Cam bearing Reengineering for PD motors

[Mach1]

The bearing shells can move, depending on temp, cam load, presures applied to different vectors, and interferences, thermal expansions differences and material type. If the material type cant stand up to pressure applied, guess what? the bearing can get smashed.

There is going to be some movement, you want to minimize movement.

 

[bthober]

A tough question

I just did a camshaft, follower and bearing replacement on my '06 BRM using Frank '06 oil port modifications on the camshaft caps. It seems that there are a lot of us that are deealing with a manufacturing flaw that VW refuses to recognize.They say we used the wrong oil but I know that I made damn sure that I used the right oil at every interval. I feel that by myself I have no chance of getting any satisfaction from VW. I propose that those of us that have had this problem with our camshaft/followers consider a class action lawsuit . Don't get me wrong I'm not looking to get rich I just think my costs should be covered. I love this car and engine I just wish VW would stand behind their product a little more. I mean the engine should just be getting broke in at 100k. Let me know what you all think. Thanks Ben.

 

[Jnitrofish]

I propose that those of us that have had this problem with our camshaft/followers consider a class action lawsuit .

I think some already beat you to the idea.

http://forums.tdiclub.com/showthread.php?t=262312

And as far as them saying you didnt use the right oil. I know in some cases they do say that, but I have also talked to service advisers who have said they have had cars in for the cam replacement even with complete records saying they used the right oil. So its debatable where the communication breaks down on the oil issue.

 

[Rod Bearing]

I had a cam in advanced wear state at just over 50,000 miles when the DMF shucked itself to pieces, locking the engine up so fast it jumped time and bent valves and ruined one cylinder. I got a replacement of both engine and trans in warranty. I have all receipts for the VW dealership purchses of oil, filters, and picture documentation of the services done on time every time. The cam was failing.

Since the new installation the replacement engine has had the same VW sourced oil and filters till recently, but it was already showing signs of eating it's camshaft by 20,000 mles.

 

[hid3]

Remanufactured cam?

Check your engine replacement records. Do any of the parts contain 'X' in the end of part number?

 

[Bob S.]

I changed my mind on the value of turning the lower cam bearing around.
At first, I didn't see the advantage, but that was due to my reversed thinking.

I have another thread showing what I'm talking about.

Basically, turning the lower shell around moves the original oiling slot past the point of greatest pressure. The bearing mod I have created oils the top bearing.

As the oil is forced around to the lower bearing, the oil will wedge into the decreasing space between the cam bearing and cam journal. The wedging of the oil increases the oil pressure into the hundreds of pounds. If the lower bearing shell is not turned around, the pressure that has been built going onto the lower shell is lost by being funneled into the OEM oil path of the existing galley hole. That loss of pressure will reduce any advantage of the top bearing modification.

Instead, if the bearing shell is reversed, there is an uninterrupted pressurization of the oil as it crosses into the peak pressure point. In order to carry a film of oil, that pressure rise is paramount. Anything that takes away from that pressure rise is an issue that needs to be dealt with.

Frank, This was my concern with leaving the lower bearing in the original orientation. My sense is Rod Bearing is also correct in:

I am able to get my mind around a way to reduce the injector spring pressure significantly, as I personally believe the lower bearing wear issue is found there and there alone due to static loading at hot shutdown and then a resulting lack of oil between the cam and the bearing at the next cold startup, and on and on...over and over.

. Hopefully a pre/post lube system will compensate for this condition.

 

[Franko6]

There are a couple of things that have been broached, like a wear-coating for the bearing shell and reduction of the spring force in the injector.

If a hard-surface coating is applied to the bearing shells and there is insufficient oiling, then the bearing shell damages the camshaft journal instead of the other way around.

If you reduce the spring pressure of the injectors, that does very little compared to the hydraulic pressure exerted by the internals of the injector. That is where the greatest force is. Lowering the cam lift would be a better compensation.

