General fuel system health questions (newb edition)

[73Polara360]

So during the recent inspection I had done there were no crusty lines observed and the car overall is running fine. Moving on, I was wondering whether people use inline filters such as the one pictured below. Also, I understand from searching there's a fuel filter after the pump likely along the fuel rail somewhere, and there's also an in-tank filter. (?) This is for a 1973 Polara Custom 360la / 5.9L. Because this is a carbureted system is it true that the system is not pressurized like an EFI car? If I pinch lines properly is it safe to disconnect components anywhere along the system and change out filters with spillage pressure limited to gravity/1 atmosphere, or, does the fuel system require a de-pressurization prior to disconnecting any lines and failure to do so would result in a sudden violent release of fuel? Lastly, is there any recommended product I can use to add to the tank with a fresh tank of gas and really give the system a good cleaning, i.e. components such as the internal filter, by using a product such as SeaFoam, or some other formulation best for older engines that in your experience you've found reliable? I am not a fan of snake oils but I just worry about the in-tank filter varnishing over time. Thank you.

 

[Blusmbl]

There is typically a sock filter in the tank, and a canister style filter between the fuel pump on the engine and the carburetor inlet. If you disconnect the line at the carb immediately after the engine was running, you *might* get a small bit of spray but it will be very minor, it is not under the pressures of an efi system. I’ve never worried about depressurizing first on anything carbureted.

If you disconnect the line at the tank or the inlet to the fuel pump, depending on the level of fuel in the tank it will gravity drain out, but again, won’t spray, there is no pressure in the system. You can either use a set of pinch off pliers or stick a bolt in the end of the hose after you disconnect it.

 

[bronze turbine]

It's not pressurized like an EFI fuel system. If you take apart the fuel line while the engine is off you will just get a dribble of fuel. The filter in the tank I believe is just a sort of cloth bag and I've never heard of them varnishing up. The inline fuel filter is mounted in a rubber hose on the outlet side of the fuel pump. You don't need a fancy $50 filter. I think a stock type filter is fine and it's probably less than $10. I don't know of any good fuel system cleaners, I don't use them, but I've heard that ones with I believe "Techron" are supposed to be good.

 

[Big_John]

I'll echo what has already been said. I'll also say that you don't need that fancy gas filter.

If I haven't already, I'm also going to strongly suggest that you download a copy of the service manual from Service Manuals – MyMopar as this will have some illustrations showing the gas lines etc. If you don't want a digital copy, look on eBay for a used factory service manual. Not the generic Chilton manual, a genuine factory manual.

For a replacement filter, I suggest buying one with a metal can rather than the plastic version. The plastic ones can melt in a minor fire and cause even more damage. Stay away from any glass filters too as they can break and spray gas all over the hot engine and generally spoil your day.

The metal can version will look like this and is under $5 just about anywhere.

 

[73Polara360]

I'll echo what has already been said. I'll also say that you don't need that fancy gas filter.

If I haven't already, I'm also going to strongly suggest that you download a copy of the service manual from Service Manuals – MyMopar as this will have some illustrations showing the gas lines etc. If you don't want a digital copy, look on eBay for a used factory service manual. Not the generic Chilton manual, a genuine factory manual.

For a replacement filter, I suggest buying one with a metal can rather than the plastic version. The plastic ones can melt in a minor fire and cause even more damage. Stay away from any glass filters too as they can break and spray gas all over the hot engine and generally spoil your day.

The metal can version will look like this and is under $5 just about anywhere.


View attachment 730736

Thanks for the replies fellows.
Good to know I can relax regarding the in-tank filter.

I actually do have service and chassis manuals, I was at work and didn't have them at hand (guilty as charged on one count of 1st class laziness!)
According to it, the in-tank filter rarely requires replacement, echoing what has been said here, so that's good news.
Section 0-13 of 'Maintenance' says the V8s up to 360 have a disposable canister filter on the suction side of the pump.
In section 14 of the fuel system there isn't much on filters per se, but there is a quick blurb that says the filters are located in the engine bay on 8 cylinder engines.

Good points about the metal canister being least disaster prone - I will buy a simple metal canister replacement as pictured, use my channel locks and pinch the lines sufficiently to prevent dribble and not worry about the pressure, and replace this filter only.
Sounds like a plan!

 

[Gerald Morris]

Thanks for the replies fellows.
....
Good points about the metal canister being least disaster prone - I will buy a simple metal canister replacement as pictured, use my channel locks and pinch the lines sufficiently to prevent dribble and not worry about the pressure, and replace this filter only.
Sounds like a plan!

