fuel pump question

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Jan 24, 2012 | 03:48 PM

commander_47

Thread Starter

Burning Brakes

Joined: Oct 2011

Posts: 956

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From: McDonough Georgia

fuel pump question

I have an 81 and there are two outlets from the fuel rank to the fuel pump.

My AIM says one is fuel delivery, and one is fuel return.

One of these lines is bigger around than the other.

Can someone tell me which one is delivery and which one is return?

Why is there a return? Do l need the return line at all?

Thanks

Jan 25, 2012 | 08:42 AM

fanmanbd

Racer

Joined: Feb 2011

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From: Northern New Jersey

The larger line is the feed to the pump. Stock fuel pumps have the return line fitting. The return line prevents vapor lock.

Jan 25, 2012 | 12:07 PM

commander_47

Thread Starter

Burning Brakes

Joined: Oct 2011

Posts: 956

Likes: 86

From: McDonough Georgia

Quote:

Originally Posted by fanmanbd

The larger line is the feed to the pump. Stock fuel pumps have the return line fitting. The return line prevents vapor lock.

Thank you so much for that.

I'm not going to use the vapor return line.

I have a new fuel pump that doesn't have that feature and from what I understand vapor lock is pretty rare.

thanks again

Jan 25, 2012 | 12:13 PM

Easy Mike

Team Owner

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From: Southbound

Cruise-In II Veteran

Quote:

Originally Posted by commander_47

...I'm not going to use the vapor return line...I have a new fuel pump that doesn't have that feature and from what I understand vapor lock is pretty rare...

Vapor lock is rare in the dead of winter. Do you want to take the chance of seeing what happens when the weather turns warm? Why not swap your new pump for the correct one?

Jan 25, 2012 | 07:49 PM

Scottd

Drifting

Joined: Jul 2011

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From: Syracuse NY

Quote:

Originally Posted by commander_47

Thank you so much for that.

I'm not going to use the vapor return line.

I have a new fuel pump that doesn't have that feature and from what I understand vapor lock is pretty rare.

thanks again

Rare? Run an Edelbrock carb and you will experience it on every day above 90 degrees. I didnt know about this feature. Ive currently got mine blocked off. May be worth looking into again.

Jan 26, 2012 | 07:20 AM

commander_47

Thread Starter

Burning Brakes

Joined: Oct 2011

Posts: 956

Likes: 86

From: McDonough Georgia

Quote:

Originally Posted by Scottd

Rare? Run an Edelbrock carb and you will experience it on every day above 90 degrees. I didnt know about this feature. Ive currently got mine blocked off. May be worth looking into again.

I have gone through three stock fuel pumps in the past ten years.

Now the car has a 400 hp 383 and I am not sure I want to use the stock 25.00 replacement that breaks all the time.

I have a brand new stock replacement in the box that you cannot even move the lever with your hand. On the Holley, the lever pumps loud and clear just with hand pressure.

I may just slide the feed line into some nice looking heat wrap and see what happens. I can always go back to the crummy stock set up.