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two fuel return lines....OK?

sputnik 440

sputnik 440

Capt Jim
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I have been having fuel boiling problems with a 440. compartment is extremely hot partly due to 2" headers. The holley dp 4150 sits on a 1/2" insulator but it is little help. The 40 micron holley filter is in front of the carb and just before the fuel log. Having read threads related to the topics of fuel boiling out of the carbs, and in my case probably the filter as well, and threads on vapor lock at the mechanical pump, I bought a filter vapor canister with a return line and will mount it as recommended, just past the pump. I have insulated the fuel line from the upper portion of the ss/rubber line going to the filter and the filter and the fuel log. However, I want to put a holley regulator with dual supply lines and RETURN line. Now, will I have problems with running a line to the gas tank and, somewhere in that line, splicing in the return lines from vapor canister and the regulator? All my lines are 3/8", why did Mopar go from a 3/8" outlet on the pump to a 5/16" inlet and outlet on the vapor canister? I then go back to 3/8" after the canister to the fuel log and carb. Will the pressure drop effect the fuel pressure at the carb and therefore the performance?
 
Wow, a lot of questions....I'm going through a similar issue myself.
1. I don't "think" you can splice in your vapor return line into the Holley regulator return line. I suspect even the return fuel pressure will be great enough to cause fuel to "back up" into your vapor return line.
2. Have you considered putting header wrap on the passenger side header/exhaust manifold?
3. Blocking your heat cross-over on the intake/valley pan gasket?

Also, why are you adding a Holley regulator to a mechanical fuel pump? Only for the return line? I'm planning on using some Fram fuel filters with a 3rd (small) nipple as my vapor return(s) with the little nipple turned "up" to collect vapor. I believe someone on this site recommended it.
 
Last edited:
coloradodave said:
Wow! $300. for a pint! Too bad it doesn't say what size area that will coat. 90% reduction in radiated heat got my attention...
Click to expand...

This is what I found on the manufactures web site.

A 16 oz. can of ZyBar covers the exterior of an entire exhaust system or the interior and exterior of a set of long tube headers.
 
I've got the thermal ceramic, spacer, wrapped, and moved lines. IMO the ethanol is the cause. Boils at 174, well below a normal running v8 in hot ambient conditions. Going with efi and a return hoping that tuning and cooler fuel will partially solve. Decent fuel around here is not available.
It is not a cooling system issue. Fuel.
 
PurpleBeeper said:
Wow, a lot of questions....I'm going through a similar issue myself.
1. I don't "think" you can splice in your vapor return line into the Holley regulator return line. I suspect even the return fuel pressure will be great enough to cause fuel to "back up" into your vapor return line.
2. Have you considered putting header wrap on the passenger side header/exhaust manifold?
3. Blocking your heat cross-over on the intake/valley pan gasket?

Also, why are you adding a Holley regulator to a mechanical fuel pump? Only for the return line? I'm planning on using some Fram fuel filters with a 3rd (small) nipple as my vapor return(s) with the little nipple turned "up" to collect vapor. I believe someone on this site recommended it.
Click to expand...
 
OK, Purplebeeper, you first. I agree with the concern that the fuel pressure from a return line off the regulator may back up to the vapor return. This is why I asked. Your concern makes me rethink what I need to do. Your second point...I have 100' for the wrap that I ordered last week. Going to be a bitch to put it on, but it has to be done, unless I try the coating mentioned on this thread. I like that idea, but $300 for Pint that I might knock over is a bit steep. (Murphy's law, you know.) The heat cross over is blocked. I only use the valley pan gasket with it so. Here is my thinking on the regulator for the mechanical pump. I need to get the temp down at the carb. I do not think that I can do this with out a return. The heat soak under the hood is just too great in the summer time. It heats my garage in the winter time. I'm going to put a temp reader on the engine and carb when I take it out next, and then after I wrap the headers.. So going back to the regulator with the mechanical pump. I would not only eliminate the problem carb and I suspect the metal holley filter in front of it, and the log, but if there was a pressure drop from the vapor canister being only 5/16 and going to my 3/8" line, I could take care of any fluctuation that occurred by turning the flow pressure up or down. Not that much cost to be able to control both. But, to hook up both vapor canister and the regulator, I have to run two lines to the tank. I haven't heard anyone doing this. I don't think I have a vapor issue, but I bought the canister from yearONE, 3 times as much as the one from summit or jegs, but the one people have said they don't get leaks with after a period of time. So, the vapor collection is not my problem but I will hook up the canister anyway. Thanks for your help. It is always appreciated.
jim
 
SimDog said:
This is what I found on the manufactures web site.

