engine bay hoses 1.8 L Jet, colors, arrangements etc Options

[wonkipop]

this topic arose in the thread concerning hose colors for D Jet cars.

i've started a new topic so it does not mess the other thread.

first thing to say is that the factory manual is more scant on L-Jet information than for D-Jet. There are no hose schematics with the clarity of the D-Jet layouts for the L-Jet. Secondly some of the information on the L-Jet is misleading.

First thing.

car 1974 1.8.

Green vacuum line from Distributor.
Seems to be the same as the D-Jet cars.

There is a green vacuum (retard) line out of the distributor body to the throttle body.
I think i am right saying its the retard side (sometimes gets dyslexic on that).

The green line in this photo is an original vacuum line. Along with the crankcase vent hose these are the only two lines i did not replace on my car. The crankcase line is moulded to an S - shape and we decided to stay with the original. its still sealing ok.
Same with the distributor line. We checked and still pliable and it was sealing so it stayed. We cleaned it up a little. I also left the intake manifold seals on as we did not go that far in - requires disassembly of the intake manifold. They are still in good sealing condition though looking a little aged.

There is a black vacuum (advance) line out of the distributor to the throttle body.

The green line from the distributor was the only colored line still apparent on my car.

[wonkipop]

second bit of information is that hose layout for charcoal cannister evap vapor system is incorrect on some diagrams floating around.

i've come across this before.

i believe the arrangement and design of the charcoal cannister changes at some point -
possibly when the cannister is moved into the engine bay in the 1.8 cars.

earlier cars had a charcoal cannister up front near the fuel tank.
the earlier design has the fan blower hose connected to the end of cannister along with the small diam tank expansion/fume hose. the hose to the air cleaner connected at the opposite end of the cannister.

diagram from factory manual showing early layout.
the schematic shows the fan blower hose arrangement.







the schematics for the 1974 (and later) 1.8 (and 2.0 L as well?) are from the emission warranty i have. These show that the arrangement of the cannister hoses changes.
The fan blower hose now connects at the opposite end of the cannister to the expansion/fume hose from the fuel tank and the air cleaner hose. this conforms to the hose arrangement in my car which i have never altered and i believe remains original.
i have replaced the hoses last year and simply copied what was there.

I have a view on this. I believe the original design did not work and the cannisters failed to purge during open road cruise driving. the blower hose was too long to push fumes back into the air cleaner for burning off. there is no valve in this very simple system. the charcoal is the valve. once it becomes saturated the hydrocarbon fumes escape to the atmosphere (via the fan hose or via the air cleaner after passing through the filter - in fact i can smell it in mine at the moment because i am sure the charcoal filter is saturated and the car needs a good run to purge it).

the charcoal filter cannister is located on the rear engine bay firewall in my car. which is a jan 74 build. i think it was shifted one more time in 74 to just beside the battery and stayed there until the end of production. i think they did this progressively to shorten the fan hose to make this system work. the hose plumbing is the same in both positions in the engine bay. i've looked at a few engine bay images to confirm that.

The hoses were dark grey/black standard hose colors on my car.
They had faded and have been replaced with new dark grey/black hoses.

starbear has already amended the diagram shown below for the charcoal cannister hoses in the other thread.