What would happen if you advanced the injection timing?

[Loco_Hosa]

This thread is so I can farther my understanding. I know that a Multifuel is VERY different than a 12v Cummins or a Detroit 6.2. Im expecting there to be a simple reason why this will not work on our trucks.

Advancing the injector timing in other diesels will result in EGT drop, which allows you turn the fuel up a bit more. (More power, more fuel economy, ect)

After reading the thread comparing differences between the LDS and the LDT engines one of the main differences I could understand was the injection pump. This is what sparked me doing some research, and now asking this question.

Feel free to explain all the hundreds of ways this will not work.

Theory's that come to mind: 1: The engines rotating assembly cannot handle the increased cylinder pressure. 2: The injection pumps timing cannot be adjusted efficiently.

 

[Heath_h49008]

As I understand it from my reading here....

The Multifuel engine is already very "advanced" in it's timing, as part of the multi-fuel function.

The fuel is injected in a non-atomized state onto the piston and in the "cup" at a very early point in the cycle. The flame is ignited and the fuel only burns on the surface of this puddle, until it is mixed by the compression/quench portion of the stroke and combusts more thoroughly. This "Staged combustion" allows second rate fuels to be heated, then mixed and burned.

This is also the danger for running propane or methanol in these engines... they enter in an atomized state, and will ingnite far before the intended point. That's fine on a Cummins, but on an LDT/LDS you have massive pre-ignition and might be looking for the heads you just blew off.

If I'm off on this description, please correct me guys.

 

[JOEDEUCE]

injection timing

So if I'm understanding this correctly..... if we were to retard injection timing perhaps the addition of propane and methanol would work a lil better.... but only for straight diesel use....

 

[JOEDEUCE]

injection timing

I wouldn't see a benefit in advaning timing more, and the thought on retarding timing , to try and run power adders like propane and methanol, brings me to the thought that the "lack" of fuel atomization by the stock injectors would still be an issue, since they are designed to puddle fuel on top of the piston. I suppose if you were trying to get an alternate fuel to light off in cold climates , an advance in timing might help...


Id like to see a LDT with custom pistons, copper head gaskets, a slightly reduced compression ratio, a good set of fuel atomizing injectors, and a good turbo...... and see what it does

 

[Heath_h49008]

For that much money invested, you could just drop in a DT466 out of a schoolbus and crank it to the moon.

 

[Loco_Hosa]

I wouldn't see a benefit in advaning timing more, and the thought on retarding timing , to try and run power adders like propane and methanol, brings me to the thought that the "lack" of fuel atomization by the stock injectors would still be an issue, since they are designed to puddle fuel on top of the piston. I suppose if you were trying to get an alternate fuel to light off in cold climates , an advance in timing might help...


Id like to see a LDT with custom pistons, copper head gaskets, a slightly reduced compression ratio, a good set of fuel atomizing injectors, and a good turbo...... and see what it does

From everything I have read, it would ventilate the block and not be able to run on WMO.

I was just wondering if this was a legitimate way to decrease egts

 

[JOEDEUCE]

Wmo

I've heard so many things about running that stuff, some say its great, others say its terrible..... however you dont see it listed as a suggested alternate fuel....no matter what your opinion is on waste oil is, its not something intended to go into the tank.

 

[JOEDEUCE]

Dt466

I seen a thread on somebody trying to do a DT 466 swap, didn't sound very convincing to me. Think I'm going to be the LDT guinee pig I have some ideas about swapping to self sealing copper gaskets, and better injjectors,retime the pump, and basically leave the pistons alone

 

[Loco_Hosa]

Your absolutely correct, but I get a kick out of running it. I filter down to only 2 microns, and separate water. My trucks a bit hard to start, but I have a few theory's on that. Till I move I cant work on it or drive it anyway!

If I did blow up my Multi, heaven forbid, it be a tough call between another multi and more WMO or a more modern and more efficient diesel engine.

We all take the facts that we like on the forum, and we kind of dismiss the others. I have read that the block is weak, so even if you custom made an entire rotating assembly, you would still loose #6. My question about ignition timing was more for increased fuel economy.

I want my deuce to be able to do many long trips and efficiently as possible. I put 3000 miles on my truck in only about 2 months. Filtering WMO takes time, and if I can somehow squeeze 2 additional MPG out of my Deuce, I am a ****ed happy bass mother trucker.

Speed and acceleration are less important. I am in no hurry.

 

[Loco_Hosa]

I seen a thread on somebody trying to do a DT 466 swap, didn't sound very convincing to me. Think I'm going to be the LDT guinee pig I have some ideas about swapping to self sealing copper gaskets, and better injjectors,retime the pump, and basically leave the pistons alone

(From what I have read)

This will increase your power, at the cost of your engine being multifuel, wouldnt it be so much easier and cheaper to install a water injection system and crank the fuel up more? Or install an intercooler?

I think you would spend less money and have MUCH more power and reliability with a cummins or some such.

