Another Weber carby question...

Hi Everyone!

I am starting to look for some nice triples for my car and there are a few things I can't seem to find any info on:

-When I am looking at a casting number on a Weber there are 2 bits of info, one is the type of carb (ie 45 DCOE9) but then there is a serial number or something below it (see circled area in photo). I know the numbered suffix of DCOE (ie "9") has to match, but are there are rules related to the second numbers (should they match or be in succession?)

-Secondly, will 45mm DCOEs be okay on my mildly worked L28? The car is mostly street driven but will be seeing sprints and motorsport in the future. I don't mind changing plugs every few months but obviously reliability and the extra hp would be good too

Thanks, Alex

Great info, thanks Dimitri!

Anyone else?

I don't believe they need to have sequential serial numbers. Mine don't, they're not even all the same model! (two are type 52's and the third is an 09 or something)  I don't think it matters.

Having said that, mine aren't running yet (I'll let you know on Monday 

Keep in mind too that the tops are interchangeable with some other models (as long as they're all 40mm or 45mm etc) and seeing as how easily the mounts for the pin the float swings on can break, there's no guarantee that they're correct on a second hand pair.

weve covered this heaps of times, and for a mild-stockish L28 you should stick to 40dcoes & not 45mm. its wiser to choke & jet-up 40's rather than choke & jet-down 45's.

There is heaps of literature which gives you the maths for literage V's choke size. always start with a mild recipe for a mild L28....ie 40mm carb with say 32-34mm chokes and say .25 mains. start lean and dont drown the carbs.

We have covered this heaps of times you are correct... and the outcomes of those discussions are still conflicting in opinion (yes I did search). In addition the literature I have in front of me is a book titled "How to modify your Nissan & Datsun OHC Engine", and for an L28 they recommend 45mm throttle bores ie a 45 DCOE.

For my current set up I will be using 40mm Webers as I agree with you however given the cost of the exercise to move from 40 to 45mm DCOEs I thought I would double check first.

i have seen the benefits of the bigger carbs on Roberto's L28 ,it had more torque from 2000 rpm all the way to the top of the rev range and the 40mm carbs max out at 260hp atfw with 37mm chokes and the 44mm carbs had 39mm chokes, power was up in all areas over the 40s, this motor was for a streat car with a high lift 72 cam and 10.5 comp with the best head you can get power with the 44s was 283hp ,