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]

VAPOR EMISSIONS CONTROL SYSTEM.

(aka the charcoal canister or how it is plumbed).

this has been debated previously.

refer here.

http://www.914world.com/bbs2/index.php?showtopic=347951

in summary owners of original condition 74 1.8s with the engine bay canister know it is plumbed in an arrangement contrary to some hose diagrams that have been published and in a manner contrary to 73 and earlier year 914s.

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the events of 1973 concerning the EPA case cast some light on the VECS (vapor emission control system).

the design of the system incorporated in the 1970-73 914s is in principle the same as the system used by porsche for 911 models from 1969-73.



in 1973 for 1974-77 years porsche revised the system for its 911 models.




note - the element that is altered is that a different end of the can is connected to the fan feed line.

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the schematic layout of the 1974 VECS is shown in the emissions warranty for the 1974 914 model. this emissions warranty came with a 1974 1.8 model.




the plumbing of the 914 1.8 hoses is consistent with the update porsche carried out for its 911 models for 74 MY.


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the changes to the VECS that porsche introduced for the 74 MY across its range brought the system into line with VW designs for the VECS that had been in place since 1969.







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the original factory installed plumbing arrangement of the VECS in a 74 1.8 is characterised by an S-curved hose from the fan feed port on the fan housing to the lhs of the engine bay mounted charcoal canister. the rhs of the can is connected to the hose from the air cleaner and the fuel vapor line.




note - this is only known to apply to 1.8 cars with the engine bay canister location update.


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the canister location update occurred between 20 Nov 73 and 28 Nov 73.
(refer schedule 2 at beginning of thread).
EDIT JUNE 2022. further example has come to light indicating changeover is either side of weekend 17/18 Nov 73.
refer page 2 of this thread for information/data.

cars before the update had the VECS cannister in the front trunk.


cars after the update had the canister in the engine bay.




note - it has not been established how the front trunk mounted canisters were plumbed.
the system may have conformed to the earlier porsche design for 69-73 MY cars.

EDIT MAY 2022 - further data has been obtained which clarifies the plumbing layouts for the front trunk mounted canisters and the engine bay mounted canisters.
This data has been entered on page 3 of this thread.
the frunk mounted canisters used the Porsche design earlier version of hose hookup dating from 1970 MY on. the engine bay canisters used the VW design for the hose hook up from approx Nov 20 1973 on.


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1974 914 1.8 HOSE LAYOUTS.

the engine hose layouts by Pete Klager and published on the Pelican Parts website are the most accurate diagrams.

the diagrams are for the 1975 1.8 EC-b (california version).



note -

for the 1974 EC-B engine the EGR is deleted (along with T connection to dist-T/B vacuum advance line). the position of the charcoal can is on the rear bulkhead of the engine bay instead of next to the battery but with the plumbing arrangement shown.

for the 1974 EC-A engine as above for EC-B, but additionally the vacuum line connecting the dist-T/B advance line is disconnected at the T/B. the T/B either does not have a vac advance port or the port is capped with a seal. the hose from the advance port on the distributor is tucked under the distributor and left open.

this has also been previously explained by Dave Darling more than 10 years ago.
DD noted there were two versions of the hose layout for L-Jets.
at that time DD had not made a connection between the layouts and the emission stickers indicating either EC-A or EC-B or that the engines may have been sales market determined variations.

EDIT JUNE 2022
final hose layouts for 1974 EC-A/EC-B are posted on page 3 of this thread.


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EC-A v EC-B

in principle it was (is) very simple to turn an EC-A engine into an EC-B engine.

simply connect the vacuum advance hose from the vac advance can on the distributor to the vac advance port on the throttle body (assuming the throttle body has a port).

and in reverse to alter an EC-B into an EC-A.

this may have been porsche and vw intention with the ambiguous emission sticker that stated both versions were USEPA and California conforming.

the adjustment may have been an easy matter for dealers to carry out (if the EC-A was fitted with a throttle body that had only a cap seal on the port).

it may have been a strategy to provide flexibility in terms of stocks of cars available for sale across the USA including California. given the delayed introduction of the 1.8 which did not it appears commence production until Nov 1973.

it is unclear how this would have worked in terms of annual emissions tests on vehicles.
CARB documentation implies that testers would technically have only had approval for EC-A stickered cars.

?