Soldering vapor return onto a factory sender - how to avoid melting isolator?

[cudak888]

I'm at that point of vapor lock (joys of modern fuel and hot Florida) where I'm running a factory-style 1/4" fuel vapor return hard line down my framerail, with the now-popular Wix 33040 (or 33041 if you're on 3/8" lines) just before the carb, and plans for a 1/4" return through the sender. Basically, a good combo to keep hot vapors from creating vapor lock - based on comments from a few members here and many other enthusiasts around the internet who've farted around with this issue.

This said, I'm at the point where I need to slide in a bit of 1/4" line through a new hole on the sender. Easy enough. I'm also not too concerned about getting the fuel vapors off the sender so it's safe to solder - I figure enough time letting the vapors evaporate outside and a bit of CO2 sprayed through the hard line ought to cover it.

But there's not much room on this thing - and importantly, I'm concerned about the plastic isolated sender connector. Short of a wet rag, are there any suggestions that those who've done this before might recommend?

Also - just to get this in before anyone suggests it:

• No, not interested in replacing with a repop sender - I went out of my way to replace the repop with an original because of the oft-repeated issue of the float resistor's mismatch with the factory gauge OHM range. I've even repaired the resistor unit in this one. Plus, the stud on the repops seem undersized - the pigtail always seemed loose when installed (not so on the original). Of course, the steel disc at the lock ring is paper thin as well, just like the bad ring repops themselves. Put simply, the repop senders are poopie in my book, and I won't use one. Also, the only ones with 1/4" returns are the 3/8" versions for 440 cars - I'm running stock 5/16 lines and have no reason to replumb the entire thing or introduce unnecessary potential leakage points with a step down fitting.

• I know it's an option, but I'm not really that keen on plumbing the vapor line to the filler neck. Wouldn't be surprised if this fills with gas regularly on a fairly full tank during normal acceleration.

• Also don't want to do the crush-fit tank bung out there. Not keen on something that probably results in at least a few metal shards in the tank, has a rubber gasket that will probably go bad eventually, and - most importantly - isn't removable.

-Kurt

 

[BeepBeepRR]

I would think if you are using a gun and not a torch you may be alright soldering it without damage to the isolator. Just a thought.

 

[moparedtn]

I would think if you are using a gun and not a torch you may be alright soldering it without damage to the isolator. Just a thought.

think so too....or if it was me, I'd be rigging up a compression fitting sort of deal instead.

 

[BeepBeepRR]

I will be doing this same thing to a 67 Impala sender soon. But I will be using an Earls AN fitting setup. It will be for a 3/8 return line for a sniper.

This https://www.jegs.com/i/JEGS/555/110845/10002/-1 and this https://www.jegs.com/i/Earls/361/AT985008/10002/-1 with a lock nut and 2 of those round gaskets. More like this not the first link. https://www.summitracing.com/parts/...QqqRyfLvvBGMWU-wyCkOKAagU5MURf8saAtxwEALw_wcB

 

[Darter6]

Do a google search for low temperature solder.

 

[cudak888]

I would think if you are using a gun and not a torch you may be alright soldering it without damage to the isolator. Just a thought.

I've give that thought, given that I've got my trusty 140W Weller 8200 at hand, but I'm not certain it'll be hot enough for the job.

Anyone know if I should be looking at a 300W iron before trying this?

think so too....or if it was me, I'd be rigging up a compression fitting sort of deal instead.

Most of what I've found have been bulkhead fittings made to pass fuel through panels, but not through a panel holding back fuel. Any chance you can point me in the direction of a fitting that might be suitable?

I will be doing this same thing to a 67 Impala sender soon. But I will be using an Earls AN fitting setup. It will be for a 3/8 return line for a sniper.

This https://www.jegs.com/i/JEGS/555/110845/10002/-1 and this https://www.jegs.com/i/Earls/361/AT985008/10002/-1 with a lock nut and 2 of those round gaskets. More like this not the first link. https://www.summitracing.com/parts/...QqqRyfLvvBGMWU-wyCkOKAagU5MURf8saAtxwEALw_wcB

I thought about it. Not much room on the Mopar sender for one of these, given the steel plate tacked right in the middle of it.

Do a google search for low temperature solder.

