TDI Pumpe Duse PD Cam Bearing Oiling and Related Wear (eddif)

eddif

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Dec 17, 2006
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MS
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2004 Jetta PD Automatic
GoFaster

Crush fitting works well in steel rods with steel backed bearings or cast iron blocks with pressed in steel backed bearings. But even then the term spun bearing / bearings comes up at times. Aluminum rods do use steel backed bearings, but often use shuffle pins to keep down problems. VW air cooled engines used shuffle pins in the magnesium block to maintain bearing position. Metals with different expansion rates are hard to make use high crush values. My belt end cam bearings had turned in the head about .060" US.

You have said the cam is not under constant loading, goes all over the place when running. There are no marks on the cam bearings to show contact toward the top of the engine (top cam bearing marks especially the center three) or on the rear side of the lower cam bearings. The marks show stable position to me. That is not to say the cam does not move, I just see no signs of this movement you describe. My cam bearings are slick and smooth ( no chatter signs) , only show copper wear in one place, and show no top or rear signs of wear (you will have to take my word for the top bearings are still in the engine). The top end bearings on the high wear set) do show IMHO cocking wear in the worn set.

You related the entire top of the engine might be starving for oil. There are no complaints of follower clatter / ticking till just before the follower tops wear through or crack to bleed off oil the last few miles / time period.

Since the lower end does not usually fail when the follower tops wear out, the restriction must be about correct to the head. Correct restriction keeps lower end bearing failure from happening with head problems. No clatter problems shows the restriction is close to correct. I realize there are mentions of clatter right before the engines start missing, but for thousands of miles there is not a common complaint (that I have heard).

Loose fit of the followers should oil the tops better and cause clatter if oil was limited, but the followers do not clatter and follower tops seem dry.

If cam bearings are too close then we should see marks. Since we see no marks they must be loose, but since mine looked pretty good at 107,000 miles US they must have been oiling fair till that point. My lobes were starting to show copper streaks though . Changed out cam bearings restored the cam looks.

I covered the oil pressure comparison on post #31 and agree with you.

The injection roller seems to hold the cam very stable (no ramble marks like the ALH). Enough oil is available till something happens.

I really need to cut some bearings and get them in, but a deep valve cover (inspection tool) is still something I do not have.

eddif
 

GoFaster

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2006 Jetta TDI
abctdi said:
After going thru all the posts, I get the impression this is talking about the NA 1.9 PD only and not the NA 2.0 PD?
The bottom-end of the 2.0 PD is quite different from that of the 1.9 PD although the cylinder head is essentially the same. Still, the difference in the bottom end might make a difference in how much oil gets to the top end. The 2.0 PD has its own set of headaches, but that's been covered elsewhere. I seem to recall Oilhammer having to do a camshaft/lifter job on a Passat TDI 2.0 PD, but it was high mileage 400,000+ km, and honestly once an engine gets to that sort of mileage, *anything* can go wrong and it can still be said that the engine has done well ...

Marginal oil starvation won't necessarily cause clattery lifters. Clattering comes from GROSS oil starvation, and I can assure you that's not the case by design, because if that were the case, the number of PD engines that survive to high mileage without major mechanical problems would be ZERO, and that is far from the truth.
 

SBAtdijetta

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'10 Jetta Cup 6spd, '02 Jetta Auto
GoFaster said:
(snip...) The bottom-end of the 2.0 PD is quite different from that of the 1.9 PD although the cylinder head is essentially the same. Still, the difference in the bottom end might make a difference in how much oil gets to the top end.
GoFaster,
Due to the possible different failure rates maybe we should be focusing on these differences then? What are the main differences in the bottom ends of the BHW vs the BRM? Well besides the BS and chain...:( Unless you think that is significant for this issue. Oil galleries, Oil pump, Crank? I could see each playing a different roll in direct or splash lubrication.
 

Nutsnbolts

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2000 Jetta, Silver Arrow
Building upon what has been theoriezed here:

How about this-

Is it possible that once the cam gets worn enough, or the oil pump/check valve wears enough, that the oil in the feed passage(s) can bleed back down to their source, and that the wear we are seeing is from starvation only at startup? The lifters would remain pumped up due to their own internal check valve, and wouldn't have enough time to get pounded down (thus no clatter at startup), but the film strength of what little oil remained in the top end wouldn't be enough to prevent damage to the lower cam bearings and cam lobes during those critical dry seconds, and the lack of hydrodynamics may indeed allow the cam to move more than normal...

Food for thought/discussion. Interesting thread.

