Classic cars forum & vehicle restoration.

eddie · Joined: 07 Jan 2008 Posts: 14

Hi pals, I have just purchased a 1967 MK 111 midget with twin su carbs what I don't understand is there is no vacuum advance can anyone tell me why. Also can anyone advise how to set the carbs as the engine idles lumpy contact breakers are ok spark plugs are new I am not certain about the timing it is a 1.275 cc I could do with advice on how to set that .
Edd

Rick · Site Admin Joined: 27 Apr 2005 Posts: 22437 Location: UK

Hi eddie, welcome to the forum, I'll move this into the Restoration Tips and Advice category, see if anyone can help you out

cheers, Rick Smile

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peter scott · Joined: 18 Dec 2007 Posts: 7117 Location: Edinburgh

Hi Edd,

Welcome to the forum. When you say there is no vacuum advance do you mean that there is a diaphram on the distributor but you can't find a point to connect it to the manifold? Close-up photos might get more replies.

You might find this useful for setting up http://www.oldclassiccar.co.uk/balancecarbs.htm

Setting the ignition timing will be fairly straight forward and will be set out in something like the Heynes manual
http://cgi.ebay.co.uk/MG-AUSTIN-HEALEY-MIDGET-SPRITE-1958-1980-Haynes_W0QQitemZ220244145012QQihZ012QQcategoryZ36089QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

I know Haynes manuals aren't perfect but if you haven't got anything better then it would be worth investing in a copy.

HTH

Peter

pigtin · Joined: 23 Nov 2007 Posts: 1879 Location: Herne Bay

Hi Eddie,
I've recently been working on my Sprite and changed the distributors.

As you can see there is a diaphragm on the distributor and it should connect, by pipe, to the left of the left hand(front) carb, close to where it bolts to the manifold.

It will certainly run rough if this pipe is missing.

eddie · Joined: 07 Jan 2008 Posts: 14

Hi Peter, There is no vacuum unit on the dissi at all !! I.am baffled
Eddie

peter scott · Joined: 18 Dec 2007 Posts: 7117 Location: Edinburgh

Hi Eddie,

Is the body of the distributor designed to take a vacuum unit (like in pigtin's photo) but the unit is simply missing?

In some more modern distributors the body is a pressing rather than a casting and the vacuum unit just screws onto the side and a rod pokes through a hole to rotate the contact plate.

Another, most unlikely possibility Laughing

is that your car has somehow been fitted with a pre-war distributor that never had any vacuum control. (Not a serious suggestion) Wink

Peter

ukdave2002 · Joined: 23 Nov 2007 Posts: 4104 Location: South Cheshire

Hi Eddie and welcome

A vacuum leak in the induction system can often cause a rough idle, which if the hose is missing might account for both problems.

Dave

eddie · Joined: 07 Jan 2008 Posts: 14

Hi Peter,
There is nowhere on my dissi . for a vacuum unit to attach.
So where do we go now its beyond me !!
Eddie