeler gauge - and measure the thread count.

Once you have that information you could probably find one at the tank suppliers.
It seems to be a fairly common size.

P&J and similar would be good places to contact as well.

I'm fairly sure the re-pro Deuce tanks use the same size cap.

 

How close is the outside diameter of the cap threads to the inside of the tank threads? If there is enough meat on the cap, it can be turned down/threaded if I know the thread in the tank. PM me if you can't find anything.

 

its actually 1/4" too small. I need 2/4" fine thread. I just got back from NAPA and they do not have anything in there catalogs even for big trucks. the closest they have is 2 1/8". I didnt realize what a pin in the *** this was going to be. Next time I will buy one with a cap

 

I liked RichFox's idea, especially since you don't seem to be having much luck finding a ready made unit. Maybe he can make you one. Or PM Brianangus, I do know that Brian is a machinist and has made specialty parts on his lathe before. Might be worth a try, at least you might discover an estimated cost for such a build. You will have to know a lot of spec details in order to get something machined.

Good luck, and you're right, sometimes bargains ain't bargains.

 

Any chance that a large diameter AN type fitting might fit.

Not sure of the AN style nomenclature but it will have hex top, o-ring provision, and fit in a female thread.

A lot of the early California stuff was based on military surplus.

Buff off the blue anodize and go from there.

Or get a piece of aluminum and whittle away everything that not look like a Moon tank cap.

K

 

The old ones are Military style threaded caps,,Check for old Military fuel caps,,some old Semis used teh same style caps

 

this one fits mine.