gas vapor/percolation improvement

Bob K. St Paul

Bob K. St Paul

Junior Member
The A and I suffered last season with gas vaporization issues on hot days in traffic and at long stop lights that caused rough running and one forced stop to cool down before continuing. This spring I removed the radiator and sent it to a shop for cleaning ( no overheat problems, it would run to 195 idling when hot with a 160 thermostat). I removed the thermostat and covered the fuel line with plastic wire loom. I increased the idle and run the timing more advanced. The engine now has about 800 miles on it. Today, for the first time in stop and go rush hour traffic and several traffic lights on a warm day the engine ran smooth the entire time. The gas used has the mandated ethanol blend.

I do not know if any one or a combination of the changes helped but it was nice not dealing with the issue today.
 
Did your thermostat have some holes drilled in the sides to let a little extra water flow through it all the time? Typical is maybe 3 holes 1/8 inch or a little larger in diameter.
 
That's interesting. I'm curious as to the benefit of adding a thermostat. I never really caught on to using thermostats in Model As because they restrict flow (not a good idea in stop & go traffic) and only serve to bring the coolant temperature up to some value sooner than without one (useful in modern cars with heaters). Once the engine produces enough heat to open the thermostat, the temps are really a function of power and how well the system can reject the heat. Insulating the fuel line probably helped the percolation problem by delivering gasoline closer to the bulk temperature of the tank. Glad it worked.
 
Bob K. St Paul said:
... I removed the thermostat and covered the fuel line with plastic wire loom. I increased the idle and run the timing more advanced. ... QUOTE]

Hi Bob,

Can you give details on the plastic wire loom? Thanks.

I know another Bob who's vaporization problem also seemed to end when he advanced the timing.

Steve
Click to expand...
 
You must log in or register to reply here.
Back
Top