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Cam Adjusters - Hilite International

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akdub View Drop Down
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  Quote akdub Quote  Post ReplyReply Direct Link To This Post Topic: Cam Adjusters - Hilite International
    Posted: 06-Nov-2008 at 04:40
Sold to the lowest bidder. I traded it in on a truck when nearly every CEL light on the board came on. ABS, ESP, ESC. The dealer had just been burned on a VW that needed expensive repairs (1.8T) and would not go above low book. That was fine with me...I walked with the better end of the deal. See below for Hilite. Interesting stuff.
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  Quote akdub Quote  Post ReplyReply Direct Link To This Post Posted: 06-Nov-2008 at 05:38
Hilite Int'l Update:

Hilite Int'l built the cam adjuster, or cam phasing units for our cars, as posted earlier. The guys in the states were willing to talk with me, but I recommend a really smart techie ask all of the right questions if you want to get more details or take a claim to VWOA. I got somewhere, but think you could do better. Here's the gist:

Hilite in GERMANY would have built the cam units for our (yours now) cars. They operate on a similar principle so if you can only get the us tech to talk to you then that should suffice for general questions.

I was correct in my hypothesis that the cam units operate much like a servo. pressure differential(oil, in this case) on either side of a servo like mechanism will cause the unit to send an electronic signal to the cam assembly to tell it what position it should be in (based on how much oil flow there is and where the sensor is temporarily and purposely locked). Low flow times is when this is most difficult and critical for the unit to sense, which is why this always rears its ugly head at or near idle speeds.

read the above explanation again, then download the pictures of all the crazy routings the oil in a W8 motor goes, then think to yourself...gosh...is a 10,000 mile oil change interval realistic? VW is at fault here for ever suggesting it would be IMHO and this is a contributing factor to SOME of the failures.

Mix the possibility of imperfect oil (from external conditions like road grime, hot or cold climates, extended or not enough idling, et al), a tiny micro screen that may have issues tearing or clogging, and junk from the manufacturing process that gets trapped in the system when its built and you have a recipe for disaster.

When I asked Hilite - 'wouldn't the servo-like cam assembly be highly susceptible to failures due to very small amount of contaminants in the engine oil?' he answered yes. I expressed dismay that oil would be used as opposed to a closed system with hydraulic fluid or something similar - he somewhat defended the practice of using oil, saying that the closed system would be a huge cost and that the oil system was already there so that's why the oil would be used. I'll say again though - I was a helicopter pilot and the idea of using engine oil to work a servo assembly is preposterous - then again that is life and death and this is just expensive and aggrivating...I digress...sorry!

Q: Could condensation in the oil that occurs regularly in cold climates cause gunk, goo in the oil that would restrict the oil flow enough to cause out of phase (cam) issues? A) Absolutely. He then added that Antifreeze has additives that would be especially detrimental to the 'health' of the oil and that could lead to the cam phasers becoming susceptible to failure. Some mixing of those fluids can happen on occasion, I think, particularly if there is a failure like head gasket.

When I told him that the failure of the cam assembly had led to my (sorry - the dealers (chuckle)) chain becoming stretched and or skipped he was genuinely shocked, stated that it was highly unlikely. I said that in my research I had found at least one other owner with the same exact problem. He pondered that for a while and said that (Mind you I was upfront about trying to remedy the problem with Seafoam) in the case of a failing cam assembly all of the the screens and or Cam assemblies should be replaced before the failure was catastrophic. CATASTROPHIC is his word, not mine. - Take note he did say ASSEMBLIES, so change em all if you go digging around in there - I replied to him that the Screen failure or the Cam adjusting unit failure in and of itself was catastrophic with this vehicle because it costs 7-9 thousand to replace them because of the quadrant of the engine they are located in. He was surprised and sympethetic that they were so inaccessible and pointed the finger at VW for bad design (location,location,location) on their part. I couldn't agree more. As I've said before on this forum this (screen and Cam failure) is a fairly common problem with other autos including some audi A4s. You just don't hear about it so much because its only (chuckle) a thousand dollars or so to fix.

This one's my favorite:
Q: Why place a bunch of remote screens that are prone to fail by way of becoming clogged or torn when the oil system already has its own filter assembly that can and is changed easily at normal intervals?. A (you'll love this): When the engine is manufactured it is common for the process to produce remmenant junk (like chips, chards or metal, etc) that could damage the assembly (servo) on the initial run. He stated in fact, that the highest risk to the motor is right off the line.

Now, when I think of this answer from the user standpoint I'm thinking...ok...I have these small filters located in the most remote portion of the engine that may already be clogged or torn to some extent. They are protecting a part that has a tolerance that must be just Eventually most of these engines are susceptible to this problem.

Well, its getting late and there is more, I'm sure. I'll try and get back with you soon. He is supposedly going to research weahter the part that is being used now is of a new design or not and provide other info. He was fair to me and I won't post his number online, but If you provide me contact info I may give it to you over the phone or via email if you promise to be fair with him in return. Finally, I'll try and attatch the PDF of how these things work. Good luck with your cars. I mostly miss mine, but not the threat of 'auto bankruptcy'. Apologies to typos and grammar. Its too late to check for that. Chus.
Oh yeah...formerly known as alaskadub. I lost my password and had to create a new email to get back on the forum.
Okay, this is one of my favorites...
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  Quote akdub Quote  Post ReplyReply Direct Link To This Post Posted: 06-Nov-2008 at 05:53
How cam phasing works...

http://www.autozine.org/technical_school/engine/vvt_3.htm

Could someone please cut and paste the appropriate data and pics from the below link. W12 and W16 will work on the same principles with our w8: This will show you why the concept is susceptible to failure - its straight from germany hilite:

http://www.hydraulik-ring.com/fileadmin/Pictures/News/Brochures/nwv_0507_1_en.pdf





Edited by SirRangeALot - 06-Nov-2008 at 21:25
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  Quote akdub Quote  Post ReplyReply Direct Link To This Post Posted: 06-Nov-2008 at 12:56
http://www.hydraulik-ring.com/de/produkte/motor/nockenwellen-versteller/article/28th-vienna-motorsymposium.html

Sorry about the german...go to the bottom of the page for a video representation of how the system works. Our cams were shown on that page.




