Hey Guys,
Yep, as usual the story is more complex than simple... Wouldn't you
think I'da learned by now to give plenty of details when answering...
My post stating that SU's were the "normal" Plus 4 carb is, I believe,
correct. The inference that (Zenith-)Strombergs were, therefore, not
"correct" is an overstatement. Jim G.'s statement that << ALL +4's from
1964 to eaily 1967 had the 175CD Zenith carbs from the factory. >> is
wrong.
I am again reminded that it always pays to check a couple of references
when dealing with Mogs...
A quick look at the "Morgan Four Owner's Workshop Manual," which covers
four cylinder Mogs from 1936 to the end of production of the "real" Plus
4's, reveals that "All TR engined Plus/4s (sic) except the Super Sports
model have been fitted with twin S.U. carburetters EXCEPT for a short
period when Stromberg-Zenith (sic) units were utilised." (p. 55, para
2:15, emphasis added).
No less than our own Fred Sisson states in the Morgan Bedside Reader (p
27, para one), "Through the years the common carbutetor (sic) on Morgans
was either a Solex in the very early years or SU ... which was
introduced on the TR engines and continue through the carbureted +8s."
The balance of Fred's carb section discusses mainly SU carbs with a
short bit on Webers (fitted to the SS at the factory) and a passing
mention of Holley (which is sometimes fitted to Plus 8's in the
aftermarket). Fred makes no mention of tuning the Zenith-Stromberg carb.
The Plus 4 operator's manual (doubtless still available from The Works)
contains info on both the SU and Zenith-Stromberg carbs.
Incidentally, in re: TR engines, the current Haynes manual for SU carbs
lists model H4 for TR2 (1953/55), model H6 for TR3, TR3A, TR4
(1956/62), and model HS6 for TR4A (1965/66 and 1968, note differing
spec numbers for US and UK applications). I note that the manual does
not list an application for the years 1963/64.
It might be interesting to hear from Listers as to how many of their
Plus 4's are fitted with factory original Zenith-Stromberg carbs. I
would suspect not many and those are most likely in the years 1963 and
1964, the years that David and Jim G. are most interested in. I would
not, however, be really surprised to find some scattered in the other
years because... Well, it is The Works, ya know!
Am I correct in my belief that the 4/4 guys don't have this situation?
Is the Solex pretty much the 4/4 carb, at least through Series II?
At any rate, my advice to David remains the same: Sell the car. (The
questions only get tougher from here on out...)
--Colin Cobb, Las Cruces, NM, USA
'66 Morgan Plus 4 Four Seater, RHD (with twin English spec SU HS6 carbs)
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