CR engine HPFP analysis

[specsalot]

It goes to a page of various manuals in from which the 6.7L (20mb) must be selected. Clicking on the 6.7L manual downloads that pdf.
Speaking of parallels to discussion here, check out this locked thread, also from FTE.

It's becoming clear that Bosch has a lot more CP 4.X pumps out there than any of us have imagined. The Ford thread was painful but clearly reflecting experiences here. I have a real sense that Bosch has also done a lot of coaching with Ford on this issue as well. Pretty sad excuse at damage control an example of corporate 'denial'. I guess the best defense remains being on offense.

I guess the bean counters believe the bottom line will go up if the service portion of the biz can make deny fly with the customer. Maybe they are just to Keynesian in their thinking - aka - "In the long run we're all dead." One thing is for sure - Anyone who keeps shafting customers like this is going out of business. Especially so in this economy.

 

[Niner]

It goes to a page of various manuals in from which the 6.7L (20mb) must be selected. Clicking on the 6.7L manual downloads that pdf.
Speaking of parallels to discussion here, check out this locked thread, also from FTE.

I spent some time reading that thread.... and you know what the common denominator is? Bosch, their procedure for warrantying any pump that is theirs for failure, lack of spares, lack of inventory, lack of availability, and long delays before you get your vehicle back and running... with denial, always water in the fuel, contaminated fuel, blue tech additive in the fuel, or poor lubricity of the fuel... always, someone or something elses fault for what is obviously again the rollers rotating in the bore and spinning 90 degrees out of on line with the cam, a defective design. It works for Bosch because all technicians do now it bolt and unbolt parts, they never look for the root cause of the failure... unless it's to deny warranty coverage. Look for water in fuel, look for gas in fuel... hmmm, check pressure sensor after everything else for defective fuel can no longer be ruled as the problem on the customer. A customer lacking savvy is a customer that will be on the hook, or their insurance company, if VW thinks they can get away with it. Criminal... really.

Bosch is the problem... their CP4.1 and 4.2 series are not up to the task, due to poor design... noticed how Delphi patented their shoe roller design?

Seriously... my days of owning anything newer with a Bosch fuel system on it are numbered. In this day and age, it's unacceptable. VW's first generation and attempt at clean diesel in the North American market is a failure. Time will tell, but I doubt the 2012 Passat has solved the problem for the HPFP either.

 

[N2UADTDI]

1. Pump inspections to illuminate internal condition.

2. Cleaning / flushing of the LP casing.

3. Periodic replacement of the follower piston / roller assembly using after market or Bosch OEM components based on Internal conditions.

I agree with this route...
So who's going to get started? If I had a dead pump I'd take it to the local machine shop to see what they think about making new parts (#3 above).

 

[specsalot]

Ive been in engineering O&M most of my working life. The suggestions Ive posted reflect typical responses of RCM to address the failings here. Can't say much more except I'm working on it. I have skin in the game. I'll be looking for beta testers from the out of warranty population if I get to the point where I have a working proof of concept I believe in. Commercialization becomes an alternative if VW / Bosch don't step up for customers. People bought these vehicles based on beliefs in their expertise and committments to customer service. Finding a lifecycle estimate of 150,000 km on VW's website was a real slap in the face for me.

 

[eddif]

1. Pump inspections to illuminate internal condition.

2. Cleaning / flushing of the LP casing.

3. Periodic replacement of the follower piston / roller assembly using after market or Bosch OEM components based on Internal conditions.

I agree with this route...
So who's going to get started? If I had a dead pump I'd take it to the local machine shop to see what they think about making new parts (#3 above).

Your thoughts are to fix the wear problem. Your only concern is to keep the whole system protected while you do your tests. I would suggest you provide some sort of filtratation protection for those running tests....

Of course my questions to you are:
1..If you do not add a filter between the low pressure side of the HPFP and the return fuel / high pressure piston, how will you protect the whole system while you run tests?
2..How will you know if you are cleaning the system before the wear material has gone to critical areas?
3..How will you protect the system if the replacement parts do not correct the wear?
4..How will you keep the wear material you disturb during the cleaning from causing total system failure? It talks easy to clean all the wear material out, but there is wear material (on some level) everywhere in a stock system.

