-------------- Forwarded Message: --------------
From: keltro@att.net (Kelly Troyer) 
Subject: Re: ad plenum and cowl design
Date: Wed, 1 Dec 2004 16:48:29 +0000

 

> > >> Paul, over the last year there were few people complained about
> > >> dribbling injectors after shut down. I wander if it is healthy to have
> > >> standing gasoline in the plenum, which can happen in the one you are
> > >> showing? I'm thinking about the possibilities of a big BOOM! :)
> > >> I made sure my injectors and runners face downhill towards the engine
> > >> ports. On my engine also the original injectors were oriented to face
> > >> downhill. What do you think?
> > >> Bulent
>
>
> > > How does it help to face them down hill?
> > >
> > > Paul Lamar
>
> Matt Prather wrote:
> >
> > I'd rather have the gas stay in the plenum than soak/clean
> > the innards of the engine. If the fuel sits in the engine
> > there's a better chance of corrosion in the places where
> > the fuel washes the oil coating from the parts.
> >
> > In old CIS mechanical injection, leaking injectors were
> > one form of failure - replace when you find that. I suspect
> > modern injectors are the same.
> >
> > Regards,
> >
> > Matt-
>
    Group,

        One way to address leaky injectors ( a common problem with high

mileage RX7's ) is to put  a bypass between the pressure side of the fuel

pump to the fuel return line after the fuel regulator . A .020 +/-  oriface will

bleed off the fuel pressure (35-40 psi) after shutdown and prevent or

severely reduce leakdown and potential flooded start and/or the possible

washdown of lube from rotors and housings. As Mark Steitle has noted

previously this fix also provides a way to purge the lines of air after

running a fuel tank dry which causes a air lock in the fuel system . The

fuel pump has plenty of excess capacity to compensate for the slight

loss of pressure during normal operation. FWIW

 

Kelly Troyer