Inside the HPFP

JFettig said:

Brian,

That particular pump might be different than the one you have, we'll have to wait and see. It would be nice if the snout and shaft was even longer, would make for adapting it a lot easier.

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I (we) ordered the same part# as the picture Jason posted in post 13

Excellent! that should make it very easy.

bhutchins said:

are the shaft lengths and the front face flange differences the same so a spacer plate could be used?

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not sure what you are trying to ask, are you trying to make a 4.2 fit in a VW with a 4.1 pump currently in it?

are you asking if the extra length in the shaft is equal to the extra length of the flange?

2004LB7 said:

not sure what you are trying to ask, are you trying to make a 4.2 fit in a VW with a 4.1 pump currently in it?

are you asking if the extra length in the shaft is equal to the extra length of the flange?

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yes, same 4.2 you have into my 2010 jetta

If the flange "snout" and the shaft protrude from the flange face equally, a spacer could easily be made to make it fit, with the timing belt pully in the same position as currently

i see, just have to check the space behind the pump to see how much room we have to play with.

i will see if i can get the measurements tonight

yes, that's what I was looking for. can you double check the 4.2? because 2-7/8 - 1-5/8 is 1-1/4 not 13/16

or should that be 1-3/16? that would be very close to 1-1/4

1.25"

That 7/8" of extra length will be super nice for making an adapter plate, pleanty of meat.

Fixed. it was 2-7/16th not 7/8th

2004LB7 said:

roller assembly. item #10

close up of the roller

inside where the roller assembly sits. you can see one of the the lobes

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Is this roller assembly allowed to rotate within the bore of the pump? If not, what stops it from rotating at will?

its a roller cam follower, diesel lubricated

there is nothing really designed into the pump to prevent twisting of the roller assembly. it is somewhat self aligning but if it gets too far off it will seem to want to twist out perpendicular to the lobe and ride 90 degrees out of whack . the spring pushing it down does prevent it a little bit but only as much as there is friction between it and the roller assembly.

frankly it is a bit scary.

there is more discussions about this on the sticky's about HPFP failures.

personally i think Bosch should have made the roller assembly oval but that may be to costly/technical challenge

2004LB7 said:

there is nothing really designed into the pump to prevent twisting of the roller assembly. it is somewhat self aligning but if it gets too far off it will seem to want to twist out perpendicular to the lobe and ride 90 degrees out of whack . the spring pushing it down does prevent it a little bit but only as much as there is friction between it and the roller assembly.

frankly it is a bit scary.

there is more discussions about this on the sticky's about HPFP failures.

personally i think Bosch should have made the roller assembly oval but that may be to costly/technical challenge

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This roller and corresponding lobe/cam is what actually wears and causes failure, does it not?

A couple thoughts come to mind:

1. I assume the viscosity of ULSD (or any diesel, new or old) is too low to prevent failure if one specially machined a 'flat tappet' type roller in lieu of the #10 assembly. (Think old-school SBC lifter that could spin/rotate at will. Due to the lack of lubrication, this would potentially wear just the same as the low friction setup.)

2. What about designing a new roller assembly with a provision machined in place with a corresponding receiving slot in the body of the pump? As long as it's precise, the only purpose of the groove/key-way would be to eliminate minimal initial forces which cause the assembly to spin. When it's in it's ideal position, #10 seems like it would have minimal tendency to spin (but it certainly does based on photos from other failed pumps.)

bhutchins said:

its a roller cam follower, diesel lubricated

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I understand the assembly. It appears this roller can spin/rotate at will and the roller tip will be misaligned with the cam lobes. (thus the reason hydraulic/solid roller lifters use locking bars or links to prevent them from moving about and ruining the lobes. Flat tappet lifters do not have this requirement and can rotate in their bores without fail (it's actually required to maintain the uniform surface, similar to the way an ALH camshaft and lifter function. The lifter rotates within it's bore.)

in regards to building one like a flat tappet lifter, would titanium nitriding the friction surfaces be able to make this a viable option?

also, in another thread, there was discussion about isolating the lower cam area of the pump from the fuel supply and high pressure areas and running oil (perhaps from the engine) in the body of the pump to help with the lubrication issues. it seams to me that if this was doable, as the largest problem discussed was diesel leaking past the pump piston and diluting the oil, the a flat tappet design would be a very good idea as it has been proven for many millions of miles

2004LB7 said:

in regards to building one like a flat tappet lifter, would titanium nitriding the friction surfaces be able to make this a viable option?

also, in another thread, there was discussion about isolating the lower cam area of the pump from the fuel supply and high pressure areas and running oil (perhaps from the engine) in the body of the pump to help with the lubrication issues. it seams to me that if this was doable, as the largest problem discussed was diesel leaking past the pump piston and diluting the oil, the a flat tappet design would be a very good idea as it has been proven for many millions of miles

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I believe this is one of the uses (coating friction surfaces) but I'm not a materials engineer and would have to do quite a bit more research before saying yes/no for sure.

If you could isolate the pump and use engine oil to lubricate this roller/lifter, you might be able to use a flat tappet lifter. Part of the bonus of using roller lifters is the ability to use more aggressive camshaft lobe profiles. I would assume this should be analyized by a company specializing in camshaft profiles.

edit: regarding the flat tappet style lifter, this isn't going to work if it's it's solid (as far as I understand the fluid flow through the pump.) Does fuel completely surround the #10 roller assembly, top and bottom, and flows through the roller assembly? If so, I would have to re-think this...

From a casual inspection of this design, based on the amount of contact area between the roller in it's assembly on one side (half of the roller) and to the cam lobe on it's other side (basically just a straight line); it is hard to imagine (practically instead of theoretically) that this roller would spin at all in it's assembly instead of just slipping on the cam lobe.

does anyone know where to find fuel in/out fitting for the CP4.2, Bosch p/n 0445010622?