DON'T pinch the rubber hose w Channel locks much, lest you mangle the rubber hose, causing a leak. PLUG the hose w a 5/16" or 3/8" bolt instead. If you have some hemostats or a small "vice grip" that might pinch the hose shut sans much damage, but its best to plug it. Mind you, if you plan to replace the rubber, then go ahead and pinch away, but if you wish to save it, have a little care.

 

[CBODY67]

Personally, I would NOT pinch the fuel lines. Reason is that ethanol'd fuel (even if the local regulations do not call for labeling on the fuel dispensers in this regard) can get brittle with age (even normal age), so a "pinch" could hasten that process and cause leaks/seeps.

Just remove the clamps and carefully twist and pull the filter out of the rubber line. Reverse the process to re-install the filter.

Never have seen a pre-pump filter on a Chrysler product (or any other car back then or now), unless it was placed in that position by an owner wanting to filter out any things which got past the fuel sender inlet in the tank. FWIW

We've used the plastic Fram filters for years with no issues, but there is also a reason why OEM Chrysler fuel filters were the metal ones.

Enjoy!
CBODY67

 

[73Polara360]

DON'T pinch the rubber hose w Channel locks much, lest you mangle the rubber hose, causing a leak. PLUG the hose w a 5/16" or 3/8" bolt instead. If you have some hemostats or a small "vice grip" that might pinch the hose shut sans much damage, but its best to plug it. Mind you, if you plan to replace the rubber, then go ahead and pinch away, but if you wish to save it, have a little care.

Personally, I would NOT pinch the fuel lines. Reason is that ethanol'd fuel (even if the local regulations do not call for labeling on the fuel dispensers in this regard) can get brittle with age (even normal age), so a "pinch" could hasten that process and cause leaks/seeps.

Just remove the clamps and carefully twist and pull the filter out of the rubber line. Reverse the process to re-install the filter.

Never have seen a pre-pump filter on a Chrysler product (or any other car back then or now), unless it was placed in that position by an owner wanting to filter out any things which got past the fuel sender inlet in the tank. FWIW

We've used the plastic Fram filters for years with no issues, but there is also a reason why OEM Chrysler fuel filters were the metal ones.

Enjoy!
CBODY67

sage advice, I will plug them and not pinch them. They appear to be in good condition but why tempt fate.

 

[Justin Plant]

If you decide to get a Glass "Mr Gasket" style filter. Please don't. I burnt a D100 truck to the ground with one. I used them for years with no issue. Somewhere along the line they changed the ends to plastic from brass. Don't know for sure if that's the issue, but the truck is probably Pepsi cans by now.

 

[live4theking]

If you have an old scrape of cardboard put it under the car and change the filter. It will catch the very small amount of fuel that leaks. Use a metal filter like Big_John put a picture of.

 

[Big_John]

Thanks for the replies fellows.
Good to know I can relax regarding the in-tank filter.

I actually do have service and chassis manuals, I was at work and didn't have them at hand (guilty as charged on one count of 1st class laziness!)
According to it, the in-tank filter rarely requires replacement, echoing what has been said here, so that's good news.
Section 0-13 of 'Maintenance' says the V8s up to 360 have a disposable canister filter on the suction side of the pump.
In section 14 of the fuel system there isn't much on filters per se, but there is a quick blurb that says the filters are located in the engine bay on 8 cylinder engines.

Good points about the metal canister being least disaster prone - I will buy a simple metal canister replacement as pictured, use my channel locks and pinch the lines sufficiently to prevent dribble and not worry about the pressure, and replace this filter only.
Sounds like a plan!

The new filter usually comes with 2 new pieces of hose.

I always replace those 2 pieces even if it didn't come with the filter.

Don't worry about spilling a little gas. (Unless you are on a nice blacktop driveway LOL) As long as the engine isn't hot, there's nothing that's going to happen. It's not going to spray out. It might dribble a little, but nothing bad. I just remove the old clamps and try to get the filter off... If it doesn't come off easy, I just cut the old hoses and be done with it.

 

[Big_John]

Section 0-13 of 'Maintenance' says the V8s up to 360 have a disposable canister filter on the suction side of the pump.
In section 14 of the fuel system there isn't much on filters per se, but there is a quick blurb that says the filters are located in the engine bay on 8 cylinder engines.

I could have sworn there was an illustration of the fuel filter in the FSM. I looked and there isn't.

I know I've seen a decent illustration of the gas line and filter, but it must have been in an earlier year FSM or maybe it was a parts book. Anyway... It's not hard to find.

 

[Big_John]

If you decide to get a Glass "Mr Gasket" style filter. Please don't. I burnt a D100 truck to the ground with one. I used them for years with no issue. Somewhere along the line they changed the ends to plastic from brass. Don't know for sure if that's the issue, but the truck is probably Pepsi cans by now.View attachment 730784

Yea, those are the glass filters that I've seen a lot of warnings about.

