Vintage Minor Register

Having had the carb rebuilt by Burlen Services, they claimed not to have any data on which needle would be fitted to a minor, so i said to just leave the one that was in it when i took it to them, however, now that the engine is complete, and with it's 12/12 cam, i suspect that even a standard minor needle won;t give quite enough of the flammable stuff...... anyone have any idea which needle would be better suited...... i'm thinking the 'M' type standard, or maybe 'rich' one....

???

SU General Information Sheets dated 1951 list the following:

1930 MG 850 c.c. - single 1·125" HV2 carb - Rich 1, Standard M.5, Weak M.6

1933 MG J2 850 c.c. - pair 1·0" OM carbs - Rich A.E; Standard D.8, Weak W.X.1

1933 & 1934 Morris Minor & Van - single 1·0" OM carb - Rich M.7, Standard M.9, Weak M.O.

Jet size and number for all three carbs ·090" , number 112

Ronald

This might be a good time to ask Halbe what needle is fitted to his very original Minor. It might be best to try the original needle and check the mixture and gas emissions when you next have the car MOT'd if you have not got access to an exhaust gas analyser.

I'll check my needle later today or tomorrow and let you know asap.

Halbe

Ronald
The 1930 MM Salesman's Manual states that the needles are: Standard - MR [none such needle exits and so this is assumed to be a misprint for M9]; rich - M and weak M0.

The MG M Type [according to 'MG Workshop Manual' by WE Blower] uses: standard M5 [or G2]; richer M6 and weaker - No. 2. HOWEVER, I plotted the needle profiles on an Excel graph and found that this info is also wrong insofar as the weak and rich needles have been transposed. To be clear then: M6 is weaker and No 2 richer than the standard M5.

As expected, No 2 provides the richest mix of all these MM amd MG needle profiles throughout the throttle range.

Needle type M provides a good average of all the six profiles and provides almost as rich a mixture as No 2 at max thottle opening.

I used type M when I fited a 12/12 camshaft 33 years ago but have recently tried an M9 again. I can't tell the difference, but my engine is now worn and tired.

I suspect that only a rolling road test will show the best needle to use - we would all like to know and so how about putting MT on one it will only cost a few hundred quid!?

Ken

Well done Ken, you confused the hell out of me, but that doesn't take a lot!!..

Oddly the needle that is in the carb at the moment is an MD, or maybe MO...... so lord knows where that came from!!

Rolling road.... Hmmm, Janspeed have one in salisbury, which ironically is smack bang next door to Burlen..... what a coincidence...!!!

What i really wanted was to find a needle that was roughly right to run it in on... cos what i'd like to avoid is it running too weak and getting warm.... i'm also considering leaving the fan off to see what happens.... hang on, i need to fit the engine first eh!!!..LOL!!

Thanks all!!

Hi Ronald
Sorry if I was not clear.

I should have mentioned the obvious - that the Minor and MG M Type have different size carbs and inlets - 7/8inches MM and 1+1/8 inches - MG M Type. There is therefore not a direct comparison one to another although the graphs I plotted of the needle profiles - diameter/distance along the needle - are interesting.

Use a Type M needle unless you decide to use a rolling road. In this case the technicians who operate these devices should make up their own needle profile to suit and so we will never know the nearest off the shelf match.

Who knows what difference modern petrols make to needle selection?

I advise running with a fan as without one your engine will be prone to boiling on long hills of which there are plenty in Dorset. I don't know how MG M Type Midget owners manage without one. I took mine off once a few years ago in Wales on a long run on a cold March day and all was fine until we hit a long hill...Otherwise my car has never boiled.
Ken

Ken & others

I have just borrowed a Bullnosed Morris data book which lists the carb needles for all the Morris's of about that time, I do not have it with me at the moment but will list them all later. The needle for the OHC Minor is listed as M.R - may be it is not a misprint but a special needle made for Morris. It will be interesting to see what needle Halbe has in his car.

My 32 sv Minor 2 seater runs rich. I have tried needles but to no avail. I have done all the adjustments but on the coldest days I can start the minor straight away with the coke out for only 2 seconds and she pulls away no bother, no need for the clothes peg. I am happy with the performance but only get 30 mpg. By the way the plugs are not sooty. What mpg do you boys get? Alister.

Hello everybody,

I think i have the M9 Needle ( see picture ), but see for your self



Would you let us know what is going to be your set up?

Regards Halbe

VJ has an M9 fitted or is it a 6W?
Chris

Re: Highlanders mpg problem. Do you have the right weight of piston? I have several and they are all different.
Ian

Interesting point, the 1951 SU General Information Sheets list the following re Suction Pistons

1933 MG J2 850 c.c. - pair 1·0" OM carbs - suction piston no. 1381, material ZINC

1933 & 1934 Morris Minor & Van - single 1·0" OM carb - suction piston no. 3166, material BRASS

presumably the brass piston is heavier than the zinc one

The 1930 MG 'M' Type 850 c.c. - single 1·125" HV2 carb - suction piston no. 3169 material BRASS

Most other MG models 1930 to 1949 are listed as having brass or aluminium pistons and all Morris models from 1933 to 1951 either brass or aluminium.

We have a good stock of new M needles if anyone is in need. Looking at Ken's posts, this looks like the rich needle for Minors.

Well, today i decided to start removing the old engine, and the first thing i did was check what needle was in the current carb, it's an M5, so i'll either use that, or get an M from Ian....... whe he gets back off this trip thing he's on.....