Wet stacking after startup

[LanceRobson]

Wet stacking is the presence of unburned fuel and, usually, moisture in the exhaust system when an engine is not running hard and hot enough to burn all the fuel and dry out the cold exhaust system. Most of it comes from fuel condensing on the relatively cold cylinder surfaces before it can be burned and the moisture is both a combustion by-product condensation in the cold exhaust and whatever moisture was in the exhaust system at start-up.

Extensive idle of the engine at too low an RPM to really warm up the engine can contribute to oil contamination and dilution due to unburned fuel condensate getting past the not quite seated piston rings and washing into the crankcase.

If you ever idled the engine for a while and on revving up had little (or not so little) black droplets spray out of the exhaust and stain your canvas, paint (and the wife's gold Le Sabre ), you're seeing the result of wet stacking.

Wet stacking after the 5 minute warm up is a sign that the engine is still too cold and if the truck is going to idle for a while the idle needs to be run up.

Regarding the "well here's the way I do it..." posts, the Department of Defense bought and maintained well over 60.000 of these things and I'll trust their judgment. I recommend following the instructions in the operator's manual.

A lot of folks keep the engine stop pulled out and crank the engine for several seconds to begin filling the oil filters before starting up. We do that, especially when the truck hasn't been started in a while. It does shorten the time to oil pressure considerably.

From memory, the -10 manual instructs the operator to use a faster idle (1100 RPM?) AFTER the five minute warm up if the vehicle will be idling for a long time. The 2 strokes have more wet stacking issues. When some of the Detroits in military applications were going to be extensively idled they wanted to be idled as high as 1400 RPM to warm up enough to stop it.

Lance

 

[stumps]

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...

That is exactly correct. The oil pump pumps the same amount of oil per crankshaft revolution at 100rpm as it does at 2600rpm... plus/minus a little for pump leakage. The bearing load increases drastically over that same rpm range. You do not want to be hammering poorly oiled bearings at 2000+ rpm!

If you follow the -10's recommendations of cranking the engine for 5 seconds with the fuel off (to check for hydro lock), and then start the engine and let it IDLE until the oil is flowing, and the air is up, you will be doing the best you can for your engine. [better would require a pre oiler pump]

Do NOT under any reasonable circumstance race the engine up to 2000+ rpm on start up. You are ruining your engine. Crank it 5 seconds with the fuel off, crank it again with the fuel on, let it idle for a few minutes, then when the air is up, go. Drive it gently until it is up to temperature. Cold transmissions and differentials need a break while they are warming up too!

-Chuck

 

[oldshep]

If you have any worrys about oil pressure, just get the spin on filters. My truck gets pressure nearly 10 seconds sooner now. I would rather not run my truck at 2000 right after start up. A few seconds after startup up u can actually hear the turbo getting oil pressure. I am also a firm beliver in the Lucas Oil Additive. That stuff is sticky! Im running a gallon of it in my truck. The bearings oughta be in good shape!

 

[cranetruck]

Prelubing, OPCOM style, is the only positive way, even with the filters filled, it will take several seconds, 5 or 6 I have read....

 

[GoHot229]

This is getting long-winded, but the point of all this is durability of your motor for years to come by extending lubrication charicteristics of your oil system. The seperate pieces, the bearings and the turbo are to be considered. The sound I'm hearing on start-up without pulling the stop cable mind you, (Which changes immediatly due to Stumps suggestion) may infact be the sound of the turbo lubing up and mabe not the bearings as I had thought. I think the addition of Lucas as oldshep suggests is a debate and will continue to be debated in many posts to come. I however find His suggestion as just one more posative twards longevity of the motor. I have in the past used Duralube, and found immediate differences in running noise, and what seemed an mpg improvement. Not sure if that was not wishfull thinking. I guess the best thing we all could do is in order of cost, 1 do the spin-ons, 2 the prelube. But certainly LanceRobinson's instructions about start-up barring the ability to afford these pieces for the system, is affordable to all of us.

