11 replies to this topic

[mariner]

If you have never heard of the Minnow Fish carb. don't worry, it is an automotive oddity which had a moment of fame in the 1960/70's as THE demon tweak on small engined Mini racers.

 

it is being re launched as mentioned here

 

http://www.reece-fish.co.uk/

 

A diagram is here

http://www.reece-fis...nts/diagram.pdf

 

It is neither an SU type nor a fixed choke type carb. In fact it doesn't even have a choke venturi at all. Basicaly the butterfly shaft is hollow and the hollow shaft extends into the float chamber which is sort of quadrant shaped. An arm, , also hollow, and connected to the hollow butterfly shaft, ha sa  pick up hole against a very carefully cut groove in the back face of the float chamber. So as the throttle opens the arm swings up and the deepening groove allows more fuel to flow into the hollow butterfly shaft.

 

All the depression required to "pull" and atomise the fuel is provided by the butterfly thickness restriction in the inlet manifold.

 

Tuning is by adjusting the relationship of the arm start position to the butterfly closed position and by a fuel regulator screw.

 

Amazingly this simple device really did work and could match an SU , or a Weber cab. in back to back testing. For some resaon it only ever was popular on A seies engines but work, and win races, it did.

 

David Vizard , one of Britian's top engine tuner/writer guys used them and some comments are here

 

http://www.imps4ever...k-in-carbs.html

 

It fell out of favour but it had two big advantages - all mixture tuning was by adjustment and no jets to swap, and it could be mounted at any angle by swiveling the float chamber/drop arm.

 

I though it may be of some interest as the complete opposite of the amazing sophistication of the ultra high tech MB hybrid PU.

[Magoo]

Neat. Thanks for sharing. 

[gruntguru]

They need to make some larger models.

 

I wonder how easy it is to synchronise mixtures in a multi setup.

[JtP2]

They need to make some larger models.
 
I wonder how easy it is to synchronise mixtures in a multi setup.

From what I saw, impossible. There was a fellow who sprinted a Mini Marcos with twin Minnow Fish carbs. I remember he used to spend all day trying to set them between runs.

[mariner]

Maybe synchroising  problems were why it wasn't used more. Certainly it seemed to be most useful with the siamesed ports on the old BMC A series mini engine.

 

I suppose in this electronic age you could envisage a needle going into the float chamber end of  hollow butterfly fuel tube and connected to a piezio crystal driven by a wide band 02 sensor to continuously make micro fuel flow adjustments driven by the A/F ratio.

 

that might help synchronisation too.

[gruntguru]

As Bosch demonstrated many years ago with the Bosch Pierburg electronic carburettor, it is possible to dramatically simplify the design of a carburettor by adding electronic control.

[Canuck]

And to do away with 99% of it's fallible eccentricities by going to fuel injection.

[Allan Lupton]

And to do away with 99% of it's fallible eccentricities by going to fuel injection.

I've always had the reverse view, which is that if Karl Benz and/or Gottlieb Daimler had started with fuel injection in the 19th century, the subsequent invention of the fixed-choke self-compensating carburettor (such as the Zenith) would have been hailed as a truly wonderful break-through.

Never did think that either Fish carb was the way to go, though.

[Chris Wilson]

A probably little known curiosity is that Fraser MacKellar, one of the world's  top Motec ECU engine mappers, had early work experience at this company. From perhaps the simplest form of fuel regulation to some of the most complex and capable aftermarket ECU's. for fuel injection and much more.

Edited by Chris Wilson, 12 March 2016 - 19:26.

[vrroomcd]

I had one of these on a peugeot 304 coupe, great carb

[Chris Wilson]

I had one of these on a peugeot 304 coupe, great carb

 

 

And a pretty little car! Are there any left running in the UK I wonder? the 504 Coupe and convertible were lovely, too.

[BRG]

 

And a pretty little car! Are there any left running in the UK I wonder? the 504 Coupe and convertible were lovely, too.

 

Try here.  Not sure which model is the coupe.