As there is more failure in the BRM's compared to the BEW's, that seems to follow. The BEW cam has a lower lift and duration in the injector lobe.

 

[nic_a_bod]

Frank can you help me out with some of the information that he is requesting?

Here is the email

Thank you for your inquiry Nick.

Nick, BryCoat can offer a couple of coating solutions to perhaps remedy the
wear issue:

1) Tungsten Disulfide(WS2). This is a dry film lubricant that is used to
reduce friction
and wear. The only caveat is it is mechanically bonded to the substrate.
My concern is
that it may not have the longevity as the 2nd option, Physical Vapor
Deposition.

2) PVD(Titanium Nitride or Chromium Nitride). Both of these coatings are
used in performance
engines to reduce friction and wear. The PVD coatings are very durable
and depending on the
application, can have a indefinite life span.

Nick, it may be reasonable to consider having both coatings applied to the
bearing shells and cam.
We would apply the PVD coating first and apply the WS2 over the PVD coating.
For your review, I've
attached BryCoat's TiN, CrN And WS2 specification sheets.

Before moving forward, can you tell me what type of steel are the bearing
shells and cam made of?
Also, I'll need the dimensions of the components e.g., length, width,
thickness, etc.

I look forward to your response.

Best Regards,
Ken


Ken Gulla
Sales Engineer
BryCoat, Inc.

 

[Hurst89]

As there is more failure in the BRM's compared to the BEW's, that seems to follow. The BEW cam has a lower lift and duration in the injector lobe.

Remember, the BRM also has smaller plungers than the BEW engine. I believe I read they were 7mm while the BEW had 8mm, so if you did swap to the BEW cam (which I have been thinking about if my cam decides to eat itself), there still isn't any evidence that the BEW cam will have enough lift to operate the injector correctly at even stock HP levels. But there's also no evidence that the BEW cam cannot either. The BRM cam is very similar if not the same as the ARL PD150 cam. This is all from other posts I have found searching the forum. So, there's a chance some of this is wrong, but it was all stuff I remember reading in the past.

Hurst

 

[black knight]

A shameless bump for an important thread. Late 2006 brm Jetta 174k.km. Cam and related parts in the mail.Will start cam replacement soon.

 

[Moesauction!]

frank do you also do 6 cylinder mercedes diesel heads too?

 

[CoolAirVw]

frank do you also do 6 cylinder mercedes diesel heads too?

Check your PM's.

 

[Franko6]

frank do you also do 6 cylinder mercedes diesel heads too?

I try to work exclusively VW TDI's. That keeps me plenty busy enough.

Sorry...

 

[black knight]

Found on head bolt

I'm doing a Frank06 cam replacement and found this piece of aluminum round stock in the #1 outside head bolt while cleaning up the oil. Can someone tell me what it is?
Thanks Don..

Here are the pictures I took so far.Someone please tell me what that piece is in the last pic.I found it in the front #1 head bolt
PS Careful with the pop through on the drilling.
Can someone please tell me how to post pix

 

[DanG144]

how to post pictures

http://forums.tdiclub.com/showthread.php?t=207484 for how to post pictures.

 

[black knight]

DanG144 Thanks Ill try tonight.
Don.

 

[black knight]

I posted in members albums under Black knight ,don't know if I can link them here.

 

[DanG144]

These are black knight's photos.

Open another browser window and look at your photos. Click on the photo you want, find and click on the "copy to clipboard" button. Then go to your post in the other window and paste the link there.

You have already done the hardest part by posting them in the photo section. Thank you for persevering.

I do not recognize where the dowel came from. Does it have a passage through it? It is a bit blurry, is the indentation I see round or hex or what?

 

[black knight]

Found dowel

The aluminum dowel is about 200 thou long and around 6 mill dia with 5 thou taper over its length. On the large end it has a conical hole that is flat at the bottom. I found it in the twelve point drive hole of the #1 front head bolt as I was cleaning up. It looks a plug for a oil passage that may have been dropped on initial assembly.

