[alfa] RE: 164 up in flames

["Graham Davis" <grahamldavis@xxxxxxxxxxx>]

Jeff Matson wrote:

I noticed that someone mentioned purchasing replacement fuel injection
hose for $1.00 a foot.  This is either a really good deal, or may not be
injection hose.  I believe that SAE 30R7 is low pressure line
(carburetors, etc), and that SAE 30R9 is the high pressure fuel
injection line.  I pay over $5 a foot for this stuff at my local
discount auto parts place.  I would double check what you've got, as you
want the higher rated stuff for this purpose.

and Joe Elliott wrote:

I'd say that you're pretty lucky to have gotten 32000 miles out of
it.  That's the hose that's frequently blamed for fuel leaks in
European cars that are supposed to have 7.5mm fuel lines.  It's the
wrong size, and the wrong spec.  30R7 is only rated to 50psi working
pressure.  That doesn't give you shit for factor of safety.  If you'd
gotten high-pressure EFI hose (SAE 30R9) at AutoZone, you'd notice
that it's actually more expensive than getting it in the proper size
from a BMW dealer.  I don't mean to be an ass, but I've seen this
stuff installed on these cars, and even when it doesn't leak, it
deteriorates very quickly.  Even if it didn't deteriorate, I hate to
think what would happen if the regulator failed (not unheard of) and
the fuel rail pressure jumped over 50 psi.  (In case anyone cares, I
do feel safe using 30R7 in the wrong size for the RETURN line, since
the pressure isn't as great and there aren't any of those push-on
connectors involved.)

 Well gentlemen, seem I've touched a hot button, no pun intended.

Be that as it may, I did my homework on this issue.  On the L-Jet system
cars the injector and fuel rail barb necks measure 8mm dia. and the
shoulders (2 each) measure 10mm dia.  Obviously, 7.9mm I.D. hose works
for me along with several other Alfisti in our local chapter but as I
stated previously, if you are more comfortable with 7.5mm I.D. (.0157 in.
less) imported hose, by all means, buy it.  A primary issue regarding
disassembly is not to score the barbs with a razor as this can lead to
leaks.  The factory recommended method is to cut/burn thru the old hose
with a soldering iron.  A second but equally important issue is to
square-cut the new hose so the cup washers function properly.  Difficult
with a razor or knife; fast and easy with a cheap and proper
hose-cutter.  Motronic system cars use 8mm dia. steel tubing with a 10mm
dia. bulb on the end and crimp hose clamps so the only real issue is the
hose rating.  SAE 30R7 fuel injector hose has a working temperature range
up to 250 degrees F., a minimum bend radii of only 2.5 in. (important in
routing to the L-Jet cold-start injector; 30R9 min. bend radii is 3.75
in.), yes Joe a working pressure of 50 psi (and nobody is calling you an
ass) and a minimum burst pressure of 250 psi. (you can look it up).  The
maximum psi a blocked Bosch pump can produce is about 85 psi; a 3/1
safety factor which is well within my comfort zone and you must admit,
the price is right. 

On a lighter note, I failed to mention re. my Italian/international
Milano Verde the Sanden AC compressor (Japan but now manufactured in
Singapore).  Just didn't want to leave any country out. ;-)

Graham L. Davis

------------------------------------------------------------------------

Send and receive larger attachments with Hotmail Extra Storage.
--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided