[TR] rear oil seal conversion

[Dave]

The stock crank is good beyond regular 6000 revs.  6500 on the over rev, if it is machine with the correct radius on the journals, balanced and nitrided.  I have good experience with this and learned the facts from experts.  The rods are the weaker link, but if they are crack checked and balanced, they should be good to 5500.  They are designed for 5-5500 stock.  Kas Kastner used all factory parts in his factory team cars for years, because those were the rules, and his drivers certainly revved them well beyond 5500.  The rods are known to break at the oil hole in the middle of the length of the rod.  The hole provide lubrication to the piston skirt and liner.  In the past, for racing, the holes were welded up to prevent failure there.   Carrillo rods, or something similar from a quality supplier are great insurance for a performance build.
The seal shouldn't need to be changed, unless during set up or other reasons it is leaking badly.  Of course, if the engine is apart, always replace. 
The newer seal design is superior and the scroll doesn't need to be machined off the crank.  It combines the original crank seal design, with a groove machined for a Viton radial oil seal.  So far, they have excellent results eliminating rear seal leaks. 

Rev on,
Dave H.

Sent from my iPad

> On Mar 14, 2018, at 2:45 PM, auprichard at uprichard.net wrote:
> 
> List:  what is the general consensus about replacing rear oil seal conversions?
>  
> I have a smallmouth TR3 which is pulling well way past the 5500 rpm mark, so rather than risk a failure of a 60 year-old cast iron connecting rod, I think I will pull the engine and install steel rods.  I had thought about a steel crank, but the 4-cylinder engines have a remarkably robust crank (and money does become an option).  The car has many upgrades, and I really should have gone with steel rods originally.
>  
> Anyway, the engine has the Moss rear oil seal conversion (with the machined crank).  Should the seal be replaced as a matter of routine?  The engine only has about 2000 miles on it.
>  
> Andrew Uprichard
> Jackson, Michigan
> 
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