Minor manifold any difference

[Hunsta]

Just a query. Is there any difference in using a two piece manifold for an 803cc and a one piece for a 948cc/1098cc on a 948cc engine. I know that statement may be self explanatory. But just asking.
Cheers
Craig

[philthehill]

There is no difference in utilisation.
The two piece manifold can be fitted with either a H2 or HS2 carb with the respective air filtration system.
I believe that the two piece manifold was produced to allow the fitment of the Zenith down draught fixed choke carbs as originally fitted to the Austin variant of the 'A' Series engines without having the expense of a specific one piece manifold for the Austin.
https://www.ebay.co.uk/itm/Classic-Aust ... Sw5FJa4f9o
Or you could say that the two piece manifold was produced to allow fitment of the SU carb as the 'A' Series engine was derived from an Austin design.
https://en.wikipedia.org/wiki/BMC_A-series_engine
The exhaust part of the manifold was the same on my 948cc A35 and 948cc Minor.
Later Austin 'A' Series used a common one piece manifold with HS2 SU carb which was the same as the later Minor.

[Hunsta]

Thanks for that Phil. Your a font of "Minor" information. LOL

Cheers
Craig

[Chipper]

I've used the exhaust manifold section (with blanking plate) of the 2-piece on my 1275cc MG Midget-engined Traveller for years, along with a HIF 44 carb on a Flowtech alloy inlet manifold.

I originally fitted it so I could fit the twin 1.25" SUs originally intended for a Midget.

Seems to work pretty well, and of course, allows the standard Minor exhaust to be fitted, to keep it looking stock.

[IslipMinor]

Is the bore of the 803 inlet manifold the same size as the 948/1098? The 803 uses an H1 SU (1 1/8" diameter), whereas the 948/1098 uses an H2 SU (1 1/4"), but were the inlet manifold internal bores different?

[philthehill]

Richard
You are right about the different sized carbs...…………803cc H1 carb Pt No: AUC704/AUC738 & 948cc H2 carb Pt No: AUC833/AUC852.

Quoting from the BMC parts manual.

The original part number for the alloy inlet part of the manifold was Pt No: 2A540 which was superseded with alloy inlet manifold Pt No: 2A718 until that was superseded in turn by the one piece cast iron manifold Pt No: 2A896.

See also:-

https://www.moss-europe.co.uk/shop-by-m ... minor.html

Phil