[AT] Statistics In Tractor Manufacturing Was Bicycle Program
Jim Becker
mr.jebecker at gmail.com
Thu Sep 19 19:06:47 PDT 2019
I still think that before Satoh wrote a service bulletin about the head
shrinking because of overheating, somebody there would have done before and
after measurements and be able to tell the difference between a head
squishing out of spec and a stretched bolt.
Jim Becker
-----Original Message-----
From: szabelski at wildblue.net
Sent: Thursday, September 19, 2019 7:51 PM
To: Antique Tractor Email Discussion Group
Subject: Re: [AT] Statistics In Tractor Manufacturing Was Bicycle Program
My guess is that when the engine overheats the head expands and gets thicker
(standard thermo dynamics). When it expands it stretches the head bolts, all
of them. As a result it would appear that the head got thinner.
Finding all the head bolts loose, one might guess that’s the head shrunk
uniformally from the overheating. If the head shrinks every time it
overheats, one should eventually see a head that is getting noticeably
thinner and thinner.
Note that when the bolts are stretched the bolt shanks get a little thinner.
If they get too thin they will not hold the required torque, and will loosen
up easier. This is due to the fact that a bolt that is too thin will twist
easier without applying the expected clamping force.
When we serviced military equipment that required a high torque on certain
bolts, we always replaced those bolts with new ones before applying any
torque. Torquing a bolt does stretch it and you can only stretch a bolt so
far before it no longer will clamp properly. Not knowing how many times a
specific bolt was torqued, or if it was ever over torqued, made it necessary
to not take a chance on reusing a bolt that was stretched to far.
We also never reused lock washers or self locking nuts since, there was no
way of determining how many times they may have been taken off and put back
on. They were simply replaced and we knew they were 100% good. When the
bolts, lock washers, or self locking nuts were removed, they immediately
went into a scrap bucket to make sure they didn’t make it back into the
assembly.
A five ton main gun slamming rearward as it comes out of battery (it’s
mounting) due to degraded bolts will easily slice a tank commander or the
loader, sitting basically behind it, in two, maybe both of them. It can also
do some serious injury to the gunner sitting along side of it. There are
also dozens of pieces of equipment mounted to the interior walls. If they
break away and become secondary missiles, they can do a lot of secondary
damage and injury. We and the army never wanted to risk that or anything
else like that happening, and always put crew safety as our first priority.
It did drive up the cost of the field installation kits because we had to
included a replacement bolt, lock. washer, and nut for every one that was
touched during maintenance, retrofit, or upgrade.
----- Original Message -----
From: Jim Becker <mr.jebecker at gmail.com>
To: Antique Tractor Email Discussion Group <at at lists.antique-tractor.com>
Sent: Thu, 19 Sep 2019 16:25:28 -0400 (EDT)
Subject: Re: [AT] Statistics In Tractor Manufacturing Was Bicycle Program
I agree the whole head isn’t going to shrink. However, I can imagine the
pressure from the head bolts acting on the overheated head to cause some
displacement of the head material. When cooled back to a normal
temperature, the dimension from where the head bolts contact the head to the
gasket surface could be reduced. This could be confirmed by measurement
before and after.
Having not seen the actual wording of the bulletin, I could imagine it
stating something to that effect. I would presume someone at Satoh made
such measurements.
Jim Becker
From: Stephen Offiler
Sent: Thursday, September 19, 2019 2:23 PM
To: Antique Tractor Email Discussion Group
Subject: Re: [AT] Statistics In Tractor Manufacturing Was Bicycle Program
I don't buy that, Cecil. I don't think the head shrinks regardless of what
the service bulletin said. I think it expands when overheated, putting a
permanent stretch in the head bolts, resulting in insufficient torque when
it cools down. Retorque it, then overheat it again, and they stretch again,
and again.
Steve O.
On Thu, Sep 19, 2019 at 9:27 AM Cecil Bearden <crbearden at copper.net> wrote:
Back in the early 70's when I was working at the tractor shop, we were the
Satoh tractor dealer. The tractor had an aluminum head on a cast iron block
w/ steel studs. we sold it to a couple of sisters who had been suing a Cub
Farmall with a belly mower. The Satoh would get grass built up in the
radiator and overheat. When it cooled down, the head would have to be
re-torqued. The first couple of times we replaced the gasket. The last 2
times we just re-torqued the bolts. Later we got a service bulletin that
stated the head would shrink when it overheated. Maybe that is the reason
the rocker arm bracket gets loose on the Kawasaki..
In our case the sisters filed a lawsuit and we had to go find another Cub
Farmall to replace the one they traded in. The boss convinced the
purchaser of the used Cub Farmall to trade for the Satoh that overheated and
that owner was very happy as he did not mow Bermuda grass.
