anti drainback fuel filter '73 K-10

[Brady]

Hi guys.  I have a '73 K-10 that I had a guy rebuild the Quadrajet carburetor on.  I had him seal the plugs in the bottom of the bowl with epoxy, because I would have to prime it to start if it had been sitting for more than a couple of days.

Now, it is much better, but he told me that I should get a fuel filter with an anti drainback valve and that Advance Auto could order them, but didn't have them in stock.  Only one older clerk knew anything about them and ordered the one that he thought it was, but when it came it didn't have that valve.

Does anyone know the details of getting one of those?

TIA,
Brady

[bd]

The short version filter should be ACDelco GF470 or equivalent.

The long version filter should be ACDelco GF471 or equivalent.

A '73 K10 V8 should use the short version fuel filter.

[bd]

Adding to the prior post, if the original fuel filter was sintered bronze (image), converting to a newer style paper element filter doesn't work, because of filter housing size differences.  The sintered bronze filter occupies a slightly narrower diameter cavity than that required by the paper element.  The metal end caps of the paper element are larger in diameter than the filter cavity originally manufactured for the sintered bronze filter, which prevents proper seating of the paper element in the carburetor's fuel inlet nut.

[VileZambonie]

Regardless of fuel filter, the fuel bowl does not drain back through the inlet. That being said if the truck sits for long periods of time, it will do this regardless unless you use a priming mechanism. It's the nature of the beast.

[blazer74]

Early attempt to prevent fuel from draining from lines in a roll over.

Not only being a check valve it takes a small amount pressure from the pump to open it.

You don’t need it unless it needs it makes you feel better. You can get just the valve and put it in.

Best bet is a non windowed needle and seat to keep the bowl from draining below the top of the seat.

Personally I prefer the fuel pressure to drop off after shutoff. Helps prevent hot start issues on hot days when fuel expands in the lines, pressure goes up overcoming the needle and seat causing flooding.

Most of the issue is fuel boil off after shut down on heat soaked engine, Evaporation and worst case leaking well plugs in the carb.
Will cause hot start issues if bad enough.

Like said, nature of the beast. If you notice it’s less off an issue in the cold months. Fuel doesn’t evap as fast.

[bd]

Although the fuel bowl won't empty through the filter because of the height and position of the inlet seat inside of the bowl, if the fuel pump check valves don't provide a good consistent seal, the supplemental check valve in the filter can slow partial draining of the fuel lines for quicker recharge of the fuel bowl during subsequent cranking.  In any case, the newer style filter won't impede performance.  Just be aware that the benefit is subtle, so no one should expect a major improvement by incorporating the newer style filter.

[zieg85]

I thought I read somewhere that a weak fuel pump drains back the fuel line?

[Brady]

Thanks for all of the responses.

One reason I want to try this is because the mechanic recommended it.  I think that sealing the wells plugs helped, although he didn't think that they were leaking. 

The original filter was ceramic and was plugged solid; I couldn't blow through it.  The replacement was also ceramic.  It looked the same, but I could blow through it without restriction.  I did have to replace the fuel pump shortly thereafter.

I looked up this paper filter online, but no one mentioned the anti-leakback feature.  Is it obvious from looking at it?

Comments online also said that they did not include the o-rings.  Where do they go?

It doesn't get that hot in WVa where I live, so I have never had problems with hot restart.

[Rapid Roy]

I had thoughts about fuel draining from carb before and found this check valve on ebay. Didn't follow thru cause had carb rebuilt and replaced fuel pump. This check valve installed just before carb would probably solve drain back if that is indeed happening.

https://www.ebay.com/itm/3-8-10mm-Inline-Check-Valve-Fuel-Diesel-Liquid-Air-One-Way-Non-Return/162363795317?hash=item25cda2e775:g:5EQAAOSwImRYVbQQ:sc:USPSFirstClass!76039!US!-1&vxp=mtr

[Brady]

Thanks, Roy.   The comments of this valve are not good.  One guy said that it wouldn't work without some pressure, so that doesn't sound like it would be right for this application.

[Rapid Roy]

https://quadrajetparts.com/short-paper-carburetor-fuel-filter-with-check-valve-p-79.html

[Brady]

The short version filter should be ACDelco GF470 or equivalent.

The long version filter should be ACDelco GF471 or equivalent.

A '73 K10 V8 should use the short version fuel filter.

On Amazon it says that the GF470 does not fit my truck;  it says to use GF427.  Nowhere in any of the sources that I have found does it say anything about the anti-drainback valve.

Advice?

[bd]

GF427 is the paper element w/o the check valve.  GF470 is the same filter with a check valve.