The Stovebolt Site Forums The Shop Area Engine Shop Inline Fuel Filter

I have never had a fuel filter be so dirty that it actually blocked the fuel to the carbs. Thank goodness it did!!

I finally tried to start the 37 today, only the second time since October 2002. I had drained the tank this afternoon and put fresh $2.60 cents a gallon fuel in the clean tank. It would not start. Put a spot of fuel in the carbs - twice and it would kick right off, but would not continue to run. The filter is a glass filter placed just ahead of the first of the dual carbs. The filter was full and the color of the fuel looked like iced tea - not weak tea, but not too strong! Pulled the filter and the filter smelled like paint thinner or varnish - like the wrecking yard! Pulled the tops off of the carbs and they were bone dry.

THE FILTER DID IT'S JOB!!

I'll get a new filter tomorrow, I hope. I haven't bought one of those paper filters that goes in the glass bowl in years - BUT I NEED ONE NOW!!!!

Thanks, guys for convincing me to drain the tank last week when I asked. I would have a real fine mess if I still had the old fuel in the tank.!

Joe

Joe,

You may want to keep an eye on that filter for a wee while, perhaps even adding another inline filter between the tank and the fuel pump until all the crap gets flushed through. Good to hear that you got it sorted out.

Bob

I've had a similar problem with my fuel system. Right now I have the fuel tank out, and it's pretty rusty inside. It'll be going to one of the gas tank renew and coating places today probably.

I intend to add one of the inline fuel filters (the type with the glass bowl and paper filters). My question is, where were they originally located? Obviously, before the fuel pump is best, but do you just cut into the fuel line at a convenient place, or is there a certain distance upstream from the pump?

fredstev -
:confused:
Originally, I'm not sure if my truck even had a fuel filter. For years I put one inline next to the right side of the engine just before the line went into the fuel pump. Mine has a short span of rubber fuel line from the hard line to the pump and it was located in that spot.
:rolleyes:
Later when I went to a two carb set up, I installed it right before the carbs in the fuel line up high on the left site. I did that because it's an AC filter and I had it chromed to add some looks to the setup.

I'm not sure where the factroy put them. I'm sure someone here can tell you!

Thanks for the help!

Joe

before the fuel pump IS NOT best - the pump can handle pumpin 'lumpy gas', but if the filter gets even a small amount of build up in it, the pump has a real hard time suckin gas from the tank and you end up w/ wierd problems due to lack of enuff pressure out of pump, usually when you get below half tank, and ultimately can damage the pump - the only place for an inline filter is between the pump and carb - factory put'em right at the carb inlet, some carbs even have a strainer screen just inside the fuel line fitting

Bill

i have two suggestions
place a good inline filter close to the tank where it is easy to reach and change. I also had a big problem w/ the chunks of debris in the cab tank migrating into the line blocking fuel altogether. I solved this by making a motorcycle type copper fine mesh screen. roll the fine mesh around a pencil and solder it @ the end of a brass straight pipe coupler's end so as to have the screen extend 2'' out the end. make sure all seems are closed and screw it up into the tank. thus large debris can not get into the tank. I've now changed to a under bed tank.
gooday
jim

I agree with red58. Put the fuel filter AFTER the pump. There are lots of people here that will go to their graves swearing that the fuel filter should be before the pump, or you will ruin your fuel pump. BULL! The guys that rebuilt my 235 had my filter before the pump and it was starving for gas. When that filter put before the pump gets even a little bit dirty it will exacerbate the problem.

I suggest putting a strong magnet on the bottom of your tank to catch and hold rusty metal fragments. I also suggest using a fuel stabilizer with each tank of gas, especially if you let your truck sit for long periods of time as many of us do now with gas so high.

Also check the mesh filter in your tank at the base of the sending unit, IF you still have one. When this thing gets clogged yer sunk. Fortunately it's easy to pull and clean. Most people however forget to do this simple precautionary step. DISCONNECT YOUR BATTERY BEFORE YOU REMOVE YOUR SENDING UNIT.

hmm interesting, my 216 seems to be starved for gas. I think it was/is the carb. I put a new filter before the pump, a new pump, and a new filter before the carb. Maybe thats my problem, the filter before the pump.

what Jim and Tab said - if you have the 'sock' on the intake inside the tank [on the sender tube], there will be no large pieces getting out of the tank to clog lines - the fuel pump can handle the fine sediment that can get thru that sock w/ no problems, and the sock is 'self cleaning' to a large extent because of the normal agitation of fuel in the tank - if your sender doesn't include the fuel line pickup tube [not sure when they started, then do as Jim suggests and make a sock from very fine brass screen

where the stuff causes problems is in the carb needle/seat, either keeping it open so the bowl overflows, or plugging it so there's no fuel delivery - there is NO need for 2 inline filters particularly, ArticCat, and if you've replaced the pump and filter [between the pump and carb], and you checked/ cleaned the carb and still have starvation symptoms, check that sock in the tank, and blow a good blast of air thru the lines to insure they're clear

OTOH, if you're getting pieces of crud out of the tank big enough to really plug the lines, it's past time to pull the tank and have it boiled out and seal-coated inside, before it springs a leak from rust thru!!

Bill

This is a pretty interesting thread, eh? I took my tank to the Renu-USA guy today, that'll set me back about $125.00. I ordered the older style of sending unit from Chevy Duty and that type doesn't have the "up and over" fuel line with sock attached. My fuel line goes thru a small petcock on the bottom of the tank.

