weber jetting advice need please

S

smudge2031

Well-Known Forum User
hi, just wondering if anyone can give a starting point on idle, main jets etc etc .

my engine spec is l28, flat top pistons, e88 ported head ( Kevin Irons) and triple weber 42's.

compression ratio 11:1

Before anyone asks why 42's...got them very cheap!

thanks for any help
 
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smudge2031

Well-Known Forum User
yes there are 42 DCOE 8...pretty rare and worth a bit to be honest...i think they were used on Aston Martins and Jag's maybe......a good find
 
jonbills

jonbills

Membership Secretary
Site Administrator
I'd recommend this book - should help with initial jetting. Prob something like 36-38 chokes, 140 main, 50 idle.
Will you be getting it setup on a rolling road?
 
richiep

richiep

Club Member
jonbills said:
I'd recommend this book - should help with initial jetting. Prob something like 36-38 chokes, 140 main, 50 idle.
Will you be getting it setup on a rolling road?
Click to expand...

I'm guessing Jon meant this book!

https://www.amazon.co.uk/Build-Power-Dellorto-Carburettors-Speedpro/dp/1903706750

I've got this and it is very useful for understanding what is going on.

36-38 chokes though... isn't that rather big for a road car? I'm not sure 40 DCOE or similar size carbs (e.g. Dellorto DHLA) can even take larger than 36mm chokes (maybe 42s can though)

My L28 with ported head, 87mm Pistons, stage 3 cam has 32mm chokes in DHLA40s. Going big can sacrifice low end torque.
 
jonbills

jonbills

Membership Secretary
Site Administrator
Thanks Richie, that's the one
I think 32 is prob on the small side - I've got 39s.
I think that book would come out with 37 or 38 if you're expecting to rev to 7k.
 
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