 

[cranetruck]

.....
A lot of folks keep the engine stop pulled out and crank the engine for several seconds to begin filling the oil filters before starting up. We do that, especially when the truck hasn't been started in a while. It does shorten the time to oil pressure considerably.
......
Lance

Cranking the engine with or without fuel must be included in the "time to oil pressure"unless it can be shown that a lower rpm is less harmful than a higher one. Typical cranking rpm is 200 to 300 rpm.

The military must have been aware of this problem because one of the improvements for the LDS465-2 engine included a higher capacity oil pump. Then again, the only positive method is prelubing...

 

[stumps]

Cranking the engine with or without fuel must be included in the "time to oil pressure"unless it can be shown that a lower rpm is less harmful than a higher one. Typical cranking rpm is 200 to 300 rpm.

Time (seconds) to oil pressure is immaterial. For example, it doesn't matter to the bearings if your deuce sits for 2 or 3 years without oil pressure.

What matters to the engine is crankshaft revolutions until oil pressure. Because the oil pump is geared to the crankshaft, and is of the positive displacement type, the number of crankshaft revolutions until oil pressure is the same at any
engine speed.

The bearing forces, however, are different matter. At low cranking speed, the forces are as low as they ever are going to be. At 2600 rpm, full torque, they are as high as they are ever going to be.

Since bearing forces are directly related to the engine speed and load, your engine life will be better if you can keep those forces minimal until oil pressure has risen to normal levels.

Crank for 2-5 seconds with the fuel off. Crank with the fuel on. Low idle until the air pressure comes up. Drive away gently.

The military must have been aware of this problem because one of the improvements for the LDS465-2 engine included a higher capacity oil pump. Then again, the only positive method is prelubing...

Changing to a higher capacity oil pump is usually done because the operating oil pressure is too low at normal operating speeds. This is usually caused by wide tolerances in the bearings, or by using an SAE 15W base oil (15W40) in an engine that was designed for an SAE 30 base oil. A higher capacity oil pump will also sometimes be specified for an engine that gets too hot. The oil is directly involved in cooling pistons, bearings, and other engine parts. The higher capacity pump could help out some on starting, but probably not enough to matter.

-Chuck

 

[bassetdeuce]

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.

I know, but I like to thoroughly check my brakes for air leaks and function. To me THAT is more important. I don't need to idle forever just to get going, so if I can kill two birds with one stone (warm up, check brakes), so be it. If <=1000 RPM is so harmful, why is fast idle on warmup so important for many other diesel engines? These are not delicate fine china, folks!

 

[JTugwell]

what about using lucas oil stabilizer? mix it 20% of the crankcase volume (so 6 quarts.) ive always used it in my trucks, and i just put it in the deuce last weekend. seems to shut it up quite a bit. used that mixed 80-20 with 15w-40 oil. if anything you would think it would keep a better film on the bearings, cyl walls, ect until the oil pressure builds. anybody have any input on this?

 

[oldshep]

you're right justin. when i put a gallon in my truck things did get alot quiter alot of guy with dumptrucks around here use it too.

 

[broman78]

what about using lucas oil stabilizer? mix it 20% of the crankcase volume (so 6 quarts.) ive always used it in my trucks, and i just put it in the deuce last weekend. seems to shut it up quite a bit. used that mixed 80-20 with 15w-40 oil. if anything you would think it would keep a better film on the bearings, cyl walls, ect until the oil pressure builds. anybody have any input on this?

Anytime you include an additive to your oil you change the properties of the oil. I'm not sure what Lucas oil stabilizer has in it and what oil you use. But if you gain viscosity you may loose anti-foam capabilites, or affect your zinc/phosphorus levels. I'm sure Lucas has a high concentration of Molybdenum. In the bigger picture of things do what you want with your truck and your money.

