Combating engine vapour lock in SBC?
01-07-2005, 03:50 AM
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Combating engine vapour lock in SBC? My fathers SBC in his old Holden gets the odd case of vapour lock. It's a late 60's pre pollution car so no smog gear, no charcoal canisters etc.
Its only done it twice in 6 months and both times up hill, 1st time on a hot day and this time this arvo, was just nice and cool.
1st you notice it surge/hesitate on flats and then up hill it starts surging bad til it stalls and won't restart.
It is Vapour lock, once the pump cools down its fine again, but I need a permanent fix.
The Holden has no pollution gear, the engine is worked but runs a mechanical Edelbrock fuel pump off the motor and a single fuel filter after the engine mounted fuel pump.
I was told by mounting a return line it will cure this problem?
Is it just a matter of making a return line and geting a fuel pressure regulator and running a T piece after the reg back into the tank?
Its only done it twice in 6 months and both times up hill, 1st time on a hot day and this time this arvo, was just nice and cool.
1st you notice it surge/hesitate on flats and then up hill it starts surging bad til it stalls and won't restart.
It is Vapour lock, once the pump cools down its fine again, but I need a permanent fix.
The Holden has no pollution gear, the engine is worked but runs a mechanical Edelbrock fuel pump off the motor and a single fuel filter after the engine mounted fuel pump.
I was told by mounting a return line it will cure this problem?
Is it just a matter of making a return line and geting a fuel pressure regulator and running a T piece after the reg back into the tank?
01-07-2005, 10:24 PM
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Another fix might be to insulate the fuel line from tank to fuel pump. Also, make sure that the fuel tank vent is functioning and its vent line is working.
Found this searching:
Found this searching:
Here is my cure for vapor lock. As some of you know, I live in the hottest enviornment to own an older car not designed for the 125 plus Summers. I do not get vapor lock anymore and the cure was so simple. Since you want the metal lines found on the Imperial from the factory to stay, then what I do is wrap them in rubber hoses and tie wrap them on all of the metal lines. No matter where they are, but mainly in the engine department. I use either 3/8 or 7/16 ID hose. I slit it length wise, slip them over the metal line without disconnecting them. I tie wrap them at intervals where it will not come off. I turn the rubber so it faces the heat sources and the open slit areas away from the heat source. I add more ties where it curves so it will follow the curve of the metal lines. I have NEVER had a vapor lock in the last 16 years of desert living.
01-24-2005, 10:22 PM
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Another solution is to insulate the carb.from the intake by using a phenolic carb spacer (thin if you don't have hood clearance) these are the best insulators from heat,compared to aluminum and even plastic. Adding a fresh air duct to an enclosed air cleaner will also reduce vapor lock. Insulating the fuel lines is also a good idea.
