1974 914 1.8, the mystery of the EC-A and EC-B Options

[wonkipop]

i'll be dropping the information we have gathered over Dec 2021 in with a set of posts.

the material was prompted by mr b ( @JeffBowlsby ) who observed that for the 74 MY there was an EC-A and an EC-B engine. mr b's thought was that the EC-A was a 49 states car and and EC-B was a californian car for emissions.

mr b's view was rational and reasoned. 73 EA engines are 49 states. 73 EB engines are california. 75 engines are documented in factory literature as EC-a (49 states) and EC-b (california). the logic should follow?

BUT

as per the mystery of the 914, the truth about 74 1.8s turns out stranger than fiction (or common sense?).

the material is not necessary to running a 1.8 or having fun with a 14. (IMG:style_emoticons/default/smile.gif)

its for historical purposes and as information to 74 1.8 owners to assist with restoration if they want it.

[JeffBowlsby]

Niiiice. I see that architects hand... (IMG:style_emoticons/default/drooley.gif)

Was the EGR system an overlay to this system for the cars that had it or integrated with it?

[wonkipop]

Niiiice. I see that architects hand... (IMG:style_emoticons/default/drooley.gif)

Was the EGR system an overlay to this system for the cars that had it or integrated with it?

i did them in the style of your drawing of the 2.0 (IMG:style_emoticons/default/beerchug.gif)
a nice way to spend a wet and very cold sunday.
dusted off the drawing board. good to get away from the CAD screen.

the EGR for calif in 75 was more an integration rather than an overlay.
it used the TB of the 74 EC-B to operate the EGR vac valve and it fed the recirculated exhaust into a line that replaced the PCV valve hose with a Y branch metal tube fitting.
tells you that the EGR only operated with engine vacuum at steady state part open throttle - ie cruise. to some extent the 75 with EGR (calif) was mimicking the 74 EC-B (49 states car) with vac advance, going for fuel economy and cooler running at cruise.

the 75 EC-a 49 states was virtually identical to the 74 EC-A Calif except that the decel vavle was of a different design.

which i think explains the mystery of why VW use the upper case A in 74 and lower case in 75. it had us confused if you recall when we started this research last year. you know - how come the 49 states car in 74 was a (B) and then a (a) in 75? similarly the 74 calif is (A) and then a (b) in 75? initially we were all thinking why would they not be consistent using the A and B classification and would apply it to the state/territory the car was equipped for.

In an odd way they are consistent.
if you consider that the 74 EC-A goes on to be the 75 EC-a and its the layout that is consistent - it just happens to be it fits calif regs in 74 and then complies with 49 states in 75, to more or less the same design.

and if you squint with one eye, the 74 EC-B (49 states) kind of goes on to be the prototype of the 75 EC-b (Calif) with the vac advance timing function on distributor transformed into an EGR operated by the same TB port and with the EGR bringing the same benefits in a different way (and more expensive way) as the vac advance.

if that makes sense.
i think its the best explanation for why the A and B classification get swapped around from 74 to 75 and is altered from upper to lower case.

(IMG:style_emoticons/default/confused24.gif)

i could probably do some diagrams for 75 if there is another very cold and wet weekend this winter and i need to sit by the heater rather than drive my 914.