Datsun Roadster Forum-311s.org

Just confirming the fuel line is 1/4”

And the inline fuel filter size is 1/4” as well?

As I recall yes. The return line is 5/16"

Return line off the carbs, back to the tank?

I apologize, I have no automotive experience and trying to learn as I go.

Old fuel filter v new fuel filter. Looks like the old one is much bigger than 1/4”. This new one ok?

I'm wondering about this, too. Just checked my '70 1600 fuel line today, and the hardline from tank to engine bay measures ¼ inch OD, Fuel filter is more like 5/16 OD. Fuel pump inlet and outlet appear to be different sizes (fuel pump is on engine at shop and not available to measure). The hardline seems ridiculously small and the inconsistent sizes baffles me. Did the 2000 have a bigger diameter line?

Did anyone ever get the answer for this? I’m replacing the lines from the filter to the pump and the pump to the carbs and I’m wondering what size hose to get. It’s a 1970 1600

My car is also a 70 1600. The line from the tank to the pump is 1/4" (or metric equivalent). Then from pump to filter, filter to carbs, and return line back to tank are all 5/16" (or metric equivalent). Seems terribly inefficient that the mechanical pump has to pull through a tiny 1/4" line, but apparently it works well enough.

I have a question about plumbing fuel lines. I have a 1970 2000. I am using what is supposed to be, I guess, an OEM fuel filter. Inlet and outlet sizes are the same (guessing 5/16). My hard line from tank is small, based upon above it seems 1/4".

As to plumbing: Am I supposed to take fuel from hardline from tank- hose to fuel pump - hose from pump to fuel filter - hose from filter to carbs? I currently have it set up : hardline from tank -hose to filter - hose from filter to fuel pump - hose from pump to carbs.

My issue is that my fuel filter has both inlet and outlet the same size, and I can't get the hose from hardline to filter tight enough to draw fuel. It seems like the old fuel filter had different fittings for inlet and outlet,or maybe i am just misremembering.

Is there a filter than has different siz inlet and outlet I can use? Or do I have it set up wrong?

Thanks.

Routing: Tank -> fuel filter -> pump -> carbs

Unless you have the original glass bowl, the size of the hoses and fuel filter (inlet/outlet diameter) have likely been changed by POs based on what they picked up at NAPA, etc. over the decades. Just match what is already there (filter to hose or hose to filter size) - Clamps will do the rest. Or, you can standardize it to whatever sizes you want if there is a specific filter you want to use (Remember: There is a specific inlet & outlet side to most fuel filters).
Also, don’t worry too much about if a 1/4” outlet is too small for the fuel filter. My old 396 Nova SS (w/ mech. fuel pump) had a factory 3/8” fuel filter (inlet/outlet) for a 6.5L engine - Our 1.6L or 2L will do just fine on 1/4” - Which is why our hardlines are 1/4”

Thanks. I swear my old fuel filter (also u-shaped lie the new one) had two different size fittings for inlet and outlet. I have owned this since 1983 and I haven't changed any fittings. It seems the fuel filters have maybe changed? I got it from Dean last year.

orangedawg wrote: Fri Sep 17, 2021 6:49 pm Thanks. I swear my old fuel filter (also u-shaped lie the new one) had two different size fittings for inlet and outlet. I have owned this since 1983 and I haven't changed any fittings. It seems the fuel filters have maybe changed? I got it from Dean last year.

Since 1983? Congrats! That’s quite an achievement. Of course, someone else could have still changed things around in the 13 years before you got it. At any rate, the ones from Dean will be ‘correct’ for original inlet/outlet diameter, but like I said, it’s not an imperative, many options will work just as well - Pick one