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.

[wonkipop]

emission stickers indicate that both engine versions are california + USA conforming and there is no distinction between EC-A and EC-B (more on that later).

tune-up stickers indicate there is a difference between EC-A and EC-B.

EC-B engines make use of both vacuum advance and retard feature of the distributor. (2 hoses shown disconnected)

EC-A engines make use only of the vac retard feature. (1 hose shown - on retard side and disconnected)

the vac cannister on the distributor is connected to the throttle body.
the tune up sticker implies -
a) a different throttle body for the EC-A with only a vac connection for retard.
b) a throttle body for the EC-B with vac connections for advance and retard.

the parts catalogue has the following information:


1. replacement engine.
two part numbers are noted for replacement engines up to EC0 037 551 (end of 74 MY). one for california. other for USA.






2. throttle body
two throttle bodies are noted for engines up to EC0 037 551.
one for california. other for USA.








3. distributor
only one distributor is noted for engines up to EC0 037 551.









4. ecu

the ecu for 1974 was a single unit for all 1.8s




neither the parts manual or the factory workshop manual makes it absolutely clear what the difference between 1974 USA/california models is in terms of distributor vacuum hose set up and throttle body appearance. nor does the parts manual link the differences it does indicate to either an EC-A or EC-B designation.
-----------------------


CARB (californian air resources board) EXECUTIVE ORDER A-7-5.
(information provided by member L-JET914

the executive order covers approval for the sale of 914 models in california.
it was first issued 29 Jan 74 for 3 months, then rescinded on 25th Mar 1974 with a further approval for 3 months and a further 30 days (to the end of MY 74).
the order also indicates that 74 1.8s were not available/approved for sale until jan 74 -
almost one third into the 74 MY.
the document makes it clear that the approval is for engine type EC-a.
the engine type has a distributor with only centrifugal advance and vacuum retard function (no vac advance function).
this document supports the EC-A as the california only engine (with associated parts) indicated in the parts catalogue.












member survey / advertised cars data indicates EC-A engined cars were sold new in california (established by original sale receipts / orders).
there was one exception (more on that later).
the same data indicates EC-B engined cars were sold new in the 49 states.

this does not explain emission stickers that do not distinguish between california and 49 states. there may be an explanation for that (more on that later).

however it would seem on the basis of factory documents, CARB documents and sales documents that the EC-A engines were california and the EC-B engines were 49 state.