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Thread: clean the hard lines? fuel pump or fuel pumps?

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    Z Level: 15... no.never's Avatar
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    Default clean the hard lines? fuel pump or fuel pumps?

    hey guys. so i'm starting to get the ball going and start working on my 5/74 260z before actual rain starts. got some bumps.

    the whole fuel system is off and is gonna go back on after the front suspension is on and the tank gets cleaned. everything looks stock. it doesn't seem to make sense to me to use the same hoses after carb work. the hoses still look good but 40 years seems like a long time running. and a new mech fuel pump wouldn't hurt. so it got me thinking about a clean fuel system, or as clean as i can.

    so two things on the front. how do i clean the hard lines? the wrapped ones and the rails along the side that go to the rear. just straight flushing?

    the other is a bit of a doosie: about 2 to 3 inches of the fuel rails directly below the battery are corroded from the acid. the 2nd owner just painted over it. its not too bad, maybe just surface. doesn't leak and doesn't seem to be clogged but it's always on my mind, specially if i want a clean system. are there fixes for the hard lines? or do i look into replacing the whole rails, which doesn't sound fun at all.

    once i get to the rear i'll do the tank and probably the lines around there, but last time i looked it was a mess back there. if i remember correctly the elec fuel pump wasn't hooked up at all and the car was running on the mech, was running just fine. the elec is to regulate the pressure to/fro the tank? either way, should i replace/reincorporate the fuel pump or leave it as is and run on the mech? plus it can be loud...

    i think those are the only thing missing in the car: elec fuel pump and the heater. but in so california it's apparently unnecessary weight.

    any tips, comments, ideas welcomed.

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    Registered User conedodger's Avatar
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    See the thread about the RX-7 fuel pump in the Electrical section. It is very quiet and runs about $50 shipped. I have triple Webers so I run on the mechanical alone. The mechanical pump cannot keep up at WOT. I would run some kind of solvent through the hard lines and blow them out really well. As for the rubber, absolutely no 40 year old lines should be used. I would use modern EFI hose. It is expensive, can be $5.00 a foot but the ethanol in modern fuel will eat anything that isn't made for modern fuel. That will ruin your day and burn your car to the ground. The fire department calls that a CarBQue. Only thing is everyone is having fun but you...
    Rob
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    1973 Datsun 240Z Restoration project. New paint in original white. E31 head on 2.4 block. Nissan Motorsports header. R200 with Nissan motorsports LSD.

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    Quote Originally Posted by no.never View Post

    .....the whole fuel system is off and is gonna go back on after the front suspension is on and the tank gets cleaned. everything looks stock. it doesn't seem to make sense to me to use the same hoses after carb work. the hoses still look good but 40 years seems like a long time running. and a new mech fuel pump wouldn't hurt. so it got me thinking about a clean fuel system, or as clean as i can.
    If you have the whole system off - that would mean all the hard lines from the tank to the carb's - is that correct or not? To get the long hard lines off - as I recall you have to remove the rear suspension as well.

    Quote Originally Posted by no.never View Post
    ....so two things on the front. how do i clean the hard lines? the wrapped ones and the rails along the side that go to the rear. just straight flushing?
    You can use Chevron's Techron Concentrate Plus, it is very effective. Pour it directly into the hard fuel lines - cap one end, and let it sit for a day. Then drain it in a pan - and it can be used on several lines. After the Techron is emptied out - flush with fresh gasoline. It doesn't take much.. catch the gasoline in a pan and pour it back though a couple of times.

    A less expensive solution - but slightly less effective - is to use Toluene or Xylene. You can buy them at Home Depot by the gallon. They are commonly used as paint thinners..{but they are also used in the Techron Concentrate or other Fuel System Cleaners}. They will dissolve the varnish that forms when gasoline is allowed to evaporate - just takes them a little longer and in greater quantities than the Techron.