I've got a tube of it that I've used for a few projects; it's fantastic. I'm just worried about heating the base material enough for a good bond (though I obviously plan to clean the living crap out of the sender and hit the solder area with a Dremel to polish it up).

Either way, I may hit the line with at least one slightly cold MIG tack, on the back - just enough to prevent vibration and the solder from cracking.

Appreciate the input...keep it coming if you can.

-Kurt

 

[zyzzyx]

I would put a return line in the tank rather trying not to fry the plastic isolator. Of course,
that would require you to drop and clean the tank. Then solder your tubing right to the tank.
Or you could solder a brass fitting to the tank with female pipe thread or anything you want.
You could solder a tube or fitting into the tank in place if you don't use an open flame.
A larger soldering iron won't blow your tank up! No flame, no danger.

 

[davek]

 

[Fran Blacker]

I'd put the return line so line is against the support bracket. Hold the line against the bracket, clamped or wired. After you solder return pipe to bracket, while it's still hot move heat down bracket and solder pipe to base. Let solder set for a short time then dunk it in water.

 

[cudak888]

I would put a return line in the tank rather trying not to fry the plastic isolator. Of course,
that would require you to drop and clean the tank. Then solder your tubing right to the tank.
Or you could solder a brass fitting to the tank with female pipe thread or anything you want.
You could solder a tube or fitting into the tank in place if you don't use an open flame.
A larger soldering iron won't blow your tank up! No flame, no danger.

Thought about a return to the tank, but I'd probably get a new tank at that rate before anything else.

Sender is now out, cleaned, fuel has evaporated, and I just shot it with CO2 in every conceivable place. Put a butane torch to it and nothing went up, so should be good to go with it. Cleaned it up, and it should be good to solder.

Also, I just realized the two extra holes on the tube support happen to be quarter inch, so I might as well get the tube to exit on that side. The support might help or hinder as a heatsink. We'll see.

-Kurt

 

[pnora]

I would drill and clean the sender base as far away from the insulator as possible. Bend the return tube as needed is such a way that you can solder it to the suction tube in several places. That way it wont move when trying to solder it to the sender. Position the sender for soldering with the insulator on the bottom and cover it with a damp rag. Concentrate the heat on the tube and quickly solder it. Proper cleaning along with good flux and solder is a must. I also would extend the return with a longer hose to keep the fuel away from the suction screen. Sometimes return fuel can cause a turbulence if close to the suction sock which could create a starvation possibility. I know on fuel cells that it was always recommended when running returns keep them away from the supply ports.

 

[beanhead]

Put some alligator clips---the larger the better---between your work and the plastic piece. Same principle as heat-sinking electronic components that are being soldered into a PC board.
And, if all attempts fail and you end up melting the insulator anyway, you could put some electrically insulating epoxy or potting compound in there.

 

[cudak888]

I would drill and clean the sender base as far away from the insulator as possible. Bend the return tube as needed is such a way that you can solder it to the suction tube in several places. That way it wont move when trying to solder it to the sender. Position the sender for soldering with the insulator on the bottom and cover it with a damp rag. Concentrate the heat on the tube and quickly solder it. Proper cleaning along with good flux and solder is a must. I also would extend the return with a longer hose to keep the fuel away from the suction screen. Sometimes return fuel can cause a turbulence if close to the suction sock which could create a starvation possibility. I know on fuel cells that it was always recommended when running returns keep them away from the supply ports.

THANK YOU. Already drilled the hole so it uses the factory bracket to help the line along. Also pretty far away from the insulator. Going to start polishing the metal with a Dremel now.

That said - in regards to extending the return, shouldn't a vapor return be positioned as high in the tank as possible? I know that EFI returns should be submerged to prevent aeration (and thus unnecessary pressure in the tank), but I'm still not 100% clear whether using a vapor separator (such as the Wix fuel filter I'm planning on using) will pass enough fuel along with the vapor that it'll ever get to the tank in the first place.

-Kurt

 

[pnora]

THANK YOU. Already drilled the hole so it uses the factory bracket to help the line along. Also pretty far away from the insulator. Going to start polishing the metal with a Dremel now.

