I just got done reading this series of articles. The author talks about a lot of tips for tuning and rebuilding your engine. He helped an owner-operator rebuild the 350 HP Cummins from his over-the-road truck to produce an estimated 900 HP @ the flywheel. The owner maxed out the dyno he tested it on at 750 HP @ 2100 RPMS @ the wheels and still had another 50 psi left in reserve from his fuel pump. They figure that's an estimated 937 HP @ the flywheel.

Frickin amazing!

http://www.dieselinjection.net/BRUCE...beginning.html

 

Lots of good info there on building up diesel engines. Most of the info is about pre-computer controlled engines, though.
Like our 12 valve engines.

One thing of interest they talk about, is how dangerous to engine life it is to ADVANCE THE TIMING.

Matter of fact, they generally RETARD the timing when boosting fueling levels.

Just the opposite of what most fueling boxes do to our computer controlled 24 valve engines...makes you wonder?

 

That article seems to be right in line with what all the mechanics tell me at my local Cummins shop.
I dont know what differences there would be between the timing on a 12 an/or 24 valve.
I have asked them (The guys at Cummins) several times about timing (on my 12 valve) and they will not take it more that +/- 2 degrees beyond stock specs.
They tell me that the more retarded the timing, the better it will pull, but the less power I will notice at higher RPM's and vice versa.

Just passing this along.
Thanks for the link welder27.

Rich.

 

There's more articles to read through if any of you are interested:

http://www.dieselinjection.net/BRUCE/

 

What you have to keep in mind when reading Bruce Mallinson's articles is that he has a different goal than most of us. He's after massive torque with million mile reliability from an engine that gets worked hard every day. For his customers it's unacceptable to sacrifice longevity for quick response and a high HP number.

Most of us want a quick truck with good fuel economy, and we only expect 300k out of it. And few of us work the engines hard on a regular basis. Most of us get away with stuff (advanced timing, high compression) on our trucks that would be a disaster on a big rig because we aren't working the engines nearly as hard.

 

The old days of taking your truck to Cummins, Detroit, CAT, etc. to have them turned up, are gone. Every mfg that I am aware of will not take the engine out of spec. This is due to legal reasons concerning the EPA. If you get fined and the paper trail goes back to that mfg. then they are in big trouble. Some may have you sign a waiver but most will fall along the lines of not doing it at all when you want to take an engine out of spec.

Wannadiesel is right. Torque has direct relation to what timing your pump is set at. Timing advance = a drop in torque and a rise in HP at a higher RPM as well as increased cylinder pressure. Since they are after torque, the last thing they want to do is advance the timing.

 

The timing on the Dodge 5.9 is retarded from what Cummins designed it to be to meet emissions specs. The 5.9 used in tractors is set at 19° and in the marine version at 22°.
You're not going to hurt your engine in any way at all by advancing the timing up to the 16.5° that most folks like.

 

Can you guys with "The Knowlege" please enlighten me a bit on timing?
This is my first Diesel and it is the 600 w/ the auto. The truck is being used primarily between 5,000 and 10,000 ft. above sea level, and with light loads (empty to 7,000 lbs. max), and is stock.
What is the timing set at now, and what would you set it at, under these conditions. What should I expect to see for gain in power, mileage, change to EGTs? Emissions is not a concern in my county, plus this unit sports the cat. conv.
Thank you kindly,
Mike

 

Mike, your Cummins 600 sports an electronic fuel system. Mechanical timing is out of your hands since it varies timing by the different readings that it recieves from your engine sensors. A "chip" or performance box will change the fuel curve, timing, and fuel rail pressure by fooling the ECM. So, basically, they change the timing on there own by sending signals to the ECM.

Before the 24v engines came out in 98.5. The 5.9 sported an all mechanical fuel injection system with a mechanical pump. This let the owner change his fuel timing by removing the gear on the pump shaft and advancing the timing of the pump. On the 1st gens with the VE rotary pump. All you needed to do was simply rotate the whole pump towards the engine about an 1/8" to recieve 15* advance.

 

Monty,
Thanks for the great reply. Of course, now I have NEW questions.....such as:
Does Altitude effect diesels as much as it does every gasser I have ever had?
Is there a sensor that factors in my altitude?
Are the chips for the 600 perfected at this time, or would it be better to hold off for a while since this edition is so new? I am not so set on bombing my truck for max performance as much as I am wanting to boost the efficiency a little.....yeah, I know....this is how it starts, and a couple of years later, I am looking at an all out bomber that is no longer streetable.
Just curious.....What kind of 0 to 60 times are you and others seeing with their various models?

Thanks again,
Mike

 

Altitude has less of an effect on turbodiesels than it does on a gasser, but there is still power loss at high elevations. There is a sensor that reads manifold pressure, but I don't know if it's absolute or relative. Perhaps somebody else knows that?

 

What really amazes me is that the 12V Cummins hasn't got a rpm-depending timing in the pump. Even older trucks from the 80s over here like the Steyr 12M18 sported a timing advance over rpm with a mechanical pump. The issues with too much timing and high compression combined with high boost at low rpm (high cylinder pressures) making you have to compromise between low end torque and high rpm efficiency were bypassed by this. The 12M18 is a military truck 6.6l I6 without intercooler and 180HP with an efficient range from 1100-2600 rpm. It's an absolute animal offroad due to the very controllable torque and you can drag a 109 cannon or an FlA around offroad all day long without any issues. Most bases upped the max amount a tad to get around 250hp without smoke or heat problems. It would be very ionteresting to mount such a pump on the ISB ....

AlpineRAM

AlpineRAM

 

This would be for the 12 valve mechanical pump engines...

Anyone know what the base timing setting is on a 24 valve ISB engine??

How much advance timing comes with an Edge EX box?

Why are there instances out there where an EZ box on an HO ISB and big injectors are blowing headgaskets, and other engine damage--supposedly due to the advanced timing of the fueling box??

 

The HO has a higher compression, bigger injectors will deliver the fuel earlier, and the EZ advances timing. Use high boost at low rpm and you can get into problems. The low end defueling of the ECM is negated by the EZ and the bigger injectors. I think that this is just a case of too much (timing)

AlpineRAM

 

That's what they talked about in that article...to get high torque at the low-end you need to turn the timing backwards and decrease the compression and increase the boost pressure. That way you don't have all the wear and tear on the engine. By increasing boost pressure you negate the effects of decreased compression by stuffing more air into the cylinder. And when you have more air, you can put more fuel in.