    Quote Originally Posted by no.never View Post
    ....the other is a bit of a doosie: about 2 to 3 inches of the fuel rails directly below the battery are corroded from the acid. the 2nd owner just painted over it. its not too bad, maybe just surface. doesn't leak and doesn't seem to be clogged but it's always on my mind, specially if i want a clean system. are there fixes for the hard lines? or do i look into replacing the whole rails, which doesn't sound fun at all.
    If you have to cut a section of a hard fuel line out - it is no problem. Just cut out the damaged section - take it to any Hydrulic Line supplier or repair shop. They will have brass compression fittings that allow you to join the new sections with the ends of the older section. Of course you'll have to custom bend the new sections - and you will want to make your cuts where you have straight line on both sides of the damaged section.

    If you are worried about cosmetics - just cut the entire end off - back under the car - then use a good end from a parts car. That way the repair won't show in the engine compartment.

    Quote Originally Posted by no.never View Post
    once i get to the rear i'll do the tank and probably the lines around there, but last time i looked it was a mess back there. if i remember correctly the elec fuel pump wasn't hooked up at all and the car was running on the mech, was running just fine. the elec is to regulate the pressure to/fro the tank? either way, should i replace/reincorporate the fuel pump or leave it as is and run on the mech? plus it can be loud...
    If you are now running a set of SU's - you only need the mechanical pump in Calf. most of the time. On real hot days - if you fill an empty tank with cooler fuel - it is possible to get vapor lock if your mechanical pump is weak. Yes - originally the electric pump was put there to help eliminate vapor lock in the 73/74 Z's. The other option is to simply run a new electric pump.

    Quote Originally Posted by no.never View Post
    i think those are the only thing missing in the car: elec fuel pump and the heater. but in so california it's apparently unnecessary weight. .
    Even in Southern Cailf - you need defrosters for the windshield when you hit fog, humid weather, or go to the mountains... I'd replace the heater if this is a road driven car. Besides you never know when or if you will want to go North.. to God's Country.

    good luck,
    Carl B.

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    Quote Originally Posted by conedodger View Post
    The fire department calls that a CarBQue. Only thing is everyone is having fun but you...
    that's why i stopped driving a 280z i had just gotten as a daily: fuel leak + crappy electrical tinkering = no thanks.

    thanks for the EFI hose tip, that makes sense. i'm gonna use those that all around. it seems like the RX7 is the way to go but i think i'm gonna hold off on it. i'd like to install when i refresh the electrical. i will add it though, read up on vapor lock plus i'm running the flat tops so it's probably help.

    oh and thanks for your thread on the brakes. that gave me a motivational push i needed to get back to work. just got my calipers back from PMB and it just doesn't get any better than that. to think i almost turned mine in for some reman ones.

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    Quote Originally Posted by Carl Beck View Post
    Even in Southern Cailf - you need defrosters for the windshield when you hit fog, humid weather, or go to the mountains... I'd replace the heater if this is a road driven car. Besides you never know when or if you will want to go North.. to God's Country.
    i got the car around spring so i hadn't thought about the rain, mainly defrost. i personally have been as north as san francisco. but with my z i went up past oxnard on PCH. once she's ready i wanna go for a longer stretch. driving PCH is the best drive.

    Quote Originally Posted by Carl Beck View Post
    If you have the whole system off - that would mean all the hard lines from the tank to the carb's - is that correct or not? To get the long hard lines off - as I recall you have to remove the rear suspension as well.
    i should've said "most," hehe. just carbs to the engine are out. but yea i do want to clean those hard lines. it sounds like that hard line repair shouldn't be a problem to fix that section, still not a job for me. i probably shouldn't drag something through the lines. thanks for the tips

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    Barn Find Daily Driver Captain_Zeros's Avatar
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    You don't need the expensive $5 a foot EFI hose if you're running carbs, just make sure you get hose that's rated for fuel (not just fuel vapor, but good and proper rated for fuel). The difference being carburetor fuel line that's rated for ethanol ISN'T rated for the high pressures of a fuel injection pump, whereas the buku bucks EFI line is pressure rated as well.

    Edit: Using EFI line won't hurt though, it's just an easy place to save a couple bucks with no harm if you're running carbs. If you're gonna run EFI then yeah, you need EFI hose, but regular old ethanol rated low pressure fuel hose is perfectly fine.
    Last edited by Captain_Zeros; 10-27-2012 at 02:21 AM.

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