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Username Post: Vapor Lock on big block        (Topic#362625)
brickwhite 
Contributor
Posts: 154
brickwhite
Loc: Missouri
Reg: 09-05-19
09-18-20 09:16 AM - Post#2803741    

I have 66 impala with a 454 big block that has headers and a 700r4. The Carburator is a 770 4 barrel Holley brawler. When the engine is at temperature and the I let it sit and heat soak a little I'm having vapor lock and hot restart issues.

I've read different solutions:
a. fuel filter with vent
b. heat shielding on headers, fuel lines, carb spacer
c. electric fuel pump
d. black magic..

Current Setup Picture:





I was going to start with a vented fuel filter.
Part #: FIL 3041, but then I would have to have a return line back to the tank.

Could I have the return line "T" into the vent?



Any Further suggestions?



picture just because:













Ted


Edited by brickwhite on 09-18-20 09:19 AM. Reason for edit: No reason given.

 


bigbowtielover 
Valued Contributor
Posts: 2619
bigbowtielover
Loc: Surrey British Columbia
Reg: 09-01-13
09-20-20 12:23 AM - Post#2803844    
    In response to brickwhite

Move the fuel line away from heater hose and use hardliners from pump to carb with a short rubber hose to connect. Throw the plastic filter away and install a metal one before the pump.



 
brickwhite 
Contributor
Posts: 154
brickwhite
Loc: Missouri
Reg: 09-05-19
09-20-20 09:40 AM - Post#2803877    
    In response to bigbowtielover

Thanks,

I'll try that.

I assume you mean metal fuel lines from the pump the carb?

Like these inline tube sells:
PN -
INL30109



Long island corvette sells them too.

https://www.parts123.com/parts123/yb.dll?parta~dyn...





Ted


Edited by brickwhite on 09-20-20 04:36 PM. Reason for edit: No reason given.

 
bigbowtielover 
Valued Contributor
Posts: 2619
bigbowtielover
Loc: Surrey British Columbia
Reg: 09-01-13
09-24-20 02:38 PM - Post#2804225    
    In response to brickwhite

Yes something similar to that. You can use the line for a Rochester Q-jet and cut to fit and use a short 2" rubber hose for connection. I made lines for my car out of parts from factory lines I had from parts cars.



Edited by bigbowtielover on 09-24-20 02:39 PM. Reason for edit: No reason given.

 
brickwhite 
Contributor
Posts: 154
brickwhite
Loc: Missouri
Reg: 09-05-19
09-27-20 11:06 AM - Post#2804383    
    In response to bigbowtielover

I think I'm going to try the metal lines first... if inline tube ever mails the other 3 pieces...(they are not good with shipping)

Then electric pump if needed.








Ted


 
6T5 
"3rd Year Gold Supporting Member
Posts: 258
6T5
Age: 68
Loc: Asheville, NC
Reg: 07-22-17
09-27-20 03:08 PM - Post#2804392    
    In response to brickwhite

I would also consider using a 1" phenolic spacer between the carb and manifold, couldn't hurt...

...Ed

1965 Impala SS


 
brickwhite 
Contributor
Posts: 154
brickwhite
Loc: Missouri
Reg: 09-05-19
09-27-20 05:56 PM - Post#2804399    
    In response to 6T5

1" would make the air filter too high.

I don't want it to look goofy.

Ted


 
SSvert396 
Gold Supporting Member
Posts: 57
SSvert396
Loc: GA
Reg: 07-19-18
09-28-20 09:29 AM - Post#2804431    
    In response to brickwhite

I had all the same issues last summer here in GA. (396/powerglide) I Tried everything (heat shields, moving fuel lines, carb spacers, constant tuning) with no luck. Ended up swapping on the Holley Sniper fuel injection set up. Car starts every time, idles rock solid @ 800RPM,and cruises around @ 210 degrees even in 105 heat index traffic. Best mod I ever did...I drive it a couple days a week now!! Best part is its all hidden, no one knows your injected! Kit comes with EVERYTHING you need to install, For barely more than a good performance carb ($999). Me and the wife put it in in one afternoon.

Attachment: IMG_0794.jpg (1.46 MB) 10 View(s)




Joe

Restoration photo album below
https://www.tryimg.com/album/6DcY

1965 Impala 396 convertible


Edited by SSvert396 on 09-28-20 09:32 AM. Reason for edit: No reason given.

 
Crusty66 
"8th Year" Gold Supporting Member
Posts: 404
Crusty66
Age: 60
Loc: Albany, eNZed
Reg: 11-04-12
09-28-20 11:27 AM - Post#2804442    
    In response to SSvert396

I did a similar thing - fitted a Fitech system to my 496. I had spent a huge amount of time on the q-jet & got it close but not quite right.

Fitting the Fitech was well worth the effort.
Tuning can be done from the drivers seat.

