Hello again Thank you for the added photo which make me wonder about the bronze float chamber. All factory pics I have seen have the common aluminium ones.
I have added a pic where the original L type manifold is in the middle twin 1 1/8" SUs. The three carurettor one is a KA manifold for three 1" SUs. The newish one is an Andy King alpine variety for twin more modern 1 1/4"SUs. In "Maintaining the breed " the development of this special manifold is described as consisting of moving the carburettors apart and introducing a taper in the pipework. I feel certain that if a third carburettor had been added that would have been mentioned.
So, a picture of your three carburettor manifold would be very interesting.
Hi Sven Thankyou for your kind and informative reply to this problem. Andy King describes this manifold for the L1. Clearly there are issues with it for my car. I believe my SU's are correct for this very early car. So I'll pass this onto my engineer and get back. Kind regards Nigel
If you look at the original and how the carbies are fitted, and compare it with the Alpine inlet manifold, then what is the advantage of restricting the centre ports of fuel flow with this manifold? Am I missing something here?
The top photo [Andy King] shows a manifold in the style of the Ntype. Wide separation with balance between. This proved successful with two 1 1/8 carbs. On my N I have the standard N manifold with two 1 1/4 carbs. It works well. Geoff
Hi all I think some part of the answer is better separation into the separate ports to make it easier for the gases to flow freely and easily into each inlet port.
I don't agree with the argument that the spacing, as per N type, by itself would be more efficient.
The Austin-Healey engine (I hope you'll excuse this excursion, but it was built at Abingdon) in its final form had the same spacing of carbs as the L type but with longer separate tracts.
Has anyone ever measured the flow on different manifolds?
I understand the set up but as Sven has said how efficient in flow terms is it? Although an improvement on the original inlet manifold there is no doubt the running would be improved further with the addition of a centre carburettor, and removal of the edges as marked in ea port to improve gas flow, which is what I will do. As the K type manifold has 3 carburettors that is what I would consider a very good improvement. The centre casting could be removed and a new flange welded on.