BMW 326rb build thread...

[ctnewman]

Originally Posted by GSXRJJordan

Says it allows the rail to be tapped for 1/2" NPT, but fits -10an fittings? Am I missing something? -10an > 1/2"NPT...

I assume you're using -8an fittings/line?

Rail is extruded at .703 ID, .940 OD

10AN requires a 7/8-14 UNF thread which is a .8125 drill diameter
8AN requires a 3/4-16 UNF which requires a .6875 drill diameter
1/2" NPT requires a .703 drill diameter.

So you can't use 8AN.

An internal 10AN (7/8-14) thread has a major diameter of .875.

That would leave only .0325 (or 1/32") of material on the rail. Not enough.

With the rail already being at the exact size for the NPT tap, I chose that. In fact, tapping an SAE port fucking sucks, because you really need to machine an o-ring pocket.


Regarding line choice, I will probably run -8, simply because it's cheaper, and will deliver PLENTY of flow.

To address your question, keep in mind that it says compatible for -10 fittings because a lot of V8 guys run these type of rails, so they put a 1/2" NPT Male X -10AN Male nipple on the rail and feed 2 fuel rails w/ -10 line.

Does that help?