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Wed Jun 08, 2005 7:44 pm

I am preparing to install a newly refurbished BN4 heater from the “Heaterman” and I am shopping fuel lines, fittings + clamps. I was hoping to get a few questions answered. He suggested that I tap into the existing fuel line from the tank with a “T”-fitting and put in-line filter upstream of pump. I am told that copper tubing fuel line will also be needed to complete the installation. Heater is to be installed in a 1970 Westy with 1600SP.

1. What diameter copper fuel line do I need – I read somewhere that 10mm or ¼” will do. So I obviously need to use rubber fuel line with inside diameter to complement the copper line.
2. What diameter rubber fuel hose do I get for this job? Should I stick with the cloth covered or go with American made rubber?
3. Are fuel T-fittings common in FLAPS? If no, best source to find?
4. I was checking out the post regarding the ABA hose clamps – they seem to be the best. What size ABA clamps should I get to do the job?
5. I figured I’d redo all fuel lines while I was at it so I am assuming I can use same diameter fuel hose and clamps all around. Is this accurate?

Thanks, Ryan.

Thu Jun 09, 2005 7:22 am

Not sure of your application, but 1/4 OD tube" accomodates 6mm ID rubber hose, not 10mm. The next size up would be 5/16 th's and that is close to 8mm ID rubber hose. The original carb bays used 6mm ID hose. The FI bays used 8mm rubber hose. Hope this helps.

Wed Apr 18, 2012 7:49 pm

Quick fuel line questions please!

-The fuel line diameter should be for bn4?

- Fuel line diameter for bn6?

- where the fuel line comes through into the engine compartment - is there a grommet there? The hole is very small (1972 bus) saw a pic with and without grommet....

Also, I thought FI lines are 7mm, right? Post above says 8

Thanks

Wed Apr 18, 2012 8:49 pm

FI line is 8mm (5/16"), the line to the pump on a BN-4 or BN-6 is 4.5mm, from the pump to the nozzle is the same as vacuum advance line (whatever size that is, escapes me at the moment). There should be a grommet through the firewall, I'll go look tomorrow.

Wed Apr 18, 2012 10:18 pm

busdaddy wrote: FI line is 8mm (5/16"), the line to the pump on a BN-4 or BN-6 is 4.5mm, from the pump to the nozzle is the same as vacuum advance line (whatever size that is, escapes me at the moment). There should be a grommet through the firewall, I'll go look tomorrow.

great thanks busdaddy, i'm just thinking ahead to when i connect the bn4 to the bn6 fuel system tee down by the pump. And i think i need to punch a new hole in the bus to accommodate the FI wiring, brake booster, and BN4 gas line on the left side - i'm guessin the existing BN4 hole in the bus is perfect...but it looks so small i cant picture a grommet fitting as well.

If you have a chance to take a look i'd appreciate it!

:D

Thu Apr 19, 2012 8:13 am

the hole for the BN4 fuel supply line is small because the original line on a '72 is metal all the way to the pump, it's a ferrule type metal line. it uses a small grommet, pretty sure it's the same one as the fuel line that passes through the front tin for the engine fuel line. any rubber hose hose would be 5mm ID all the way to the pump inlet. late BN4 metering pump has 5mm inlet and 3.5mm outlet to the fuel jet on the heater. early BN4 has fitted fuel lines between pump and heater. the BA6 tee will have the right size outlet for the BN4, 5mm. the BA6 tee is 11mm on the other branches of the tee so it's meant for use on an injected vehicle, inline with the pump and main fuel filter.

Thu Apr 19, 2012 5:27 pm

germansupplyscott wrote: the hole for the BN4 fuel supply line is small because the original line on a '72 is metal all the way to the pump, it's a ferrule type metal line. it uses a small grommet, pretty sure it's the same one as the fuel line that passes through the front tin for the engine fuel line. any rubber hose hose would be 5mm ID all the way to the pump inlet. late BN4 metering pump has 5mm inlet and 3.5mm outlet to the fuel jet on the heater. early BN4 has fitted fuel lines between pump and heater. the BA6 tee will have the right size outlet for the BN4, 5mm. the BA6 tee is 11mm on the other branches of the tee so it's meant for use on an injected vehicle, inline with the pump and main fuel filter.

wicked thanks Scott, that answers it. dont think i will be using a metal line, as i am making the late FI work with the BN4 system, and bending up that bit of pipe would be a pain....well, maybe if i got some brake line....something soft....i might try it.

anyhow thanks guys!