 

[rlwm211]

On my deuce I installed a set of JATONKA oil filter adapters to reduce the amount of time it takes before the oil pressure rises. I am pleased with them to be quite honest.
I start my deuce as follows:

1) After checking the oil, and coolant, I initially crank a cold engine with the engine stop pulled out for 3 seconds or so to make sure there is no hydrostatic lock.

2) I then crank the engine and when the engine starts, I wait until the pressure is at "normal" pressure for the temperature. Usually 3 or 4 seconds, or less.

3) I raise the idle to 800 rpm.

4) I do not even consider operating until the truck has warmed up. This is at least as long as it takes to build a full tank of air. Building air does not help warm the truck, but it does take a fairly predictable amount of time and is a way to "time" your start up proceedure. Since the heater is tapped into the head, you can "feel" the air coming out of the heater for warmth to see if the engine combustion chambers are warmed up. If the air is cold from the water in the heater from the head it is still too cold to operate the engine hard.

5) Shut down is as discussed. I idle the truck for 5 minutes or so. Normally, I use the time to unload any personal items in the cab, and to plug the power connector into the S-280 I have on the back if I am home.

Anyone who thinks about it realizes you have to allow oil to get through the entire engine before you work it in any way. Perhaps the lag in the oil pressure is an achilles heel for the multi fuel but I believe carefully treated the engine can have long and healthy life. Certainly just as in any other engine, oiperator care and maintanence is key to longevity.

RL

 

[bassetdeuce]

4) I do not even consider operating until the truck has warmed up. This is at least as long as it takes to build a full tank of air. Building air does not help warm the truck, but it does take a fairly predictable amount of time and is a way to "time" your start up proceedure. RL

This is what I do. You explained this in a much better way than I could.

 

[82ABNMP]

check this out.

What about Additives?

What do you think?

David

 

[velociT]

What about Additives?

What do you think?

David

Holy friggin crap.

Glad I've never used an engine oil additive

 

[rlwm211]

additives, slobber

The original post was about wet stack after startup. I am assuming that the original author was asking about the stack spewing gobs of wonderful black stuff on start. Mine does. It is mostly water and soot. Cap the stack, and make sure water cannot seep into your stack if it rains. That will minimize the slobber about as much as you can. Idle at 800 as I described and it will dry out quickly. That is all about that I can think of, except, do not park anything you like to be clean next to your deuce when you start it cold.

As far as fuel additive, I use POWER SERVICE in the white bottle. The diesel we use is very low sulfur and sulfur acts as a lubricant for the fuel system, and also I am sure it lubes the engine as well. You can do what you think best, but I believe the additve makes a big difference in how smooth my truck runs. Less clatter is good.
Just my two cents.

RL

 

[82ABNMP]

Oil freaks

Bob Is The Oil Guy - Forums powered by UBB.threads™

Just like we have a forum about MV's....all these guy's talk about is oil

More than I ever wanted to know

David

 

[Capt.Marion]

I set my truck at 1000 RPM on the hand throttle and let it sit until it builds up air pressure. This is 300 RPM above what idle is supposed to be, but is not high enough to damage the turbo before it gets fully lubricated.

So, yes, the best thing is to high-idle, but not too high.

 

[velociT]

As far as additive, I use POWER SERVICE in the white bottle. The diesel we use is very low sulfur and sulfur acts as a lubricant for the fuel system, and also I am sure it lubes the engine as well. You can do what you think best, but I believe the additve makes a big difference in how smooth my truck runs. Less clatter is good.
Just my two cents.

RL

I use powerservice in my TDI already, tried adding a little tcw3 oil this fill up too.

I don't even have my deuce yet, but in the GL pic, it had a capped stack.

I was referring to wet-stacking as in: Wet stacking - Wikipedia, the free encyclopedia

 

[82ABNMP]

Thanks

Thanks RL, I am new to the MV's and have copied your post on "how to start up"

Sorry if I have pushed us off topic.

D