Moparts

Fuel Tank Pickup Question

Posted By: Jack Zupan

Fuel Tank Pickup Question - 10/30/10 05:23 PM

There have been a number of posts on installing electic fuel pumps recently that I find useful. I am interested in installing an electric pump in my '69 Roadrunner because I have to crank the engine for a good long time before it fires if the car sits for more than a week. I would like to keep the engine compartment more or less stock looking though it obviously isn't to Mopar people. Therefore I was considering a pump set to 7 psi and plumbed into the mechanical fuel pump to avoid having a regulator in the engine compartment. The Aeromotive 11219 pump seems to fit this need. My question has to do with the pickup in the fuel tank. The Aeromotive instructions suggest installing a sump or a high flow pickup to use with the pump. I haven't seen anything posted on this before and am wondering what other people have done to address this issue.

Thanks in advance for you input.
Posted By: RapidRobert

Re: Fuel Tank Pickup Question - 10/30/10 05:33 PM

W the infrequent starting would priming the carb w a ketchup bottle w the nozzle of gas into the pri vent be easier? yes upgrading to a 3/8 pickup/lines would give more volume but not absolutley necc (#1 is what eng/street or strip etc to figure how much fuel you need) but assuming you have that covered & just need instant priming. What carbs as eddys might not be able to handle 7 psi at idle & you MAY end up needing an eng compartment mounted regulator if you go w an electric.
Posted By: stumpy

Re: Fuel Tank Pickup Question - 10/30/10 05:37 PM

Plumbing the electric pump into the mechanical one is courting disaster. Pushing higher pressure into the mechanical pump can rupture the diaphram and push gas into the crankcase. That will not only thin out the oil making for wiped out bearings but could cause a pan explosion.
Posted By: BDW

Re: Fuel Tank Pickup Question - 10/30/10 07:40 PM

Try an insulator first.

I fought with hard starts when hot, and the typical problem of excessive cranking after sitting for several days.

I added the Edlebrock insulator type spacer and it has worked wonders.

I knew it helped when both my wife and daughter initially refused to ride in the car because of the "stinky gas" smell. They could always tell I had driven the car because they could smell gas on my clothes before adding the spacer.

Car now can sit for over a week, 1 pump and it fires right up. No problems with hot starts either.

The crappy 10% ethanol gas seems to evaporate much easier.

http://www.summitracing.com/parts/EDL-9266/
Posted By: sthemi

Re: Fuel Tank Pickup Question - 10/31/10 08:29 AM

Quote:

Plumbing the electric pump into the mechanical one is courting disaster. Pushing higher pressure into the mechanical pump can rupture the diaphram and push gas into the crankcase. That will not only thin out the oil making for wiped out bearings but could cause a pan explosion.



I used a Mallory 140 mounted on the inside frame frame rail by the back tire, and mounted the regulator before the mechanical pump, set to 4 PSI, been that way since 1992.. works great

Attached picture 6276905-PICT0070.jpg
Posted By: Jack Zupan

Re: Fuel Tank Pickup Question - 10/31/10 04:50 PM

To add more information, the engine is a hemi with inline dual Edlebrock carbs. I don't think I have enough clearance for spacers but I can't see what good they would do if the problem is two weeks after you shut the car off. Well it's really not a problem but I do have to crank the engine for quite a while before it starts and I think that is because the float bowls go dry or low. If you use a regulator set at 4 psi does that mean you think a pump set at 7 psi is too much pressure? I think the carbs are rated at about 7 psi aren't they? The only problem I would see with a mechanical fuel pump is if the diaphram ruptured. So it seems like the question would be, can 7 psi do that.
In any event, did you change the pick-up in your fuel tank when you installed your pump.
Posted By: RapidRobert

Re: Fuel Tank Pickup Question - 10/31/10 05:03 PM

Quote:

but I can't see what good they would do if the problem is two weeks after you shut the car off. If you use a regulator set at 4 psi does that mean you think a pump set at 7 psi is too much pressure? In any event, did you change the pick-up in your fuel tank when you installed your pump.


A good share of the gas gets evaporated out of the carb right after shutdown when it's boiling hot. Whichever way you go I'd check the idling psi (& been alot of prob w way inaccurate gauges) in addition to the psi at the end of the strip (or block ) & want 3 or 4 psi at the carb inlets as you go thru the traps
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