Adding Evaporative Controls to 273 2B

[KitCarlson]

I am tired of smelling gas in the garage after driving. While my 66 Barracuda with Carter BBD runs well, it is time for adding evaporative emissions control. I considered going EFI however my car is very original, the changes required would be significant.

The plan is to use a Holley 2280 R-40214 from a 1985 Dodge truck 318. Other than the evaporative bowl vent system, the connections are similar to the stock BBD, for a simple swap. I have a good carbon canister in my parts stash. A 1/4" fuel line will extend the tank vent to the canister. I plan to mount the canister in the rear passenger side engine bay.

If anyone has already done this on an early-a, please share your experience.

 

[67Dart273]

Best advice I can give you is have a look at the 72 shop manual which you can download here

http://www.forabodiesonly.com/mopar/showthread.php?t=132309&highlight=manual,+download

This would be a significant project. Are you ABSOLUTELY SURE you don't have a leak somewhere?

Another aspect may be that the carb/ fuel line is simply boiling over at shutdown and dumping gas into the throttle bores, then evaporating and stinking. It might be that a vapor return system would help or solve it, and this is ALSO a huge help with vapor lock It WILL require some sort of fitting into the fuel tank, or replacing the sender with a "2 line" aftermarket one. (I filled my tank with CO2 from my MIG welder tank, then silver brazed a fitting into the front face of the tank)

After you get that done, and a line run up front, the Wix numbers for vapor return fuel filters are 33040/33041 (5/16 and 3/8) and 33054, which is a 90* angle fitting.

33040/41:

33054:

Here's a screenshot of the 72 shopmanual evaporative control system:

As you can see, back at the tank is a great big expansion/ collector tank, and there's "some" to it. The one line from front to rear is what vents the tank, and if you want a vapor return system as well, you'd need a total of THREE lines front/ rear. One for fuel, one for the carbon can, and one for vapor return.

 

[KitCarlson]

Thank you for the comments.
I do not think there are leaks, but the spill to the bores is possible. I get what I think is good mileage, about 19 MPG with about 60% stop and go, and 40% Interstate at 70 MPH. I also run the A/C 50% or more of the time. I do not have vapor lock or starting problem when warm, it starts instantly. I do have to crank it a few seconds to get fuel after a couple days parked. Part of my problem is the gas was old at the start of driving season and the smell was terrible. It has improved some since then.

I had an Omni with a carb that had a similar return filter. Does it have a small orifice in the filter for the return path? Since I will extend the existing tank vent, I might be able to use it. The canister is above the vent, and tank, so if I do Y below the canister, it might work. edit: It wont work, now I understand the need for third line.

Other than running the vent line and the mount for the canister the hook-up is fairly simple. I have the Holley 2280 rebuilt. I think it will bolt on with minor adjustment of kick-down and choke linkages. The Omni used a thermal vacuum valve to inhibit purge when cold. I will try without first, if there is a problem I will add something similar, with a solenoid valve.

 

[RedFish]

I would first make sure the carb isn't leaking fuel inside or outside..
Ask the local part store for a later model carb spacer ( 1975 or so ). That will lift the bowl away from the intake. You'll need to alter the choke linkage accordingly.

If I did add a vapor canister I would place it as far forward as possible.

 

[KitCarlson]

Thank you for the suggestions, they agree well my thoughts.

I added the thick spacer under the carb with little improvement. When the car is warmed up, I do notice a fluctuation in the idle at random 2 second intervals, it may be an internal fuel drip. It could be porosity in the bowl, so not much of a way to solve that. The vacuum gauge does not tick, but I may check valve lash today since it happens only when hot.

I do not seem to get fuel in the oil, so it might happen slowly enough it evaporates before it spills to the cylinders. I have checked the float level on and off the car it is correct. I encountered a leak in the new fiber entry seat washer, so went to the aluminum one then had to set the float using on the car procedure. I was uncertain, so I checked again, inverted off the car and it was spot on. I use a float T-square rule to be exact.

I think mounting the canister near the horns may keep it cooler. I will try that.
I may have to give up the added radiator overflow tank that resides there.

 

[KitCarlson]

Before mounting the carbon canister I installed the Holly 2280. It was a simple bolt-on using the thick spacer gasket. I also purchased longer studs to install later. I fear busting a stud before my first test. I fabricated a new longer choke rod from a steel welding rod. I determined that measurement, by measuring the BBD choke crank with choke closed, to manifold. Then repeated the measurement on 2280, using a thick spacer gasket. The difference (1/2") was then added to the choke rod.

The return spring was moved from the throttle crank peg to the hole in the 2280 crank ahead of the peg. In the stock BBD location, the throttle crank conflicted with the spring. I also loosened the throttle cable clamp and moved the cable 1/4" forward to allow the throttle to return fully. The automatic kick-down was adjusted to spec.

I connected the purge line, and bowl vent to canister and plugged the tank vent. The canister was placed out side the grill for testing the carb. The vacuum control signal not connected, canister is inactive as far as purge. The canister will still absorb vapors.

When I removed the BBD it still contained a couple table spoons of gas, but not enough for a full bowl. It had set for 5 days, so not sure if leak, or gas evaporates that fast.

With the 2280 installed, it cranked and started after about 3 seconds, to fill the bowl. I set the curb idle to 650 RPM and adjusted the idle mixture screws 1/2 turn out from the 1 turn out initial. It idled nicely, I took it for a short drive, it was very smooth and responsive. There are additional settings to do on the power valve, and linkages. Those need to be done after curb idle is set. So far there is better idle quality, and a couple ticks more vacuum on the gauge at idle. The BBD had a little bit of surge on throttle release, not preset on the 2280.

And, it did not stink up the garage!!!!

I will report back once the canister is installed, tank vent connected, purge control installed, and full tuning is done.

 

[mcnoople]

I have considered adding an evap system to my 65 225 valiant. It is nice to know that I am not the only one that thinks it is good idea. I will probably try to find a rectangular one that I can mount under the car. I figure that since I don't have a muffler on the passenger side I will just put it there. Please keep this updated as it progresses.

 

[KitCarlson]

I found a better location for canister, before and below the battery. I need to fabricate a different lower, front battery tray support bracket.

The location has air vents for the battery and should help cool the carbon canister.

I will post pictures of the new bracket when completed.

Redfish: You were correct on both points, I think my BBD had an internal leak that got worse at higher temperature. The front mounted canister also good idea.

 

[KitCarlson]

To mount the evap canister, the front battery tray bracket was tilted, and an adapter bracket was fabricated to connect the tray, bracket, and canister.

 

[KitCarlson]

The unit install is complete, with limited testing, it works great. The tank vent was routed to the canister using 1/4" steel fuel line. The line was started at the front inside frame rail and continued to the rear of the front fender well where it crosses to the inner rocker panel, following the brake line to the rear axle rail, then crossing to inside of rail to the tank vent. Short lengths of 1/4" fuel hose connects line ends to tank vent and canister. The EGR port on the carb was connected with vacuum tubing to the top control port of the canister. The complete installation took about 3 hours including fabrication. The time did not include rebuilding the Holley 2280.

The 66 Barracuda is more fun to drive. It is much smoother running, cleaner, and no smell in the garage after shutdown. I will continue to check operation and do a mileage check on a couple fill-ups.