 

[jstar89crx]

I am preparing to replace the worn cam and all associated parts on my BEW. I have been following this thread (and all the others) from the start as I don't want to have this problem again. I still am confused by one thing. I haven't read anything about replacing the 'rollers' that are connected to the injectors. I can see some fine scratches on mine and don't understand why they would not normaly be replaced given that everything else in contact with the camshaft is normally replaced. Is there a reason for not replacing them or why they don't have to be replaced? Has anyone ever found a part number for them. Thanks!

 

[Franko6]

Unfortunately, the rocker assembly is sold as a unit.

Fortunately, the item is overbuilt. I've not seen many examples of worn rollers that need replacement.

In the event that the lifters are so worn that the outer edges touch the roller and score it, I still feel that there is so much support on the roller that it does not warrant replacement of the rocker shaft.

 

[black knight]

500 mile bearing cap pull Franko6 mod

Completed the Franko6 mod, 45 minutes @2000/3000 rpm with Joe Gibbs break in oil. Changed to Rotela7 5/40 , put on 500 miles/800 km.I pulled the caps to have a look and this is what I found.
The cam and bottom shells where left in place. The top shells are showing some break in wear, 4 of them look ok . The tb top bearing was showing wear on the inboard side and I changed it out for a good used one. I will put on an other 500 miles and do a cam pull. Cam looks real nice and polished like chrome on the tappet lobes . Posting pix.http://pics.tdiclub.com/showphoto.php?photo=62721&cat=500&ppuser=115539http://pics.tdiclub.com/showphoto.php?photo=62720&cat=500&ppuser=115539 tried to post.

 

[Mach1]

The injector roller rockers are what VW engineered correctly.

Now they should have done the same on the cam/valves and there would be No problem with the PD cams...

I havent seen any that warranted replacement.

 

[hid3]

Oh, so now we see wear on top bearings too. And just in 500 miles. Great mod

 

[black knight]

Bearing wear

hid3. Please wait for the cam pull on the week end . The miles are going to be on and I will pull the cam and do an inspection of the cam, bearings and oil passages. I will consult with Franko6 and post results and fix.

 

[hid3]

Thanks. BTW, I guess you don't have to pull the entire cam just to check/replace bearings. I think they can be rolled out one by one. Ask eddif for more info. Waiting to see the results!

 

[Franko6]

Two things I can think of... after drilling oil passages, holes must be chamfered and any burr removed. A burr will deform the bearing. I can say that there are others done, Hid3, that don't show top bearing wear like this. Except for one particular bearing, the contact land is wide. Although there is contact, it looks quite polished to me.

Also, if reversing the lower bearing, the tang should be ground below radius. It is better that a little too much is removed rather than not quite enough. Otherwise the bearing will press into the cam journal.

It's premature to think 'failure', Hid3. Quite the opposite. If the oil film provided pushes the cam upward, would you get top bearing wear? It's a thought. In any case, what I am seeing is not particularly damage. Your input is invited, sarcasm and all.

 

[nic_a_bod]

I have 5,000 on my bearings and cams now. I plan to look at things one of these weekends and post up. On that note - I was hoping to see some other pictures of this setups with a few thousands miles on them by now from someone as I wasn't the first one by any means to do this.

Can you help me with the info I need Frank that I posted a couple post ago?

 

[hid3]

Frank, I understand that this is just a break-in phase on the pictures seen. But should we still see the general 'wear' either on top or bottom bearings in a general case or should they look like new after some miles?

 

[2footbraker]

Another thing that we should be considering when doing a cam and bearing R & R is the improved cam profile currently being ground by Colt cams. When (if?) I have to replace my cam, I will definitely be getting a reground cam from Colt. He provides a performance pd cam grind as well as a stock performance, purely less wear-prone pd cam grind.