[dataway]

I've got a stock mechanical pump with an OEM steel line to the carb ... is the rubber hose between the supply hard line and the pump inlet a suitable place for the filter? I realize the intake side is not ideal ... but it seems to be my only choice.
Anyone have a favorite filter for use in this location?

[Formulabruce]

Originally Posted by dataway

I've got a stock mechanical pump with an OEM steel line to the carb ... is the rubber hose between the supply hard line and the pump inlet a suitable place for the filter? I realize the intake side is not ideal ... but it seems to be my only choice.
Anyone have a favorite filter for use in this location?

NOT a 3 piece glass one, they WILL leak..

[lust4speed]

A mechanical pump has enough problems sucking fuel through the feed line without adding a filter before the pump. I use a steel cased filter just before the carb and retain the sock in the tank on my cars that still have the mechanical pumps. If there is a filter on the supply side it should be a 100 micron and then something like a 40 micron on the pressure side.

[Kenth]

With the sock in the tank and the filter in carb fuel inlet there is NO need for an external filter.

[lust4speed]

Originally Posted by Kenth

With the sock in the tank and the filter in carb fuel inlet there is NO need for an external filter.

True. But I have found that with the limited float bowl capacity of a Quadrajet that the brass filter will have the car nose over at the top of second where removing it and putting a good 3/8" inline filter will be enough to prevent the starvation. If the car is driven sanely (and no fun in that), then the carb filter is fine.

[Schurkey]

Buy a "Fuel Injection" filter that has inverted-flare fittings at both ends that are the size of your pump-to-carb fuel tube. 5/16, more likely 3/8.

Cut the OEM steel tube between pump and carb, add flare nuts, double-flare the ends. Install fuel filter using the double-flared/flare nut attachments.

The only problem is that most OEM tubes aren't routed in a way that provides room for the bulky filter. You might have to bend your own tube, or partial section of tube, to get it to route cleanly. Make sure the filter is in a place you can access for service later.

The "Fuel Injection" filter will easily withstand any pressure a carb application would have; the double-flare connections are completely secure, and it's all on the pressure side of the pump, so no pump-suction problems.

[Cliff R]

"True. But I have found that with the limited float bowl capacity of a Quadrajet that the brass filter will have the car nose over at the top of second"

The small fuel bowl has nothing to do with it, you are either keeping up or not.

The 1967 Q-jets have a goofy fuel filter set-up with a nipple in the casting to align the bronze filter and short inlet nut. Easy to upgrade to the later filter set-up and that's what I do with most of the 1967 carbs that have been rebuilt/restored here. Even before you even look at doing all that I'd install a .135" high flow N/S assembly. Most likely it has a small one in it if the carb was rebuilt at some point.......

[dataway]

Carb is a 704 from 1971. It's a brand new NOS carb with one of your kits Cliff, I gave you the specs and you sent a kit. Seems to run great by the way (although only tested on the stand).

Anyway .. car will see no spirited driving, it's all stock, new tank, new lines, new sender .. well, new everything. Not wanting to cut the steel line from pump to carb in any way.

If the sock and the carb filter are all that's required (as it was all that came from the factory) then I'm probably good. I don't mind replacing the carb filter as necessary, easy enough to do when the threads are good.

[Cliff R]

The smallest N/S assembly I'll send for one of those would be .135" so you should be fine. I would NOT cut the steel line for any reason. You should be able to upgrade to a Marine micro-screen filter from the paper one if needed, but most likely you'll be fine as-is....

[Formulajones]

As Cliff mentioned, I use the marine micro screen filter in my Firebird Q-jet. With the stock AC Delco mechanical fuel pump it feeds the engine perfectly. Plus it's cleanable. I pull it out every couple years and just rinse it off. Actually now that I think of it, I haven't done that in probably 4-5 years LOL.

There is no need to add external filters anywhere. The sock in the tank, and the filter in the carb is enough. Keep the stock steel lines as they are.

As mentioned, the mechanical pumps have a hard enough time pulling all that fuel from the tank, the last thing you want to do is put a filter on that side of things. The sock does well enough.

You start adding more filters in the system and you'll find fuel starvation issues with the stock setup, it just makes the pump work harder than it has to.

[mzbk2l]

Originally Posted by Schurkey

Buy a "Fuel Injection" filter that has inverted-flare fittings at both ends that are the size of your pump-to-carb fuel tube. 5/16, more likely 3/8.

Cut the OEM steel tube between pump and carb, add flare nuts, double-flare the ends. Install fuel filter using the double-flared/flare nut attachments.