Cecil
On 9/18/2019 7:28 AM, Jim Becker wrote:
Henry, do you also find the rocker arm bracket bolt loose when the push
rods get bent? As Steve pointed out, it seems unlikely that sticky valves
would result in 2 bent push rods at/near the same time. My knowledge of the
Kawasaki V-twin consists of what I read in this thread. But I wonder if the
failure mode is overheating allowing the rocker arm bracket to get loose,
allowing the push rods to get loose and bend. Maybe the fix is to add a
bend-over tab type retainer to the bolt.
Jim Becker
From: Stephen Offiler
Sent: Wednesday, September 18, 2019 3:44 AM
To: Antique Tractor Email Discussion Group
Subject: Re: [AT] Statistics In Tractor Manufacturing Was Bicycle
Program
Henry, is yours is a Kawasaki V-twin? Are you just replacing the bent
pushrods? Based on the Internet chatter I've read on the lawn forums, the
root cause is sticky valves, and the permanent solution is a new head (comes
complete with valve guides and seats) and new valves. That's what I'm doing
right now, reusing only the valve springs, keepers, and rocker arms. In my
case, it wasn't even a question, because my head gasket was blown, so that
head is certainly warped too.
These engines are sensitive to proper cooling airflow. Again with the
lawn forums, seems I'm far from the only one who has had an overheat without
realizing it. Mostly it's grass clippings that cause the problem although
mine was mouse nest. People talk about removing the shrouds every X hours
to clean the fins. Actually a really easy job. The bolt holes in the
main shroud are slots, you just loosen the fasteners and pull it straight
off.
SO
On Tue, Sep 17, 2019 at 9:03 PM Henry Miller <hank at millerfarm.com>
wrote:
I've had the bent pushrod 3 times now in mine, it has always been
both, though I too can't figure out why both should go at the same time.
--
Henry Miller
hank at millerfarm.com
On Tue, Sep 17, 2019, at 8:27 AM, Stephen Offiler wrote:
Mine is a long story. All my stories are long ;-)
Gravely zero-turn with 24HP Kawasaki V-twin. I keep it maintained
by the book, and use it pretty hard but not abused. It ends up being stored
in places where mice are just going to be present, no way to eradicate them
(and yes there are cats around). Quite a while ago, could have been early
'18 or back even further in '17, I was checking the air filter (which I do
roughly every 3-4 mows) and found it had a huge hole chewed in it. That
means I probably ran the machine unfiltered a couple times. Suspicious and
worried, I pulled the shrouds, and found the #1 cylinder fins just packed
with slow-roasted mouse-nest. Most likely, I ran it a couple times with
impaired cooling on that cylinder, and it overheated. I cleaned it all out
and went back to mowing. It ran well, plenty of power, but I did notice an
increase in oil consumption. I wondered if that was the overheating, or the
ingestion of unfiltered dusty air. I didn't really feel like tearing it
down so I just kept running it. And, with an eye on oil level, it did fine
for 1-2 years, until just recently. It coughed and started running poorly.
Drove it into the shop and found #1 was barely warm; it was only running on
#2. Tore into #1 and found both rods bent plus the bolt holding the "Rocker
arm bracket" was very loose. What the internet tells me is that overheat
leads to sticky valves and when a valve sticks the pushrod gets out of place
and bends. That sounds very plausible but I'm still not sure how I bent
BOTH of them and how that loose rocker bracket happened. Oh and the head
gasket is blown on that side, which probably explains the increased oil
consumption. I am replacing the whole head, pushrods, valves, valve seals,
gaskets. Cost about $300 in parts online. Waiting right now for parts to
arrive and the grass is still growing.
SO
On Tue, Sep 17, 2019 at 8:46 AM Cecil Bearden <crbearden at copper.net>
wrote:
The only time I bent a push rod was when I over revved the engine.
It was on a 292 Ford V-8 in an old 57 4wd F100. I got stuck and had to give
it the gas to get out. I straightened the rod out on an anvil and it i
still running...
Cecil
On 9/17/2019 6:03 AM, Henry Miller wrote:
My zero turn is in the shop with the same bent pushrods issue.
Second time this summer. I'm thinking about a different engine... I have the
replacement rods, but I found a small spring by the valves that doesn't come
from anywhere obvious. I'll have to tear into it more now to see what else
is wrong.
--
Henry Miller
hank at millerfarm.com
On Mon, Sep 16, 2019, at 3:51 PM, Stephen Offiler wrote:
Mike M - that just happened to me yesterday! I've got a
Gravely zero-turn with Kawasaki V-twin that bent a pushrod at 306 hours
(known issue, easy-ish fix). It is sitting right now waiting for parts to
arrive. Yesterday, I was walking past and happened to look down and saw 600
and something hours on the meter, which was odd but didn't quite register
until it clicked over another tenth digit while I was watching. That
happens once every 6 minutes, so I got real lucky to see it. I guess the
key got bumped somehow during disassembly Now, all the service reminders
are saying "CHG NOW". I'm doing engine oil and air filter now anyway, but
losing the service reminder on the hydro units bugs me. It added 337 hours
sitting still (divide by 24 to see how long I've been waiting for parts, and
therefore how long the grass is getting!). Since I'm not likely to ever
sell this machine, I don't really care that much about the fake hours.
