I'm sorry that you have experienced so much trouble with these carbs. It's not like you bought a piece of cutting-edge technology with teething troubles to sort.
I bought mine from Mini Spares and was impressed with the quality of machining and general finish, assuming they all come from the same source.

And it is good to try and support local businesses but I found the comment from Midel that 'you might have to work with it a bit' to be an appalling excuse. Does Midel have the same attitude to the metering needle profiles - are they really all the same and it's the customer who has to work with it a bit?

It is worth sorting/rebuilding the new carbs now you have the car running with the old ones.

The supplier has contacted SU Midel in UK again with my quality control issues, who have advised the carbs be sent to SU Midel for inspection.
Other than the issue of the car not starting with these carbs, the RH carb operates fine. However the piston in the LH carb does not drop sharply, even without the needle and the damper attached. I have sent them off this afternoon, hopefully SU Midel can find a simple solution.

Thanks for the support
Regards Fritzie

HI FRITZIE
Adam from MIDEL came over today and we put your carbies on a motor on the dyno.
Fired up instantly and ran perfect. The only thing we found was you left the jet tube undone so fuel just poured out.
Adam has a video of it starting up and running. Check how you are setting them up as the carbies are fine.
Graham Russell

_________________
"It's better to be not informed than ill-informed"

Good news that Adam and Graham have taken the time to analyse your issue and eliminate possibilities. It's knowledgeable and willing people like these who make the Mini scene a better place.

Do you have breather tubes on the carby bodies? If so are they connected to anything or just blocked off? That may be your problem. The tubes on the NSW Police spec HS4's are part of the crankcase ventilation system. While the standard Cooper S with HS2's have a PCV connected to the inlet manifold the HS4's use a system called CCV (carburettor crankcase ventilation) whereby the rubber tube from the oil separator on the back cover leads to a Y piece with smaller tubes going direct to the carby bodies.

_________________
ex-NSW Police 1970 MK II Cooper S
VMCI #43

Thanks Graham and Doug,
Adam rang me this afternoon and we had a good discussion. He told me about the jet tube being only finger tight. I did not think that I had undone either of them. Maybe I did and had a senior moment.

After I could not get the car to start, I was really critical of the tolerances and could not the pistons to drop to my liking, even without needles attached. Once I had taken the carbs off the car, I tried all sorts of things to see if I could sort out the problem. My main issue with the carbs was the LH carb. which was sticky and would not drop with a distinct clunk.
I must admit that by the time I sent off the carbs the LH carb was starting to drop more freely. Maybe it just needed a bit of work to free it up.

Regarding the overflow pipes and CCV tubes. My old Hitachi SU's have overflow pipes and I just transferred them onto the new carbs. These just outlet to free air. With the Hitachi's I never used a PCV or a CCV setup and just used a filter on the hose end.
When I installed the new HS4's, I first set it up with hoses attached to both carbs. I also tried with the tubes blocked off.

There is one thing that I wish Graham and Adam tried, but it may not have made any difference. The carbs were tested without damper oil. With SAE 20 oil, I found the piston really really hard to lift. This is where I was concerned about tolerances again, as you could see wear marks fully around the base of each damper piston.

When I get the carbs back, I will certainly be trying without and with damper oil.

Hopefully I was just holding my mouth the wrong way and the mini fires straight away.

Regards Fritzie

HI fRITZIE
With 20 weight oil in the dampers it will be very hard to lift the piston, this will not affect the starting.
This is how you can fine tune the operation of the carbies,you can try using 2stroke oil atf oil or the SU oil.
All are very light oils and will affect the rate the pistons rises on acceleration but not on cruising.
As Doug said just make sure you do not have the breather tubes blocked off as it will not start, they must be open.
Graham Russell

_________________
"It's better to be not informed than ill-informed"

Out of curiosity, why do the breather tubes need to be open to allow the engine to start?

HI BILL B
If the vents are blocked off you may not be able to get fuel into the bowl because you are trying to
Compress the air in the bowl, if you have fuel in the bowl and the motor does start it will not run long
as you will have a vacuum in the bowl and the motor will not be able to suck the fuel out of the bowl.
As you have 14.7 air pressure pushing on the fuel through the vent.
Graham Russell