I imagine it would be like the Dorman 800-131 14.7mm fitting (below) except fits a 0.544" (13.82mm) hole?

bhutchins said:

does anyone know where to find fuel in/out fitting for the CP4.2, Bosch p/n 0445010622?

I imagine it would be like the Dorman 800-131 14.7mm fitting (below) except fits a 0.544" (13.82mm) hole?

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.


This new fitting could be pressed in, same as our pumps. There is a real smart reason for the way Bosch designed the rounded hose barbs on diesels!!
Sharp barbs will eventually eat into the hose, with our fine little vibes!!
I never noticed this before, but recently found it again on all Kubota fittings (see below)

.
Just a simpler version of the 2Microntech Banjo Barbs:

.
Heres a collection of smooth, diesel barbs!!
Our VW Rail, 2microntech banjo's and world famous Kubota engineering brass Banjo.

.Crazy things I never knew existed!!!
Andrew

Lots of good info in here. I would love to see this swap in our cars.

With 2micron's Pure Flow adapter, a flat tappet mod and engine oil lube it would look something like this:


did I get this right?

2004LB7 said:

With 2micron's Pure Flow adapter, a flat tappet mod and engine oil lube it would look something like this:

did I get this right?

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I like it a lot. One question. Why go to flat tappet if you are fixing the lube issue by piping engine oil into it?

How does lash adjustment in the pump work? Is the lifter hydraulic? If so will the operation of the lifter be affected by the different viscosity of engine oil vs fuel?

Sent from my XT1080 using Tapatalk

Your question about oil viscosity versus diesel viscosity is a good one. I thought there would be more difference in viscosity but the Mobile 1 5w 30 that is 507 viscosity is in the same range as D2. So maybe using oil won't be as big of a chaalange as I first thought.

2004LB7 said:

With 2micron's Pure Flow adapter, a flat tappet mod and engine oil lube it would look something like this:

did I get this right?

Click to expand...

Plumbing looks right, but I don't necessarily like the thought of engine oil and high pressure fuel within the same assembly. Diluting the engine oil will be MUCH more catastrophic than the exploding CP4. Is this a possibility or am I over thinking this? Is this how the CP3 operates (oil and fuel in the same assembly?)

Regarding the use of flat tappet lifters verses rollers, the CP3 uses three flat tappet lifters. I'm not intimately familiar with the plumbing of my duramax and cannot speak with any amount of confidence, but I assume these are lubricated in oil vs fuel.

EDIT: Correction, I'm wrong on both assumptions. The CP3 appears to use fuel as a cooler/lube too.
Internals of the CP3 are below:
http://i1059.photobucket.com/albums/t428/2micron/5c2856c1.jpg



Cam rotates inside this 3-sided fitting (I can't believe I forgot this.) Thus, the cam/bucket don't have the same interface as the CP4 at all and they're always contacting one another over this large surface area.

correct, the CP3 uses diesel to lube and cool the pump. it is possible that diesel will work just fine for the CP4 with a flat tappet. i wonder if the hadness of the lobes is different between the two pumps.

one may be able to cyro harden the lobe cheaply if it is softer then the CP3's

I'm going to try to read the other thread, with 2000+ posts, but that's likely to take me an entire weekend. that's one lengthy discussion.

This is the infamous #10 roller assembly:





Based on the above photo, is there any way to design and replace the roller/receiver assembly with a single a flat tappet lifter, with holes around the perimeter similar to this (found in the CP3 if I'm not mistaken.)

http://i.imgur.com/2rA3nBd.jpg

I want to get it to work with diesel as the cooling/lube as well. Trying to avoid the engine oil path for now...

Hay, Jesse

can you measure the black roller holder device thingy's diameter? i thought i measured mine at 25mm but i put it back into my pump.

i was just thinking, because i found a 25mm round disc made out of tungsten carbide on ebay that i was thinking could be pressed in and polished smooth

LB7, I borrowed those pics from various places around the 'net. I have no access to a CP3 or CP4 to give you any measurements.

Sorry

OK, thanks

i guess i will have to take mine apart again, not hard to do, and remeasure it. i will have to find my micrometer first as i don't know where i put it.

if you have ever played with tungsten carbide, when polished up it is surprisingly slippery. the hard part will be the polishing. it wears out sand paper in no time with out showing any affects on it self. I found a diamond sharpening stone worked but was short lived too. a jeweler can probably polish it on one of there diamond plates. then the only part that would wear would be the lobes but this may not be that bad as there is more surface area on the lobe to spread out the wear as opposed to the tappet surface.

From Wikipedia

"Early tappets had rollers to reduce wear from the rotating camshaft,[4] but it was found that the roller pivots wore even faster and also that the small radius of the rollers also tended to accelerate wear on the expensive camshaft. Tappets then developed plain flat ends, although these were slightly radiused as 'mushroom' tappets as a perfectly flat end led to 'slamming' against a steep camshaft face.

To reduce wear from the rotating camshaft, the tappets were usually circular and allowed, or even encouraged, to rotate. This avoided grooves developing from the same point always running on the same point of the camshaft. In a few engines, particularly small V8 engines with little space, the tappets were small and non-rotating"

looks like Bosch missed the ball on this one

I don't know about the CP3, but the (smaller, similar) CP1 doesn't have flat "followers" as such. The flat pad is only bearing on a ring, the ring runs on an off-centre cam on the shaft. So there's only a very small sliding component as the ring oscillates.
http://www.mefin.ro/poze/commonrail.jpg

edit: that's a BIG image. methinks a link is better...