Wet stacking after startup

[velociT]

I figured like most diesels, the best thing once started would be to high-idle.

I just wanna make sure I got this right, after seeing this label:

Is it really ok to idle under 1k after startup?

 

[Westex]

I personally disagree with the decals. High idle the thing to get the oil pressure up. Especially with 2, yes 2, dry upside down canister filters. This gets the filters filled faster and pressure lubes the assembly. I know there will be disagreement, but whatever, I've torn down lots of engines. Hit 2,000 rpm when it fires and keep it there 'till you get pressure.

 

[Westex]

I personally disagree with the decals. High idle the thing to get the oil pressure up. Especially with 2, yes 2, dry upside down canister filters. This gets the filters filled faster and pressure lubes the assembly. I know there will be disagreement, but whatever, I've torn down lots of engines. Hit 2,000 rpm when it fires and keep it there 'till you get pressure.

Oh, forgot, once you get pressure, THEN let it just idle on a multifuel. Lubes the turbo.

 

[BugEyeBear]

These procedures are focused around preventing Turbo damage.

Coking & bearing failure can occur if shut down when very hot.

Thermal temps differences are a concern at start-up as the oil is relatively cold compared to the exhaust gas temps. Putting a lot of heat into the turbo & cooling it with "cold" oil at start up can cause turbo failure.

ALSO Cold Oil is THICK Oil, so it doesn't flow to the turbo as quickly/freely. If you rev the engine during warm up the turbo might not have received a full supply of oil yet.

Allow it to warm up. & allow it to cool down. This will prolong the turbo's life!


http://www.turbo-power.com/how.html


(This is another argument for always doing a hydrostatic lock check prior to starting. Especially on a cold engine. This will have the added benefit of helping to build oil pressure prior to starting.)

 

[WillWagner]

I personally disagree with the decals. High idle the thing to get the oil pressure up. Especially with 2, yes 2, dry upside down canister filters. This gets the filters filled faster and pressure lubes the assembly. I know there will be disagreement, but whatever, I've torn down lots of engines. Hit 2,000 rpm when it fires and keep it there 'till you get pressure.

OUCH! You are a brave soul...and lucky.

 

[fireman9]

Not in any of my trucks......idle, idle, and more idle and after driving more idle time to cool down the spinning power genie.

 

[stumps]

I personally disagree with the decals. High idle the thing to get the oil pressure up. Especially with 2, yes 2, dry upside down canister filters. This gets the filters filled faster and pressure lubes the assembly. I know there will be disagreement, but whatever, I've torn down lots of engines. Hit 2,000 rpm when it fires and keep it there 'till you get pressure.

I think I can see why you have torn down lots of engines. That has to be the worst advice I have seen in a long while.

Faster is when the bearings are under the greatest stress. It's the worst time for them to be without oil.

Let it idle.

-Chuck

 

[Westex]

All post so far are in cold climates. Understood. It's hot here. It's all about pumpability. And by the way, I tore down the Other guys' engines.

 

[Westex]

O.K., re-read the thread. I do agree to let it idle for 5 minutes before you shut down. That is extremely important. I was referring to the start up cycle. I back down on my advice for anyone in a cold climate with regular oil in the sump. Sorry, but this is Texas and it's generally plain hot here.

 

[bassetdeuce]

Right or wrong, this is what I do whether its a Multi or a Cummins: 1. Start up 2. Get the engine up to 1000 RPMs and hold it there to build up air pressure 3. Once the pressure is up to 100psi, idle normal for about a minute. 4. Drive gently, keeping RPMs below 1600 until the engine is up to 120 degrees. 5. Drive normally. All of this goes out the window if Im in a hurry READ: zombie attack, or dad getting impatient

 

[fireman9]

I understand that it gets hot in Texas, But it gets hot in Connecticut too. We have a fair share of 90's in the summer. BUT hot to engine oil is 200+ and flows different at that temp than at ambent temp when your at start up. Cold oil is thick oil and makes more pressure than thin hot oil. That said I still wouldn't push the starter and hammer down the throttle hot or cold weather the truck has sat a week or was running 20 mins. ago

I'll wait till the oil pressure has come up then throttle up some to build air pressure and tempature weather it my Maxidyne 285, 6-71 or the Deuce.

 

[WillWagner]

Maybe that's the reason there are so many failed after rebuild engines? Operator error.

 

[BugEyeBear]

Cold Oil is thicker & more resistant to flowing freely.

That is why Cold Oil builds more pressure than Hot Oil. (esp at idle)

But in this case higher pressure is more an indication of flow resistance that it is of flow volume. The increased pressure is required to force the cold oil to flow.

Lower viscosity oils are typically installed in cars during winter operation to counter this characteristic. Cars with "summer" oils in them are harder to start in the winter & oil doesn't get to parts as quickly at start up. But the Oil Pressure Guage will zip up to HIGH right away!