A 16 oz. can of ZyBar covers the exterior of an entire exhaust system or the interior and exterior of a set of long tube headers.
Click to expand...
SimDog, I like the concept and the reports but not the price and the application to installed headers concerns me. I can barely get to the plugs, let alone try to paint the headers in that confined area. I think it said you can wipe it on. I'd hate to either not get enough on, or to run out while I was putting it on. Another can and another $300 is of concern. Has anyone on here actually used it? Does it work as advertised?
 
Bill Monk said:
You also need a sending unit with a return line nipple. The hemi and 440 6bbl cars used the vapor separator I posted above and a 3/8 line to the carb and 1/4" return line
Click to expand...
bill, that is the canister I bought, only the one from yearOne. $80 bucks. I still don't think I need one, but, I got it and will put it on and run a line to the tank. do you have a feeling about running it to the line that will go from the regulator to the tank? Do you agree that the pressure from the regulator will cause back flow to the vapor canister? The 1/4" line with the small orifice on the return nipple of the regulator may not give the pressure i the line that we are imagining.
 
Dennis, yes, the gas we get now is for s%*@. I run 93 with no ethanol. At least that is what the say. Here in the Ozarks people say a lot of crap and that don't mean you get it. Haven't had a problem except for running this summer. I don't have the problem with the FAST efi on my duster 383s, so you are right, that does seem the way to go it you have a concern for quality of gas and/or fuel boiling out of a carb.
 
sputnik 440 said:
bill, that is the canister I bought, only the one from yearOne. $80 bucks. I still don't think I need one, but, I got it and will put it on and run a line to the tank. do you have a feeling about running it to the line that will go from the regulator to the tank? Do you agree that the pressure from the regulator will cause back flow to the vapor canister? The 1/4" line with the small orifice on the return nipple of the regulator may not give the pressure i the line that we are imagining.
Click to expand...
If you have a functioning return, I think you will eliminate any concern with vapor lock. I still don't really understand your logic on the regulator with a mechanical pump but I can't give an opinion on the issue because honestly I've never heard of anyone doing that. Let us know what you end up doing and how it works
 
sputnik 440 said:
SimDog, I like the concept and the reports but not the price and the application to installed headers concerns me. I can barely get to the plugs, let alone try to paint the headers in that confined area. I think it said you can wipe it on. I'd hate to either not get enough on, or to run out while I was putting it on. Another can and another $300 is of concern. Has anyone on here actually used it? Does it work as advertised?
Click to expand...

I assume they recommend the application of the product with the headers not installed on the vehicle. From what I read from the application instructions is that you paint it on the exterior and if you wish to coat the inside that you saturate a no lint cloth and pull it through the header pipe, making sure to keep the cloth saturated enough as to fully coat the interior, followed by a curing time. No thinning required. Just as with any application of painted on products, they make it very clear that the headers have to be clean from any contaminates prior to application.
 
I get your pressure drop think vs. regulator Sputnik.....I've never heard of anyone doing that, but your idea makes sense to me. As one of the other guys mentioned, you do need some place at the tank for the return fuel/vapor to go. In my case, I'm running electric pumps from a rear tank sump, but my return will be the "original" 3/8" line that used to supply the fuel out of the tank and is now blocked off. I agree with Monk too.... the vapor (aka boiling fuel) is the problem....same thing...fix that issue with some type of return or better insulation or whatever and you're golden.
 
just a thought has anybody thought about a fuel cooler
 
oldbee, been putting fuel coolers on big equipment for a few years now and we do it two different ways. put in the grill area like a trans cooler or the best is in the return line to the tank underneath with a fan mounted to it.
 
How about running with or near ac lines.
 
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