AN Fittings

Does your line go from 10AN to 6AN, or do you need a T-piece to split the fuel or oil supply? In this category you'll find AN fittings, adapters and couplings for anyone building or modifying hose systems in a project with AN hoses.

How AN fittings work

AN fittings typically seal metal to metal on a conical surface with a 37-degree angle, so the joint can be taken apart and reassembled without a gasket. The size is given as an AN number, e.g. 6AN, 8AN and 10AN, where a higher number means greater flow. Here you'll find, among other things, adapters between two sizes, couplings, T-pieces and carburetor fittings, e.g. from Russell, and brands such as Fragola, Vibrant, Moroso and Nitrous Express are also represented.

How to choose AN fittings

• Size: The fitting must match the hose, and the size depends on the flow the system needs to deliver.
• Male or female: Check whether each end needs to be male or female, e.g. 10AN female to 6AN male.
• Thread on the component: If the pump, filter or engine block has a different port, combine with ORB fittings, NPT fittings or metric adapters.
• Fluid: Check that the fitting and hose are designed for the fuel, oil or nitrous in your system.

Installation and maintenance

Hold the fitting with one wrench and tighten with another so you don't twist the hose or the component. Aluminium can deform if you overtighten, and a scratch in the sealing surface can cause leaks. Check the joints for leaks after the first start-up and during regular inspections. If the hose needs to pass through a firewall or panel, use a bulkhead fitting instead.

Frequently asked questions

Can an AN fitting be screwed directly into an NPT or ORB port?

No, the AN thread seals on the conical surface and does not fit an NPT or ORB port. You need an adapter with AN on one end and the port's thread type on the other.

Do AN fittings need thread tape?

No, the seal typically happens on the conical surface, not in the thread. Tape or paste on the sealing surface can cause leaks, and residue can get into the system. A little oil on the thread can make tightening smoother.

Why does a new AN joint leak?

Typical causes are the wrong size, a scratch or dirt on the sealing surface, an incorrectly tightened joint or a mix-up with a 45-degree flare, which looks like AN but does not seal against 37 degrees. The hose end may also have been assembled incorrectly.