_________________
"It's better to be not informed than ill-informed"

Hi, this seems to be going around in a few circles.
I dont believe in lot of years with minis /dynos etc I have ever had a dud carby ! worn out yes.
We do not have enough information to make informed guesses.
On my own Mitsubishi with twin Hitachis the main jet tubes are .092" id not .090" and you cannot use su needles. Hitachi are a bit different to tune ! cannot swap needles
You do not show any photos of the installation, whether you took off the inlet manifold and fitted a new decent quality inlet gaskets, I cannot see heat shields, what does the inlet to carby face of the inlet look,like ?Is it a proper 1-1/2" su manifold? how many new carb base gaskets are there. Is there a booster hose open?
Twins are an absolute pain to fit and get correct at the best of times.
Not all extractors clear Su, highly possible for air leak there
You have purchased pollution carbies, as Winabbey says maybe you should throw away all the Hitachi hoses and set it up as the Police Cooper S.
Fuel pressure and pump? maybe hitachi pressure does not suit SU?
Those distributors can play up timing wise.
I believe there is a good chance of air leaks, but I will only call it a good chance at this stage.
That supplier has gone to an awful lot of trouble to try and help you out.... TRY AND GET THAT SUPPORT FROM ANY UK FIRM..
cheers Lindsay Siebler Melbourne A lot drier LOL

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1959 Austin A40 Farina fun car
1965 Mk1 Cooper S restored
1970 Colt 1100F SS restored
2014 Mitsubishi Imiev fully electric daily driver
1948 Allard M coupe Olds 215 v8 project
1971 Twin cam Escort ex Uk championship winning rally car project

Thanks for the reply.
However, I think there is some misunderstanding of terms.
Winabbey made reference to 'the breather tubes on the carby bodies' and I assume he meant these:



Then GR explained the breather tubes had to be open to let the engine start, referring to the fuel bowls and vacuum created by closed breathers.
I don't think we are talking about the same 'breather tubes'.
Besides, the overflow vent holes in the top of the fuel bowl lids would let air in and out.

HI bill b
On his carbies there were no vent holes there were brass tubes coming out about 10mm long,
if these were blocked off there would be no air getting in.
I'm taking about the top of the fuel bow.
Graham Russelll

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"It's better to be not informed than ill-informed"

Sorry if I confused things. Different “vent tubes”.

_________________
ex-NSW Police 1970 MK II Cooper S
VMCI #43

Lindsay, You were spot on with your good chance of air leaks. Actually you were spot on in regards to another matter as well. I am truly gratefull for the trouble that that Adam and Graham went to. Hats off for SU Midel and Russell Engineering. In addition to that, Adam sent the carbies off yesterday afternoon and they arrived at 10.45am this morning. I stuffed my back yesterday, but it miraculously got better when the carbies arrived.

I started the car up with the Hitachi SU's on and let it warm up. Took them off and installed the HS4's. Do you think I could get it to start. No way. In the end I hooked up the choke, pulled it out about halfway to engage some choke and it gave a cough. Pulled the choke fully on and it started, but would only run with full choke. I knew straight away, I must have a problem. Once I got it to idle I had to richen by about 1 turn of the mixture nut, still not right but it was starting to sound sweeter.

I rang Graham to let him know the carbs were working OK and as soon as I mentioned the choke, he told me that I had a major air leak somewhere.

Probably explains why the Hitachi's ran so well with CP4 needles. Thanks again to Adam and Graham and to all with your suggestions. Much appreciated.

Regards Jon

Fritzie - what was the outcome of your troubles?

_________________
ex-NSW Police 1970 MK II Cooper S
VMCI #43

After my last post, Graham got me to do some testing with the mixture nut turned down another 3 flats. It ran better and Graham suggested getting a richer needle. We ended up going with an ABD needle. It is richer after station 4 when compared to the AAK's, that came with the carbs.

As I was putting one of the springs on the new needles, it was hard to get on and twang, it ended up somewhere in the garage. I ended up installing the new needles, however one was without the spring. It ran a lot better, however there was a slight flutter on idle and a definite fluttering on part throttle. It accelerated well and appears to have done the trick. I still needed the mixture nuts turned down 15 flats from level with the bridge. It would start with full choke when I tried with 12 flats down, but idled quicker as I turned down the mixture screw. Checking the mixture by lifting the piston slightly, verified that it is about right at 15 flats downs. I am still to check with my colortune as I dropped my 50 year old one and should get a new one on Tuesday.

Graham also got me to advance the ignition on my old 29D distributor. I had been running 10 degrees static and would foul plugs at 8 degrees. I probably increased a bit far at first, as when starting it sounded like the battery was flat. I just retarded enough so that the car started as per normal cranking. I have found the car is not needing full choke now and will start with just a smidgen of actual choke.
I got the new needle spring on Friday and have since been for a couple of runs. It is running well and there is no fluttering on part throttle. All seems good.

I never had a proper choke setup on the old Hitachi SU's and was only choking on one carb. The new HS4's are a dream to use in comparison. The HS4's do not suck as hard as the Hitachi's and to date the HS4's do not perform as strong as the Hitachi's. However I won't make a final call until I do further fine tuning. Living in the country means I can check acceleration rates etc on different settings with a stop watch.

The mini community is so lucky to have Graham Russell. He is such a lovely lovely man. Thanks Graham.