[AT] Statistics In Tractor Manufacturing Was Bicycle Program

Cecil Bearden crbearden at copper.net
Thu Sep 19 19:55:42 PDT 2019


I agree with the analysis that the bolts were stretching, instead of the 
head shrinking.  However, this was the late 60's early 70's and there 
probably was a lot lost in the translation between Japan and Oklahoma 
Via Dallas..  I helped to write some of the service manuals in the early 
days as I had more hands on experience with Satoh tractors in the US 
than any other mechanic, and I also had experience with writing 
technical manuals.
Cecil

On 9/19/2019 9:06 PM, Jim Becker wrote:
> 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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