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Fuel filter and pre filter


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Hello, I am new to the forums. I just picked up (on 7/12/13) a 1975 Datsun 620 pick up and been trying to fix it since (less than a week). I will be visiting this forum often.

 

So my problem right now is that I just discovered that my truck does not have a fuel filter! this is bad. I decided to park it (2 days now) and wait until I buy the filter (im on my way). The only thing is that I have been looking on the internet and discovered a couple of threads talking about a pre filter for the fuel system. I want to know more about it. Which one to buy, and where to install it. One guy said he bought the Fram G3 fuel filter and installed it before the tank. I am not very familiar with fuel systems but I can't imagine where this "before fuel tank" place is at. Can I just put it right next to the fuel filter? or does it have to be close to the fuel tank? I don't know. Any help is appreciated! :-) Pictures would be GREAT!

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If you get them for a couple of bucks change them every year. The last two I took off had the filter element rattling around inside. They are very cheaply made these days so get a good one or change often.

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this is what you will need, no pre filter needed. Not that it would hurt but its not needed

 

http://compare.ebay.com/like/281129590034?var=lv&ltyp=AllFixedPriceItemTypes&var=sbar

 

That filter is nice, because you can see inside it.  You can see when it's dirty and if the element falls off.  It's also the stock style so it will fit in the stock location.  I'm running one on my 510.

 

Mike is right, one filter that is changed regularly is enough for a Carb. 

 

This one is nice for the reason you can see inside, but it's also reusable.  You can unscrew it and change the filter.  If you wanted to run a second filter, you could put this one back by the fuel tank.  Two filters isn't necessary, but ideally, you should have the filter closer to the fuel tank.  This way, if you have rust or debri in the tank, it will get caught in the filter before it has the chance to clog your fuel lines... The factory wasn't worried about this, but that's when the truck was new.  Now it's had 30+ years to aquire rust.  I have a '76 Bronco that had the problem of the mechanical fuel tank selector switch (dual tanks) getting clogged.  I put filters on both lines between the tank and the selector switch....  No more problems.

http://www.summitracing.com/parts/mrg-9747/overview/

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If you get them for a couple of bucks change them every year. The last two I took off had the filter element rattling around inside. They are very cheaply made these days so get a good one or change often.

 

 

Oh for the good old days of the glass bowl filter housing with "rag bag" [looks like silk but that would dissolve in gasoline] filter element.  You periodically removed the rag bag and reverse flushed it.  the only possible wear out element is the gasket on the bowl to top hat fixture and the secondary gasket on the filter element to housing inlet to filter junction.  Mine is 45 years old and works like a charm!

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im assuming you 620 has an L motor?

Yes sir! its the L20B. Sorry for the late response. My car is fixed by the way... I managed to brake the breather hose and thought the piece of metal on the valve cover was a PCV valve. I learn the hard way... I'll fix it tomorrow, I think the 620 is drive-able. 

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That filter is nice, because you can see inside it.  You can see when it's dirty and if the element falls off.  It's also the stock style so it will fit in the stock location.  I'm running one on my 510.

 

Mike is right, one filter that is changed regularly is enough for a Carb. 

 

This one is nice for the reason you can see inside, but it's also reusable.  You can unscrew it and change the filter.  If you wanted to run a second filter, you could put this one back by the fuel tank.  Two filters isn't necessary, but ideally, you should have the filter closer to the fuel tank.  This way, if you have rust or debri in the tank, it will get caught in the filter before it has the chance to clog your fuel lines... The factory wasn't worried about this, but that's when the truck was new.  Now it's had 30+ years to aquire rust.  I have a '76 Bronco that had the problem of the mechanical fuel tank selector switch (dual tanks) getting clogged.  I put filters on both lines between the tank and the selector switch....  No more problems.

http://www.summitracing.com/parts/mrg-9747/overview/

 

when i had a lot of rust in my tank (before i cleaned it) i ran 2 filters. i used the filter klassic mentioned as a pre filter

mrg-9747_w_ml.jpg

and i ran the stock style filter after it. that mr gasket filter is much finer, yet not restrictive. it catches a lot more rust than

my stock filter would. NOW im just running the mr gasket  style filter.

 

with the mr gasket filters, you dont actually have to change that filter inside there. you CAN but you dont have to. its reusable, i just hit mine up with carb cleaner.

they are known to have defects/problems. nothing big deal... sometimes the gaskets in them fail. mine has been failing for the last year. perhaps because i overtorqued the end caps (there is not torque called out.) i tightened it pretty tight because obviously i didnt want any fuel to leak by. even with one of my gaskets kinda messed up, its still not leaking.

eventually i will get one of the older style glass bowl types.

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Had a bad experience with the glass filter leaking. Fuel leak under hood = bad

completely agree. however, its not as dangerous since the exhaust mani is on the other side of the engine.

but no leaks are better than some. 

 

I've only had problems with the Mr Gasket filter when I over-tightened it....

yeah. i wish everything had a torque spec, so i would stop over-tightening shit

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