<VV> Re: IDing Tufftrided crankshaft

[Tony Underwood]

At 12:00 hours 10/12/2004 +0000, djtcz@comcast.net wrote:
>> Message: 10 
>>> Subject: Pile -o- Crankshafts 
>> 
>> All: 
>> I need to find a LM 140 crank out of a pile. 
>> How do I tell a 140 from a 110 ? 
>> 
> Are you after the Tufftriding ? I would be too, as it is remarkably scuff
resistant in emergency situations, and can improve the fatigue live 3 to
100 X. 
>
>On the original Spyder crank a better steel was used as well as
Tufftriding.  Don't know about the steel on later non Tuff-tride cranks.   

All long-stroke Vair cranks use the same improved chrome alloy steel.
Early standard short-stroke cranks were carbon steel... *except* the turbo
engine cranks which were nitrided chrome alloy steel.   



>Use a sharp fine file (but not your best file) to kiss a crank shoulder.
The file will skate across the hard surface with out digging in.


Yep.   It's hard as Hell (no pun) to scratch a nitrided crank even with a
fresh file.   


You think those were hard...  you should have seen the 392 c.i. hi-perf
Hemi cranks which were flame hardened via the time consuming and tedious
(if done right) heat-quench process.   The toughened surface was not only
hard, it was deep, extending as much as .06 into the crank journal.   It
made for some dulling of the cutting tools if you ever had to turn one of
those cranks.   Nitriding works as well, isn't as likely to cause cracks
like flame hardening (if not done precisely), and it's cheaper.   


tony..