The only problem is that most OEM tubes aren't routed in a way that provides room for the bulky filter. You might have to bend your own tube, or partial section of tube, to get it to route cleanly. Make sure the filter is in a place you can access for service later.

The "Fuel Injection" filter will easily withstand any pressure a carb application would have; the double-flare connections are completely secure, and it's all on the pressure side of the pump, so no pump-suction problems.

I did that many years ago on my Cutlass that had just enough rust dust in the tank to clog the paper filter more often than I liked.

[Old Goat 67]

Originally Posted by Kenth

With the sock in the tank and the filter in carb fuel inlet there is NO need for an external filter.

That SOCK was removed in my first week of ownership of my GTO.
The horror of previous GM ownership was enough to make that happen (water in fuel causes that to block all fuel pickup).

Put an in line filter down there external to fuel pickup line.
Been that way for 55+ years.

[ZeGermanHam]

Originally Posted by mzbk2l

I did that many years ago on my Cutlass that had just enough rust dust in the tank to clog the paper filter more often than I liked.

Any idea what part number the filter you used here is?

[mzbk2l]

ACDelco GF652

Amazon

[ZeGermanHam]

Originally Posted by mzbk2l

ACDelco GF652

Amazon

Thanks. Does this filter also require o-rings, though?

[abefromen]

Originally Posted by ZeGermanHam

Thanks. Does this filter also require o-rings, though?

yes

[Formulajones]

Yeah that filter is also metric with a M16-1.50 thread pitch if I'm not mistaken. Typical 3/8 flare fitting won't work which is 5/8-18 thread.

That GF 652 is meant for newer cars from the 90's on up I believe and does use an o-ring. Or I should say it's supposed to.


The only steel inverted flare filters I'm aware of that work on older cars with the correct american style thread is either the GF90 or the GF416.

The 90 has smaller 5/16 connections if I remember right, so adapters would be needed for 3/8, Don't care for that. I think I have one on the shelf.

Or spend the big bucks for the GF416 with 3/8 fittings that were for the 396 chevelles and corvettes in 1965. Restoration shops get $70-$80 for those, I don't think you'll find them in the local stores.

Typically these were held inside brackets bolted to the engine as well because they don't hold up too well to engine vibrations, and sometimes crack at the fittings over a period of time if suspended in mid air by the steel lines themselves. just an FYI

Frankly, the carb is designed to hold a filter, it's convenient. That's where I'd have it.

[mzbk2l]

You guys are right; that one does require o-rings. I went back in my Amazon orders and I see I ordered two Dorman 800-153 STEEL FUEL LINE REPAIR KIT. 3/8 IN. x 18 IN. w/16mm fitting. Those have the correct metric o-ring fittings for the filter ends, and I flared the other ends for my carb and fuel pump inlet. I'd forgotten about that.

[tjs72lemans]

I have a 72 with a warmed over 400. I also kept the stock line, but wanted another filter. I did put another plastic see through filter before the pump. I don't want to risk messing with the carb filter and messing up those threads. Plus, you don't know when it needs replacing until it shuts you down. At least the see through style is observable and easy to replace. I have had no issues with pump pulling fuel through it.

[ZeGermanHam]

Originally Posted by Formulajones

Yeah that filter is also metric with a M16-1.50 thread pitch if I'm not mistaken. Typical 3/8 flare fitting won't work which is 5/8-18 thread.

That GF 652 is meant for newer cars from the 90's on up I believe and does use an o-ring. Or I should say it's supposed to.


The only steel inverted flare filters I'm aware of that work on older cars with the correct american style thread is either the GF90 or the GF416.

The 90 has smaller 5/16 connections if I remember right, so adapters would be needed for 3/8, Don't care for that. I think I have one on the shelf.

Or spend the big bucks for the GF416 with 3/8 fittings that were for the 396 chevelles and corvettes in 1965. Restoration shops get $70-$80 for those, I don't think you'll find them in the local stores.

Typically these were held inside brackets bolted to the engine as well because they don't hold up too well to engine vibrations, and sometimes crack at the fittings over a period of time if suspended in mid air by the steel lines themselves. just an FYI

Frankly, the carb is designed to hold a filter, it's convenient. That's where I'd have it.

It's surprising that there's so few options for a basic inexpensive fuel filter with a typical 3/8 double flare connection.

In any regard, this discussion has led me to think that since I have an in-tank electric fuel pump with a sock filter, I'll probably just hook the fuel line up directly to the carb and rely on the carb's inlet filters rather than running an external inline filter. It will ultimately be a simpler and cleaner install with fewer connections.