Yeah, common practice seems to be having a filter between the fuel pump and the carb, and that's what I'll do. Also took a quick look at the plugs, #2 and #5 were pretty sooty, although the engine seems to run good. Picked up a rebuild kit for the Rochester and that'll get done after the tank is re-installed.

Ok, I have a bit of a different question.

At first, the restoration shop installed the glass bowl inline filter I bought just in front of the fuel pump. I questioned if that was the proper location for it. So, they moved it to the inlet in front of the carb.

One of the guys at inlinners.org suggested that I move it to in front of the fuel pump (back where it first was reinstalled) as the glass bowl filters are known to leak and cause fires when installed in front of the carb. (When I asked him if this was because of the chance of fuel dripping on the exhaust manifold, he said yes.)

So, my question is this. How many of you agree with his suggestion? If not, do you run a glass bowl filter in front of your carb on your I6?

I am seriously considering moving the filter back to the fuel pump. Maybe right at the outlet of the fuel pump.

What does everyone think?

Well, I did a little checking with Google on fuel filter use, and the concensus seems to be that it's better to push fuel thru a filter than pull it thru. Typical comment on a F**d service page:

"Fuel should be pushed through the fuel filter. Pulling fuel through a filter can cause cavitation."

Most of the filter manufacturers sell the inline cartridge-type filter (the ones with the arrow showing fuel flow direction), and they speak of having it located "away from heat and mechanical obstructions", they don't comment much on location. Remember, though, many vehicles nowdays have the fuel pump located right in the fuel tank - let's see ya put your extra filter upstream from THAT.

I think that I'll probably install my filter just past the fuel pump - I agree with what Jim Karras pointed out about having the filter mounted above the exhaust manifold isn't a good idea.

A properly sized filter can go before or after the pump. Biggest problem I've seen with filters before the pump is leaking. They can allow air to get sucked in, making you think it's starved for fuel. If you put an inline filter before the pump, seal the connections with Hylomar.

The originals on these trucks were sediment bowls on top of the fuel pumps. Problem with them was that you couldn't clean them without spilling fuel.

The important part is to have a filter and maintain it. Glass bowls are nice, allow visual inspection. I prefer a sediment bowl followed by a paper filter. If the filter gets plugged, you should be sure the fuel line is clean before putting in a new one.

the ones w/ the glass bowl on the pump filtered on the outlet side of the pump - GM discovered that a better way was the inline filter , which the factory put on at the carb inlet - for awhile it was hard to find replacement elements that fit them properly, so most went the easy way w/ throw-away plastic filters, like most V8's got later

fire danger over the manifold? if you have leaks they can/should be fixed - no greater danger than having the carb "over the manifold", and the factory unit is less likely to leak w/ the correct fuel line fittings

Bill

I've got my fuel filter right before the carb which is right over the exhaust manifold. I think I'll move it back toward the fuel pump.

Has anyone considered or tried putting in an electric fuel pump after the tank, then a cannister style fuel filter, then the mechanical pump, then another filter between the pump and carbs?

Heck, with a cannister style filter between the tank and stock pump, say concealed beneath the cab, you probably wouldn't need one between the stock pump and carbs.

This is what I did
[img]http://www.thesavoy.de/assets/images/Carbdetail.jpg[/img]

Frank

Many good points written here all in all, but I tend to think some are going overboard a small bit. What I mean is if you have problems w/ your tank sheading crud down the line, replace the tank . Install a screen @ the tank, that's always a good idea. If your tank is that bad off then replace it or a good boil out @ least so no rust leaks occur and messes in your cab. I now have an under bed tank and more room in my cab. I have little fath w/ sealant compounds poured into the tank, pouring them into a boiled out or rusted tank and adheasion issues a rise. The large inline steel filter (NO plastic ones here) is close to the tank and large enough to last a good long year or two along w/ a good functioning fuel pump. Routine maintainance should include replacement of a filter (5 bucks+-) once and awhile. It's just good to look under the truck every once and awhile. I love glass filters, they look really cool BUT that's about it anymore. I even have one (for looks only) on the 1939 80'' chief. I find them easy to clean, be careful w/ that cork ring, but should the glass crack/ break and you don't have extra bypass line, phone home. This leads me now to using a very good fuel line hose. I prefer 5/16'' steel for most of the plumbing and rubber where applicable. The cheap hose will crack, check, colapse (kink) and leak. Even the good German cloth wrapped fuel line on my 356 cab cracked and I had an engine fire. About 30 seconds and $4400.00 damage. The re-formulated gas here in (arnold) caleforn'eia has an additive in it that 'eats' the rubber, that's another long story... Good fuel line is about $6-8.00/foot, cheap insurance. Carry a Halon (not powder) fire extingusher somewhere easy to reach. I agree w/ the fact you should not have any areas that may leak above the manifold. I prefer to solder on a compression ring fitting at the steel line end where the hose comes in contact w/ the line and a hose clamp and no sealants. The hose goes over the comp. ring and helps make a better, tighter seal. I just don't think we're pulling gas fast enough to worry about where the filter is located. After all it's just an old hippie farm truck.......
gooday
jim

Thanks everyone for all of the informative comments.

The only thing I know for sure is that fuel filters do their job. The filter didn't let anything into the carbs. I bought two (2) new filters, one to install and the extra goes in the glove box. And, by the way, they come with a rubber gasket in the box if the one you buy is a WIX #33034. No more cork!

Thanks again!

Joe