-Rich
 

abctdi

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GoFaster said:
The bottom-end of the 2.0 PD is quite different from that of the 1.9 PD although the cylinder head is essentially the same. Still, the difference in the bottom end might make a difference in how much oil gets to the top end. The 2.0 PD has its own set of headaches, but that's been covered elsewhere. I seem to recall Oilhammer having to do a camshaft/lifter job on a Passat TDI 2.0 PD, but it was high mileage 400,000+ km, and honestly once an engine gets to that sort of mileage, *anything* can go wrong and it can still be said that the engine has done well
Yay for me...just got the BS replaced with gear type. Didn't want another engine issue.
 

eddif

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Dec 17, 2006
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MS
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2004 Jetta PD Automatic
Flywheel End Cam Bearing

I finally found a cam that showed the flywheel end. It is not the best. Came from the BRM Cam Failure thread. You will be able to see the cut down area that does not allow full contact with the flywheel end cam bearing. This lack of length allows the flywheel end cam-bearing to tilt so much.


eddif
 

eddif

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MS
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2004 Jetta PD Automatic
Copper Danger

I had a few minutes and went back and pulled the valve cover. Everything still looks good a thousand miles later. You can still see a minute copper trail hint, but nothing a camera would catch. I do not know how those few flecks of copper can be so much trouble. I do not know how hot it gets with reduced oiling, but it sticks to the cam surface. You only have about a 200 mile window to stop the problem (Guess). If not for grace I would have missed the whole thing. At the just copper stage I had good results.

It is looking like I will have to buy a new valve cover to cut up. A used one would be nice.

eddif
 

SBAtdijetta

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Nutsnbolts & GoFaster if the conditions at start up (little hydo. lube, pumped lifters) are causing the wear on the cam, lifters, and bearings as they may well could be can't additives be part of the solution? Again I hope so, I am not sold yet but I need a path/direction to go forward and test, I mean I/we have to try something IMHO.

I think I racked up lots of start ups compared to most on my car in 38k maybe close to 2-3x as many as most. So 80k-120k worth of starts on my car puts it at the level when other cars failures have occurred.

I am really interested in what my bearings, cam, and lifters will look like tomorrow...:confused:

Eddif hope to have bearing pics up for you soon.
 

SBAtdijetta

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2footbraker said:
You're getting the old pieces back tomorrow?
Yea will be driving up North for a bit, and while I am there Steve G. (mtbr297) will be doing the cam R&R tomorrow, all new parts in then we break it in right and I will go home with the old ones.

Still need to find somebody to test the extra black lifter I bought... Anybody know where I can get that done, Meister suggested a Vickers test...
 

Bob S.

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Central MD.
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A B4V, some ALHs & BRMs
When the bearings come out, please try to get some good measurements to see:

1. Did the lower bearings deform on (or over) their supports? It might be very tough to measure. The wear patterns indicate uneven and, for the center bearings, wear in the bearing center. Are the outside (exterior) bearings surfaces still flat? Or did the bearing shell change shape such that the exterior is slightly concave and the wear surface essentially flat? Or did the wear surface wear concave.

2. Try to get a good outside, maximum, measurements of the new cam at the maximum lobe heights. This will give us a reference number to measure against during inspections.

3. As the outboard (end) caps come off, Do you see the same cocking that eddif sees? Is it possible to measure. Is it visible at the bearing shell tops without removing the cam?

Good luck.
 

zanzabar

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Petaluma, CA
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2004 Jetta BEW 5spd (dual duty track car and daily driver beater)
I'm doing a BEW cam this Saturday (at the NorCal GTG) and would be more than happy to document all these meausurements and take pictures and post all the info here. I haven't done this kind of thing before (measuring with calipers, etc.). If someone could spell out in idiot language exactly what I need to do and what tools are necessary that would be helpful. The car is a 2004, 145k miles, with at least one cam lobe badly worn, but still running ok.
 

eddif

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MS
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2004 Jetta PD Automatic
Bob S. said:
When the bearings come out, please try to get some good measurements to see:

1. Did the lower bearings deform on (or over) their supports? It might be very tough to measure. The wear patterns indicate uneven and, for the center bearings, wear in the bearing center. Are the outside (exterior) bearings surfaces still flat? Or did the bearing shell change shape such that the exterior is slightly concave and the wear surface essentially flat? Or did the wear surface wear concave.

2. Try to get a good outside, maximum, measurements of the new cam at the maximum lobe heights. This will give us a reference number to measure against during inspections.

3. As the outboard (end) caps come off, Do you see the same cocking that eddif sees? Is it possible to measure. Is it visible at the bearing shell tops without removing the cam?

