1275s carb question

[ateichert]

I am just getting started on my carb. recondition and found out they are off a 1275 midget aud327 carbs and 12g1451 manifold. Can I use this setup? It has been 20 years since I ran the engine so I don't remember how it ran.
Thanks Mike
1961 Austin Countryman
Folsom California

[Peter Laidler]

Too little info Mike........... So far as I can tell, with the limited info you've provided, you can't use the upright inlet manifold for a start. It's got to (?) be the angled inlet manifold. Are they 1.25" SU's. If so, then, basically, yes providing that they are needled to suit the application

[johnv]

You also need to change the float chamber washer things to 30 degree ones

https://sucarb.co.uk/float-chambers-sp ... 11203.html

[surfblue63]

What engine size is your Countryman. If it is the stock 850, then twin carbs from a Midget might be a bit too much for it.

[Peter Laidler]

Here, here....... +1 to Surfy above

[ateichert]

Sorry about too little info. My car is a 61 "internal tank" Austin Countryman.
'Yes they are HS2 carbs. The engine is a 1275s from 69-70 or so. It was in car when I got it.
Are all HS2 carbs created equal? Should I try to get a proper manifold? If I order a rebuild kit will it have the correct float camber spacers "ie" 30 degree? And what needles should they have?
So many Questions.
Thanks Mike

[Peter Laidler]

Thinking on my feet, I don't think that the rebuild kit will have the float chamber alignment thinggies. BUT......., as I seem to recall, you can change them over, left to right and carefully cut out another recess that will allow the float chamber to sit at the right angle - but don't quote me!

There are many little variations of the HS2 carb bodies, including left and right handed of course, but these little things can all be overcome if you're not an originality fiend. As for what needles you want...... That's best left to the bloke setting them up afterwards.

You've got to get the angled manifold

[1071 S]

Just to clarify... your Spridget carbs will work fine with your Mini engine.. They just won’t fit in your Mini.

The Mini manifold is “bent” upwards so that the jet mechanism will clear the cross member that runs behind/below the carbs.

And, having tipped the carbs up you need the fitting adjusts the float bowl back to the horizontal.

Needles and springs are another matter in that they need to be the “correct” ones for your particular engine.

Cheers, Ian

[surfblue63]

Here's a link to the spec of the 1964 to 1970 HS2 as fitted to the Cooper S models. If your engine is a standard S type then it would be a good place to start with needle and spring choice.

https://sucarb.co.uk/carbspec/carburett ... s/id/1721/

This is a link to the full spares list which shows the float chamber adaptors.

https://sucarb.co.uk/carbspec/carburett ... s/id/1721/

This is a reproduction of the inlet manifold that you will need.

http://www.minispares.com/product/Class ... EG488.aspx

[ateichert]

Thanks all, The last entry about "they not fitting my mini" would explain the "modification" A previous owner had made to the cross member "bashed in a Bit" This Car has been a very long project and not even close to being done. Had the new wood sitting in my closet for 2 years. I am great at buying parts, just a little slow at installing them.
Thanks again for all the replies.
Mike
Folsom CA

[iain1967s]

My previous thread may be useful.
viewtopic.php?p=204220

[ateichert]

Great post Iain. A couple more questions.I am a MGB guy and have done a lot of carb work on them. I noticed in one pic. it looked like there were spacers (plastic) between carbs and manifold. Does the mini setup use spacers? Also I have the oil separator on front tappet cover, my original (Midget) carbs each have crankcase breather tube ports. I noticed a Smiths PCV valve. Should I run one and cap the port?
Again Many Thanks
Mike

[Peter Laidler]

Great reminder article Iain and worth reading again. I bet that there's quite a few Cooper and S owners - including me - with a spare set of carbs just waiting to be rebuilt.

[iain1967s]

The ‘plastic’ spacers are made from a phenolic resin. They act as a thermal barrier between the engine and the carbs.

I think it is mainly to avoid heat soaking back from the head after switching off the engine, so the fuel in the float bowls doesn’t vaporize.

Earlier cars had aluminium rather than resin spacers, but they were less effective. A spacer is nearly always required on a mini to avoid the carb linkage from hanging up on the manifold and jamming open at wide throttle.

The PCV/clacker/gulp valve is optional, it’s really for emissions control to have the carbs scavenge bypass gasses from the crankcase, and needs to be used in conjunction with a vented rocker cover cap not a sealed cap.

You can also vent the crankcase to atmosphere if you prefer - pre 1966 all minis just vented out the crankcase down into the airstream below the front subframe. Or you can connect it up directly to either a carb breather port before the butterfly, or into the air filter box, both schemes were used at different times during production. If both carbs have a breather port, either use just one and cap the other, or better connect them with a Y piece as they did on the mk3 S.

Don’t connect the breather directly after the butterfly, e,g. to a manifold port, without also fitting a PCV valve to prevent the mixture from weakening. Else you could end up melting holes in the pistons if it sucks in too much air when the engine is loaded.

[ateichert]

Just one more question, What about overflow tubes? I have not seen any pictured or listed in parts books.
Thanks Mike

[ateichert]

Ignore my last post. Just looked at carbs. Float lids have no overflow ports. Like I said before, I am a MGB guy
Thanks Mike(wanna be a mini guy)

[ateichert]

Ok, Here is another question concerning fuel lines.The front carb float lid has two places for fuel lines to connect lines to and the rear only one( just like a MG). Looking at fuel piping and hoses for twin HS2 it shows a pipe(12a284) that only requires one connection at each float lid. Which is correct.
Thanks Mike

[iain1967s]

For a Cooper S the fixed distribution pipe 12a284 is ‘correct’. But either will work - for your setup just connect the second fuel inlet pipe on the front carb using a flexi hose to the fuel inlet pipe on the rear carb, per my photo. http://mk1-forum.net/download/file.php? ... &mode=view