Hey, just a few questions about the carbys fitted to 105 series Alfa Romeos. I know these cars came with Weber, Dell`Orto or Solex Carbs. I've heard in many places that the Weber carbys are better, but just how bad are the others? I've heard some good things about the Dell`Ortos, but I've heard that the Solex carbs are not so good. Why is this?
Secondly, how different is the jetting between engine sizes? For example, if I was to use the carbs off a 1750 engine on a 2000 engine, how well could I expect it to run without changing jets?
Cheers, Gab
I personally prefer the Dellorto's. However many prefer the Weber as they were more widely used and parts availability better. None of them are "bad". They all have their shortcomings.
The 1750 carbs could possibly have smaller chokes. Fitting these carbs to a 2000 would cause the mains to come on a bit earlier and top end power would be down a bit given the excessive throttling losses caused by the smaller chokes.
Although "slightly" undersized chokes is not a bad thing - keeps the air-speed up a bit more. If its a road car, why focus on top end power at the expense of drivability.
Solex side draft carbs have a 2 piece shaft between the butterflies that requires extra effort to sync. In short more maintenance. Sounds like you have a 105 2.0l with perhaps carbs that have seen better days. If I wanted hassle free ownership I would buy 2 new 42DCOE Webers from the UK dealer set up for the 2.0l 105.
Solex have no throttle shaft bearings: just direct into the body and are usually flogged out and leak, with no ability to replace any bearing/seal.
Weber and Dellorto function about equally well, but Webers are more parts availability friendly.
1750 and 2000 have the same basic set up with choke sizes (both 32) and most other basic parts. The 2000 models have slightly larger jets etc., the sizes for each found in workshop data. Jets are easily obtained and changed.