To illustrate this take 2 plastic bottles of pancake syrup.
Put one in a cold refrigerator.
Put the other in warm water.
Leave them to "soak" until the one is well chilled & the other is quite warm.
Open the cold one and squeeze. You will notice that the syrup resists flowing & requires significant pressure to squeeze it out of the bottle.
Now open the warm one and squeeze. You will see that the syrup flows freely & requires very little effort to quickly cover your pancakes!


Think of your Turbo as being these pancakes. I like mine with plenty of syrup!

 

[clinto]

http://www.steelsoldiers.com/deuce/5534-discussion-slobbering-multifuel-cure.html

http://www.steelsoldiers.com/auxillary-equipment/39373-what-wet-stacking.html

 

[GoHot229]

I start up and listen for the oil to arrive at he bearings, about 10-12 seconds, at which time it sounds different 'quieter' and after that increase the idle till it is smooth, somewhere about just under 1,000 (if my tach's right), mabe 800 rpm, and idle there for several minuates before take-off to drive. Id think reving dry bearings could increase wear or catastrophic failure likleyhood. And on shutdown, since I'm in a rural place, I have the luxury of slowing down to third idle about a block from my place and idleing on up to where I park and then setting for two or three minuates at idle before shuting down, for a total of 5-6 minuates at idle. This is wrong?

 

[cranetruck]

Sounds about "by the book" Gohot, engine should go to idle on its own, though.

Read about it on the old site PS mag section. Steel Soldiers :: Military Vehicles Supersite

 

[GoHot229]

I'm a little stumped here, so I re-read as Westex said, and heres my thoughts. Supose a multifuel takes a certain amount of revolutions after start-up before the oil arives at the galleys and initally starts lubing the bearings. Lets sa this amount of 'crankshaft' revolutions amount to say 600 complete revolutions before the oil is pumped, fills the cans and travels to the gally and then is directed to each bearing, and in just a moment all bearings are recieving oil..................................................OK, prior to that time the bearings are DRY, so from start-up time untill lube time, it's dependant on oil-pump revolutions to make the oil travel the distance it needs to go to finnaly hit the last bearing in the sequence of bearings, since its a pathway (the gally) and the oil arives at the first then the second then the third and so-on untill finnaly the last in that line of the oil flow is reached.....then of course you have uninterupred, constant oil flow to the entire system. SO.....My thinking is this: if you rev at startup, you risk higher abrasive loads on the bearing shells, and revving only gets the oil there quicker by virtue of (our time scale) not the motors time scale. since it takes a certain number of revolutions for the start of oil travel to come to the end of its destination.....either slow or fast revolutions of the crankshaft will have the oil ariving at the same time.......let me expound to clarify. We'll say the entire distance through the internals of the engine that the oil travels before it drains back to the sump is 4 inches of linear distance per 1 revolution and the entire path traveled through the oil gallys is 6 foot, each revolution will force the oil 4 inches, first r=4, second r=8, third r=12, fourth r=16 inches and so-on until the entire 6 foot is traveled. So reving does quicken in terms our our time, BUT it is ultimatly a matter of how far each revolution moves the oil through the path. And if we increase the rpm right from start, we increase harmonic load considerably, mabe ten-fold ......With-out oil......

 

[GoHot229]

Right or wrong, this is what I do whether its a Multi or a Cummins: 1. Start up 2. Get the engine up to 1000 RPMs and hold it there to build up air pressure 3. Once the pressure is up to 100psi, idle normal for about a minute. 4. Drive gently, keeping RPMs below 1600 until the engine is up to 120 degrees. 5. Drive normally. All of this goes out the window if Im in a hurry READ: zombie attack, or dad getting impatient

Air pressure is ultimatly unimportant in that it is only needed to run aparatus's that operate in the air system, and are entirely seperate from the oil system, which is VASTLY more important than air supply My suggestion is let the air build slowly, its not anywhere as important as lubrication supply, a short while it will fill anyway as the motor is idleing. NOT abrasing the bearings is of vastly more importance. If I'm wrong, someone please correct me. Ultimatly the end-product is complete circulation of oil with as little wear as possable. Before it is Driven at speed.

 

[cranetruck]

How long does it take for the bearing surfaces to be truly dry? A thin, residual oil film may be okay for low rpms, but not so good for say, above 1,000..?

 

[GoHot229]

As Cranetruck says, This is a variable also. Which leads me to wonder about such items as Duralube which claims to adhear to the crank journals and bearing caps, (And everything it touches) for a greater amount of time, before the coating of lubrication is exhausted and not on the surfaces but returns to the sump over time between starts. To me, it's only about engine longivity, period, so whatever gives that to me, Ill do. Ultimatly what I'm trying to acomplish is the least amount of wear possable upon start-up on the rod and main bearings. LanceRobinson's comment below about pulling the stop cable out and cranking for several seconds sounds to me as the best head-start for the lubricaton system possable, barring a pre-oiler or a Jatonka filter system. When I do start up and go through the warm-up, I go to the road and travel up to speed slowly, within a mile or two until I'm comfortable with the motor responce and ability to run smoothly at speed. But Yea, I have seen those tale-tale spots, minimal but none the less there.