<VV> Distributor rebuild

[corvairs]

Hi Kids - And time marches on - I too had reservations about the double 
bushing distributors until I learned 2 things - The first person to make 
double bushing rebuilt distributors an item was Dave Langsather of Dale 
Manufacturing. When those went on the market Corvair consumers started 
to DEMAND double bushing distributors. 2) After having hundreds of them 
in service the past 30+ years I have never heard or seen of one that 
seized up.

Unlike many Corvair vendors, past and present, I have a strong 
machinist/manufacturing backround. There are some rules you don't 
violate in design. One of them is to put three bushing/bearing points on 
a shaft - unless of course you can guarrantee perfect alignment at all 
times. Obvious exceptions to this would be when the shaft is either 
heavy enough, long enough, or under severe lateral stress where it might 
create sag or deflection. The Corvair distributor shaft has none of 
those requirements. It's light, short and sits nearly vertical. And 
everyone is right when they say (as I have all along as well) that the 
steel insert at the oil pump is a bushing. That's 3 bushings - you don't 
want to do that - except........

Dave Langsather is a college trained (with a degree) mechanical 
engineer. He holds more credentials than probably all of us vendors 
combined (that certainly includes me too). He knew from the beginning it 
would work - and SURPRISE - it does. Would I be happy if we could start 
doing all our rebuilt distributors with only the top bushing? Of course 
I would. (one less bushing to buy and machine/fit). But I'm afraid.

Seth (and others) keep telling everyone on the internet that double 
bushing distributors are a bad idea. Like so many other ideas/theories 
(both right and wrong) people will start to accept it because it's on VV 
or Corvairforum.

Lon
www.corvairunderground.com


>  
> In a message dated 9/25/2008 7:37:31 A.M. Pacific Daylight Time,  
> vairologist at verizon.net writes:
>
> The  Distributor housing is thoroughly cleaned and then machined
> for a second  oilite bushing at the base. With two bushings, the shaft is
> stabilized,  effectively eliminating dwell variation. These bushings
> are line bored to  be in perfect alignment.---------------------Smitty says:  
>  I  seriously doubt the value of installing a second bushing in a  
> distributor.  The bottom of the shaft where it is tapered may not be the  finest fit but 
> it would have to be horribly sloppy to allow an influence on  dwell like the 
> normal bushing does when it is worn.  All a second bushing  does is prevent 
> lubricating oil from getting to the normal bushing.  All  arguments to the 
> contrary will receive the same answer.  You Are  Wrong.  ggg 
>
>
>
>
>
> I won't argue with you, Smitty. I do want to add another point. The Corvair  
> already has a lower bushing, the aluminum in the rear housing that locates the 
>  bottom of the shaft as it slips into the oil pump. If the upper bushing is 
> good  and the aluminum hole is okay. That is why I don't recommend the  
> "double-bushing" distributor rebuild. Also possible, however is the modification  to 
> the housing that allows a sealed ball bearing to be placed in the housing  
> replacing the upper bushing. DALE has done several of these for me. This does  
> two things, first it allows a ball bearing fit for the shaft - no play at all -  
> and it is supported just underneath the advance mechanism. Second, it keeps 
> oil  from entering the housing top, slowing down the contamination of the 
> points and  advance mechanism. We had to drill a drain hole in the racing 
> distributors in  the 70s because of pressure build-up in the crankcase would blow oil 
> by the  bushing. One final note. With two bushings in the distributor and 
> another in the  rear housing, how well aligned would three bushings be? - Seems 
> like they would  self correct - or is that "wear-in" eventually. - Seth  Emerson
>
>
>
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