https://www.truckandenginemanufactur...df&C=documents

From August 2005...

 

That's why I have a DCR.

 

Sure... but even if I did, I'd still use additives for additional cetane and for keeping the fuel system clean...

And pretty wild they were recommending that in 2005 IMO... for 460 rated fuel that is...

 

Similar info from bosch in the summer of 2002...






Back when I was driving a 1984 Dodge Aries-K coupe after getting my license....

 

As far back as I can remember, diesel HPFP's were always the weak link and diesel additives were even used back in the 80's. Having said that, I thought Ford/Navistar/CAT was smart when they implemented the HEUI injection system.

 

There you go... "many low numbers" of the widely varied cetane levels of 44 to 57 in different US fuel samples (why I use add additives that adds cetane) AND "80% of the various samples Lubricity greater than 460 Microns" (again why I use lubricity additive)...

Great post... thanks.

In 2002, was already on the police dept and driving my 1996 F250. Graduated HS in 1984 and already had my driver's license....

 

The presentation is interesting in that it implies that wear exceeding 10 microns will lead to failure and that at 1000 hours of use with fuel a little worse that US standard is when 10 microns is reached. I guess that since I am at 938 hours and 31K miles I am almost at the point of failure. One MAJOR issue with the presentation is that the pump referenced throughout the presentation is the Bosch VE pump, which is a totally different design than the CP4. You cannot equate the wear characteristics of the two and the presentation is over 20 years old, a lot has changed since then.

 

So, looking into the Bosch VE pump, it seems that there can be internal pump wear which involves the cam ring and roller (sound familiar?) and plunger and barrel wear. While I am not a diesel fuel engineer or even a mechanic, but this does sound like the VE pump had its fuel related problems. The company that manufactures the pump put that out about fuel being used in vehicles with the VE pump. Yes, pumps did change and with higher pressures of common rail fuel systems, it seems that fuel related issues can be more of a problem than the days of lower fuel pressure applications like the Bosch VE pump.

As to your own your truck, you have to decide where your comfort level is and it appears you are not worried. Good for you... we all have our opinions and comfort levels when it comes life and our trucks.

While I will admit that the numbers of true CP4 failures that are fuel related (and not owner error related like gasoline, DEF or lack of maintenance) are probably low compared to the actual units out there running and driving, the fact remains that failure CAN happen and it DOES. That said, all fuel being sold around the country is NOT the same. Some are better than others. Question is, how would you know?

Me? I'm not a "roll the dice and run" guy... and not since I became a LEO. I respect Mr. Murphy's outlook. But to each their own and YMMV... I could be wrong, but this is my approach and mine only.

If the 922k mile CP4 of You Tube fame proves when it came out in like new condition, it says something, just depends on your outlook, about running fuel additives. My two cents...

 

yes, it’s a shame it didn’t catch on as they were working on hydraulic valve actuators to make the engine entirely electronic.

 

You totally missed the point, reread my first sentence. The presentation implies that at 1000 hours of usage the pump is near failure at near US fuel standard, if this was true for the CP4 then LOTS should fail at @30K miles, which is not the case. Metallurgy and hardening techniques have changed in the over 20 years since that presentation was done. The same testing of the VE pump should be done for the CP4, Bosch probably has done this but they have not released it. The VE to CP4 comparison is like comparing a Porsche to a VW bug, same company so they should be the same, right? The CP4 is prone to failure and yield catastrophic damage, but it also has many examples of long life. Religious use of additives does not guarantee problem free use, one user on this forum had a failure at 20K with additive use at every fill up. The true root cause, not user caused (gas, water, DEF in fuel) probably is due to random manufacturing defects. The level of risk one is willing to take will dictate their response. The "I don't care" will do nothing and just drive it. The "I am concerned" will do one of the following: use additives all the time, install a DPK or do both. The risk avoidance one is install a DCR, this is my choice since I tow a travel trailer on long trips, sometimes to somewhat remote places and I am very risk adverse.

 

This has become my take on it as well.

My longer version... lubricity matters, but I don't think lubricity is the whole story. If roller-on-cam contact were automatically doomed without perfect lubrication, then the 7.3 Godzilla lifter (indulge me on some apples to oranges for a moment...) should be one of the safest parts in the Godzilla engine. It sees lower load, with pressurized engine oil, anti-wear additives, and no high-pressure fuel plunger to drive. Yet those lifters can fail in a way that looks awfully familiar, roller distress, bearing failure, cam damage, metal contamination.

That tells me the common denominator is not just lubricant quality. It is design margin.

A CP4 survives at all in a brutally worse environment than a gasser lifter. Imagine if you could put a CP4-style roller/tappet mechanism into the 7.3 lifter's operating world, I'd expect it to be boringly durable. The fact that the 7.3 lifter can still be a known failure point suggests somebody accepted a part, supplier, bearing design, heat treat, or tolerance stack that was only barely good enough.

And I think the same logic applies back to the CP4. Yes, lubricity additives may help. But additives don't turn a marginal mechanical design into an overbuilt one. If the pump's fate is heavily influenced by surface finish, hardening depth, bearing quality, alignment, tolerances, or tiny production variation, then fuel additive may move the odds a little, but it does not eliminate the lottery. Some of you got a good pump, and some of you got a bad one.

In other words, I'm not saying lubrication is irrelevant, I'm saying I think we tend to over-blame lubricity, hope too much for solutions in lubricity, and let the design off the hook. A robust design should have enough margin that normal fuel, normal oil, and normal manufacturing variations don't decide whether you get a long-lived part or a grenade.

 

I would love some more information on this either links or anything you could share. I have worked on both the Navistar and CAT HEUI at the dealer level before and during the transition to HPCR. I always felt a separate tank and pump for hydraulic oil to feed the HEUI system rather than using engine oil would have fixed most of the troublesome issues with the system.

 

Wow I just got a flashback...I remember many years ago my cous told me while he was getting trained on the brand new 7.3PSD back in the 90's, he learned that I guess Navistar was working on a hydraulic valve actuator but don't know why it didn't make it to production.

 

IMHO lubricity is a component (one of the fuel I have some level of control over) of the puzzle but just one piece. Central to all this is the design of the CP4, Bosch went aggressive with the design of the pump to make it modular and higher pressure than most consumer grade injections pumps available at the time. This lead to very tight tolerances, high pressures and low margin for errors (installer, user and manufacturer). Bosch has made some 60+ million of these things worldwide, which is more than stanadyne (the pump manufacturer for the DCR) has made in the entire 75 year history of the company. It can live at pressures a CP3 can not, however it does has its famous pitfalls.

 

I wholeheartedly agree the CP4 is a very different animal than the VE pump and the report is less polished than I would like to see. The 575um data set that just stops... why? Implied pump failure, unacceptable wear accumulation, excessive wear rates..... printer ran out of ink... what? Also the 'many high/low numbers' and 'ok' utilized on the slides would have gotten me eaten alive 20+ years ago in my materials science class (awesome class, got to break so any things).

Conversely, the VE pump, which I believe dodge spec'd on the 89-93 B series engines they got actually might present a bit of a worst case scenario since that pump was designed long before ULSD was a thing. You are 1000% correct that no external entity will change the design and function of the CP4. It all comes down to risk appetite. Fortunately for all of us, there are a lot of options now for varying degrees of mitigation.