The Stovebolt Site Forums The Shop Area Engine Shop Where to Put Fuel Filter?

I'm going to use a Fram inline fuel filter and not the glass bowl filter on my 261. Where would you put it?

Between gas tank and fuel pump?
Between fuel pump and carb? If so, would you install it horizontally just before the carb or in the vertical line just after the pump? The latter is where I had it on my 235.

Wally,

I put them at the carburetor inlet. The 1954 truck installation instructions place it in that position. Search on "fuel filter" and "gas filter" in this forum; there are a few long discussions on the variety of places people have installed a bowl-type and an "in-line type" fuel filter.

One thread is here: http://www.stovebolt.com/bboard/cgi-bin//ultimatebb.cgi?ubb=get_topic;f=2;t=002876#000007

Here are a couple pictures:

1954 235 with dual action fuel pump

1960 261 with stock fuel pump in a \'54 pickup

Tim

If you do not use the glass bowl fuel pump which has a screen before the check valves, you need a filter before the pump otherwise the check valves can fail from debris getting stuck in them.

Put the filter before the pump,I had one of those aftermarket glass filters that screwed apart to clean and change the filter come apart and catch the motor on fire. The previous owner installed it and luckily it did not do much damage.

I think that a fuel filter should go AFTER the pump. The guys who rebuilt my 235 put one on before the pump and my engine was starving for gas. Took me a while to figure it out. Fuel pumps push better than they suck. I just use a WalMart cheapie in-liine metal filter.

Thanks for the advice. Tim, your photo reminded me to use metal tubing for my dual action fuel pump. I used rubber tubing on my 235 for the manifold vacumm. Your setup looks nice and clean.

I think I'll put an inline modern filter just after the fuel pump on the vertical rise. The manifold area will look a lot cleaner that way.

Thanks, again.

Wally - now to contradict an earlier post.

I have an inline filter between the shut off valve at the bottom of the tank and the steel line going to the pump.

I also have an inline at the entrance to the carb.

The bottom one required changing about 3 times before the tank grit was sloshed out from driving.

That is the only time I experienced fuel starvation. I didn't know what the junk would do to the pump and figured I would rather not pump it through.

I replaced the little internal cartridge filter in my Rochester Monojet carb with a metal cased external one which screws into the same hole. It's a Fram G3427. It uses a piece of rubber tubing but any future leaks would drip on the oil filter of the 261 and not the exhaust manifold. The carb fuel inlet is on the fender side of the carb.

I'll then put a Fram metal inline filter before the pump and will watch for low fuel to the carb like Tab said.

Thanks, everyone!!

The in-tank screen filter should be enough to keep your fuel pump clean. A fuel filter mounted before the pump is a bad idea. It will fail prematurely because there is to little pressure pushing the gas through the filter.

Tab - I gotta disagree with you on that one. There is no screen on the tank outlet on an AD truck or any old truck that I have ever worked on from the 30's to the 60's.

Also - the only time I have experienced any fuel starvation is when the filter below the tank is plugged. Fuel runs like a faucet through the filter when it is new.

AD tanks are in the cab and the bottom of the tank is higher than the fuel pump. The fuel pump has plenty of suction to give your hand a hickey . . . certainly enough to pull through an inline filter as long as it isn't clogged. If it is clogged - be happy you kept the suspension stock so you can crawl under it to change the filter without using a jack!

Better to catch the rusty sediment before the pump with a $4.00 NAPA filter than to ruin a $35 NAPA fuel pump by destroying the check valves and diaphram with grit.

I have to totally agree with Ken on thiis one

I'm curious, when you crawl under to change your fuel filter, do you have a petcock installed to stop the flow of gas or do you work real fast to keep from getting showered with gas to badly . I like the idea of having the filter underneath the tank :p .

Lots of good advice from everyone here. The tank of a '48 is under the bed and doesn't produce the head of pressure that a behind the seat tank would. A quick filter change would release some gas but might do some good on the driveway grease.

Pumps indeed don't pull as well as they can push. When they pull, there's a maximum of 14 psi (atmospheric pressure) doing the job for you. They can push at whatever they were designed for.

So, I'm going with a metal in-line filter before the expensive dual stage fuel pump (and watch the performance) and the little one that screws onto the carb.

Thanks everyone!!

Steppen - the cab tanks have a petcock valve in the bottom of them to shut the fuel off. It has an 1/8th inch NPT female pipe thread that you can screw a 3/8" barb fitting into and then a NAPA fuel filter can fit right in and make the distance to the hard steel line about 6" away.

If fuel filter flow concerns you, just put two in parallel.

I did not have any fuel filter before my pump, and it got clogged up with junk from the tank. The junk was in on the valves so they wouldn't seat, and I got no fuel. I now have a glass-bowl pump. When I first bought my truck it had no filter at all, but the float valve stuck open with all the crud and just about had Niagra Falls. I installed an inline filter before I drove it away. Sounds like you've got your bases covered Wally, just keep the filters clean/new and you shouldn't have to worry about flow rate.

Hey Ken, Is there a specific Napa filter number that you use? I finally looked under under my tank and I indeed have the petcock on the bottom of the tank. I can use the barb fitting on the petcock but I'd hate to cut the fittings off of the hard line that is 6" away.

I just looked on the parts shelf for an inline filter that had the right line size, as well being transparent, so i could see the junk in it. Changing it not a problem even with gas, i use a pare of vice-grips to pinch off the line a little. the number i found was a GF68PL which has 1/4 lines and about 2 inches long lines on oppisite ends.

My 62 has a screen filter at the end of the pickup line in the tank. Shouldn't that be enough to keep the fuel pump clean? The guys who rebuilt my motor put the in-ling filter BEFORE the pump. This led to a fuel starvation problem for me.

I now just rely upon the screen mesh filter in the tank on the base of the pickup line as a filter for the pump and use a chepie metal in-line filter AFTER the pump for the carb. I'm not to worried about my fuel pump failing prematurely.

Steppenwood - dont cut the tube, just slide the flare fitting from the end and put the hose right over the flare.