Fuel Pump with vapor return.
Thread Starter
Burning Brakes
Joined: May 2014
Posts: 884
Likes: 128
From: Rhine Georgia
Fuel Pump with vapor return.
Looking for recommendations for my 420HP 383. I'm having a vapor lock issue and need to replace my crate engine fuel pump with a return line model. My current pump has no return and car vapor locks after 10 mins at idle with a warm engine on a hot day. Thanks in advance.
Melting Slicks
Joined: Mar 2006
Posts: 3,456
Likes: 102
From: Piedmont Va
St. Jude Donor '11-'12-'13,'19-'20
I have a 383/450HP with a Holley 750DP and use a stock small block 350 pump with integrated return. Same that came on the car with the L-48. Rock Solid! (and not expensive). No regulator required!
Race Director
Joined: May 2006
Posts: 18,737
Likes: 2,583
use a fuel filter with a 1/4" return line, no need to change the pump
https://willcoxcorvette.com/corvette...r-gf-432-68-69
https://willcoxcorvette.com/corvette...r-gf-432-68-69
Thread Starter
Burning Brakes
Joined: May 2014
Posts: 884
Likes: 128
From: Rhine Georgia
use a fuel filter with a 1/4" return line, no need to change the pump
https://willcoxcorvette.com/corvette...r-gf-432-68-69
https://willcoxcorvette.com/corvette...r-gf-432-68-69
Instructor
Joined: Oct 2014
Posts: 143
Likes: 24
From: Prince George BC
I was experiencing what I thought was a vapour lock issue with my new motor upgrades earlier this year . I tried three different carbs , took off my fuel pump that had return line and installed edelbrock 110 gph no return line and installed new distributor and still had issues . I was using a 91 octane fuel with 10 percent ethanol . Switched to 94 octane and no ethanol problem fixed . I would be happy if I could get 91 ethanol free but cost more than the 94 so will keep running it . Just a thought worked for me
Le Mans Master
Joined: Mar 2001
Posts: 5,738
Likes: 644
From: Lincoln, CA
use a fuel filter with a 1/4" return line, no need to change the pump
https://willcoxcorvette.com/corvette...r-gf-432-68-69
https://willcoxcorvette.com/corvette...r-gf-432-68-69
Works great.
Drifting
Joined: Jul 2015
Posts: 1,765
Likes: 254
From: Catlett VA
Looking for recommendations for my 420HP 383. I'm having a vapor lock issue and need to replace my crate engine fuel pump with a return line model. My current pump has no return and car vapor locks after 10 mins at idle with a warm engine on a hot day. Thanks in advance.
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Thread Starter
Burning Brakes
Joined: May 2014
Posts: 884
Likes: 128
From: Rhine Georgia
You might also try an insulating gasket between the carb and intake manifold. Edelbrock makes a good one. Heat transferred from the engine to the carb on my 454 boiled the gas until the fuel bowls were empty when the car was hot and then turned off. The insulating gasket fixed the problem.
My engine temp nor my underhood temp seems to be a issue. Both run cooler than most. coolant temp was 190ish and I have a air temp sensor thats mounted on back firewall. It registered 98. Both numbers recorded at time of vapor lock
Only thing I know to try at this point is the fuel return.
Last edited by Bloodzone; Jun 1, 2016 at 07:04 PM.
Intermediate
Joined: Sep 2012
Posts: 27
Likes: 1
What kind of line are you running? I have been running braided hose for a couple of years now with now issues. I detuned my 383 from my drag racing days and have not experience it. What kind of vacuum are you running at idle from the carb? Timing? I had stumbling issues this spring after i installed a new oil pump. I had to readjust the timing for the hot humid days. Just a thought.
Running a Holley 110 gph with -6an lines.
Running a Holley 110 gph with -6an lines.
Thread Starter
Burning Brakes
Joined: May 2014
Posts: 884
Likes: 128
From: Rhine Georgia
what did you do with the hose that came from the vapor separator near the tank to the canister? Left it open or closed it?
Race Director
Joined: May 2006
Posts: 18,737
Likes: 2,583
Vent or no vent
I would first look a little closer back near the tank to see what they did with that line before going to a vented cap.
Thread Starter
Burning Brakes
Joined: May 2014
Posts: 884
Likes: 128
From: Rhine Georgia
I would first look a little closer back near the tank to see what they did with that line before going to a vented cap.
Last edited by Bloodzone; Jun 2, 2016 at 05:01 PM.
Thread Starter
Burning Brakes
Joined: May 2014
Posts: 884
Likes: 128
From: Rhine Georgia
I had a Bubba moment......
Plan is to remove my NPT in line fuel pressure gauge. Replace it with a NPT to 1/4 Barb fitting and run line to my old capped off return. Then test for vapor lock.
Anyone see any reason this wont work?
Plan is to remove my NPT in line fuel pressure gauge. Replace it with a NPT to 1/4 Barb fitting and run line to my old capped off return. Then test for vapor lock.
Anyone see any reason this wont work?