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can you fit a hs 6 su carb to an ital manifold
Posted: Mon Feb 16, 2009 4:39 pm
by lukedauvergne
exactly what the tital says i have some carbs sittin around off my old dolomite just wondering if they will fit to the ital manifold?
Posted: Mon Feb 16, 2009 5:16 pm
by Lukey
Posted: Mon Feb 16, 2009 6:02 pm
by lukedauvergne
how much does the hole have to be widened by and does it involve moving the studs to hold the carb on. how does it behave when driving?
Posted: Mon Feb 16, 2009 6:07 pm
by Lukey
It just needs to be widened by 45mm. I'm not sure, the carb and manifold haven't been used yet.
Posted: Tue Feb 17, 2009 11:11 am
by Kevin
Lukey wrote:My ital manifold has been widened to take a HIF6.
Well the Ital came with the Hif44 as standard so the manifold would be the correct size in the first place so an HS6 (1 3/4") will also fit with no opening out needed.
Posted: Tue Feb 17, 2009 4:25 pm
by bmcecosse
It should fit ok! Perhaps the manifold that needed widening (but hopefully not 'by 45 mm' (sic)) was ex Marina.
Posted: Tue Feb 17, 2009 7:04 pm
by lukedauvergne
thats great new thanks everyone.
Posted: Tue Feb 17, 2009 7:15 pm
by bmcecosse
Unlikely the needle will be suitable for an A series. Probably need something like a BDL although it depends what has been done to the engine.What size engine ? HS6 is a bit big for a 1098 - ok for a 1275.
Posted: Wed Feb 18, 2009 4:13 pm
by lukedauvergne
yer it will be a 1275 from an ital
Posted: Thu Feb 19, 2009 6:35 pm
by lukedauvergne
bit of a novice question maybe but what is the need to change the needle? i dont understand the inner workings of a carb:(? whats a BDL needle from?
Posted: Thu Feb 19, 2009 7:11 pm
by Peetee
The needle profile (amount of taper) affects the amount of fuel delivered as the revs rise. Every type and size of engine requires a different profile. You might find bolting on a HS6 results in worse performance than the previous carb because the needle profile is unsuitable.
Posted: Thu Feb 19, 2009 10:15 pm
by bmcecosse
The SU carb is a very clever design having a variable venturi which ensures a good highspeed air flow over the fuel supply jet. The car achieves this with a piston that is pulled upwards by the manifold vacuum, and the tapered needle is fixed to the piston and rises with it - thus metering the fuel to suit the increasing air flow. The BDL was used on the 1275 MG Metro and is a good starting point for any 'warmed up' 1275 engine.