Cool it!

[markrinker]

Back on the farm, my dad always instructed anyone operating our turbo diesel John Deere 4430 and 4630 tractors to provide at least 5 minutes of idling before shutting them down after any significant pull or load, to cool the engine oil, drop water temps, and cool the engine block.

I leave my 6.5 diesel running at fuel stops when towing loads - stops where I would shut down a gasser. Also, I always idle my trucks after any loaded pull for at least 5 minutes, sometimes leaving it running in the driveway at home, and returning outside to shut it off.

Is this necessary? Is it a habit, or a good idea?

[a5150nut]

Not a bad practice at all. They even make Auto shut off setups that will allow your truck to cool to a preset temp, then auto shut down. A lot of big trucks use these.

[rjschoolcraft]

I allow mine to cool until the EGT drops to 300F or below. Having been around gas turbines, I've seen a lot of coked oil. For turbochargers, the #1 killer is coked bearings that lock-up. If you allow the EGT to drop below 300F before shut down, you eliminate the risk of heat soak coking your bearings.

The 250 helicopter engine that I used to design parts for has a mandatory 2 minute cool down for this very reason.

[markrinker]

So its actually more of a function of cooling exhaust temps for the turbo's sake...whats a little wasted fuel, if it saves one big repair bill?

Looking back on the 'farm years', I find it interesting that we had so few engine problems. (Mostly transmission replacement on pickups, trying to use them to pull loads like tractors!!!) Its interesting that a John Deere 4630 can till 800 acres three passes per year for two decades and never need a clutch, turbo, injector pump, or even a rebuild.

http://www.machinerybrokers.net/graphics/DSC00497.JPG

[Spindrift]

Nothing runs like a Deere!

[markelectric]

I prefer Red paint/power.

[rjschoolcraft]

To each his own, but...

Having operated Deutz, Allis-Chalmers, Ford and John Deere, I can truly say that "Nothing runs like a Deere!" When Deere introduced the 4020 in the early 1960's, it revolutionized the ag equipment business and Deere has been in the lead ever since.

I grew up on (literally) a 4020 then came of age on a 4620. Incredible machines. We even still have several old two-cylinder John Deere's working hard.

My dad recently bought a 4020 to keep here at my place (cool, huh?). He also uses it to help a buddy of his with his farming operation. I used to work for this guy when I was in high school. I ran his (then new, late 1970's vintage) Allis 7020 in all kinds of operations... it was (and still is) a real piece of junk. He also has an Allis 7080 now. Dad says it is a better machine than the 7020, but still has problems. Dad's friend used dad's 4020 to mow hay last spring (and is using it now) and couldn't believe what a machine it was. Mind you, this is a 37 year old tractor. He has been pestering my dad to sell it to him since last spring. He is nearing retirement from his farming operation and is really bummed now that he didn't buy "green" years ago. His tractors have next to no re-sale value. He had to buy a combine recently because the Gleaner he had was giving up. He bought a 4 or 5 year old Deere and is amazed at how well it works.

Many people hold on to old allegiances and are faithful to their brand loyalties...and that's good...it's just not supported by fact, really.

[Beedee]

Going back to the original thread. Yes, anytime you can idle down for a few min before shut down is a good idea, it allows the hot spots to cool. Look at it this way, would you flash up your truck and with a huge load on it, on the coldest day of the year, put it in gear and just give it????
I didn't think so.
I maintain heavy equipment for a living, we pay our operator to warm up and cool down their equipment everyday. It makes a big differance.
As for the Deere's that I work on. They take a perfectly good Hitachi :D , put a John Deere engine in it :mad: , paint it yellow and call it a Deere :( . Guesse what the weak spot is. Not the Hatachi part, thats for sure. It's a good thing that they have the best service manuals going, cause they get used alot. :eek:
Brian

[markrinker]

So, that being said - which manufacturer is the 'John Deere' of trucks? Diesel trucks?

Over the long haul, I believe it has been Chevrolet. I have to admit that the 6.5L diesel version has tested my brand loyalty, but I am hanging in there.

