Special tuning H4 carbs

General Chat with an emphasis on BMC Minis & Other iconic cars of the 1960's. Includes information on MK1 Action days.
NicholasUpton
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Special tuning H4 carbs

Post by 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.
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timmy201
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Re: Special tuning H4 carbs

Post by 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
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Re: Special tuning H4 carbs

Post by mk1 »

There is no such thing as a "correct" manifold. Any Mini twin manifold modified for 1.5" carbs would be perfectly correct.
AndyPen
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Re: Special tuning H4 carbs

Post by AndyPen »

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

;-)
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MiNiKiN
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Re: Special tuning H4 carbs

Post by MiNiKiN »

:) Oh. this comes in handy... hi-jacking this tread :lol: . 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)
If only I knew the power of the Dark Side...I wouldn't have made contact with an Innocenti :mrgreen:
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Roadrunner
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Re: Special tuning H4 carbs

Post by 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
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MiNiKiN
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Re: Special tuning H4 carbs

Post by MiNiKiN »

Roadrunner wrote: Thu Nov 17, 2022 2:44 pm 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?
If only I knew the power of the Dark Side...I wouldn't have made contact with an Innocenti :mrgreen:
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Roadrunner
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Re: Special tuning H4 carbs

Post by 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
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Re: Special tuning H4 carbs

Post by 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
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Re: Special tuning H4 carbs

Post by 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
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