Where does my second fuel filter go???

[billlsbird]

Hello Everyone! .... I have a Mallory canister style fuel filter that is mounted behind & below my fuel cell & behind & below this I have a Holley Blue fuel pump. I ran -8 an fuel line to the front of my car {a '32Ford}. Now I am planning on mounting my fuel regulator on the firewall & running -6 an line to my carbs {dual double pumpers, feeding a blown 392}. My question is; is it ok if I run my second fuel filter {I was going to get a Earl's} into my regulator or would it be better to plumb them closer to the carb's? Thanks Bill

[IC2]

Rule of thumb - your main filter goes BEFORE an electric fuel pump and any secondary filter - wherever it fits best but generally near the carb.

[billlsbird]

....Thank You IC2, yes my 1st. filter {the Mallory} is right out of Fuel Cell. I attached a pic of my carb set-up. I could either put a filter right into the fuel pressure regulator or right into the fittings that you see in the pic's. Going into the reguator would be cheaper/easier so I'll do that! Thanks again, Bill

[Dave Severson]

Don't forget to put a shut off valve between the fuel cell and the first filter!!!!!

[stovens]

So if your running a mechanical pump should the main filter go before the pump too?

[IC2]

So if your running a mechanical pump should the main filter go before the pump too?

While you can (should??) put a non restrictve filter before the mechanical pump, there should always be one between it and the carb.

With an electric pump you are first trying to protect that tight clearanced rotor then secondarily the carb. The mechanical pump valves can tolerate some level of dirt so here your primary objective is to protect the carb (does that make sense)

[Don Shillady]

Well my wiring work is much lower quality than other work on this Forum and I will try to clean it up, but about a month ago I did finish my fuel system installation. I was able to use a left over piece of stainless steel sheet to bolt to two fender bolts to provide a mount point to the replaceable filter I got from Speedway. I got a shut off valve from JEGs and put that before the filter so I will be able to change the filter with the valve closed. I am not as ashamed of this as for my wiring so far and it seemed to turn out pretty well with a long 3/8" steel line under the right (passenger) running board up to the mechanical pump on the SBC 350. I am a little worried that due to my large rear tires and rear spring setting to clear the tires the rumble-seat-tank is actually about 1" higher than the carb base at the engine which might lead to a siphon through the carb. That condition only holds when the tank is topped off completely full but might be worse when parked on a hill. I bought an electrical shut of valve but I have not installed it for simplicity hoping the float needles in the carb will seal the fuel when the engine is not running, BUT if I do experience siphoning I can install the electrical shutoff valve in the line from the mechanical fuel pump up to the carb. Maybe as I gain more skill with the wiring I will add that valve anyway. Actually the tubing looks pretty good here but each piece is at least the third try! You can see the vent hose because I have not yet drilled a hole through the quarter panel to the fender well for the vent. I have tested the space under the filter bowl and it can be removed and replaced with mount shown.

Don Shillady
Retired SCientist/teen rodder

[stovens]

While you can (should??) put a non restrictve filter before the mechanical pump, there should always be one between it and the carb.

With an electric pump you are first trying to protect that tight clearanced rotor then secondarily the carb. The mechanical pump valves can tolerate some level of dirt so here your primary objective is to protect the carb (does that make sense)

Yes thanks!

[Don Shillady]

So it looks like I need another filter between the mechanical pump and the carb. It is going to be interesting to prime that system so I don't have to crank the engine a lot on the first start. Maybe a suction bulb wil pull gas through all of that restriction. On a previous car (MG midget) I had a whole box full of plastic see-through filters with small paper filters inside and they flowed pretty good. They were just inserted in the fuel line before the carb and held with clips; I changed them frequently due to a rusty gas tank but I could see if anything was in there. With my first filter shown above I would think the gas should be pretty clean after the first few minutes flushing the new line. Now I have to rethink another filter.

Don Shillady
Retired Scientist/teen rodder