72 gas leak question

[Russ S.]

Re: 72 gas leak question

Paul, Thankyou so much for the great exlanation of it's workings. That helps a lot.

[Joe L.]

Re: 72 gas leak question

Thanks Paul,
That is how I was figuring it was. I think for now I will be very careful filling up and see how that goes until I decide if I will drop the tank or try and get to the valve in place.

Looking at Alan's picture I am trying to visualize where the level line would be in relation to the valve hose fitting and fill tube?

Gary-------


The operation of the system is exactly as Paul has described. Here are a few additional points:

(1)------ The 1970 (with EEC) and 71-74 tanks used an extension attached to the filler neck which extended further into the tank than the 63-69 and 1970 (without EEC) design. This was intended to prevent filling the tank above the level of the left side EEC system nipple. This is also why the 1970 (with EEC) and 71-74 tanks were specified at a capacity of 18 gallons rather than the 20 gallons of 63-70(without EEC). The configuration of the tanks was, essentially, unchanged (except for a minor difference for 1963-E69 tanks which did not really affect capacity). The filler neck extension difference was what "subtracted" 2 gallons from the 1970 (with EEC)-74 tanks. However, it is possible to "overcome" the fill tube and "force feed" the tank. This will result in the fuel level rising above the left side EEC nipple. Of course, if the separator works as intended no liquid fuel should enter the EEC system. The problem is that, for one reason or another, the separator might not work as intended. Then, you may have problems like you experienced.

(2)------All 1970-74 tanks incorporate an integral pressure vacuum valve. This is sufficient for tank venting even if no EEC system is utilized. In fact, 1970 without EEC uses this exact venting methodology and uses a sealed design cap just as 1970 with EEC uses. So, one can cleverly plug the EEC hose between the tank and separator and, thus, effectively eliminate the EEC system and all of its "travails" without causing operational problems. If done cleverly (which is quite easy), the system will appear intact and no judge will be the wiser. Be advised, though, that doing so would be a violation of federal law and the laws of many states, most particularly California.

[Gary R.]

Re: 72 gas leak question

Gary-------


The operation of the system is exactly as Paul has described. Here are a few additional points:

(1)------ The 1970 (with EEC) and 71-74 tanks used an extension attached to the filler neck which extended further into the tank than the 63-69 and 1970 (without EEC) design. This was intended to prevent filling the tank above the level of the left side EEC system nipple. This is also why the 1970 (with EEC) and 71-74 tanks were specified at a capacity of 18 gallons rather than the 20 gallons of 63-70(without EEC). The configuration of the tanks was, essentially, unchanged (except for a minor difference for 1963-E69 tanks which did not really affect capacity). The filler neck extension difference was what "subtracted" 2 gallons from the 1970 (with EEC)-74 tanks. However, it is possible to "overcome" the fill tube and "force feed" the tank. This will result in the fuel level rising above the left side EEC nipple. Of course, if the separator works as intended no liquid fuel should enter the EEC system. The problem is that, for one reason or another, the separator might not work as intended. Then, you may have problems like you experienced.

(2)------All 1970-74 tanks incorporate an integral pressure vacuum valve. This is sufficient for tank venting even if no EEC system is utilized. In fact, 1970 without EEC uses this exact venting methodology and uses a sealed design cap just as 1970 with EEC uses. So, one can cleverly plug the EEC hose between the tank and separator and, thus, effectively eliminate the EEC system and all of its "travails" without causing operational problems. If done cleverly (which is quite easy), the system will appear intact and no judge will be the wiser. Be advised, though, that doing so would be a violation of federal law and the laws of many states, most particularly California.

Hi Joe
Thank you, I had no idea about the filler necks differences. Makes sense now though as I wondered why I never had issue filling my 67 or 69 in the past. You are exactly right, I did force feed the tank and created the problem. The separator must be bad but that is going on the punch list for now.

I also wondered about plugging the tank and the effect it would have, if I would need a vented cap or not. My car is never going to be judged and I drive it much for it to be a EPA concern, in my opinion.

[Paul O.]

Re: 72 gas leak question

When I had the same problem removed the separator sprayed a lubricant into it and after a small amount of time the float ball was free and it worked normally again.

[Gary R.]

Re: 72 gas leak question

Thanks again Paul.