return line to gas tank

[Shannen Durphey]

mrvette wrote:
> 
> Greg Hermann wrote:
> >
> > GENE--
> > >
> >  But I don't recall ever having an engine with intake and exhaust on the
> > same side of the cyl head,
> > >that's a very poor design rite from the get-go....
> >
> > Archaic, maybe--but I would hesitate to call an engine that will run 400K
> > miles (like a certain B-30 Volvo I have has) a POOR design. And if you have
> > not worked on any Volvo (pushrod), MG, Morris, Fiat (pushrod)
> > Triumph-Standard, Chevy (either stove bolt 231/261 or late model
> > 240/250/292) , Ford, Chrysler, GMC or IHC in line 6 cylinder motors in 35
> > years,, WOW!! Or maybe all that time was spent sniffing Fiberglass resin??
> > :-)>
> 
> Well first off I'm in America,  So I don't seemany of much you describe,
> certainly don't remember them and have never worked on them....including the
> American ones you mention...I been a V8 man from the get go...
> > >
Damnit, this is ridiculous.  98-35=63.  First Chevy V8 debuted in 57,
only 5 years earlier.  Do you really mean to say you've NEVER worked
on a Chevy inline six? You've been working on cars more years than
I've been alive, and I've seen plenty of inline sixes, and even I8's.
Hell, GM used I6 engines to 85 or 86 and Ford was still using them in
89.  Even early vette's had I6 engines.  Seems like every hotrodder I
know who's got any years at all tried to modify a single carb I6
intake for multi carbs.

> > >colder intake charges, both fuel and air, does make more power,
> >
> > Yes indeed they do, and for several reasons. One of which is no $%^&**((
> > bubbles in the *%&() float bowls/jets/injectors!!
> 
> at injector pressures you going to have a hell of a time boiling
> fuel.....period.....

No, No, No.  Get your self to southeastern MT, and you'll see
plenty of vapor lock problems.  Main culprits are Fords, but Dodge
runs pretty close 2nd.  And beyond a doubt, it happens in PFI
applications.  I worked on plenty, and I mean plenty, of them this
summer.  The fuel would vaporize in the fuel rail as fast as it could
enter, and the injectors couldn't purge it fast enough.  The rail was
so hot you couldn't touch it.  But guess what, system pressure on a
gauge was normal!  I could start them every time by releasing the
pressure test fitting and cranking the engine until the VAPOR blew out
of the line and there was enough fuel in the rail to cool it.  I'm a
competent mechanic.  Believe me when I say I diagnosed it well enough
to be sure
it was vapor lock.


and in a carb, assuming it is NOT suspended above a glowing
> red cast iron exhaust manifold in a close engine compartment,  will allow the
> fuel to blow off the top (hopefully down the stack) and the rest of the fuel is
> drawn into the jets from the BOTTOM of the carb.....anything less is poor
> design....period....
> ><snip>
> > >Modern stock engines run too hot anyway, those stat's are set at 195 to
> > >open, as
> > >a min engine temp. the fans in most cases don't turn on untill ~230 degrees
> > >coolent temp....that is WAY TOO HOT....good for EPA readings,  bad for engine
> > >longevity, seals, rings,
> >
ASK the guys who wrench in the dealerships day in and day out if they
see vehicles lasting longer.  Pickups and cars are being traded in
with 100Kmi or more, and after 5 years of hard use.  This is some
pretty tough country on trucks, and there are relatively few of them
needing engines before they're traded.  Not like it was a few years
ago.  And most of the engine swaps are because of lack of
maintainence.  I haven't seen a late model engine with anywhere near
the cylinder wear as the older blocks have.  And it's pretty unusual
for me to find a late Chevy pickup with an engine soaked from end to
end with oil.  That's a lot of progress from the old ways.  


<snip>
> 
> the fuel slosh problem is caused by my doing a DPFI system with that antequated
> Bosch patented pressure regulator device, requiring a return line,  thereby
> requiring a rate of continuous feed from the tank that allows the slosh problem
> and temporary line air suction to be a problem in engine operation...I
> personally have not found an adequate solution to the problem as yet,  but I am
> looking at a pressure modulated fuel pump electronically driven as to a
> possibility of solving that problem in MY '72 vette which came with a carb, and
> never had the problem to begin with.....

Baffles in the tank.  That's it.  The fuel could slosh away from the
pickup for short periods with a carb, because the fuel bowl could
cover it.  FI swaps require some type of baffle system to prevent the
slosh.  No reason not to run the return line, no need to modulate the
pump, find a way to put in baffles.

> >
> > Old Scotch (?) proverb: "If you ain't never lost, you ain't never raced,
> > mate!!" :-)>
> 
> I have lost a few, and even won a few,  not that I truely give a damn,  I'm in
> it for the tech fun,.....
> 
> GENE
> 
> --
Shannen