[AT] O.T. Woodruff vs straight keys

[Mogrits]

Ken

I didn't realize Smokey Yunick ever raced snowmobiles!

Warren

On Tue, Aug 15, 2017 at 3:25 PM, Ken Knierim <ken.knierim at gmail.com> wrote:

> Charlie,
>
> You might find this if they were trying to get more timing advance as well.
>
> Lots of different parts have been used in racing. I know of one (former)
> snowmobile racer that used one smaller cylinder out of the 3 on his sled.
> When they had to get a tech inspection after the race, he pulled the
> (smaller) cylinder down for the inspection and it magically met the specs
> for the engine. Interestingly enough, the other two were larger
> displacement cylinders from a bigger engine variant but they had the same
> exterior. The rules for the tech inspection only required one cylinder get
> measured.
>
> Ken in AZ
>
> On Tue, Aug 15, 2017 at 11:33 AM, charlie hill <charliehill at embarqmail.com
> >
> wrote:
>
> > Larry, you reminded me of something.  Years ago I had buddies who raced
> go
> > carts.
> > They often ran souped up 5hp B&S engines.  One of the tricks was to run a
> > 3HP flywheel
> > on the 5HP engine to reduce weight.  In order to do that they had a
> special
> > crank key
> > with a slight offset in it to get the timing back to the correct setting.
> >
> > Have you ever run into that?
> >
> > Charlie
> >
> > -----Original Message-----
> > From: Rena Glover Goss
> > Sent: Saturday, August 12, 2017 11:42 AM
> > To: Antique tractor email discussion group
> > Subject: Re: [AT] O.T. Woodruff vs straight keys
> >
> > A key can be used as a safety limiter on torque so that it shears instead
> > of
> > breaking gear teeth, etc.  In that case, the length of the key can be
> used
> > to adjust the break-away torque load.  Some small engines (like Briggs)
> use
> > a particular metal for the key to get this type of safety.  In the
> > lawnmower
> > repair shop business, I often ran into engines where the owners had
> > replaced
> > the OEM key with a steel one.  I presume they thought that "any ol' key"
> > would do the job.  Never mind that when they hit a gas pipe with their
> > lawnmower, they twisted off the crank shaft!
> >
> >
> > Larry
> > ---- Dennis Johnson <moscowengnr at outlook.com> wrote:
> > > I think there are 2 main reasons for woodruff keys
> > > 1 - these keys are contained from side to side so they cannot slip. You
> > > can also use other types of key ways that enclose the keys, but the
> most
> > > common is to cut keyway to the end of the shaft.
> > > 2 - the woodruff keys may take less material out of the shaft. This
> might
> > > weaken the shaft slightly less.
> > >
> > > Dennis
> > >
> > > Sent from my iPad
> > >
> > > > On Aug 11, 2017, at 8:13 PM, "joehardy at epix.net" <joehardy at epix.net>
> > > > wrote:
> > > >
> > > > My brother is rebuilding a corn chopper and having difficulty
> replacing
> > > > bearings on the pick up head. Couldn't get to slide the bevel gears
> off
> > > > drive shaft. He asked me why woodruff keys were used instead of
> > straight
> > > > keys. Thought I'd throw his question out to our group. Ref: Read
> > > > discussion on Practical Machinist. Joe Hardisky, Ryman Farm, Dallas,
> PA
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