Steve
1966 Caprice 396 496 496mkII TH400


 
66cayne 
"2nd Year" Silver Supporting Member
Posts: 2909
66cayne
Reg: 08-06-08
09-28-20 05:51 PM - Post#2804474    
    In response to brickwhite

It wont look too goofy. See pics below. I am running a 1" phenolic spacer (primarily because it picked up 30hp when it was dyno tested before installation). Mine is a 496ci masquerading as a 427. I am running the factory '069' manifold, 750 Holley and Hooker Supercomp headers. Same factory style dual feed hardline as you are installing. I did splice in a GF90 metal fuel filter. Also, my mechanical fuel pump is rated 120GPH with a preset of 8psi and it has 3/8" inlet and outlet. Are you running a 3/8" line from the tank to the pump? Good luck!

Attachment: 20200928_153750.jpg (2.91 MB) 11 View(s)


Toms 'L72" eng. compartment


Attachment: 20200928_153804.jpg (2.31 MB) 9 View(s)


Tom's 'L72' fuel line and filter


Attachment: 20200928_153950__1_.jpg (2.77 MB) 7 View(s)


Tom's 'L72' with air cleaner




Edited by 66cayne on 09-28-20 05:53 PM. Reason for edit: No reason given.

 
brickwhite 
Contributor
Posts: 154
brickwhite
Loc: Missouri
Reg: 09-05-19
09-29-20 06:22 AM - Post#2804500    
    In response to 66cayne

Yes, I ran all new 3/8"steel fuel line when I replaced the frame last winter.



Did you have any clearance issues with the air cleaner?

And you were having vapor lock issues before?



Ted


 
66cayne 
"2nd Year" Silver Supporting Member
Posts: 2909
66cayne
Reg: 08-06-08
09-29-20 11:58 AM - Post#2804510    
    In response to brickwhite

No clearance issue. I did not have any prior vapor lock problem. Also, are you running a vented gas cap.



 
brickwhite 
Contributor
Posts: 154
brickwhite
Loc: Missouri
Reg: 09-05-19
09-30-20 07:28 AM - Post#2804553    
    In response to 66cayne

no vented cap

Ted


 
steve65 
"5th Year" Gold Supporting Member
Posts: 926
steve65
Age: 62
Loc: New Westminster BC
Reg: 09-25-13
09-30-20 10:59 AM - Post#2804558    
    In response to 66cayne

I thought you could not have a vented gas cap on our cars due to the fuel tank filler pipe being soo low behind the license plate?
Steve

Steve Duncan
66 Impala 2dr Coupe
Not sure of color yet
work in progress



 
Crusty66 
"8th Year" Gold Supporting Member
Posts: 404
Crusty66
Age: 60
Loc: Albany, eNZed
Reg: 11-04-12
09-30-20 12:45 PM - Post#2804562    
    In response to steve65

You don't need a vented cap, there is a vent tube elbow that runs up inside the trunk.

Steve
1966 Caprice 396 496 496mkII TH400


 
redflags 
Contributor
Posts: 122

Loc: Palmerton Pa.
Reg: 07-21-12
09-30-20 01:50 PM - Post#2804565    
    In response to brickwhite

This is probably no help, but I have had the steel carb to pump fuel line on my L-72 since day 1 and never had a problem with vapor lock. Just make sure it isn't touching anything that will transfer heat into it.



 
brickwhite 
Contributor
Posts: 154
brickwhite
Loc: Missouri
Reg: 09-05-19
10-01-20 09:16 PM - Post#2804637    
    In response to redflags

Hard lines it is... BUT

Tell me how to fit these hard lines without them leaking?

What is the trick?

Carbs side first then pump?

Block first then Carb?

pump first then Block??

UGH...



Also no one tells you the fuel ports on the new holley brawler are 3/8 tube and inline tube sells 5/16" tube. So you need fuel bowl adapters...live and learn..













Ted


Edited by brickwhite on 10-01-20 09:16 PM. Reason for edit: No reason given.

 
brickwhite 
Contributor
Posts: 154
brickwhite
Loc: Missouri
Reg: 09-05-19
10-02-20 10:57 AM - Post#2804663    
    In response to brickwhite

I figured out the hard line leaks,

Start at the fuel bowls clean up all fittings with steel/wool or brillo pads and tighted as you get closer to the pump. That seemed to work. Wrapped all connections in a temp shop towel and turn the engine over till you see fuel in the bowls. No leaks or wetness on the shop towels.



Remove the towels....

Took her for a short ride got to temp checked the lines 2 more times for leaks so far so good.


As for the vapor locking:
It's about 70 today so not quite testing the hot start / engine vapor lock issue but seems ok after about 20 mins.

Ted


Edited by brickwhite on 10-02-20 02:03 PM. Reason for edit: No reason given.

 


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