Fuel Cap

[tqwrench]

This bird is missing the main fuel tank cap. Struggling to find a replacement. I measured 2.775" OD, looks like fine thread on the OD. Not sure if this is a 2 3/4" or 2 1/2" cap, also vented or not vented (at the cap).

[brhodes]

2 1/2" NPSH brass fire hose cap and chain


https://www.mrosupply.com/hydraulics...3_fc250_dixon/

[tqwrench]

Looks like it would work, got me the 8 NPT dimension piece of it, thank you. Digging more, I found Stant 10602. Only benefit there is it has what looks like lead blow out plugs in case the tank collapses in a collision, it can vent in an emergency. https://www.rockauto.com/en/moreinfo...hNPWEMqQ%3D%3D

[1984Lodge]

Originally Posted by tqwrench

Looks like it would work, got me the 8 NPT dimension piece of it, thank you. Digging more, I found Stant 10602. Only benefit there is it has what looks like lead blow out plugs in case the tank collapses in a collision, it can vent in an emergency. https://www.rockauto.com/en/moreinfo...hNPWEMqQ%3D%3D

So my 84 PT was a 2-1/2” NPT cap not the NPSH cap. I purchased a brass one off Amazon but looks like it’s no longer available.
Here it is after my brother the machinist and I turned it and cleaned it up, my brother did the bird on it:


If that tank collapses in an accident I don’t think you will be around to have to worry about it.

[mose]

Originally Posted by 1984Lodge

If that tank collapses in an accident I don’t think you will be around to have to worry about it.

Hahaha. Or maybe the diesel will put out the propane fire.

[tqwrench]

Originally Posted by 1984Lodge

So my 84 PT was a 2-1/2” NPT cap not the NPSH cap. I purchased a brass one off Amazon but looks like it’s no longer available.
Here it is after my brother the machinist and I turned it and cleaned it up, my brother did the bird on it:
Attachment 79217

If that tank collapses in an accident I don’t think you will be around to have to worry about it.

Nice job on that fuel cap! I like your YouTube videos too. As I'm ramping up to pull my injection pump, they've been helpful.

On the fuel cap emergency vents. Whoever hits this bus hard enough to collapse the tank is a) meeting their airbag, then b) meeting God anyway. At the end of the day, it's a purpose built item, intended for fuel storage.

I'll go with that Stant cap and report back after RockAuto delivers my first $1000 load of parts .

[1984Lodge]

Originally Posted by tqwrench

Nice job on that fuel cap! I like your YouTube videos too. As I'm ramping up to pull my injection pump, they've been helpful.

On the fuel cap emergency vents. Whoever hits this bus hard enough to collapse the tank is a) meeting their airbag, then b) meeting God anyway. At the end of the day, it's a purpose built item, intended for fuel storage.

I'll go with that Stant cap and report back after RockAuto delivers my first $1000 load of parts .

Excellent, thanks for watching!
Are you replacing the injection pump, having it rebuilt? PM me if you are having your pump rebuilt.

Yea, you do not have to worry so much about the vent with a diesel tank but its protected by a tank.. ha..

[Cahoots]

Hi Kris,

On my 1989 FC it was the Dixon fire hose cap that was correct. I am not sure of what you have but there is one big difference between the NPT thread from Stant and the NPSH thread from Dixon. The Dixon is a straight thread meaning that the outside diameter remains constant along the thread length. The NPT is a tappered pipe thread where the thread gets larger the further down you measure.

From a sealing standpoint, the Dixon straight thread has a rubber seal inside of the cap that seals against the top edge of the threaded filler tube. The NPT cap from Stant will seal in the threads like all pipe threads do.

Good luck with it.

[tqwrench]

Aha, the plot thickens. I believe I have a thread pitch gauge that could be of some service here, then. Or, I can go to Lowe's or Menards and see if they have pipe that big and a cap to make a "dry" run. If it's truly NPT, then a 2.5" galvanized, or black iron cap should fit, right?


Edited, since I found this. Looks like either could work.


"Is NPT the same as NPSH?

Fire hoses with National Pipe Straight Hose Thread (NPSH) has the same threads per inch as National Pipe Thread (NPT) but the threads do not taper. ... The male side of a fire hose coupling with NPSH threads will only connect to fittings, nozzles or hoses with NPSH threads."

[1984Lodge]

Originally Posted by tqwrench

Aha, the plot thickens. I believe I have a thread pitch gauge that could be of some service here, then. Or, I can go to Lowe's or Menards and see if they have pipe that big and a cap to make a "dry" run. If it's truly NPT, then a 2.5" galvanized, or black iron cap should fit, right?

Yup, but it may be hard to find anything that size in the regular box stores. I think they must have changed at some point to the NPSH caps, I have a new one that I bought that did not fit mine. I need to bring it to WOG one year and get it to someone who needs it.

Funny story, when I purchased my bird it had the lesser known "red solo cup" option for the fuel cap. I was not happy traveling across country with that, so we wheeled into a Lowe's thinking I would find a NPT pipe cap.. no dice, but I was not deterred. I kept looking around and found an electrical PVC pipe female adapter that was 2-1/2" npt and then I went into the plumbing department and found an oatey pipe plug, the one that has the wing nut on it so you can tighten the rubber gasket down. That is how we made it home on our first trip, and why I made the new one.