On 2/11/05 2:39 PM, "Paul" <sqpilot@bellsouth.net> wrote:

>
> ----- Original Message -----
> From: "Ernest Christley" <echristl@cisco.com>
> To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
> Sent: Friday, February 11, 2005 12:24 PM
> Subject: [FlyRotary] Vapor lock
>
>
>> I'm not sure that I understand vapor lock completely.  Is the problem
>> that the fuel gets hot, or that the fuel boils and then the pumps no
>> longer work?
>>
>> I have a plan for a stone cold simple fuel system.  With only one tank
>> positioned high, I plan to put both fuel pumps directly under the tank
>> which is located behind the cabin (tractor configuration).  Position the
>> fuel regulator beside the pump, and I will only having a single line
>> running out to the engine compartment.  Think of it as one LONG header.
>> The issue will be that the fuel will not 'circulate'.  What goes out to
>> the header at the engine will stay there till it gets used.
>>
>> Is this a prescription for 'vapor lock', or will any boiling fuel simply
>> get blown through the injectors?
>>
> Hi, Ernest....I might have it wrong, but I seem to recall that I was told to
> put the fuel pressure regulator just AFTER the injectors/fuel rail. That's
> what I did...maybe that's part of my problem?  Paul Conner
>

Paul is right and another thing. I have my filter before the pumps. You
don't want any junk or water getting to the pumps. Also if any contaminants
are in the fuel, you'll be forcing them through the filter. If you get
water, the pumps will beat it into emulsion and most likely push it pass the
filter.
Buly