This conversation is not intended to stop the tests, but provide a method to contain the wear materials you will possibly be disturbing during testing. I think the filtration comes first and then the pump improvement testing. 4 ea $8,000 USD failures ($32,000?) during extended testing is pretty expensive. Of course 4 ea $2,000 USD possible failures ($8,000?) would be bad enough. Hopefully with filtratation you would not have the $2,000 failures and just repair and test to your hearts content (replacing filters and defective trial parts).

After you have the new non wearing parts developed you can decide on the need of the filtration for everyone. I think that the filtration would be a good thing even with an improved HPFP.

A lot of people have worked in making suggestions for all of this.

The jerk from Mississippi

eddif

 

[N2UADTDI]

eddif,

Good points. Since specsalot is already working on the issues there's no use in more than 1 person doing the work. But if I were making mods or repairing pumps I'd set up a test system on the workbench and run it under computer control for days on end until it's proven to work or not.
Running tests on a car brings in too many variables - as you note.

 

[eddif]

eddif,

Good points. Since specsalot is already working on the issues there's no use in more than 1 person doing the work. But if I were making mods or repairing pumps I'd set up a test system on the workbench and run it under computer control for days on end until it's proven to work or not.
Running tests on a car brings in too many variables - as you note.

There is always a need for more people to be involved IMHO. When the design is a club effort you can choose the best product / effort. I was describing drilling holes in the HPFP when an adapter was mentioned. The thoughts were for two filters till I suggested two adapters and one single filter. I think right now we are still running on that idea, but there can always be better ideas as we interact. I have been slow in getting my own design adapter done.

eddif

 

[specsalot]

Comments in blue

Your thoughts are to fix the wear problem. Your only concern is to keep the whole system protected while you do your tests. I would suggest you provide some sort of filtratation protection for those running tests....
Of course my questions to you are:
1..If you do not add a filter between the low pressure side of the HPFP and the return fuel / high pressure piston, how will you protect the whole system while you run tests?
2..How will you know if you are cleaning the system before the wear material has gone to critical areas? Wear materials are likely present in all operating pumps building cumulative damage all the time. Cleaning is a remedial solution that will reduce damage. During every cleaning cycle inspection will reveal underlying conditions. This will be a PM task.
3..How will you protect the system if the replacement parts do not correct the wear? I'm honestly not sure anything can prevent this issue. As many here have pointed out this appears a design issue. Converting the LP body to oil lubrication may be one of the most positive changes that can be put into place. Not as easy as it would appear if you want something that can perform in summer and winter. A oil lube solution will need to be able to inform the owner of issues (level, pressure, temperature limits).
4..How will you keep the wear material you disturb during the cleaning from causing total system failure? It talks easy to clean all the wear material out, but there is wear material (on some level) everywhere in a stock system. The risk in every cleaning cycle would be migration of foreign material to the HP section. During cleaning the HP section is not on the pump. So all you can really do is to endeavor to get a good flush out followed by a visual inspection. If you can reduce the amount of foreign material, you will be lowering it's contribution to creating more wear material. Cleanliness during the process is key. So is doing a good final flush.
This conversation is not intended to stop the tests, but provide a method to contain the wear materials you will possibly be disturbing during testing. I think the filtration comes first and then the pump improvement testing. 4 ea $8,000 USD failures ($32,000?) during extended testing is pretty expensive. Of course 4 ea $2,000 USD possible failures ($8,000?) would be bad enough. Hopefully with filtratation you would not have the $2,000 failures and just repair and test to your hearts content (replacing filters and defective trial parts).
After you have the new non wearing parts developed you can decide on the need of the filtration for everyone. I think that the filtration would be a good thing even with an improved HPFP. As long as you use stock parts there is no such thing as non-wearing parts. The steps I've outlined are remedial measures not real fixes. Good enough to maybe buy time and extend life while controlling / managing the process to limit impacts. All engines have recommendations for inspection, wear limits, and conditional replacement of parts. Because there are none for these fuel pumps, these units progress to catastrophic failure. There is no magic fix that I can see here. These measures are a way to play the hand we've been dealt. Re-engineering pump internals hasn't done much good so far.
A lot of people have worked in making suggestions for all of this. Absolutely true and in the end this is how any solution gets built. One set of eyes and one brain are never enough.