My brother's '65 Mercury burnt to the waterline because of a broken gas line.

 

[Gerald Morris]

If you decide to get a Glass "Mr Gasket" style filter. Please don't. I burnt a D100 truck to the ground with one. I used them for years with no issue. Somewhere along the line they changed the ends to plastic from brass. Don't know for sure if that's the issue, but the truck is probably Pepsi cans by now.

ANY multi-piece fitting meant for gasoline is apt to leak, regardless of what its made of, if ONE component has ANY flaw, preventing a perfect seal. I would buy brass barbs for one of those if I had some compelling reason to use one, but I don't, so I won't. BEST by far to use the simplest components in such a crucial system. It occurs to me that even under the mild pressure of a mechanical fuel pump, the slightest failure can result in catastrophe. This applys to carburetors also, alas!

 

[73Polara360]

Decided to go with this for my filter:
In-Line Fuel Filter | 400BF840

And since it's a small number of shekels I'm going to get this for the canister mounted on the passenger side inner fender:
Fuel Vapor Canister Filter | BWDEC224

 

[Gerald Morris]

Decided to go with this for my filter:
In-Line Fuel Filter | 400BF840
View attachment 731034

And since it's a small number of shekels I'm going to get this for the canister mounted on the passenger side inner fender:
Fuel Vapor Canister Filter | BWDEC224

View attachment 731035

You did alright w that fuel filter, but most of Lordco's prices are too high for my liking. I admit to Gaelic Thrift here....

 

[Big_John]

You did alright w that fuel filter, but most of Lordco's prices are too high for my liking. I admit to Gaelic Thrift here....

$6.68 in USD.

 

[CBODY67]

One BAD thing about advancing age is, IF we pay attention to car parts costs in those earlier times, we realize just how much things have gone up! AND, can see the real cost differences between levels in parts supplied (as in the Fram air filters) to make a better price/quality/benefit purchasing decision.

I have NO issues with doing business locally. It might be a bit more expensive, but if their head is in the right place, if you have any fitment issues and such, THEY can be more help, in person, than somebody on the other end of the phone line.

In the 1990s, if I ordered a GM part and it was stocked in a Canadian warehouse compared to a Michigan warehouse, it took one extra week to get the product due to it having to cross the border. Which could mean two weeks to get the part.

The bad thing about the oil sands crude oil is that it is some of the most corrosive and "dirty" crude oils around. Hence, it takes a refinery that can deal with it to use it for fuel production. Something which was not really talked about when they were "the next big thing" in cruse oil, back then. Although the cost of the end product is increased as it taking more effort to refine.

Retail gas pricing is a complex mix of factors. ONE of which is the desire to end up with corporate profitability remaining high. Another is how much production comes from well production. In the USA and Canada, NO government official can tell the private-entity companies how to run their business! Certain things can be advocated for, but it is the Board of Directors that make the ultimate decision, not the government official. Stockholders, on the other hand, CAN better influence the BOD, but any dip in profits affects what the stock trades for and ultimate quarterly dividends.

"Foreign Aid" can be a fickle issue. For ages, the USA has given foreign aid to people on the other side of the planet, as a show of friendship to help eradicate diseases there (before they might travel to the USA). Just as we have provided humanitarian aid in the way of food for babies, so they can grow and become adults to help their countries become more prosperous in the future. Consider these things "humanitarian aid". I've recently become aware that Canada has done similar to Gaza. As the USA sends $B to some foreign countries which provide universal health care for their citizens and also free universities . . . as those costs in the USA skyrocket.

The best thing WE can do is to make the best purchase decisions we can with what we have to purchase with. Just like in prior times. Planning for future needs and watch the sales BEFORE the needs happen. Planning ahead, but not too far ahead. Seems like there is some reason to have a sale very 30 days, these days! Which can be a sign that prices are artificially too high or sales volume is weak.

Have the best time on this earth you can!
CBODY67

 

[Nadir Point]

"...a fresh tank of gas and really give the system a good cleaning, i.e. components such as the internal filter, by using a product such as...?" No. 50yo gasoline systems manufactured predominantly with mild steel and rubber components inevitably fail in a variety of ways over time, regardless of any maintenance activities. Only way to avoid that would be to keep it stored with the tank full of something more than gas in a high desert location.

IF you expect to drive it regularly and NOT bring it home on a rollback from time-to-time, I'd recommend replacing the tank and everything between it and the carb. Don't waste ur time. ;-)

Electric pump wouldn't hurt, either.

 

[bronze turbine]

Just my 2 cents, but I don't recommend an electric fuel pump unless you have a fuel pressure gauge, fuel pressure regulator, and some kind of automatic shut-off in case of an accident like modern cars. My reasoning--the same reason why they don't use them in NASCAR.