510 fuel cap

[DattoDime70]

I have a 1970 510. Should they have a vented cap? I have a non vented which I think it's making vapor lock.

[danfiveten]

I dont think my 71 has a vented one, but im not sure. Battery is dead or id pop the door and take a look. (have electronic trunk and gas door). But i usually here a pop when i take it off so i dont think it is.

[ggzilla]

A 1970 should have a non-vented cap (w/vacuum relief). The tank is vented through the vent line that goes up the engine compartment. This is different from the 1968 & 1969.

[DattoDime70]

A 1970 should have a non-vented cap (w/vacuum relief). The tank is vented through the vent line that goes up the engine compartment. This is different from the 1968 & 1969.

THEY deleted that vented line,it's only a line going to the fuel pump. And I'm guessing that vapor line,they had put a bolt in there I guess to close it?

[ggzilla]

Bummer. You can try a vented cap, but other Datsuns splash gas out (don't know if the 510 will do that or not). Or maybe find where they cut or plug the vent line and restore it.

 

They will be remembered.

[DattoDime70]

But if I was to put a vent line,how would It go? Cause the two outlets of the tank from there they just covered the vent line and ran only the fuel line.

[DattoDime70]

Bummer. You can try a vented cap, but other Datsuns splash gas out (don't know if the 510 will do that or not). Or maybe find where they cut or plug the vent line and restore it.

 

They will be remembered.

But if I was to put a vent line,how would It go? Cause the two outlets of the tank from there they just covered the vent line and ran only the fuel line.

[ggzilla]

You could do it like the early 510s: Take a long hose, loop it up far above the level of the filler cap, and route the end down to a hole in the floor (vent the tank to the outside).

 

 

For less gasoline fumes, route the line all the way up to the engine compartment and hook it up to the stock Flow Guide Valve.

 

If the FGV is missing, get a charcoal canister from a newer Datsun. They only have three connections: 1) large hose to tank vent 2) Purge hose to intake manifold vacuum 3) control hose Tee into vacuum advance line.

 

I did the last on my Datsun and it controls the fumes better than the stock Flow Guide Valve. It cost me $10 at the wreckers. Get the check valve that is back by the fuel tank of the newer car and fit that too.

[DattoDime70]

You could do it like the early 510s: Take a long hose, loop it up far above the level of the filler cap, and route the end down to a hole in the floor (vent the tank to the outside).

 

 

For less gasoline fumes, route the line all the way up to the engine compartment and hook it up to the stock Flow Guide Valve.

 

If the FGV is missing, get a charcoal canister from a newer Datsun. They only have three connections: 1) large hose to tank vent 2) Purge hose to intake manifold vacuum 3) control hose Tee into vacuum advance line.

 

I did the last on my Datsun and it controls the fumes better than the stock Flow Guide Valve. It cost me $10 at the wreckers. Get the check valve that is back by the fuel tank of the newer car and fit that too.

Could I get it off a 79 510 wagon? Cause I ordered a vented cap today and it's coming in tomorrow but I don't know if that'll fix it so should I just loop it up cause I have a coupe but uses a sedan gas tank which is the big tank in the trunk, in back of the rear seat.

[ggzilla]

Well a 510 coupe was a non-US version, so they just used a loop. They loved the smell of gasoline wafting through the streets.