Engine identification Duetto

[Dave44]

Hello

I'm a new member. I've just bought a 1967 Duetto (I owned a 1968 1300 Junior Spider from 1977 to 1988 so know the cars well). My new car has ch.no. 105.05.710163 verified by Marco Fazio as manufactured 8 May 1967. It should, according to Marco have engine series AR 00536. It actually has 1750 engine (I knew this when I purchased) AR 00548 B2319. The gearbox is also 1750 but it has a cable clutch and 1600 bell housing. The gearbox is faulty and I discovered when replacing it with a recon. 1600 unit that the bellhousing had been modified (very professionally) with a sleeve so the 1600 shaft was too big for the hole (1750 gearboxes have a narrower shaft at the gearbox end). Easily solved with a used 1600 bell housing. The purpose of this sleeve is beyond me as it does not appear to assist fitting the narrower inner diameter 1750 oil seal and the 1750 shaft would have simply gone through the bigger 1600 hole. The gear lever is an early collapsing type with the mechanism disabled since the 1750 gearbox has the reverse protection plate. Can anybody tell me when my engine was manufactured? Fusi has no B prefixes and Willie R has suggested it could be 8 but there is a normal 8 in the 00548 (82319 would mean a 1970 engine according to Fusi). However, 2319 would be a 1967 engine and my thought is that it could be a factory fitment. Willie tells me a small number of 1967 "1600" Spiders may have had 1750 engines. The British government registration documents show the car as a 1750cc. Alfa Romeo GB London bought this car on 10 May 1967 and did not register it (for sale I suppose) until 24 January 1968.

Sorry this has rambled on. It's maybe a typical Alfa saga.

One or two pictures attached including from its back-to bare metal restoration in mid 2007.

[papajam]

Congrats on your purchase and welcome to the AlfaBB!

After perusing a number of Alfa published documents, I found only one document that references a prefix letter in the type 00548 1750 sequential engine number. The letter 'S' is referenced in Technical Service Bulletin (TSB) #04.73.2.2 dated 16 May 73 to indicate an engine thus stamped is equipped with an emcon (EMission CONtrol) system.
I could find no reference to a letter 'B' in a 1750s sequential serial number. This does not mean however that a B prefix does not exist, it simply means that I do not have any information on it.
The same holds true for 1750 engines being installed into Spider 1600s at the factory; it may have happened but I've no documentation to verify it.

If the letter B in your engine number is indeed the number 8, this would make engine 82319 a late Series 1 1750 (Series 2 engines [for the 1970 model year], according to Alfa Information Sheet (IS) #03.70.2.1 dated 21 May 70 start with engine #90001). If this is the case, then an engine swap has taken place.

[Dave44]

Dear Papajam

Many thanks for your reply. What you say is as far as I got. I have an enquiry in with the British license authority (DVLA) which might give information on pre-1986 ownwers. Somebody has told them at some point that it has a 1750 engine. It depends how complete their records are. Will post any further information.