The challenge in fixing something is always the same, finding the resources to devote to the problem. As I've posted before this is not an issue I really want to take on, but the waiting game doesnt look promising. I have time, some formal training and lots of machinery repair / overhaul experience. I'm hoping this will be enough to keep me out of trouble. So far it has and on many occasions I've been able to fix things my peers could not. I also have a friend (with similar training, even more extensive overhaul skills AND a full machine shop) who will help with prototyping and end to end solution design.
The jerk from Mississippi
eddif

 

[specsalot]

eddif,
Good points. Since specsalot is already working on the issues there's no use in more than 1 person doing the work. But if I were making mods or repairing pumps I'd set up a test system on the workbench and run it under computer control for days on end until it's proven to work or not.
Running tests on a car brings in too many variables - as you note.

There is always a need for more people to be involved IMHO. When the design is a club effort you can choose the best product / effort. I was describing drilling holes in the HPFP when an adapter was mentioned. The thoughts were for two filters till I suggested two adapters and one single filter. I think right now we are still running on that idea, but there can always be better ideas as we interact. I have been slow in getting my own design adapter done.
eddif

No one has a monopoly on ideas or development efforts. As far as I'm concerned the more the better. The test bench concept is a good one but not cheap. Setting one up would provide an ability to do a deeper dive on this issue. It can speed up the development process. I agree that this would be absolutely necessary if internal pump components will be changed. We all assume that Bosch did this extensively in their design efforts. Kind of makes one wonder why the let this solution our the door with out at minimum the PM's I'm suggesting to go with the design.

There is more likely more to these failures that we are able to conceive at this point. Remediation is probably a good target for this reason.

Another open question would be whether Bosch would ever permit derivative solutions to exist. One way to preserve the myth that there are no design flaws would be to crush any efforts to commercialize retrofits addressing them.

 

[N2UADTDI]

The test bench would not be easy or cheap but I personally don't like getting stuck on the side of the road by some mistake I made. I've done this before with hydraulic components I've rebuilt. Since then I don't need the test setup anymore.
I could imagine a 3 phase motor running off a 1 phase to 3 phase inverter for speed control. Short 'timing' belt and tensioner. Or direct drive if an adapter is made. Fuel piping, rail, and pressure regulator from a CR TDI. May not need the injectors. A computer can monitor the rail pressure and use the pump's PWM control and shunt regulator on the rail to run pressure testing of the pump.
If the goal is to only rebuild the pump back to OEM then the test bench would not really be needed.
The real question like you say is why did this ever get into production? Looking at the pump with the filter screens where they are - it's obvious they knew that the metal particles had to be contained in the pump. Then the only way the owner would know there's a problem is when the engine stops running. Otherwise metal particles could cause multiple problems elsewhere in the system with many trips back to the dealer and frustration for all involved.
I've been working with Bosch fuel injection gasoline systems for years and so far I'd have to say they are very reliable and top notch. Somehow this CR system got out the door in basically an unfinished state.
My 2 cents worth...

Specsalot - are you working on making replacement parts? So you could pull the parts out, clean it up and put the new parts in? All on the car?

 

[CedarPark68]

3. Periodic replacement of the follower piston / roller assembly using after market or Bosch OEM components based on Internal conditions.

If someone will supply me with a relatively clean follower piston / roller assembly .... I WILL PAY for the CUSTOM FABRICATION of a new and hopefully more robust offering.

In 12k miles, as I am at 24k, I would then be willing to drop this into my 2011 JSW.

If we could keep it from turning 90 .....

 

[specsalot]

Specsalot - are you working on making replacement parts? So you could pull the parts out, clean it up and put the new parts in? All on the car?

If someone will supply me with a relatively clean follower piston / roller assembly .... I WILL PAY for the CUSTOM FABRICATION of a new and hopefully more robust offering.

In 12k miles, as I am at 24k, I would then be willing to drop this into my 2011 JSW.

If we could keep it from turning 90 .....

I think Bosch will wind up having to "break this pump open" - (i.e. sell internal components). That is the easiest solution to replacement of the part most effected by swarf. There is a chance these internals are already available in Europe's supply chain. The follower assembly is clearly marked with a part number. Posters here have indicated that Bosch is already doing pump overhauls.