Steve O.
On Mon, Sep 16, 2019 at 4:09 PM Mike M <meulenms at gmx.com>
wrote:
I have a Scag zero turn that I bought new, I put about 350
hours on it over the course of several years. When I parked it this last
fall, I accidentally left the key on, so when I went to start it this Spring
I had 3500 hours on it. Fortunately my daughter works at the dealer so I was
able to buy a new one.
Mike M
On 9/16/2019 2:42 PM, Spencer Yost wrote:
New tractors have hours embedded in the computer.
Replacement computers are easily spotted by the metadata in the computer.
So for approximately the last 10-15 years we have a reliable indicator of
usage or computer replacement/tampering on most models.
However, being able to obtain the equipment and software
necessary to read the computer is still a sticking point and at the heart of
the right to repair lawsuits going around. These lawsuits are extending to
other equipment and devices. So farmers were actually at the forefront of
this movement.
Ok fine print for the following:
This is not a political statement. I absolutely
positively never endorse any presidential candidate publicly on this list
nor should the following be construed as support for the candidates
mentioned. I only add the following statements and link as a way to let y’all
know that our frustrations with equipment are being heard by some. Ok
enough with the fine print:
Elizabeth Warren added support for the right to repair
movement as one of her written policy planks - To my knowledge the only one
but the movement should grow to the point candidates probably won’t be able
to ignore it. Here’s Warren’s policy paper on agriculture in general but in
that she specifically mentions right to repair:
https://medium.com/@teamwarren/leveling-the-playing-field-for-americas-family-farmers-823d1994f067
I am watching the right to repair movement closely.
Spencer
Sent from my iPhone
On Sep 16, 2019, at 10:29 AM, Al Jones
<farmallsupera1 at gmail.com> wrote:
No. If your tachometer goes bad, you get a new one with
0000.0 hours.
Al
On Sun, Sep 15, 2019 at 11:52 PM Cecil Bearden
<crbearden at copper.net> wrote:
Probably not, and the mileage on the title of an auto
or truck is
nothing that can be relied on... I used to be able
to tell by the wear
on floorboards, rust, paint scratches etc if a trucks
mileage was
right. Tractors are a different animal. Usually just
change the tires
and if repainted, change the hoses and belts, new seat
and cab interior
and it is a new tractor.
Cecil
On 9/15/2019 8:36 PM, Jack wrote:
> Tractors are not titled. Automobiles and trucks are.
When you sell an auto, you record the mileage at time of sale and your
signature. Is it even illegal to alter the hour meter on a tractor?
>
> -----Original Message-----
> From: AT <at-bounces at lists.antique-tractor.com> On
Behalf Of Cecil Bearden
> Sent: Saturday, September 14, 2019 7:33 PM
> To: at at lists.antique-tractor.com
> Subject: Re: [AT] Statistics In Tractor
Manufacturing Was Bicycle Program
>
> The New Holland Money Pit is what it is because
somewhere in its history the hour meter was turned back. New tires were
installed and it was made to look like a 5 yr old tractor with about 200 hrs
per year.
> Cecil
>
> On 9/14/2019 10:26 AM, James Peck wrote:
>> Some years ago I did participate in an academic
Statistical Quality Control course. Much of the course involved the Weibull
Distribution. If I remember correctly, the Weibull Curve predicted the
lifespan of a manufactured assembly such as a tractor. It appears to be a
gift from the mathematicians.
>>
>> https://en.wikipedia.org/wiki/Weibull_distribution
>>
>> The same distribution probably predicts that Cecil’s
New Holland money pit will continue to be so and will suffer an early
demise.
>>
>> [Stephen Offiler] I never took a whole semester of
Statistics. Instead, we had a course called Engineering Experimentation,
which was heavy on experiment design and statistical data analysis. That
gave me a very good appreciation for the practical application of
statistics. Out in the real world, on-the-job training programs in quality
control principles in manufacturing (Deming, Juran, Lean Six Sigma)
continued to solidify the practical applications.
>>
>> [Cecil Bearden] Steve: I nearly flunked statistics
I only passed because I was a graduating senior. However, I did flunk Rocks
& Clods 2124 and had to find another 4 hours to graduate. Then 35 years
later I retire as a Geotechnical engineer designing foundations. !!!
>>
>> [Stephen Offiler] I'm not sure if that is an
interesting statistic, or simply predictable statistically. All you just
said is that a bell-curve distribution for 2-year degrees overlaps a
bell-curve distribution for 4-year degrees.
>>
>> [ James Peck] The interesting statistic is that
some technical 2 year programs have higher starting incomes than many 4 year
degree programs. People who complete such a program can later take a 2+2
program to get a four year degree if they choose.
>>
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