That said - in regards to extending the return, shouldn't a vapor return be positioned as high in the tank as possible? I know that EFI returns should be submerged to prevent aeration (and thus unnecessary pressure in the tank), but I'm still not 100% clear whether using a vapor separator (such as the Wix fuel filter I'm planning on using) will pass enough fuel along with the vapor that it'll ever get to the tank in the first place.

-Kurt

As long as it is only venting. I would be curious what that Wix filter actually does. For information sake install it and run a line into a can and see what is returning out of it. Curious minds want to know.

 

[70chall440]

Small hand held butane torch provides a high degree of control and accuracy for applying the heat. As mentioned, direct the heat mostly onto the tube neat the hole it is to go through and have the solder at the ready. It won't take much heat or time to get it done. I have done probably 3 or 4 of them this way.

 

[Fran Blacker]

How about a picture and schematic of what your doing? What pnora brought up about the wix filter is going separate vapor. I looked up wix filter I see what your getting at but will it work? I'm not an expert on vapor lock but is it possible it vapor locks before your filter? https://www.oreillyauto.com/detail/...rator/6bf814fc80d2/wix-fuel-filter/wix0/33040

 

[pnora]

How about a picture and schematic of what your doing? What pnora brought up about the wix filter is going separate vapor. I looked up wix filter I see what your getting at but will it work? I'm not an expert on vapor lock but is it possible it vapor locks before your filter? https://www.oreillyauto.com/detail/...rator/6bf814fc80d2/wix-fuel-filter/wix0/33040

What I believe is these filters are just a way of returning a metered/restricted amount of fuel back to the tank. Not vapors. What it is doing is allowing cooler fuel to be circulated throughout the system and hopefully lessening vapor lock. Without the return fuel is deadheaded and prone to higher temperatures. Will all this fix the vapor lock? Jury is out.

 

[Fran Blacker]

Rather than pulling tank a second time I'd have your returned submerged now.

 

[cudak888]

As long as it is only venting. I would be curious what that Wix filter actually does. For information sake install it and run a line into a can and see what is returning out of it. Curious minds want to know.

I think the Wix isn't metered, as opposed to the original 440 type which has the .060" metered orifice. Seems to work well for many though, including a fair number of forum members.

Small hand held butane torch provides a high degree of control and accuracy for applying the heat. As mentioned, direct the heat mostly onto the tube neat the hole it is to go through and have the solder at the ready. It won't take much heat or time to get it done. I have done probably 3 or 4 of them this way.

Well, I took the plunge and did it already, and - sure enough - the 150W iron was only hot enough to get the solder onto the surface, but following that up with a small butane torch did the trick. I wound up using a socket as a heat shield and heatsink, and it worked perfectly.

Now, if it's not clear in the photos, I did wind up tilting the tube up, for better or worse. I was going off of some original 440 senders and it appears as if they were designed to dump above the fuel level, so I imitated that. Probably because they were metered.

I went ahead and started soldering before anyone had posted whether to point it down or up, so apologies to those who have suggested otherwise.

However, there's nothing stopping me from flaring the end for a fitting and connecting an inverted J-bend back down with an extension. Come to think of it, it may be the only way to do it and still get the sender to slide into the tank.

What I believe is these filters are just a way of returning a metered/restricted amount of fuel back to the tank. Not vapors. What it is doing is allowing cooler fuel to be circulated throughout the system and hopefully lessening vapor lock. Without the return fuel is deadheaded and prone to higher temperatures. Will all this fix the vapor lock? Jury is out.

Makes sense. Seems to work pretty well for many on the forums though, and there's one or two videos on YouTube praising it. Doesn't necessarily mean it works for all situations, but I don't mind giving it a shot.

FYI, the vapor lock wasn't the primary issue - I'm installing an electric fuel pump at the moment - but I decided to add it into the mix as it'd be an opportune time to drop the tank.

Rather than pulling tank a second time I'd have your returned submerged now.

Duly noted - see my reply to 70chall440 about my error in pointing it up.

-Kurt

 

[cudak888]

Oh, FYI, I haven't pressed the flare into the 1/4 line yet. That's also why it's so long - I couldn't flare it before installation, and I had to extend the line this long to give me enough room to flare it.

Should also help to clear the 5/16" line when it's clamped in.

-Kurt