I haven't discussed the question of doing internal part fabrication with my partner. Right now we're focused on adapter prototyping to shift the pump to oil lubrication. Shifting to oil lubrication looks like the low hanging fruit. There are potential downsides. It's not a done deal. I resisted this idea for a long time before realizing it needs to be explored for feasibility and implemented if possible.

The consensus belief (I think) is that the roller typically doesn't turn 90 Degrees until the pump is already pretty much toast. Basically if you keep the swarf down you win the game. The key is changing out internals before rolling friction becomes sliding friction. That is how you keep the swarf down.

 

[manual_tranny]

I want to see someone replace all internal moving parts with titanium, then replace the bores with titanium sleeves. Add oil lubrication, problem solved.

 

[specsalot]

I want to see someone replace all internal moving parts with titanium, then replace the bores with titanium sleeves. Add oil lubrication, problem solved.

Did you say titanium or was that 'unobtainium' - It's wicked expensive to have parts manufactured in titanium. But I guess if Yamaha can make intake valves out of it, HPFP parts are possible

 

[eddif]

I want to see someone replace all internal moving parts with titanium, then replace the bores with titanium sleeves. Add oil lubrication, problem solved.

Do you have any details of order priority of which parts should be replaced 1st, 2nd, 3rd etc. I do not think it is reasonable to replace everything but there might be a part that is most critical. Could you give us the most critical part and tell us why? How does titanium wear against titanium? Might not some of the parts be of other materials?
++++++++++++

If someone will supply me with a relatively clean follower piston / roller assembly .... I WILL PAY for the CUSTOM FABRICATION of a new and hopefully more robust offering.

In 12k miles, as I am at 24k, I would then be willing to drop this into my 2011 JSW.

If we could keep it from turning 90 .....

Could you tell us what would be your rough guess as to materials of choice, dimensions etc. I think a cermet roller holder would be good. What are your material choices? Tool Steel ? Which parts would be which material?
++++++++++++

In discussing oil lubrication what rough thoughts do we have on:
1..How much added clearance will the slider require?
2..How much added clearance will the bearings require?
3..What viscosity oil will be needed 0W-5 (?) ? Other lubricant (?)?
4..How will the oil effect roller diameter needs?
5..What flow volume will be needed through the HPFP?
6..Will the filter act as an oil cooler?
7..What sump size would be needed?
8..Would a stock boost pump do for the lubricant pump?
9..How many microns would the filter need to be?
10..What is the estimated increase in drag using the heavier lubricant?
11..Will the bypass hole for the bearings need to be increased?
12..Will the stock seals be compatable with the new lubricant?
13..Can a lower chamber orifice bypass drain be fitted into the design?
14..What will be the new roller lubricant clearance?
15..What hose material will be needed.
16..Other things added by others???

Just a few things that go along with the discussion (some of which I have mentioned on another VW web club).

We have a huge lot of work to do, but every now and then we just slack off and look to others. We really need Grace to get all this done. Plenty of opportunities for everyone. Contact with some innovative vendors might yield results. Any contact persons out there?

eddif

 

[manual_tranny]

Guys, I don't know enough to comment on your questions.

My titanium suggestion was a half-joke, since 1. It might as well be "unobtanium", 2. It would add incredible expense with no guarantee for success.

But you have to admit... it sounds like something that might work...

EDIT: Titanium does not wear well.

http://www.ewp.rpi.edu/hartford/~le...ribological properties of titanium alloys.pdf

http://www.azom.com/article.aspx?ArticleID=1219

"Titanium Alloy Ti 6Al-4V, and Ti alloys in general, have a tendency to gall and are not recommended for wear applications"

 

[manual_tranny]

http://www.roymech.co.uk/Useful_Tables/Matter/Titanium.html

Grade 12 Titanium alloy including 0.3% molybdenum, 0.8% nickel. High strength. Good Heat and Wear resistance. Used for shell and heat exchangers, hydrometallurgical applications. industry. Good corrosion resistance: Highly weldable.

I'm not sure how the wear resistance compares to different steels. I'm looking for a chart of different metals/alloys' wear resistances. While titanium is still intended as a joke... it is probably worthwhile to investigate other materials.