Good luck.
Bob S.

You are right about tough to measure. The thickness of the material above the copper is in the range of .0005 " US, That leaves you needing to have an accuracy of about .0002" US and that is really tough to measure. Just looking at the wear you woud think in .001 to .003 " US, but it does not take much to show the wear patterns seen. I just gave up and guessed at .0006" bend or so while out of the car, and about .0015" inch deflection while running (total guess). It is not so much the wear as it is the copper release (.0005 and you are about to copper), and the covering of the oil holes that cuts down on the flow to the follower tops. It is just about stupid and I agree. If someone told me .0004" US was a lot of wear I would freak too. My first paragraph said it was tough to see.

I do not want to defeat your measurements just help.

Try and forgive me of this comment, but you are talking an exercise in futility to try and get what you want. If someone is choking you around the throat and you can not get enough air to stay alive, what difference does the windpipe opening measurement make (one person might live and another die at a given measurement). I have run some old bushing electric motors that had too much bearing clearance, but as long as the bearing was slick oiled and nothing was scrubbing anywhere they sometimes would last a long time. Ball bearings are so much better. Roller followers are better and we are stuck with 1988 technology (switching to rollers started about then).

I am for taking the measurements and am for your trying to get something to go by. There are some racers that run tight tolerances and some that run high / open tolerances. Try and not define what wear someone can run. Somewhere in all this art takes over and is mingled with science. Just as soon as you define what will work a bumble bee takes to the air and defies all science measurements.

If all this was simple the cars would have been fixed years ago.

SBA measure and post pictutes, and maybe even find something I missed.

eddif
 

Bob S.

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eddif, What I am trying to get to is: 1. Are the bearings changing shape, deforming, under load on the lower supports? 2. If so, is the deformation permanent? or Elastic. The unloaded shape of the exterior lower bearing should tell the tale. Simply comparing it to the top should suffice. 3. What is the nature of the outer bearing wear? Is it simply a wear pattern, Not properly seating (cocking)? & is it a measurable.

Simply, I am attempting to put some numerical quantification to the photos.
 

eddif

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MS
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2004 Jetta PD Automatic
Bob S. said:
eddif, What I am trying to get to is: 1. Are the bearings changing shape, deforming, under load on the lower supports? 2. If so, is the deformation permanent? or Elastic. The unloaded shape of the exterior lower bearing should tell the tale. Simply comparing it to the top should suffice. 3. What is the nature of the outer bearing wear? Is it simply a wear pattern, Not properly seating (cocking)? & is it a measurable.

Simply, I am attempting to put some numerical quantification to the photos.
Short version of statement. To look at the wear you would think you would see several thousanths wear. If measured you actually see only one half thousanths wear before copper release. Since the measurements are so small, you have to look for what is causing the picture you have (what the wear looks like). Each of those layers is only about .0001" US This is a high tech bearing. Part deformed part elastic. The exterior (head bore) is deformed / worn by about .0001 per 100,000 miles Us (guess). Since it is a see saw effect the copper winds up being exposed.

When the oil film is established it floats the hundreds ( ?) of pounds of injection roller pressure. The only problem is when the oil holes begin to close there is no place to establish this wedge of oil. If you had .0015" US clearance you could establish that film. Raise the introduction point just above the maximum cam diameter and you have the space needed. The oil holes are just about .250" too low and being covered. I suggested using the upper slot because it was there. I really wish the whole head was redesigned, but that is probably never going to happen. So here I sit trying to figure out how to use a slot .500" US higher. Knowing it is a little high,and if not metered just right it is going to spill too much oil. Also knowing that VW will probably never listen and fix this mess. Knowing without my fingers and frowns and smiles you are lost in this description. My voice does not work, because I have talked to some about it and they could not follow along. All I can do is sound like an old broke record and say over and over the oil holes are being covered. I really am sorry. It is kind of like a tall dresser. Put an eight inch shim under the front legs of the dresser, and the top may move 3/4 inch toward the wall. The wear is .0003 and the slot is closing .0008" US. (another guess based on the wear marks I see). All this motion hits right at the oil slot. Come on SBA. At least he knows to take the pictures of the oil supply slots.

The cam is walking on a frictional surface (the followers are not friction free _especially when the copper hits). The injection roller is slightly over center and pushing the cam to the front. The dry cam bearings are friction walking the cam to the front. And those low placed Oil holes are in just the right spot to be covered. If those slots would have been .250" US higher we would have never have seen all this. IMHO Raising the slots to the top slots is a partial gamble, but the bearing oiling and follower lubrication is in need of help.

