To: "Engstrom Par, Bergslag" <par.engstrom@bergslag.telia.se>
> hi, if you got the time i'm grateful for any picture
> of the emissioncontrol layout,snailmail/e-mail.
> i can view most picture formats of my computer,
> a discription would be nice aswell, cheers!
>
> par, falun, sweden, mgb -72, ford cortina gt -66, mini -67
>
> par.engstrom@bergslag.telia.se
> ----------
I will photocopy the page of the manual and send recent pictures of my
'71's emmision system via snail mail.
I recall Scott Fisher gave a good description of this once before...
ANYWAY.,,,
The emmisions system on the '71 MGB (US), and I think it is identical
to the '72 MGB, goes as follows..
Exhaust gasses are pumped out of the cylinder head via a copper header
pipe attached to an air pump (belt driven off the cooling fan pulley).
Gasses flow through the pump, mixed with outside air (comes through a
small air filter) and sent to a "gulp" valve. The "gulp" valve has a very
small vacuum line attached to the intake manifold (which actuates its
opening and closing, I guess based on speed) and allows the pumped air to
be gulped into the intake manifold via yet another line out of the gulp
valve. Any additional gasses which are not burned, or which acumulate in
the crankcase and do not come out of the head to the pump and re-burned
as above, come out of a breather pipe attached to the left (forward)
pushrod cover. The fumes from here are drawn into the carbeurators, an
additional air line entering the top of the float bowls on each carb. and
the third component... any fuel spilling or overflowing out of the float
bowls, or gas fumes primarily I suspect, are sent via a "y" header pipe
and a hose and metal tube to a charcoal absorption canister mounted above
the passenger footwell, in the engine bulkhead. Another fume/fuel
recovery line comes from the fuel tank area, there is a recovery canister
attached to a vent hole in the fuel tank top and is secured to the rear
right corner of the trunk (boot). This line also goes to the charcoal
canister under the hood (bonnet). AND FINALLY, a recovery line, larger,
goes from the charcoal cannister to the rocker cover, via a copper pipe
with a very small hole mounted to the rear reight corner of the rocker
cover. This allows these gasoline fumes to be drawn into the crankcase
where they would come out through the previous system, via the PushRod
cover vent to the carbs.... A closed but breathing system, actually as
Scott Fisher put it, quite simple really...
well, thus ends my '71 / '72 MGB emissions dissertation, partly c/o Scott
Fisher #1....I will post this part for others....
Correct me ya'll if I blew anything here....
POSTED FOR REF TO OTHERS. "non-tech chat" deleted.
CHEERS....
Jim Fink
'69 & '71 MGB's
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