Fuel fitting sizes - TDR Roundtable

Fuel fitting sizes

04-25-2003, 01:25 PM

#1 (permalink)

Ncostello

Offline
Join Date: Aug 2002 Location: Indiana Posts: 2,161 Photo Gallery Old Reader's Rigs Gallery

Fuel fitting sizes

When considering fuel filter heads that come with various size ports..which is larger? 1/2-20 UNF (SAE O-ring) or 3/8-18 NPTF? I think it takes a 37/64" drill bit when tapping for 3/8-18 NPTF...but I have no idea how the SAE fittings are measured.

Guess my point is which will flow more (bigger opening) when the fitting is installed. Stanadyne said the 3/8"x18 NPTF filter head they sell actually had larger ports than the 1/2"x20 SAE O-Ring one. I couldn't discuss it with them since I had no idea. Thanks TDR.

__________________
91.5 D250 LE
Regular Cab, Red
Automatic
H1C 21cm housing
Stock Condition

Non members can only view the initial post on threads more than 7 days old. There are 5 additional replies on this thread that you could view if you were a member.

TDR Membership offers many benefits including:

4 issues of the TDR magazine per year including these columns:
- Tailgating - A Letter From The Editor
- Letter Exchange - Responses From The Readers
- Member2Member - Members' Solutions To Members' Questions
- Technical Topics - Service/Parts Update
- First Generation - Owner-Specific Articles On The '89 - '93 Dodge Diesel Trucks
- 12-Valve Engines - Owner-Specific Articles On The '94 - '98.5 12-Valve Dodge Diesel Trucks
- 24-Valve Engines - Owner-Specific Articles On The '98.5 - '02 24-Valve Dodge Diesel Trucks
- Third Generation - Owner-Specific Articles On The '03 And Newer Dodge Diesel Trucks
- Blowin' In The Wind - Industry News
- Shadetree - Back To The Basics
- Celebrity Corner - The Shadetree Mechanic - Sam Memmolo
- From The Shop Floor - Tips From Turbo Diesel Repair Shops
- Products Showcase - Featured Products
- TDRelease - Vendor Press Releases
In many areas of the country a local chapter with events
A yearly printed copy of the TDR Travel companion listing approximately 700 TDR members across the country willing to help you if you have trouble on the road
Complete access to the TDR website including:
- Ability to do advanced searches over 1.1 million posts
- Access to members only forums (Truck 911, FAQ Forums, Discontinued parts support, Rigs spotted, Pay it forward, Other, and Political)
- Posting ability to the forums
- Ability to read an unlimited number of posts from the forums
- Can customize your forum list to your interests
- Can choose 1st, 2nd, 3rd gen, or rotating header graphics
- Limit searches to forums your interested in
- View posts since you last logged on
- Private message ability to other members
- Chat room access
- Diesel truck specific TSB listing by model year
- Online access to the Travel Companion database (with most current information)