IP Pump Calibration For Economy

[SasquatchSanta]

Floridianson Wrote:

Sounds like you had your hands full. You still thinking about lowering the numbers.

Yes, I did indeed have my hands full. At the low speed (1,600 RPM) tests I was laying black marks with the front tires on a couple of the tests. The front wheels were locked up and the rears were pushing thefront wheels on the pavement. I can't help but think that doing these tests is hard on the truck.

Yes, I still want to lower the numbers. I'm making what I feel it too much blue gray smoke. I don't know what blue/gray smoke signifies but I'm making a lot of it.

Based on the test results (someone correct me if you feel I'm wrong or have a better idea) I think I need to turn down the primary fuel adjustement another flat and then start turning down the droop screw until I can tell a difference and then check the mileage.

I'm open for input.

 

[SasquatchSanta]

Streatch 44875 wrote:

May want to try higher gears for your load test. Less strain on the drivetrain/brakes.

I think you are right. Perhaps the military called for 1st gear in the tests for safety reasons --- so the truck wouldn't be running too fast when it blew up.

 

[OPCOM]

well you already got the big tires on it.. do you have an air-shift? disengaging the front driveshaft will make a 1-2MPG difference when used with lockout hubs.

 

[SasquatchSanta]

Yes I have an air-shift and lockout hubs

 

[Floridianson]

That was first gear high range right? By your numbers the 9.66 and the book 9.82 you are at the top end for the main and your 6.66 is just a little high of the book 4.91.
So to see if the droop screw does affect your pump you could mark where you start and turn it clockwise maybe 1 full turn?

 

[Floridianson]

Black smoke is the most common emitted from diesel engines and indicates incomplete combustion of the fuel. Black smoke causes can vary widely and include ..

Incorrect fuel injection timing
Dirty or worn fuel injectors
Over fuelling
Faulty turbocharger, or turbo lag



White smoke is caused by raw, unburnt fuel passing into the exhaust stream. Common causes include ..


Incorrect fuel injection timing
Defective fuel injectors
Low cylinder compression
Low cylinder compression may be caused by leaking valves, sticking piston rings, ring wear, cylinder wear, or cylinder glaze.

When white smoke occurs at cold start and then disappears as the engine warms up, the most common causes are fouling deposits around piston rings and/or cylinder glazing.


Continuous evidence of white smoke indicates a mechanical defect, or incorrect fuel timing.

Faulty or dirty exhaust gas recycling (EGR) system
Incorrect valve clearance
Incorrect fuel to air ratio
Dirty or restricted air cleaner systems
Over loading the engine
Poor fuel quality
Cool operating temperatures
High altitude operation
Excessive carbon build-up in combustion and exhaust spaces
Black smoke can occur across the entire operating range, but is usually worst under full power, or during the lag before the turbocharger boosts air supply to match the fuel usage such as in the early stages of acceleration and during gear changes. Moderate turbo lag smoke is acceptable, otherwise black smoke should be hardly visible in a correctly running engine.White smoke ..

 

[SasquatchSanta]

Yes ... I was in high range.

It sounds like we are thinking alike.

The last thing I want to do is invite completities but I wonder how changing the timing would effect overall fuel effitiency. If you've got an engine that was designed and configured to pull three of four times the weight its pulling does it stand to reason that it could/should be timed for a lighter load. My truck is a hobby horse. It's not loaded any heavier than a light duty pickup.

Thanks

 

[Floridianson]

Blue smoke is caused by engine lubricating oil burning. The oil can enter the combustion chamber from several sources including ..

Worn valve guides, or seals
Cylinder &/or piston ring wear
Cylinder glaze
Piston ring sticking
Incorrect grade of oil .. too thin and getting past rings, or valves guides
Fuel dilution of the oil, making it too thin.

Blue smoke is often evident at cold start, which can reflect reduced oil control due to carbon fouling deposits around the piston rings and/or cylinder glaze. Blue smoke should not be evident at any stage.



An engine may burn oil without the evidence of blue smoke, because good compression burns oil quite cleanly, however, it is not acceptable for any new engine, or engine in good internal condition to burn large amounts of lubricating oil.
Sorry I had to copy and paste

 

[ken]

Your blue smoke could be comming from the turbo. It may not be hot enough to expand and let the piston ring on the turbine side seal. Are you doing this at normal engine operating temp? Also you may be loosing some effency from your dual exaust set up. I don't know how much restriction you added. But the longer the pipe the more restriction and the less effecent the turbo will be. What RPM are you turning at your normal crusing speed? I've noticed i get the best economy at 1800. But that's way too low ground speed for most tastes.

