Extremely interesting article about the HEUI and Oil Problems

[hammersley]

This is at the Ford site . It is very interesting - bottom line is contained in the post copied below: Read the 4th para...



A short discourse on Mobil Delvac 1 and its viscosity retention. I work with fleets that do 125,000 mile drain intervals in class 8 over the road use. Even in that extended service drain interval Delvac 1 comes out in grade. i. e. it is *very* shear stable. .

Likewise in off-highway, severe applications. Normal mineral base drain interval 250 hours, yet Delvac 1 easily goes 1,000 hours, even 1,250 hours, and stays in grade, with excellent TBN and additive retention. .

That said, we are seeing some unusual things occurring with HEUI's. One company I work with that normally gets 15,000 to 20,000 hours out of its CAT engines using Delvac 1300S 15W-40, is getting 2,500 to 3,000 hours on the same piece of equipment with the only difference being HEUI.

In CAT's case, we are requiring the oil to work at 3,000 psi levels. This level of fluid pressure idealy is using a high quality hydraulic oil; a very high quality base stock with hydraulic oil specific additization. We are seeing the high pressure oil pump gear plasticizing severely. The engines which are normally spotlessly clean have considerable deposits.



]I am suspecting that with the 6. 0 some of the same issues may be taking place; i. e. that of requiring the engine oil to perform at hydraulic levels of performance, which it has not been designed for.



It would be interesting to check particle counts to see what the ISO cleanliness levels are of the oils and then the (hopefully) positive effect of supplemental ultra fine oil filtration.

Also, it would be interesting to do some double testing with two labs to see how the vis's check. .





Full post (long) here...



http://forums.thedieselstop.com/ubb...&page=0&view=collapsed&sb=5&o=31&fpart=1[/url

 

[Blakers]

I don't know what HEUI means... and I have a petroleum engineering background. Please explain.



Blake

 

[Speedo]

I could be wrong but I think that it stands for Hydraulic operated, Electronic actuated Unit Injector



Gus

 

[CPjMech]

You got it Speedo.

 

[Blakers]

Is this what we have?

 

[Duluth Diesel]

No, the Fords have it.

 

[lmills]

From what I understand on the Fords the diesel is delivered into a chamber on the injector. After it is in there it is pressurized by a piston. The oil is what is on the other side of the piston doing the pressurizing. Unlike other diesel where the injection pump does all the pressurizing. Or like the new common rail that has one high pressure pump and the injectors are solenoid actuated

 

[gtobey]

HEUI

From what I understand on the Fords the diesel is delivered into a chamber on the injector. After it is in there it is pressurized by a piston. The oil is what is on the other side of the piston doing the pressurizing. Unlike other diesel where the injection pump does all the pressurizing. Or like the new common rail that has one high pressure pump and the injectors are solenoid actuated







You're right. The gallery for the diesel fuel is pressurized by the supply pump system, and feeds through the cylinder heads to the fuel supply chamber in the injector. The hydraulic (engine) oil is pressurized by the gear pump on the engine and is fed through the cylinder head in a separate gallery from the fuel. An o-ring seal on the injector separates the two from mixing. Simply stated, the electromagnet atop the injector allows high pressure hydraulic oil to push a intensifier piston/plunger down in the injector to deliver fuel through the injection nozzle into the combustion chamber. Signals from the computer tell the injector how long of a signal and how strong it needs to be to determine how much fuel is delivered to the cylinder.



Here're links to heui explanation:

heui cat heui

 

[HEMI®Dart]

HEUI Injectors = Crap?

 

[nickleinonen]

Originally posted by HEMI®Dart

HEUI Injectors = Crap?

no...



ford=crap :-laf [just poking fun dieselstop boys :-laf]

 

[fbaurley]

The ford 7. 3 had HEUI's also. They only thing I every heard was that the oil change interval was less, and if oil got excessively dirty, the could have some problems. This was the rumor about 5 or 6 years ago. The system is a Cat patented system, but they sold he rights to navisatar in the early 90s so they could use it on the 7. 3, but cat also uses it on its smaller engines. Its interesting form an engineering point, but seems complex. I believe it was the first system to be able to vary injection timing and pressure independant of engine speed.