BTW - I was born in 1963, the 4th generation on our family farm. There was a John Deere "B" sitting in the weeds, with stuck rings. (Long story from previous generation that my dad wouldn't elaborate on, and grandpa took to the grave without telling any of us kids.) Work tractors were 4010 standard gears and 4020 with hydromatic. 4020 traded in late 70s for 4630 with synchro-mesh manual and 175 HP 'at the drawbar'. A 4430 with hydromatic soon followed.
Both of the '44' series tractors were traded in the early 90s by my brother on JD iron that I don't even know the numbers on. Big 'uns with front wheel assist. All sold now, dad has alzheimers and older brother has MS. End of an era for sure.

Farm is now all cash rented, 4010 is only John Deere tractor remaining.

[FarmerDale]

Since, as my moniker indicates, I am a farmer, I will weigh in with a couple opinions at this point.
First, on the 'A' pillar of our JD tractors, there is a metal plate that instructs the operator to let the engine run at idle for several minutes to cool the turbo. ALos, if the engine is killed while working you should attempt to restart as soon as possible. I have been following those instructions, and our 4440, which had been the workhorse until I purchase an 8100 5 years ago, just turned up 6100 hours. The only engine problem showed up this spring, when I suddenly had only 5 cylinders firing, and dust puffing out of the air intake. There was a broken pushrod, which JD says "never happens". 2 other pushrods were filled with oil, so all 12 got replaced.
Second, the JD of trucks would be the ones that cost a little bit more to purchase, a little bit more to maintain, and are worth more at trade / resale. Along the way, they do the same amount of work, but do it with a little more style and operator comfort. In my opinion that describes the GM trucks, but I currently own 4 Chevys with over 100k, so I am biased(both pickup brand and tractor brand).
Third, Mark, I have heard of some people freeing up the pistons on the 2-cylinder JD's. The process includes soaking the cylinder in kerosene or diesel for a couple days, hitting the piston with a sledge hammer, then repeating the process as required. This is second-hand information, so accept it as such.

[rjschoolcraft]

Farmer Dale,

Direct experience with the "freeing" technique occurred about 20 years ago with a 1936 Model A John Deere that had been sitting for about 20 years at the time. We didn't have to remove the head, but soaked everything in diesel fuel, put it in gear and pulled it back and forth (with a John Deere 720 Diesel) until they freed. We then pulled it around to pre-lube everything with the diesel fuel. It actually fired on the diesel fuel without any ignition wires hooked up. We got it running on one cylinder and drove it around a little (after replacing the diesel fuel with gasoline and connecting ignition wires) hoping the other cylinder would catch. It didn't. Dad pulled the rocker cover off the front. I rolled the engine through with the flywheel and we found that the exhaust valve was stuck open on the dead cylinder. Dad squirted some oil on the stem, and drove it closed with a hammer and wood block. I rolled it through again and it stuck open. Repeated this process several times until it would close on its own. Put the rocker cover back on and it started immediately and ran on both cylinders. Alas, it's been sitting since that one summer back in the early 80's and is probably stuck again.

Back on the original topic, oil has an upper limit on temperature capability. Natural oils will begin to coke (break down chemically forming solid deposits) above 320F or so while most synthetics can go a little higher. Mil-L-23699 aerospace oil can operate up to about 400F without coking.

If you shut a turbocharged engine down immediately after a hard pull, the exhaust temperature may be about 1300+F. At the instant of shutdown, the oil temp is not much above 300F because it has been continuously flowing through the turbo bearing cavity and back to the sump and through the oil cooler. Sump temperature should be lower than that. When shut down occurs, the oil stops flowing. All of that exhaust heat then soaks back elevating the temperature of the housing and the oil sitting inside. It is at this time that the oil is "baked" and breaks down. Therefore, if you let the engine idle until the exhaust temperature drops below 300F, there is no longer any heat source with the potential to drive the oil temperature higher and you save your oil from coking. If you don't have gages, idleing for two to three minutes should suffice. I rarely have to idle more than a minute to get the EGT down below 300F.

[ 06-15-2004, 11:46 AM: Message edited by: ronniejoe ]

[markrinker]

Our John Deere model 'B' had dual fuel tanks - one for gasoline and one for diesel. It was started on gas, and after it was up to temp, switched to diesel if you preffered. Dad said it would burn kerosene or "probably old drain oil". I never looked closely at the intake to know how this worked, but plan to study it more carefully this weekend when I travel home for Fathers Day. (Don't forget good old Dad!)

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