 

[eddif]

http://www.roymech.co.uk/Useful_Tables/Matter/Titanium.html

Grade 12 Titanium alloy including 0.3% molybdenum, 0.8% nickel. High strength. Good Heat and Wear resistance. Used for shell and heat exchangers, hydrometallurgical applications. industry. Good corrosion resistance: Highly weldable.

I'm not sure how the wear resistance compares to different steels. I'm looking for a chart of different metals/alloys' wear resistances. While titanium is still intended as a joke... it is probably worthwhile to investigate other materials.

Manual
This is working out great. Science fiction is tomorrows technology. Jokes are fine, especially if they lead to learning something. Thanks for getting us started on the metals research.

eddif

 

[CedarPark68]

Could you tell us what would be your rough guess as to materials of choice, dimensions etc. I think a cermet roller holder would be good. What are your material choices? Tool Steel ? Which parts would be which material?

eddif

eddif,

I would combine some of my own due diligence with input from the company I select for fabrication in order to obtain the answers to you questions.

I am speaking of a like for like .... if I had a pump in my possession, I would consider other options, but since I do not I am only speaking of replacing the three piece follower/roller assembly. A simple drop in replacement.

This exercise may not offer any advancements or in fact over time may tell more of the story.

It is being said that the X labeled pumps are in fact being bored, again as I do not have a pump, I am not able to consider a sleeve/bushing.

Regardless of all of the above, without the three pieces in hand to farm out, it is all just conjecture as is candidly thus far, this whole thread.

 

[specsalot]

In discussing oil lubrication what rough thoughts do we have on:
1..How much added clearance will the slider require? A better question - Will the existing clearances provide for successful lubrication using oil instead of diesel.
2..How much added clearance will the bearings require? A better question - Will the existing clearances provide for successful lubrication using oil instead of diesel.
3..What viscosity oil will be needed 0W-5 (?) ? Other lubricant (?)? Clearly a low viscosity oil will be required.
4..How will the oil effect roller diameter needs? A better question - Will the roller continue to function as designed if oil lubrication is used in place of diesel lubrication?
5..What flow volume will be needed through the HPFP? A flow rate sufficient to remove the same quantity of heat as the original fuel flow + additional heat created by the friction of the higher viscosity of the lubricant.
6..Will the filter act as an oil cooler? Depends on location.
7..What sump size would be needed? Depends on overall design.
8..Would a stock boost pump do for the lubricant pump? Very likely yes but depends on the overall design.
9..How many microns would the filter need to be?
10..What is the estimated increase in drag using the heavier lubricant? Depends on the lubricant used.
11..Will the bypass hole for the bearings need to be increased? An adjustment will have to be made, but not likely in passage / hole diameter.
12..Will the stock seals be compatable with the new lubricant? Very likely yes
13..Can a lower chamber orifice bypass drain be fitted into the design??
14..What will be the new roller lubricant clearance? A better question - Will the existing clearances provide for successful lubrication using oil instead of diesel.
15..What hose material will be needed. Likely no change required from VW spec.
16..Other things added by others??? Will the spring need to be changed to a stronger one?

eddif

Great questions - The idea of oil lube is a relatively simple change. But it impacts many aspects of the current design. Lubricant selection will be constrained by the existing design and whether or not any internals are going to be modified. The is what makes 'design by committee' very difficult going forward. A diesel solution can be done "as is". But an oil solution holds out greater promise for longevity. This is where the PM items I've mentioned really come into play. They can mitigate the difference between a diesel solution and an oil solution. Right now we're all driving a Bosch diesel oil lubricated HPFP that works very well until it fails miserably.

 

[wreck111]

I had a question regarding the Bosch CP 4.1 diesel pump as i read on a VW forum there had been some failures with the cam and follower .
The pump is lubricated by the fuel so it occured to me that fuel quality could effect the reliability of the pump .
Got this reply from Bosch technical dept .
Incidentally i didn't ask a leading question with regard to the expensive diesel types ..
Subject: RE: CP 4.1 common rail diesel pump
Fuel additives are definitely important! It is not easy to recommend particular fuel brands though, but the special fuels (eg excellium) that the major fuel brands sell at a slightly higher price than standard diesel, should be beneficial even if only used periodically.