 

[Blakers]

Sounds like it's kinda like the air injection systems used on huge stationary diesel engines.

 

[ChrisTucker]

So basically you are saying that Ford 7. 3 and 6. 0 do not use a high pressure injection pump??

 

[hammersley]

That's a Big 10-4

Not only do they not use a high pressure injector pump - there is no injector pump at all!

 

[Big_Daddy_T]

They use a high pressure oil pump. Referred to as a hpop.



The problem is there is hydraulic fluids and there is lubricating fluids. Believe it or not they share few characteristics. Used engine oil is a poor excuse for a hydraulic fluid. Great idea in its time but it seems outdated. It was cats way of getting by emissions for awhile. It has many benifits and many more problems.



It has very good cold starting capabilities. The injection event can be precisely timed or split. This is also possible with common rail. Ford has realised that common rail is the technology of the future and is moving in that direction.



The cost of the heui system is similar to a PLN(pump line nozzle), which is whats on the 5. 9 before the common rail. The problem is heui cannot deliver near as much fuel as even the lowly vp44. From an uprating point of view. 500hp would be close to max on fuel alone for a heui engine. The injectors fail and they are expensive compared to the little 30-50 dollar cummins injectors. The injection pump offsets the savings.



One of my coworkers had one of these engines. He replaced 3 injectors in a year and had replaced several before and more since. 150k on his truck. Not sure if this coincides with others experienced reliability but it did not inspire confidence in this setup.



The piston in the heui injector is a 7 to 1. Meaning 600 psi(oil pressure)would be 4200(fuel) at the tip. The hpop is capable of as high as 3300 psi. I believe it requires 650psi oil pressure to fire. Explains the slightly longer cranking time of the 7. 3.



The condition of the oil can greatly affect driveability. Any foam and your screwed(coincidently one of fords oil pan gasket materials caused severe foaming) A simple change from 15 40 to 10 30 can change the manner of the engine completely.



I believe this system would work much better in the medium duty apps as there is a much larger volume of oil. Making for a more consistent medium. Lessening the impact of oil degradation.



It was a stop gap for emissions and I think its usefulness has been outlived. Just like the vp44 is extinct. So too should the heui be. Ingenious but flawed.

 

[Big_Daddy_T]

As for the heui and oil viscosity. A pattern has been seen but it is very early to point the finger. What if it is from the egr? Is this heui system so different from the last? A lot of this oil is contaminated with fuel. Some of the original factory oil is still present in many of these engines in small quantities.

In other words. It is too early to tell what the real culprit is. Just that there is a pattern. I am intrigued.

 

[Royal]

The new 2004 VW cars have a simular system made by Bosch. They require a special synthetic oil that wasn't available in the USA several months ago. VW dealers were selling it for $12. 00 per quart.

 

[Big_Daddy_T]

Originally posted by Royal

The new 2004 VW cars have a simular system made by Bosch. They require a special synthetic oil that wasn't available in the USA several months ago. VW dealers were selling it for $12. 00 per quart.

Sounds about right. I would think they are getting off lucky at only 12 bucks a quart at the dealer. Im sure you could mail order a case from germany for cheaper than 5 or 6 quarts cost at the dealer.

Wonder why they would switch to an oil actuated unit injector. Youd think the ongoing issues with the PSD would be a turnoff for unit injectors.

 

[Gonzo 1066]

Originally posted by fbaurley

The ford 7. 3 had HEUI's also. They only thing I every heard was that the oil change interval was less, and if oil got excessively dirty, the could have some problems. This was the rumor about 5 or 6 years ago. The system is a Cat patented system, but they sold he rights to navisatar in the early 90s so they could use it on the 7. 3, but cat also uses it on its smaller engines. Its interesting form an engineering point, but seems complex. I believe it was the first system to be able to vary injection timing and pressure independant of engine speed.

IH also uses the HEUI on the 466&530,570 inline 6's

 

[Big_Daddy_T]

They really liked the idea I guess.