QUOTE(lesorubcheek @ Jan 20 2022, 04:58 PM)
One change that is referenced in the PET for 1974 was the brake pressure regulator. The PET calls out VIN 4742915751 as the changeover point. No idea if the other changes listed have any correlation with this VIN.
Dan
no. its not to do with that vin.
and much as i respect dr914, its not a start of jan 74 thing either.
at least for some of the changes.
the charcoal can shift (for 1,8s) is between vin 09104 and 09760 - which dates at between 20 and 28 Nov 73.
the 2 different 1.8 hose set ups for dist advance and retard has nothing to do with a changeover at a date. california cars from the start are no advance hook up, 49 state cars are advance and retard hook up. that was established beyond a doubt.
the documents which clarify which are which are houseed in the CARB (california air resources board) archive. one of our members here L-JET914 found the documents.
production of 1.8s does not commence until very late october 73.
i'm not sure whether that was well known. i'm guessing knowledgable folks here already knew that. from august to late october 73 the factory produced 2.0 L cars exclusively it would seem. possibly euro spec 1.8s were produced before late oct 73.
as to other changes.
some folks have the dates for things like petrol tank change to plastic.
silver versus black dials.
i think mr. b (jeff) has a handle on quite a bit of it all. i would agree with his view that its more random and the changes don't all happen at once at or around one date.
all we 1.8 owners found to add to the information was.
1) a narrowing down of the window on the charcoal can to a week in november. (this date may have already been pinpointed by dr. johnson - i don't have his latest edition of restorer's guide to see what he said). that change seems to occur just after the factory commenced production of 1.8s in oct 73.
2) documentation that confirmed there were two types of EC engines.
An A and a B. simultaneously produced. one for calif. one for rest of USA.
this cleared up the mystery and debate around hoses that occurred a decade ago.
additionally members had access to information that said where cars had been originally sold new. this confirmed that there was one vac hose set up for cal cars and the other for USA.
what we found is all in that thread i linked.