Multiple HPFP damage points
This shore ain't agona be no easy task. LOL
You can notice the roller assembly is scuffed up.
So if we look at several failures we will find out which comes first, second third etc. And then one failure may start one place and another failure start another.
We have:
Roller damage
Roller cup damage
Roller outer sleeve damage (?)
Aluminum bore scuffing
Aluminum released
Steel released
I guess we are to the point of looking at each individual failure and try to see how many damage areas have occured and the order they took place.
You are all getting some pretty good information in to sift through.
This from VWSHPFRMN is interesting too.
I think his text tells just the roller was really the only failure. If the thing was that hot how long before the aluminum scuffing starts?
Mercy
eddif
You are looking at the steel treatment rather than the design. That can be a good viewpoint. Here is another viewpoint about the design of a steel part run in an aluminum cylinder. He also brings up the first flakes seen in the filter may be aluminum instead of steel. I guess a magnet would decide if the first filter housing flakes are steel or aluminum? Since an aluminum particle will tend to float more (?) we still may not know from the filter inspection which came first, even if we know which arrives at the filter first. Steel released first can cause aluminum release. Aluminum released first can cause steel roller problems. In one case the aluminum is first, but in the other case the steel is first. Fail, Fail either way.For example having a steel forger change a heat treat process slightly to obtain a higher finished hardness would not necessitate a part number change.
Personally I feel the problem is in the supplier consistent material arena and not in the design of the part.
Seeing and reading all of the posts with metal shavings in the filter and the fuel tank is a strong indicator that someone in the supply chain was not following constant/consistent heating/cooling practices with the steel. You do not test every part in a lot, just a representative sample.
This shore ain't agona be no easy task. LOL
If you look at the first photo in a viewer.It just struck me this morning at 5am. Something that has always puzzled me. Where do those initial metal particles come from? So far I have been of the belief that lack of lubrication of the roller starts the whole failure off. The roller heats up and starts to shed metal which turns into a cascading effect that sometimes ends in catastropic failure of the hpfp.
Here is my new theory. Its still a lack of lubrication,but what I'm thinking now is that the piston cup and piston cup bore are responsible for the making of the first metal particulates that develope in the fuel system. The piston cup being made of steel and the piston bore being made of aluminum. Once there is insuffient lubrication between the piston cup and piston bore the harder steel starts to wear the aluminum bore. Hence the fine metal particles that are found on the fuel filter top. Minimal wear that really doesn't have much affect on the fuel system. Conversely if this contact area between the piston cup and piston bore becomes too dry due to lack of lubrication the aluminum bore starts to wear dramatically. Once enough metal is made in this manner,some of it may become trapped between the roller and the roller holder. Tolerances are very close in this area as the roller rides on a thin film of fuel. Any particles large enough to wedge between the roller and roller holder start to score the roller making more metal particles. Once the roller is scared up enough it starts to wear the cam. From there on out it ain't pretty. Game over.
So, its still a lubricity problem,but I now believe it is the hpfp aluminum case w/ the steel piston cup running inside that precipitates the failure.
dweisel
LUBRICITY,LUBRICITY,LUBRICITY!
You can notice the roller assembly is scuffed up.
So if we look at several failures we will find out which comes first, second third etc. And then one failure may start one place and another failure start another.
We have:
Roller damage
Roller cup damage
Roller outer sleeve damage (?)
Aluminum bore scuffing
Aluminum released
Steel released
I guess we are to the point of looking at each individual failure and try to see how many damage areas have occured and the order they took place.
You are all getting some pretty good information in to sift through.
This from VWSHPFRMN is interesting too.
I think his text tells just the roller was really the only failure. If the thing was that hot how long before the aluminum scuffing starts?
Mercy
eddif