fuel plumbing question

I am just building a blown bbc altered and hope someone can help clear my mind about a fuel return question. On my last blown car (more years ago than I like to say) I ran my return lines directly to the tank. The setup I have now has the shut-off loop and the other return also plumbed back into the inlet of the fuel pump, with no returns to tank at all. (using K-valve) My main concern is will there be cavitation or excessive pressure causing possible damage to the pump when shutoff valve closed at end of a run?

 

Most cars are plumbed this way, should not be a problem.

 

Just because EVERYBODY dose it that way, don't mean it's right, first thing is the fuel went true the pump and got hot already, now your going to send it threw again and heat the new fuel, then your interfering with the flow of the main line, I like going back to the tank, As does most of the old time fuel company's, the new guys just like to sell parts, we used to call it being CALIFORNIANAIZED, JMHO.

 

My stuff is plumbed back to the front of the pump.

Search for other info on this site it's been talked about before.

 

You can't go wrong by sending the fuel back to the tank. (however make sure the return lines are where they are suppose to be, ck www.fuelinjectionenterprises.com , Spud wrote a great article on fuel cells) If you run the check valve lines back to the pump, where's the air that's in the lines go? You're asking for trouble. Most of the time...I assume...the guys running the lines back in the pump get a clean bill of health after the burnout, but still I wouldn't want air going in the motor when there's suppose to be fuel there...even for a second. just my quarter

 

Bad joke

What the f*ck is that supposed to mean?

 

Facts

I know I'm just a welder, but I also like to understand things. I've heard all the stories, I think, so I'd like to state what I had to find out for myself with probably over 100 hrs. in front of a flowbench (which happened to be in California).
1. "I ain't puttin' no screen in my barrell valve". A SAE cone shaped screen shows NO pressure or volume drop.
2. "I am scared of air in my lines causing a lean spot". If you "wing" the motor once, or do a burnout, all the valves have probably opened once or for sure when warming trans, the bleed lines have opened. If you've got air, check for cracked fittings.
3. "Plumbing returns to the bottom of the pump will disturb the flow". I found no evidence.
4. "Returning into the main line isn't worth the cost or effort". If done at, at least a 30* angle or more in the direction of flow, the FREEFLOW of the pump will actually increase about a tenth of a gallon, put less backpressure on the pump, helping longevity of the pump.
Nexttime you play with your rubber ducky in the tub, create a whirlpool with your finger and watch the ducky get sucked in!!
I've had discussions with Gorr, Davenport, Conway and a few others on these subjects. Unless one of them has changed their mind lately, they all agreed. Disclaimer: results won't vary by state or country, (Watched fluid go right down the drain at Ken Lowe's bench in Australia, and not at his forehead as some yanks believe)

 

Thats Priceless

do you think you could tell me about the duck one more time,
thanks bob you made my day.shows how pittyfull my life is.

 

Bob and Mike; sometimes being old and investigative can bring fun too. On the subject of the south of the equator stories, after 14 trips downunder, everybody asks about the water in the drain, but I find it more interesting that ladies breasts sag up!

 

plumbing question

Guys, thanks to all who responded to this. I guess now I don't feel quite so "technologically challenged". Thanks again, Les

 

I personally have never heard Of this so my question is would you have a regulator just before the pump then or how does one do this to regulate fuel pressure . We currently have our regulators on the outside of the fuel cell .

 

I made a big fuel log out of inch and a quarter alum. tubing and placed it appox. 12 in. in front of my pump (1100 enderle).It has three an AN 6 bungs welded into it, at a 90 deg angle, it seems to work fine allowing the fuel to mix with fresh fuel before re-entering the pump. I would have perfered to run the returns to the tank but 15 ft fuel lines seemed worse than this fix. Would like to try the 30 deg angle though over the winter.