 

[specsalot]

Bosch seems willing to hedge their bets 6 ways to Sunday. Niner posted an article that outlined that most lubricity additives are basically surfactants. The article pointed out that surfactants may impact the ability of filters (if so designed) to remove water. This explains why some have reported cloudy fuel in the bottom of the VW fuel filters during element changes. In the past, anecdotally VW has called any thing out of the ordinary (like cloudy fuel in the filter) as 'contamination'. These days VOA seems to be taking a more generous relaxed approach with US customers. This circular logic on additives is enough bring us to tears. Especially if VOA reverts to their old customer attitude after the NHTSA Engineering Evaluation is concluded. I use additives because I believe this pump needs all the help it can get with lubrication. My local Dealer SA says that additives are not needed. That basically it's a waste of money.

 

[Niner]

Bosch seems willing to hedge their bets 6 ways to Sunday. Niner posted an article that outlined that most lubricity additives are basically surfactants. The article pointed out that surfactants may impact the ability of filters (if so designed) to remove water. This explains why some have reported cloudy fuel in the bottom of the VW fuel filters during element changes. In the past, anecdotally VW has called any thing out of the ordinary (like cloudy fuel in the filter) as 'contamination'. These days VOA seems to be taking a more generous relaxed approach with US customers. This circular logic on additives is enough bring us to tears. Especially if VOA reverts to their old customer attitude after the NHTSA Engineering Evaluation is concluded. I use additives because I believe this pump needs all the help it can get with lubrication. My local Dealer SA says that additives are not needed. That basically it's a waste of money.

Everyone is hedging bets...

http://delphi.com/pdf/diesel/FIEM_Common_Position_Statement_2009.pdf

Read the fuel lubricity comments too, and note that all the fuel mfgs wash their hands on amount of longevity out of components on 520 micron fuel, and that it will be shorter... but they show a graph elsewhere that 530 0r 550 micron fuel will limit the pump life to 1000 hours. If you average 35 to 40 mph over the life of the pump in traffic, thats 35000 to 40000 miles, just out of warranty.

 

[specsalot]

For sure a lovely situation. Reading between the lines at all the references to bio-fuels, it seems that biofuel tends to have 'out of blend' experiences. I've seen earlier versions of this statement. It's uninspiring unless your a shareholder in one of these firms. They are doing their best to cover their backsides.

The fuel biz has always been kind of slimy. I could tell a lot of stories here from my maritime days but they would not build any confidence in the supply chain. Know this - if you want a premium fuel the only way to get it is to pay premium pricing for it. Otherwise you get LCD ( the lowest common denominator - min spec). The challenge these days is just getting what you think you are paying for.

 

[HeAvYfUeL]

I had a question regarding the Bosch CP 4.1 diesel pump as i read on a VW forum there had been some failures with the cam and follower .
The pump is lubricated by the fuel so it occured to me that fuel quality could effect the reliability of the pump .
Got this reply from Bosch technical dept .
Incidentally i didn't ask a leading question with regard to the expensive diesel types ..
Subject: RE: CP 4.1 common rail diesel pump
Fuel additives are definitely important! It is not easy to recommend particular fuel brands though, but the special fuels (eg excellium) that the major fuel brands sell at a slightly higher price than standard diesel, should be beneficial even if only used periodically.

Time to fill up with VPower from time to time.

 

[oxford_guy]

I'm not sure how the wear resistance compares to different steels.

Iridium will probably do better than titanium, for a price!

 

[kjclow]

Actually titanium is not as inexpensive as it used to be. In the last three years, the price of ore out of the ground has more than doubled.

 

[oxford_guy]

Actually titanium is not as inexpensive as it used to be. In the last three years, the price of ore out of the ground has more than doubled.

Iridium is the second-rarest element in the earth's crust, as far as I recall. Only Osmium is rarer. Iridium is the most corrosion-resistant metal, also, from what I recall. It's also quite hard and is used for fountain pen nibs.

I don't know if iridium or osmium can be alloyed with iron or not, at least in a useful way.

 

[manual_tranny]

Is corrosion a factor in failing HPFPs?

 

[Elfnmagik]

There's evidence it is in the tank.