John,

Your point is well taken.

I should have said "...one need only replace the seal AND BUSHING to 
banish it for another fifty years."

Still both simple, cheap and effective long term.

Thanks!

WRB

-- 

On Mar 9, 2010, at 13:31, John Cooper wrote:

> On 3/9/2010 2:06 PM, William R. Bayne wrote:
>> I would think the "perfect balance" in which the
>> seal allows just enough oil to stop bushing wear (not absolutely, but 
>> a
>> definite rate reduction) would last a very long time; and when that
>> first drop of oil does make it to the end of the shaft, one need only
>> replace the seal to banish it for another fifty years.
>>
> No, the problem is that once the bushing wears the shaft can move 
> around
> enough that the seal doesn't seal effectively. A new seal my slow 
> things
> down for a while, but the real problem is not the seal but the shaft
> movement.
>
> As far as the legality of machining the case to accept the seal, I 
> don't
> see it as an issue. Most starters that I have seen have already been
> modified.  My only concern is that the correct seal be used, which is
> quite thin. I've seen starters with the wrong seal where the metal lip
> of the seal protrudes and bears on the starter drive gear.
>
> Skyport stocks the correct seal.
>
> I guess what I'm really saying is that if, 50 years ago, no one worried
> about the occasional drip, nothing would have changed and there 
> wouldn't
> be any starters leaking more than the occasional drip.  Modifying the
> case for the seal also reduces the length of the bushing and reduces 
> the
> axial bearing capability, which contributes to the wear and ultimately
> the leak.  The law of unintended consequences...
>
> -- 
> John
> Skyport East
> www.skyportservices.net
>
>
>
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