I have triple Webers for my L28 and they came with banjo fittings for the fuel inlets. However, the fittings only have metal washers for both sides of the banjos. Even at the rather low fuel pressure needed for carbs, I don't think that metal washers alone are a good way to ensure against leaks.

Buna-N rubber has high resistance to gasoline so I was thinking of using O-rings or thin flats cut from 1/32" sheet material in addition to the metal washers. But in doing so I'm not sure that the stack height will give me enough thread engagement with the carb body.

Has anyone got useful experience either way?

I'll probably call Pierce Manifolds to see what they have to say. Honestly, I would have thought that an M12 x 1.5 threaded hose barb fitting, Buna-N O-ring and gasoline-rated Teflon tape would be a better call here. There are nickel-plated copper fittings (the plating gives it extra corrosion protection) of that size on Amazon so I'll probably get some.

Just miffed at having to spend the extra money.

My OER banjo fittings have copper washers from the factory. Replacement p/n shows the same.

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I'm not sure why we need to reinvent the wheel here. Aluminum (or copper) crush washers are an industry-standard sealing interface for probably billions of hydraulic interfaces world-wide. Most of these run multiple orders of magnitude higher pressure than the 3-6 psi that your carbs will see. This is a severe case of over-engineering. ;)

You might just want to sit tight and see what’s happening once you fire it up. You are using the fpr which will regulate where you want to be.

Well, that's the thing, @LeonV , the washers I got are not copper. I've gone with the M12 x 1.5, 90 degree hose barb fittings and be done with it.

A lot of my grief is because I'm using the Nissan competition fuel rail from JDM-Car-Parts (https://jdm-car-parts.com/) that has three outlets - one for each Weber, like wiring something in parallel. I'll likely just do direct, in-series plumbing for my other L28 with Webers when I get to that one.

Curious how you’re going to get the directional angle correct if you install threaded elbows. Don’t know if that was a series of reasons to go the banjo route other than ease of installation.

We'll see once they arrive later this week. I think I have plenty of room to twist them into a proper up-angle and still have a good seal with gasoline-rated Teflon tape. Probably won't even use the Buna-N O-rings unless I have to.

I believe you can buy AN banjo fittings that will fit.

Earl's banjo for Weber

Ooh, they look nice but quite pricey.

that was the first and easiest to link to. there are others that are cheaper

19 hours ago, Seppi72 said:

Well, that's the thing, @LeonV , the washers I got are not copper. I've gone with the M12 x 1.5, 90 degree hose barb fittings and be done with it.

A lot of my grief is because I'm using the Nissan competition fuel rail from JDM-Car-Parts (https://jdm-car-parts.com/) that has three outlets - one for each Weber, like wiring something in parallel. I'll likely just do direct, in-series plumbing for my other L28 with Webers when I get to that one.

I bet those washers are aluminum. Do they stick to a magnet? Steel is not a good idea but copper or aluminum crush washers are industry-standard. What is absolutely not industry standard is using teflon tape to seal fuel fittings--this is a great recipe for an engine fire. I've never heard of gasoline-safe teflon tape and even if it did exist, I would absolutely not trust it compared to a crush washer.

I made my own fuel rail and used the Earl's fittings on my Webers that @astrohog mentions. The carbs are plumbed in parallel like you say and use aluminum crush washers as the sealing interface. I've had no leaks or issues in over 10 years of running this setup. The parallel fueling setup is superior in terms of keeping equal pressure on all 3 carbs, as compared to plumbing in series. It's not clear to me what sort of grief this causes?

They are non-magnetic, so probably aluminum but with thicknesses around 0.90 mm how much "crushability" do they have?

The grief is that the carbs came with banjos set up for series fuel delivery: two T connectors and one single bent at 90 degrees so I had to get something for the parallel setup.