Weber carb return line, where is the T Options

[Type 47]

pictured is the carb setup from when I took the engine out.

It was a single line feed but I want to put a return line back to the tank.

Where would I T that in the plumbing?

[GregAmy]

You will need to change to a return-type fuel pressure regulator, otherwise pressure would be almost zero as it flowed right back into the tank (easiest path).

The return will be on the bypass side of the pressure regulator.

Edit: something like this should work, mounted before the feed lines to the carbs: https://www.holley.com/products/fuel_system...rs/parts/12-887

Kinda curious: why? Worried about vapor lock? You're still going to have that last bit of feed to the carbs that will not be full flow, and that's the most-common locations for vapor lock.

[Type 47]

You will need to change to a return-type fuel pressure regulator, otherwise pressure would be almost zero as it flowed right back into the tank (easiest path).

The return will be on the bypass side of the pressure regulator.

Edit: something like this should work, mounted before the feed lines to the carbs: https://www.holley.com/products/fuel_system...rs/parts/12-887

Kinda curious: why? Worried about vapor lock? You're still going to have that last bit of feed to the carbs that will not be full flow, and that's the most-common locations for vapor lock.

So in the below thread (3rd post down), it was suggested to have a return line to avoid vapor lock. After reading the post again, I think I overlooked the answer the Weber banjo. but now I should investigate using a regulator also.

http://www.914world.com/bbs2/index.php?showtopic=362785

[VaccaRabite]

So in the below thread (3rd post down), it was suggested to have a return line to avoid vapor lock. After reading the post again, I think I overlooked the answer the Weber banjo. but now I should investigate using a regulator also.

Vapor lock tend to be more about where your pump is (early location low in the engine bay or late location in the front trunk). The early location would get hot, adding more heat to the fuel, making it more prone to lock. Also adding phenolic spacers to your intake runners does a LOT to fight vapor lock with carbs. Without the spacers, heat from the heads goes up the runners into the carbs and can boil the fuel in the bowls. A return line allows fuel to flow back into the tank instead of the fuel getting backed up behind the regulator/carbs and soaking up heat.

As to the regulator - there are only 2 ways to successfully run fuel to carbs. Using an internally regulated fuel pump, or using a fuel regulator. The regulated pumps are non-adjustable and you buy the one that has the right pressure (under 5 PSI). Regulators come in bypass or non-bypass versions. The stock regulator has a bypass, and the excess fuel goes back to the tank. Many carb regulators don't have a bypass, and are designed with only one line to be used (no return). This does require a low pressure fuel pump too - you can't use the stock pump regulated or not.

For whats its worth, I never ran a return line when my car had carbs, and I never had vapor lock issues. But my pump is in the front, and I was using phenolic spacers to block the head heat.

Zach