Evap valve
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Evap valve
Having never seen a 510 with the original carb...all have been weber converted. How then is the Evap valve on the drivers strut tower properly hooked up to a weber conversion? (1) line from the expansion tank, (1) line from the block vent, (1) line from what part of the induction system? Thanks
Re: Evap valve
Hey Chip, long time! I don't think that any of the Weber carbs or dual Hitachi SU's will have any of the necessary plumbing points that the OEM carb had. Like with the MG's & Triumph's, I always tell people to leave the hard line tube that goes BACK to the gas tank, OPEN.......do not plug it off. Example, if you disconnect all the emission crap on a 70's MG, you must leave the vapor line (back to the tank) and the vapor cannister line (from the tank to the vapor cannister in the trunk) OPEN, or you will suck the gas tank in on itself! Seen it a hundred times over the years. I would assume that the 510's system is similar, but what I do not know is if the 510 hard line actually carried raw fuel back to the tank, or simply vapors back to the tank like the MG/TR system? Hope all is well on the east coast!
TJ
(now in Denver!)
TJ
(now in Denver!)
1973 510 2dr
1972 521 flat bed
1972 510 Wagon parts car
2009 Toyota Matrix S AWD
LOTS of 510 parts!
1972 521 flat bed
1972 510 Wagon parts car
2009 Toyota Matrix S AWD
LOTS of 510 parts!
Re: Evap valve
The 510 hard return line carried fuel back...on some years. Other years of 510 didn't have a return line. Variances in how Datsun decided to take care of emissions regs for a given year.
If the carb in question doesn't have a return line, there's nothing to send through the valve to the tank.
If the carb in question doesn't have a return line, there's nothing to send through the valve to the tank.
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson
Re: Evap valve
That illustration makes it look like the hard line that is near the left strut tower cycles/flows "forward", or do you think that just references where the tube comes from?? I always thought that it flowed from the carb to the tank.
Maybe I have been thinking backwards?? It also mentions "resevoir tank" in the illustration, which I assume is the long tank above the fuel tank. Is the "cycle/flow" from the fuel tank, to the resevoir tank, forward up to the carb to burn off the excess vapors??
Maybe I have been thinking backwards?? It also mentions "resevoir tank" in the illustration, which I assume is the long tank above the fuel tank. Is the "cycle/flow" from the fuel tank, to the resevoir tank, forward up to the carb to burn off the excess vapors??
1973 510 2dr
1972 521 flat bed
1972 510 Wagon parts car
2009 Toyota Matrix S AWD
LOTS of 510 parts!
1972 521 flat bed
1972 510 Wagon parts car
2009 Toyota Matrix S AWD
LOTS of 510 parts!
Re: Evap valve
The Flow Guide Valve and its connections are well described in the 73 FSM on pages EF-22 adn EF-23.
It is not part of the fuel supply or return system, but guides the VAPOR recovery tank output to either the air cleaner or the block vent. If you don't use the guide valve, leave that line from the tank open as suggested above.
It is not part of the fuel supply or return system, but guides the VAPOR recovery tank output to either the air cleaner or the block vent. If you don't use the guide valve, leave that line from the tank open as suggested above.
Re: Evap valve
As an emissions tool, it would be bringing vapor forward to combust.
Because when you spend a silly amount of money on a silly, trivial thing that will help you not one jot, you are demonstrating that you have a soul and a heart and that you are the sort of person who has no time for Which? magazine. – Jeremy Clarkson
Re: Evap valve
Now that makes more sense! So tr6racer, the long black metal vapor cannister hanging right above the fuel tank in the 510, is the same component as the round silver cannister in the MG's!
1973 510 2dr
1972 521 flat bed
1972 510 Wagon parts car
2009 Toyota Matrix S AWD
LOTS of 510 parts!
1972 521 flat bed
1972 510 Wagon parts car
2009 Toyota Matrix S AWD
LOTS of 510 parts!
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Re: Evap valve
There are three connections to the flow guide valve one to thegas tank, one to the crankcase and one to the inside of the air filter.
Engine off
The gas tank is sealed. When gas vapor pressure rises to about 0.4 in. of Hg. the flow guide valve opens and the excess vapors push through and into the crankcase where they are stored.
Engine running
Stored vapors in the crank case are drawn out by the PCV valve and burned.
As the gas tank is emptied and there is a negative pressure the flow guide valve open the line to the air filter and filtered air is allowed into the gas tank to replace the used fuel.
This system will work just fine with any carb. The hose to the carb only goes to the filtered air side of the air filter.
Engine off
The gas tank is sealed. When gas vapor pressure rises to about 0.4 in. of Hg. the flow guide valve opens and the excess vapors push through and into the crankcase where they are stored.
Engine running
Stored vapors in the crank case are drawn out by the PCV valve and burned.
As the gas tank is emptied and there is a negative pressure the flow guide valve open the line to the air filter and filtered air is allowed into the gas tank to replace the used fuel.
This system will work just fine with any carb. The hose to the carb only goes to the filtered air side of the air filter.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs
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- Location: Richmond, VA
Re: Evap valve
Great description Mike...thanks to all who contributed!
Seems I'll be putting a fitting under my low profile K&N on the Weber
Chip
Seems I'll be putting a fitting under my low profile K&N on the Weber
Chip