Re: leakdown tester

["Tony Clark" <lotus.tony@airmail.net>]

Rex, the orifice size that my "home-brew" tester needed in order to
"flow" the same percentage leak-down as the factory made leak-down
tester was a number 57 drill size, not a .057" .  The actual diameter
of the #57 drill is .043".    I'm gonna disassemble my borrowed
"Auto-Test Inc" leakdown instrument as soon as I ask its owner if
it's OK.  That'll give us three observed points on the graph and
maybe some "Fluid Mechanics"  type guy will step in and "educate" us
all.
Gawd, I love this list!
Tony Clark, Sherman, TX
Texas Region SCCA   
Lotus 51 FF & Lotus 23 sports race "project cars"

Jack Ryan wrote:
> >I took apart a friend's leakdown teaster, and the orifice was
055", and the
> >calibrate pressure was 35PSI.  it very rarely turned an engine
over, and it
> >looked like the % was close to straight percent (ie 35PSI=0%,
17.5=50%).  it
> >was marked at good being between 40-30% to 10% leakage (the green
area).
> 
>                                                                    
           
>    So, with your report and several previous ones, it looks like:  
           
>                                                                    
           
>      @ 100 psi, orifice size is .060                               
        
>                                                                    
           
>      @  60 psi, orifice size is .057                               
        
>                                                                    
           
>      @  35 psi, orifice size is .055                               
        
>                                                                    
           
>                                                                    
           
>   That looks pretty consistent to me. Could all these be right? Any
formulas
> to verify this pressure/orifice curve?   Any more data points?     
           
>                                                                    
           
>                                                                    
           
>                                                                    
          
> Rex Burkheimer    Ft. Worth TX                                     
          
> Texas Region SCCA                                                  
          
> FC Reynard #19  ITB Pinto #49                                      
           
>                                                                    
          
> 
>