Edited by SirRangeALot - 06-Nov-2008 at 21:25
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  Quote akdub Quote  Post ReplyReply Direct Link To This Post Posted: 06-Nov-2008 at 19:53
Review this site to see how the cam adjuster works, what the crazy path is that the oil takes to get to and actuate the cam adjuster, and general concepts and info. Lots of helpful diagrams for us simple folk too. If I could figure out how to paste them I would. Of real interest there are the cam adjusters and oil paths, I think.

Good luck, all

http://mysite.verizon.net/b5crazy/sitebuildercontent/sitebuilderfiles/w_engine_concept.pdf

found this by googling "W Engine Concept Self Study manual" btw.





Edited by SirRangeALot - 06-Nov-2008 at 21:24
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  Quote gforce Quote  Post ReplyReply Direct Link To This Post Posted: 13-Nov-2008 at 02:20
So, lets think about how this system works, and where it may be vulnerable to what. Based on pictures and drawings only this is my understanding. Chime in if you have corrections or something to add.

Engine oil is pumped through the main oil filter which feeds into the Proportional valve which is in one of three configurations:
1. Feeding oil to one side of the stator/rotor assembly to advance the cam timing.
2. Feeding oil to the other side of the stator/rotor assembly to retard the cam timing.
3. Blocking the oil from flowing out of either side of the stator/rotor assembly - locking the cam timing where it is. This would occur when the proportional valve is in the middle position and it is blocking the ports to both sides of the stator/rotor.

Now the filters, it seems as though we have three barrel-shaped micro filter screens on the proportional valve.
The center one - would filter the 'filtered' oil from the oil pump.
The end ones - are redundant when oil is leaving the valve, but would protect the valve from any debris coming back from the stator/rotor assembly.

I'm guessing that one or more screens get damaged or fails and that debris jams the piston in the valve assembly.

Does anyone know which of the filters have been getting damaged? Also have we had failures without filter damage?

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2003 W8 Tip Sedan Black/Black - Traded In
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  Quote akdub Quote  Post ReplyReply Direct Link To This Post Posted: 13-Nov-2008 at 06:09
Gforce - Your representation of the system and its failures are well stated and accurate from my understanding of servo type mechanisms and my discussion with Hilite.

The one big piece of the puzzle that your statement was missing is that it will take only a small restriction in oil flow to cause an oil pressure differential mismatch (too much pressure or too little) at the sensing unit (servo-like assembly). At that time of course you will get the dreaded P011 or P022 and all of the fun that comes with it. The engine, IMHO, is especially prone to failure because any coking of the engine, sludge from normal driving in somewhat harsh conditions, etc will cause the screen to clog, the oil passage to become restricted, and the failure to occur. Think of it as an artery. If it gets clogged, the fluid becomes restricted, the heart will not operate normally.

Now, VW will undoubtedly tell you that 9 quarts of the right type of synthetic is highly unlikely to get sludge issues on a normal oil change interval, blah blah blah - but there have been plenty of people reporting this failure who followed better than normal oil change intervals, babied their cars and still had the same problem. If this were an older, simple design motor they would be right. Instead, they designed a motor that has a complex routins system of oil passage ways that feeds a very complex unit that relies heavily on the pressure of oil on the feed and return sides. Part of my proof - Add seafoam and the problem will likely magically go away (for a while, anyway) - until more of the crap that's floating around or coked on the inside of the engine clogs the screen, causes the pressure mismatch at the camphaser, cam assembly, servo, whatever you want to call it, then wreaks havoc on the motor.

I encourage you to get a list of questions written down and talk to the right contact at Hilite. maybe even record it and post their answers as it sounds like you are not at all mechanically challenged. Calll some good dealers of Audi, ford etc who are using variable cams and see what their experiences are. I'm sure you will find that they are having failures too, but that they are MUCH easier and less expensive to replace. Good luck.
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  Quote B5crazy Quote  Post ReplyReply Direct Link To This Post Posted: 13-Nov-2008 at 08:56
Is this problem more prone to TIP versus 6MT cars? I don't have stats to back this up but it seems so. Has it been discussed much on the German Passat Forum?
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  Quote akdub Quote  Post ReplyReply Direct Link To This Post Posted: 13-Nov-2008 at 13:11
Both TIP and Manual owners having the identical problem. I can't speak for German users, but Australia and England are having the same problem at roughly the same mileages. OEM oil is OEM oil, after all, and a variable cam is a variable cam is a variable cam. We need to get in touch with some of the Germans regardless, though.
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  Quote fitzski Quote  Post ReplyReply Direct Link To This Post Posted: 13-Nov-2008 at 17:10
Thinking of the proportion of Tips vs 6MTs, it's no wonder that it may *seem* like a more prevalent problem with Tips.

Although, I wonder if there is a correlation between 6MT owners (stereotypically enthusiasts - no disrespect... :-) ) and an inclination to stay on top of regular maintenance?
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