Quick question: NPT vs. actual nut size
Thread Starter
Pro
Joined: Sep 2004
Posts: 690
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From: Madison WI
Quick question: NPT vs. actual nut size
Okay, so I'm having some major trouble hooking up my new fuel system...I read here that the outlet nut on a stock fuel pump (72 L-48) is 3/8" NPT. I bought a 3/8" NPT to -8 AN adapter (I'm installed braided stainless hose), but the threads don't fit in the outlet of the fuel pump - the adapter is the tiniest part too big. So, I'm wondering if perhaps there's the possibility that the part was packaged wrong. That being said, what is the measurement difference between NPT and the actual size of the threads on the nut? On the 3/8" NPT fuel hose I believe the nut is supposed to be 5/8", but i'm not 100% sure...can anyone help me out?
Melting Slicks
Joined: Nov 2001
Posts: 2,668
Likes: 43
From: Eastern US XX
Originally Posted by 72Tornado
Okay, so I'm having some major trouble hooking up my new fuel system...I read here that the outlet nut on a stock fuel pump (72 L-48) is 3/8" NPT. I bought a 3/8" NPT to -8 AN adapter (I'm installed braided stainless hose), but the threads don't fit in the outlet of the fuel pump - the adapter is the tiniest part too big. So, I'm wondering if perhaps there's the possibility that the part was packaged wrong. That being said, what is the measurement difference between NPT and the actual size of the threads on the nut? On the 3/8" NPT fuel hose I believe the nut is supposed to be 5/8", but i'm not 100% sure...can anyone help me out?
Thread Starter
Pro
Joined: Sep 2004
Posts: 690
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From: Madison WI
Originally Posted by Twin_Turbo
The fuel pump uses 5/ 8-18" or 1/ 2-20" inverted flare depending on pump.
Any help?