Short Version???

eddif
 

2footbraker

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I really don't understand what you mean by the oil holes being "covered". Personally, I think the cam wears first and the wear metals lodge into the babbitt metal (as this is its purpose) but eventually the wear metals the babbitt catches become too high in concentration and the babbitt metal spalls off.
 
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eddif

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2004 Jetta PD Automatic
2footbraker said:
I really don't understand what you mean by the oil holes being "covered". Personally, I think the cam wears first and the wear metals lodge into the babbitt metal (as this is its purpose) but eventually the wear metals the babbitt catches become too high in concentration and the babbitt metal spalls off.

But whatever, this is your own little thread to play in.
A water hose runs fairly free till you obstruct the flow with your thumb. Put enough pressure on something and it will stop flow. Jamb a cam against the oil holes and flow will diminish.. wear marks show the cam is hitting the oil slot area. When the flow gets low enough the bearings and cam devour themselves. The reduced flow does not oil the followers enough and they fail.

Thanks for the cam wear first bearings destroyed last thought. If the wear materials were throughout the whole engine the lower rod and mains would be destroyed. Look at the flywheel end cam bearing, even in the bad worn bearing sets, and you will usually still see it is still slick.. If the oil was coming through the galleries that bearing should be bad too (and you may find a picture somewhere that has a flywheel end bearing bad). The flywheel end bearing is just still developing the oil wedge and still remains fairly healthy longer.

I hope this thread is ours to work in. We all make mistakes and have to help each other. I have gone back and said ultra high ZDDP will not heal cam problems. I have gone back and said the pressure on the cam base circle is not the follower failure ( I once thought it was). If I finally see the error here, I hope I can say I was wrong. I try and show evidence (even if it is visual). My car had a failing cam that is now slick. Cam bearing replacement IMHO saved the day.

eddif
 
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Bob S.

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You will need a pretty good measuring tool kit. My sense is at minimum, regular & ball micrometers, dial calipers and probably a dial indicator w/ a good mobil type support system. I agree with Bill that Plasigage would be a good way to measure the bearing wear during disassembly. It may also be a good way to measure if the lower bearing shells are deforming. Swapping the old bearings top & bottom, but installing the plastigage between the bearing OD and the bearing cap (which is presumably a consistent machined surface) and the relocated lower bearing maybe an easy way to determine if the lower bearings OD are deforming over the support base.
What I think would be helpful is if, during the next couple of cams R&R’s is to answer a couple of basic questions:

Bearings: Are they stable in their seats? Any sign of them moving within their carriers (“See Sawing”)? Is your observed wear pattern consistent with those shown in previous photos? What is the amount of that wear? Have the lower bearings deformed on their supports? If so, Is that measurable? Comparison measurements new to old & top to bottom would add quantitative measurements. Any sign of the cam moving abnormally within the bearings? Or, is the wear a function of the way the cam loads the bearings?

Cam: Measurements new vs old, particularly the max lobe height.
Oil galleries: Any observed problems? Oil holes in cam bearings, size new vs. old?

First Wear: Is it possible to get a sense of where the wear metals are originating? Cam? Bearings? Elsewhere?

Quantitative measurements of the wear would give us base measurements to work with and with which to make comparisons. Also, if you have not already done so, please add your info to the Cam failure thread. http://forums.tdiclub.com/showthread.php?t=237678
 
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dsmith1279

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None......Yet???
Bob S. said:
Bearings: Are they stable in their seats? Any sign of them moving within their carriers (“See Sawing”)? Is your observed wear pattern consistent with those shown in previous photos? What is the amount of that wear? Have the lower bearings deformed on their supports? If so, Is that measurable? Comparison measurements new to old & top to bottom would add quantitative measurements. Any sign of the cam moving abnormally within the bearings? Or, is the wear a function of the way the cam loads the bearings?

Cam: Measurements new vs old, particularly the max lobe height.
Oil galleries: Any observed problems? Oil holes in cam bearings, size new vs. old?
I've done a bit of research and have yet to find the actual specs for a cam with the misc. measurements. Does anyone have the these, or a link to them?
 

Rod Bearing

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Several
I see the pictures show areas of the bottom shells hanging out of the supports.

Has anyone had the camshaft bores in a BRM head line bored? Anyone measured one on the engine with the head torqued in place? Anyone measured a new cam for straightness and machining accuracy? Anyone had the cam journals micro polished?

Lot of questions but they are important.

Wish I had a production BRM 1.9 in a crate I could tear into and measure on.