As another member said once, (Dont member who) some guys would like to go buy a Submarine, attach wings to it, to try and make it fly. Why not just go get a plane? You can try and make your LDT more powerfull, but its entire combustion chamber, piston, turbo, (The list goes on) are not designed to have high horsepower, they are designed to burn multiple fuels.

As apposed to the cummins diesels in the late 90s pickups, which as I understand it started out in industrial applications making well over 400 horsepower (around 800 torque) and could turn your deuce into a **** of a hot rod with so much less work.

All that being said, these trucks are terrifying when you loose brake pressure. (This is from experiance) I have been involved in extreme sports and motorcycles my whole life, power and speed are fantastic. Check your brakes thoroughly and replace EVERY rubber component before hopping up your truck.

My loved ones are driving small cars on the same roads as you, and the brakes in these trucks may be a pain in the ass and expensive to service, but they are FAR more important than power and speed.

 

[swbradley1]

Not to be argumentative (but it's my nature) why screw with the engine? Tune it up byt going through the top end or contact Westech and ask him what he does to get a nice running engine and let it alone.

I run mine at 45-50mph (maybe 52) everywhere I go and it's fine. It's an old truck meant to be driven slow. Why fly down the road, if you are slow that gives people more time to appreciate the truck as you go by.

Or put a more powerful engine in it and then watch the rest of the weaker drive line start breaking since it wasn't designed for it either. Mudguppies thread on the Cummins is a good one.

IMHO

 

[abh3]

Seems like it would be more effective to run the multi until it croaks and then go with a 5.9 while adjusting your fuel mix by thinning and/or heating your WMO. In warm weather I've run up to 50% clean WMO in a '91 Dodge Cummins!

 

[Loco_Hosa]

Not to be argumentative (but it's my nature) why screw with the engine? Tune it up byt going through the top end or contact Westech and ask him what he does to get a nice running engine and let it alone.

I run mine at 45-50mph (maybe 52) everywhere I go and it's fine. It's an old truck meant to be driven slow. Why fly down the road, if you are slow that gives people more time to appreciate the truck as you go by.

Or put a more powerful engine in it and then watch the rest of the weaker drive line start breaking since it wasn't designed for it either. Mudguppies thread on the Cummins is a good one.

IMHO

I do not disagree, however, I do plan to turn up my fuel. I posted this thread because I didnt understand why the injection timing was not discussed along with trying to reduce EGTs. I didnt know why it was discussed for so many Diesel engines, but not this engine. Now I do. The engines are very timing advanced from the factory, so it doesnt accomplish anything.

As I have said, I think its fun to pay less in fuel than a hybrid owner. Turning up the fuel will increase my MPG, which is awesome.

Now when that money tree sprouts? My finger nail clipping turn to gold? Ill put a big bad Cummins in, and pay the 4.50 for diesel. Ill also daily drive an 816, but thats another story.

 

[swbradley1]

I'll also daily drive an 816, but thats another story.

After doing two trails rides in a five-ton at the rally last week and the Hardball run to the VFW in Ferroequinologist's truck I'm wondering why I bought an 818 myself. They beat you to death and I was in the springer seat.




But it does have a Cummins in it, a 14 liter Cummins.

 

[Loco_Hosa]

After doing two trails rides in a five-ton at the rally last week and the Hardball run to the VFW in Ferroequinologist's truck I'm wondering why I bought an 818 myself. They beat you to death and I was in the springer seat.




But it does have a Cummins in it, a 14 liter Cummins.

That sound like a terrible frustration.... Tell you what. Ill trade ya

 

[JOEDEUCE]

pump timing

All very good points , sometimes its easy to get carried away with ideas that could potentially festroy an otherwise perfect running engine

As for increasing mpg, id say things like lockout hubs, water injection and maybe pump up the boost, with tires there can be a gain by going to singles as long as ya don't go too tall.

As for your opinion on speed vs braking, I will have to agree with ya there, 13,000-16,000 lbs isn't something ya want to be playing around with. My truck it fairly light at the moment and gets up to 40mph about as quick as I care to go.

 

[abh3]

I too enjoy the feeling of motoring in the woods for basically nothing on WMO. Sure there's the aggravation of cleaning it, though I'm working on a centrifuge to ease that pain, but it makes sense in so many ways...

The 50% WMO in the Cummins worked surprisingly well so don't discount them, my problem is that the Alabama Dept of Revenue is a pain about checking fuel looking for 'untaxed fuel' in road vehicles, 'untaxed fuel' means ANYTHING other than on-road diesel...

 

[Hammer]

You want better mpg, build boost sooner (I am not saying you have to build a lot, just sooner.)
This will one of the few things that will make more torque under the power curve by helping to atomize the fuel that has pooled in the piston cup.
Only 3% IIRC is combusted from direct atomization of the fuel injection event. To atomize the rest of the fuel, the engine relies on high compression and a controlled air flow.
The air flow is one thing we can influence here.
Getting a better turbo with a wastegate to bring in full boost quicker and lower in the rpm range will dramatically change the power curve, and if driven for it, greatter MPG. And also be able to limit the max boost pressure.