Technical 1108 carb jetting

[firstcar-Y10]

query for any clued up techy types. Got an 1108 carb FIRE engine out of a mk1 but at the minute I have 3 carbs and a selection of jets lying about, mostly I think off 999 engines. So, does anyone know the correct jet sizes for the 1108 and is there any difference from the 999???

 

[Ucof]

All I can find in the Haynes is (from chapter 13.73 in the Mk2 Red manual):

"The Bosch Mono-Jetronic fuel injection system fitted to the 1372cc ie engine and later 999/1108 'FIRE' models is an electronically-controlled single point injection (SPI) system."

To me, that sounds like the 1108 and the 999 injection systems are exactly the same, so jets *should* fit between them.

However, this is entirely an educated guess based on my interpretation of what it says!

 

[firstcar-Y10]

thanks for the response. It's a carb'd engine though not injected, not many carb 1108s about. Just wondered if anyone had pulled one of the carbs apart. been having rough idling problems and boring out one of the spare idle jets slightly has smoothed it right out, just wondered if the rest were right or if I'm still looking for an air leak further down.

 

[Louie Bee]

All I can find in the Haynes is (from chapter 13.73 in the Mk2 Red manual):

"The Bosch Mono-Jetronic fuel injection system fitted to the 1372cc ie engine and later 999/1108 'FIRE' models is an electronically-controlled single point injection (SPI) system."

To me, that sounds like the 1108 and the 999 injection systems are exactly the same, so jets *should* fit between them.
QUOTE]

Hell no, the The Bosch Mono-Jetronic fuel injection system was fitted to loads of cars as the use of carbs was phased out in the UK, so has many options.

Don't think the MK1 Uno ever came with the 1108 but perhaps the errly MK2 with carb here.

 

[Ucof]

Good points.



All I can say was that it was early morning posting...

 

[Chas Uno]

I'm away from home at the moment so I can't check my Haynes manual for details, but I do know the following:

The carburettor fitted to 999cc and 1108cc FIRE models are the same in terms of physical venturi size but there are subtle differences in jetting. The Haynes manuls gives details of which jets are different. Both sized engines will run with either carburettor, though for optimum efficiency the correctly jetted carburettor should be used. If you have access to a mk2 Uno Haynes manual you can find the details of the 999 and 1108 jetting in the supplement section, near the beginning and in the fuel system specifications part.

Louie is right in mentioning that the mk1 Uno never had the 1108 FIRE fitted as standard. 1.1 Uno 60 mk1 models used the older 1116cc Lampredi whereas 1.1 Uno 60 mk2 models used the 1108 FIRE engine.

Hope this helps!