<VV> Help for Vapor Lock

[Bill Elliott]

>I too would be interested to know what problems an electric fuel pump
>will have making it worse than the mechanical? My '64 has an electric
>pump, right up front under the floor near the fuel tank (a common and
>oft suggested location). Only had it a couple months, but have driven
>it daily since with no troubles (not to mention about 800 miles getting
>it home when we bought it).  I have heard/read nothing but good things
>for electric pumps and had the car not come with one, I would have put
>one on. It does have a nice pressure regulator back on the engine, and
>all is well. Should it act up, it's easy to diagnose, easy to replace. 
>It will virtually eliminate vapor lock. And installation of a hidden,
>key operated cut off switch made a cheap theft deterrent, AND a handy
>way to disable it when working on the car when I want the ignition key
>on, but the pump off.  Can't thnk of a real drawback. Heck, everything
>made the last many years has electric pumps in'em, and I've had 'em in
>many other vintage cars with no troubles.


I wasn't going to post on this subject, but you've pretty much thrown down the gauntlet. (VBG)

OF COURSE modern cars have electric pumps... they are all fuel injected and mechanical pumps are limited to a few PSI. To get a real comparison, you 
need to look back at the last cars with carbs and whether they had electric or mechanical pumps from the factory.

I think you'll find that most had mechanical pumps... because they were cheaper, quieter, more reliable, and safer. 

I've found that to be the case as I've replaced MANY more electric pumps than I have mechanical pumps. 

There are many things to break down on electric pumps (especially older electric pumps) and far fewer failure points on mechanical pumps. Add a pressure 
regulator and you've added another failure point (I've replaced almost as many of those as mechanical pumps as well). Add in all the extra switches you 
mention (built to overcome the inherent problems) and you add cost, complexity, and additional failure points.

Mechanical pumps don't keep pumping with the engine off (and/or the car upside down). Mechanical pumps don't provide too much power and overwhelm 
the carbs. Mechanical pumps don't suck up juice from a dead electrical system allowing you to run much further on the battery alone. Etc. Etc.

Note that I'm NOT saying that a well-designed and well-installed electric pump is a BAD idea on a Corvair... quite the opposite (though all of my street 
Corvairs run mechanical pumps). What I AM saying is that mechanical pumps AND electric pumps both have their inherent disadvantages and you ignore 
those at your own risk.

Bill