Installing in-line fuel filter....where????

[LannyL81]

I want to remove the QJet fuel filter and use an in-line one, and would like to know what others have done.
I was going to just cut the metal line between pump and carb and place a rubber hose in-line filter just after the metal line goes vertical along the front of the block between the AIR pump bracket and block. But now I am thinking I should go with AN fittings??? How do I figure out what size to use? 6, 8, 10, 12?? I know the fuel line is 3/8" OD, how does one relate this to the AN sizes?

Also, is there a better location for an in-line filter?

Thanks.
LannyL81

 

[waterboy1976]

I installed mine in the 3/8 hose that comes out of the tank that connects to the hard line that runs to the front....that way its a "front line" defense...used a Russell Fuel Filter setup with hose ends...

 

[JohnZ]

3/8" lines take -6AN hose and fittings; AN stuff is sized by 16ths - 6AN is 6/16ths, 8AN is 8/16ths, etc.

 

[fine69]

What does "AN" mean? I've seen this used in catalogs, but don't have a clue what it means. Thanks!

 

[Dave L.]

IMHO I wouldn't use any rubber fuel hose between the fuel pump and carb. Thats a fire hazzard. There is (was) a guy on this board who lost his 69 in fire several years ago who used a rubber fuel inlet hose. If you are going to use an inline filter,plumb it in with steel line. It takes more time but is much,much safer.

 

[LannyL81]

I installed mine in the 3/8 hose that comes out of the tank that connects to the hard line that runs to the front....that way its a "front line" defense...used a Russell Fuel Filter setup with hose ends...

Not going to be able to do that...the rubber hose from the tank on the '81 is on top of the tank...only about 3" long and a real PITA to get to. I might be able to get an in-line filter between the metal line and the fuel pump...but here again, the hose is short and is "S" shaped, so this would not be easy to do either. I guess I am back at the line between the pump and carb.

My thinking for going with AN fittings on the metal line was to reduce the possibility of leaks. But then, since the pressure is only 6-8 psi...hose ends are not likely going to leak...much unlike a fuel injection system running at 43-45 psi.

AAARRRGGHHH....why is noting ever just straight forward....!!!

LannyL81

 

[74bigblock]

Just use rubber fuel injector line instead of regular fuel line. You will be fine. I use a metal in line filter between the pump and the carb. has steel line going up the block, then cut at the top of valve cover and converted to fuel injector line with the filter. You are only running ~7lbs of pressure if you have a manual fuel pump, and don't need to worry that much. Just make sure everything is tight with good clamps.

 

[JohnZ]

What does "AN" mean? I've seen this used in catalogs, but don't have a clue what it means. Thanks!

"AN" stands for "Army-Navy"; the military originally developed the design and specifications for these 37* fittings, for aircraft use.

 

[lucky76]

What's wrong with the stock Q Jet filter? It's still a filter.

 

[74bigblock]

What's wrong with the stock Q Jet filter? It's still a filter.

I actually have been running all summer without a filter. It's got a new tank and lines... pump and so what the hay right? I put the filter thing back in the case tonight and she ran like dog **** was in the tank.. hesitated on WOT like a bad case of herpes.

 

[pgtr]

Are you experiencing problems with clogging? Those filters are ridiculously small if one is experiencing problems with rust or something.

Some say the best location for the filter is close to the carb. The other school says close to the tank as possible and before the electric or mech pump. Pick your poison I suppose.

IMHO I wouldn't use any rubber fuel hose between the fuel pump and carb. Thats a fire hazzard. There is (was) a guy on this board who lost his 69 in fire several years ago who used a rubber fuel inlet hose. If you are going to use an inline filter,plumb it in with steel line. It takes more time but is much,much safer.

Presuming one doesn't make a few loops around the exhaust pipe on the way and keeping in mind the melting point of rubber - the idea that rubber is more of a firehazard than all the other issues surrounding an IC engine is unrealistic. Many automakers began evolving towards low pressure rubber fuel hoses in combination with steel lines on the supply side in the early 70s and continue to do so thru today for both modern fuel injected (high pressure) and modern carbureted (low pressure) engines.

If there is an un-steller record for vehicle fires - one should consider the Chevrolet variant of the Rochester QJet carb - they did an inexcusably horrible job of plugging the 90 degree turn at the fuel inlet with soft metal that is notorious for leaking profusely and causing fires. Anyone with a vintage QJet would do well to consider this legitimate, non anecdotal fire hazard.

In a carbureted setup there is really nothing to be gained by high pressure fuel injected rubber hose on the supply side. That being said, for pennies more per foot - overkill though it may be - I can't argue with it either!

 

[twoseater]

What does "AN" mean? I've seen this used in catalogs, but don't have a clue what it means. Thanks!

The AN stands for Army Navy (Army-Navy Aeronautical Standard) and an AN is 1/16th.

 

[srs244]

i know it might be overkill, but i put 2 filters in my system, one between the tank and the pump and the other between the pump and the carb. i used one of the billet 3" element replacable filters from summit between the pump and carb and a regular flow thru type between the tank and the pump. my tank is the original one, i believe, so i figured better safe than sorry.

steve