 

[SasquatchSanta]

I checked the oil today and found it to be 2 quarts low after approx 2,000 miles. Some of these miles were put on while weighing (grossing with trailer) 28,000 pounds so on a new (un-broke-in) engine I don't think 2 quarts low is out of line. My FDC is bypassed and my oil pressure is unchange from day one so there doesn't appear to be any fuel dilution. I had a person follow my today and he said the smoke was more gray than blue so maybe I made a wrong call.

I can't imagine that the dual exhaust is causiing a problem. The way the flow is split off into two voluntary streams I would think, if anything the added pipe volume would have less restriction than the original.

I was going to turn the droop screw down today but it started raining and I didn't feel like fighting with the elements. Given the relatively high manifold pressures during the 1,600 RPM full load tests I think turning down the droop setting will make a big difference in both smoke decrease and mileage incease. The LDS engine "may" be hitting the wall with the standard deuce air breather. If it isn't getting the air to go with the fuel it stands to reason that there would be smoke and high EGTs. I've got both.

 

[Srjeeper]

Santa, do ya think maybe the fact the engine is un-broke may have something to do with the color smoke?

Maybe it would be best to get it broke- in then start to change the settings after everythings seated-in and where it should be.

That's just my .02, but good luck which ever road you take.

 

[SasquatchSanta]

Srjeeper wrote:

Santa, do ya think maybe the fact the engine is un-broke may have something to do with the color smoke?

Maybe it would be best to get it broke- in then start to change the settings after everythings seated-in and where it should be.

That's just my .02, but good luck which ever road you take.

I don't know but with going on 2,000 miles on the engine I would "think" (once again, I'm not sure) it would be pretty close to being broke in. I'm going to change the oil for the first time tomorrow. I'm not sure how long you should run break-in oil before changing it.

 

[Jakob]

I'm almost sure large diesel engines are different. On gas engines generally the first oil is ran for about two hours of unloaded break-in (on a stand or in a parked car). Oil is changed then and ran about 500 miles during easy driving and then again at about 2000 miles after normal, and some hard, driving.

 

[SasquatchSanta]

This past Friday I finally got around to turning down the droop screw setting on the LDS engine in my bobbed deuce. The allen plug that gives access to the droop screw had been Permatexed and was a bugger to get out.

Previously, I had turned down the main fuel setting by two flats. Even with the two flats reduction, it still had ample power and LOTS of smoke. Friday I turned down the droop screw (screwed it in) 1/8 turn. WOW --- what a difference in smoke! It all but cleaned up the smoke problem and although it's early yet, I seem to still have ample power.

The access plug to the droop screw requires a 1/4" allen wrench. The actual droop screw requires a 1/8" allen wrench. It's a little difficult to find (by feel) the droop screw. When you insert the 1/8" allen wrench into the access hole it feels like the end of the wrench in coming up against a sold plate. After feeling around for about a minute it finally went in the hole and when I lightly turned it I felt it click.

I'm going to drive it for a while and see what the power factor is before doing any more tinkering. Given that I'm running up against cold weather and will soon be using straight number-one diesel it will be next summer before this project continues.

The way i understand it, the droop screw controls fuel delivery from idle to 1,600 RPM and the main fuel setting controls the fuel delivery from 1,600 to red-line.

When I installed this engine (an LDS-465-1A Tead rebuild) it was turned up way too loud/rich. The fuel density compensator (FDC) had been bypassed. I'm only guessing but It's my opinion that the pump was calibrated for an active FDC and then they bypassed the FDC without going back in and re-calibrating the pump. With any kind of load, EGTs would climb through the roof on the slightest grade. I didn't realize how bad it was until one day when I towed an M37 on my trailer.

Given the efficiency of the multi, I always felt there was some added fuel economy to be had, especially in bobbed deuces, by experimenting with pump settings. This latest go-around with the droop screw setting confirms ny beliefs.

One would think that leaning out the low end fuel delivery would also help control cold weather slobber/wet-stacking.

We'll see --- more to follow.

 

[Jakob]

Excellent write up, a lot of good information there.

 

[FMJ]

OK, I found the main fuel adjustment, but this doesn't look right to me. . . neither the main, or the droop screw are touching at zero thtottle. . . is this right????????????

 

[Billy Bobbed]

SasquatchSanta any update on your droop screw setting,and fuel economy.What MPG are you getting now.

 

[Floridianson]

Digging up old threads Billy?

Might as well keep it going.
FMJ was your motor running it the pic cause I don't see any oil splashing around?

People dont forget changing the main affects the outher. Main first droop /smoke cam next.

 

[Billy Bobbed]

You guys tested on the IP to see what it would do.You dont hear guys do the stuff you guys did.Thanks for all the info.I want to learn more about the droop screw or smoke screw.I turned my IP up,Im going to leave it alone for now.Trying to learn more on the adjusting of the fuel and the droop,smoke screw together wih out messing something up.