[Healeys] carb oil

[David Nock]

Many of the early SU carbs did not have a spring, instead they had a  
heavy brass piston instead.
The springs also vary in strength
Also the dampers vary in the amount of oil they let bypass thus  
controlling the rate the piston moves.





David Nock
British Car Specialists
Stockton Ca 95205
209-948-8767

www.britishcarspecialists.com
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On Aug 12, 2010, at 9:53 AM, Herbert Miller wrote:

> To add to what David said.
> Variables that effect piston response.
> 1.Dash pot spring. There are several available. Mk 1 Sprite had  
> none at all.
> 2.Viscosity of dashpot oil.
> 3.Friction between piston shaft and dashpot. The latest HIF44 uses  
> a ball
> bearing.
> 4.I am not positive, but I suspect that the diameter of the damper  
> plunger,
> the brass slug on the end of dashpot cap, is a tunable item. Check  
> the cap
> for a part #.
>
> All these items combined to generate a mixture curve under  
> acceleration. If
> you have a modified engine, cam, CR, ported head, etc. you may have  
> to tune
> this curve as well.