Too bad there ain't a cast iron head available. Too bad money don't grow on the spruce tree in my front yard.:D
 

40X40

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2013 Passat SEL Premium
Rod Bearing said:
I see the pictures show areas of the bottom shells hanging out of the supports.
Has anyone had the camshaft bores in a BRM head line bored? Anyone measured one on the engine with the head torqued in place? Anyone measured a new cam for straightness and machining accuracy? Anyone had the cam journals micro polished?
Lot of questions but they are important.
Wish I had a production BRM 1.9 in a crate I could tear into and measure on.
Too bad there ain't a cast iron head available. Too bad money don't grow on the spruce tree in my front yard.:D

HEY YOU!!!

Turn off that flashlight! Can't you see it's dark in here?? Heh Heh, LOL

Bill
 

AD5GB

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Too Funny...

40X40 said:
HEY YOU!!!
Turn off that flashlight! Can't you see it's dark in here?? Heh Heh, LOL
Bill
Given that I alreday have "ball mics", "telescopic gauges", "calipers", "micrometers", "PLASTIGAGE", et al.... and given the fact that my DMF is just about to fly apart, I'll be soon dissecting the {questionably} venerable BRM and will soon see first hand {for myself} the internals of the BRM; and since no one up until this point has been able to post measurements......

stay tuned...

'till then, the fishing's good! :D
 

Nutsnbolts

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Weare, NH
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2000 Jetta, Silver Arrow
Coming back to the starvation at startup subject, I may have figured out how this kind of wear could happen:

When the oil pressure gets to a certain range, the piston coolers are supposed to have spring loaded check valves that allow them to open, and when the pressure drops, they close again. If one of these coolers is not sealing properly, then the oil could bleed right out of it while the engine is shut down. I think you'll find that the coolers are teed off of the galley that feeds the head (I could be wrong about that, not sure). Anyway, the problem gets worse at startup, as the cooler being stuck open increases the amount of time that the top end runs with little/no pressure. In addition, at low engine speeds and normal operating temps, the oil pressure at the oil cooler measures only about 19-20psi, which may not be sufficient for the top end if a piston cooler is stuck open. It may be something to think about- a huge batch of bad springs in the piston coolers for the BRMs wouldn't be impossible, and maybe after a few heat/cool cycles they lose their ability to adequately seal the oil passage.

Flame on....

-Rich
 

eddif

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Rod Bearing said:
I see the pictures show areas of the bottom shells hanging out of the supports.

Has anyone had the camshaft bores in a BRM head line bored? Anyone measured one on the engine with the head torqued in place? Anyone measured a new cam for straightness and machining accuracy? Anyone had the cam journals micro polished?

Lot of questions but they are important.

Wish I had a production BRM 1.9 in a crate I could tear into and measure on.

Too bad there ain't a cast iron head available. Too bad money don't grow on the spruce tree in my front yard.:D

In post 27 page 2 (if it is still the same) I mentioned that the cam bearings were something just to get the cars to the scrap yard with a lot of miles on them. I also mentioned that if you were into racing you could do support sleeves and a host of other things. Most people will not even want to pull the head to do machine work ( boring on the car would be a trip). There is nothing wrong with all the accuracy you are all describing but most will finally just want to get 350,000 miles US for $500.00 (2 bearing sets) and call it quits.

The head just does not have enough backup for the bearings. All the fancy machine work would be highly stressed and prone to failure. If the machine shop closes its doors, where will the special sleeves come from? The bearings would would still have to be cut to stop end bearing cocking. I do not want to be a stick in the mud, but I also do not want to be a beautiful cloud that looks fine for a moment and then is blown away.
We need a workable, solid, get by, cheap solution, and if some want to re-cast heads and go racing that will work too.

Let us go after what our present economy will support, and a better solution the new better future day will support.

It could be a set of machined bearings with special coating (including copper underlay) might last way longer than my gimped up attempt. I never really thought of this machined stock bearings as a permanent solution. I need some people to try these bearings (I need to try these cut bearings). It might be realistic for us to get a redisigned bearing set from VW.

eddif
 

Nutsnbolts

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Weare, NH
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2000 Jetta, Silver Arrow
Eddie:

I think this was mentioned before, but I think that a simple small chamfer in the babbit material to expose the oiling hole to a less closed-up area (and in the direction of cam rotation) would be the simplest solution, that would be easily reproduceable without fancy tooling. If oil starvation is the issue, then let the oil out to do it's job- I know that there are concerns about pressure drop due to the human element doing this kind of modification, but it might be better than no oil at all, which is the theory you are supporting. This is the direction I would go.

How about that startup starvation theory? If we find that is the case, then bearing modification may not help the situation at all...

-Rich
 
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