Special tuning H4 carbs

[NicholasUpton]

I believe this is a set of H4 tuning carbs but trying to figure out what intake they should go on to be correct. They came with a modified Aeg179 intake, which I believe is for a 1071.

Carb float tags are AUC163 and Aud176R but but appear to be identical parts.

[timmy201]

AUD176 is the number for a LHD works setup
AUC163 is listed as “OM Carburettor for Lanchester 10 H.P 4 cyl 1932-34”

https://sucarb.co.uk/om-carburettor-for ... 32-34.html

Mark has a scan of the parts book that includes the AUD176 pair
https://mk1-performance-conversions.co.uk/h4_parts.pdf

[mk1]

There is no such thing as a "correct" manifold. Any Mini twin manifold modified for 1.5" carbs would be perfectly correct.

[AndyPen]

One of my sets came on a 179 manifold Nick, popular when you don't want all the crankcase ventilation gubbins.

[MiNiKiN]

Oh. this comes in handy... hi-jacking this tread . I too just bought a reasonably priced used set of H4 twin carbs. I am curious what makes a twin H4 an "ST H4 set" and in what respect do the LHD versions differ from the RHD ones?

I wonder if anyone has a detailed photo of all the works H4 lever knick-knack, rather than the rather low-res exploded views (no disrespect)

[Roadrunner]

If they are for an A series mini then you should be using HS4's H4's look to have been on MGt's ect. Those were old even when I first had a mini back in 1970. https://abingdonspares.com/products/com ... 2-h4-1-1-2

[MiNiKiN]

If they are for an A series mini then you should be using HS4's H4's look to have been on MGt's ect. Those were old even when I first had a mini back in 1970. https://abingdonspares.com/products/com ... 2-h4-1-1-2

Fair comment, but I want them to be "old", i.e. period. And from what I understand, H4 were "the work's choice" back in the day.

I see C-AHT 1 "Abutment Bracket" and C-AHT 2 "Anchor Bracket" for the return springs are special to ST H4s.
Both items are not available from Burlen, I reckon. Has anybody got a photograph with 1 or 2 reference dimensions, from which I could make a drawing for reproduction?

[Roadrunner]

They could well have been used on some of the works cars, they would use what was ever in the workshop. I only knew two people who worked there. Nevil Challis who dies a long time ago and the other guy I'm not sure if he is still around either. You best bet is to go in the Mini Cooper Register and ask them. If you have the manifold for the carbs to fit on you can stick them on and measure the gap needed to make the linkages up if need be. All the trays say to me is that is a load of spare bits of a carb. Only thing I recognise is the drop gear off the crank beside it

[Smithmaps]

H4's were the works choice for a very specific reason.
Group 2 Rally regs in the 60's (I think also in racing) allowed the carbs to be changed, but not the inlet manifold, which had to remain standard to the car.
HS4 carbs have a diagonal bolt pattern, as opposed to vertical like the H4, and the 1.5" H4 would be a straight replacement for the 1.25" Hs2 carb fitted as standard to the Cooper S.
In the early days they were in fact straight off the MGA, including the wrong float chambers, necessitating the fitment of extensions to get the float level correct.

[AndyPen]

This ad seems to be pretty much what my sets look like - hope it helps? I see the two spring extensions in your box of bits.


https://www.ebay.co.uk/itm/295339019106 ... gKpSvD_BwE

[AndyPen]

...and Somerford's info here:


https://www.somerfordmini.co.uk/carbure ... ial-tuning

[Roadrunner]

H4's were the works choice for a very specific reason.
Group 2 Rally regs in the 60's (I think also in racing) allowed the carbs to be changed, but not the inlet manifold, which had to remain standard to the car.
HS4 carbs have a diagonal bolt pattern, as opposed to vertical like the H4, and the 1.5" H4 would be a straight replacement for the 1.25" Hs2 carb fitted as standard to the Cooper S.
In the early days they were in fact straight off the MGA, including the wrong float chambers, necessitating the fitment of extensions to get the float level correct.

Well I though it would be something like that to get around the rules, they used stuff easy at hand that came off the line or was in the stores which would have had the parts

[251 ENG]

Also H4 will produce more power and torque on a correctly set up engine compared to HS4,s

[johnv]

Also H4 will produce more power and torque on a correctly set up engine compared to HS4,s

I wish you hadn’t said that as I’ve just changed mine for HS4’s

[MiNiKiN]

Thank you all, very helpful and informative.

[Herbert]

H4's have a longer choke tube and the butterflies turn the other way to an HS4. This gives a better mixture. On my S running H4's gave me 12hp more than the HS4's. More revs, and a better torque curve. Only a Weber will give you better figures. I would always recommend H4

[mk1]

Most points have already been covered comprehensively.

The C-AHT-1 & C-AHT-2 brackets will all be available again very soon. I am working with Catmint Gordon to get these sorted.

They will be available through Gordon very shortly.

M

[MiNiKiN]

H4's have a longer choke tube and the butterflies turn the other way to an HS4. This gives a better mixture. On my S running H4's gave me 12hp more than the HS4's. More revs, and a better torque curve. Only a Weber will give you better figures. I would always recommend H4

12HP is massive

[johnv]

Most points have already been covered comprehensively.

The C-AHT-1 & C-AHT-2 brackets will all be available again very soon. I am working with Catmint Gordon to get these sorted.

They will be available through Gordon very shortly.

M

Is there a bracket available for the throttle cable / manifold Mark?

[johnv]

H4's have a longer choke tube and the butterflies turn the other way to an HS4. This gives a better mixture. On my S running H4's gave me 12hp more than the HS4's. More revs, and a better torque curve. Only a Weber will give you better figures. I would always recommend H4

12HP is massive

It is. I had mine on the RR at RACE recently with the H4s, I'll leave the HS4s on when I go again at the beginning of December and see what the difference is. 12HP will persuade me to put them back on! (The only other difference is that I have changed to a 123 distributor)