Cam bearing Reengineering for PD motors

I think the pressure return from the bypass filter would be too low to be useful.

Tony

Its amazing that the VW guys missed the basic OHC oil 101's..they didnt take into acount for the loading of the injectors on the cam when designing the oil system..

Is the ALH oil system like this? and they added the injector lobe but kept the oil system the same and didn't take in account for the injector load???

Seems like they completely missed the ball game on this one..

2footbraker said:

Any tribology textbook will tell you the optimum location for an oil supply hole in a journal bearing is opposite the highest load.

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Actually, if the load is at 12 o'clock, the oil entry point should be at 7 o'clock. It's referred to as 'clocking'.

Spooner Miller writes: My mechanic and I still don't see the point in the "painting" effect. Just like in all "properly engineered" engines they supply the oil by using slots in the bearings. If you believe damage will be caused by cutting a slot how is that different then cutting a slot across the top.

I am not positive I understand what you are saying. I'll try to explain what I think you are asking.

What I mean by 'painting', the cam journal needs to have opportunity to get a full coating on the running surface of the cam journal As the cam journal's oiling is provided near or at the highest point of pressure, the oiling is at best, restricted. Just as in painting a house, if you move the brush too fast or push too hard, the paint will not cover. Same for the cam journal...

As for "properly engineered" bearings, not all have slots... most don't. Some, like the wrist pins often only have weep holes. Cutting a radius groove in the top bearing shell would not adversely affect cam loading. It would improve oiling. That is what I've done.

What I would not do is cut into the lower shell. That is the bearing with all the load. The more intact, the better.

The rest of what you say is difficult to understand what you mean at all.

Babbitted bearings support the journal on a film of oil. The point is to get that film of oil between the babbitt and the journal. That is the problem.

What is your 'simple fix'?

my 2 cents worth,but once the engine is started and running , its like a swimming pool of oil under the cam cover,is it not?
now thinking more then twice of buying a 130 or 150 a4 after seeing all these post

benshaw said:

my 2 cents worth,but once the engine is started and running , its like a swimming pool of oil under the cam cover,is it not?
now thinking more then twice of buying a 130 or 150 a4 after seeing all these post

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Indeed it might be. But be aware about PD150 issue (surf the local UK forums) where failure rate was even higher. I suspect that problem is somehow concentrated to NA maket/engine/environment than our European since it's very low failure rate as far as I've researched. Failures here mostly happen after wrong oil usage.

jerry_m said:

Indeed it might be. But be aware about PD150 issue (surf the local UK forums) where failure rate was even higher. I suspect that problem is somehow concentrated to NA maket/engine/environment than our European since it's very low failure rate as far as I've researched. Failures here mostly happen after wrong oil usage.

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I've got a buddy stationed in Germany right now, who has talked to lots of VW PD owners. There seem to be certain model years of the PD engines that have high failure rates. Some less so. I don't think from what I'm hearing from your side of the ditch that anybody is enamored with these engines.

What is more, there are some that I can document using the right oil, only to have a very short cam/ lifter life.

As for Benshaw's comment, 'the valve cover is swimming in oil', it's not what is splashing all over the place, but what is directed to the cam and lifter. If all the cooling/ lubricating oil is splashing onto the valve cover, it runs down to the pan without carrying away much heat. I believe the problem is HEAT.

If the oil does not get directed toward the point of friction, then the heat will rise no matter how much oil is splashing the wrong direction. Slotting the bearing will help to increase the amount of oil flow from the top of the cam bearing shell. A portion of that will go directly onto the cam and the follower. It is a hard argument to say that it won't help. In my opinion, it can't hurt.

Franko6 said:

The most interesting part of the job was taking apart the lifter plungers to find that the ruined ones were missing a spring. Also, the BRM engines only put nitrided lifters on the exhaust valves.

I will be trying to determine if the lifter manufacturing error is the contributing factor for the cam failure, or the whole cause.

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Any new news on this one Frank?

Are there any updates on this? Have anyone done this mod and ran (bottom) cam bearings for x,xxx miles and see what happens?

Jerry,

I've had numerous engineers (it's amazing how many degree'd and professional engineers there are here!) give their two cents... "It can't hurt". It's going to take some time to see what happens. I expect reports, especially of FAILURES! Heh...

Oiling has always been an issue with flat tappet engines. There are some cams that never have had a problem. Break-in is critical. Maybe that is the difference. As a rule, these engines are more temperamental, so if you can give them some massaging with incremental improvements, that is good.

About using the bypass filter as a oil galley squirt, it's not such a bad idea. That would put cooler oil directly onto the cam bearing surface. Oil starvation and the need for heat dissipation are the issues, maybe more than loading. They do play hand-in-hand. Understand, this engine is basically the same design that used to carry only 52 bhp.

I think volumes of hot oil from a galley fed spray jet would be better than dribbles of cool oil from a bypass filter. I don't know, but I suppose a pressure regulated rail could be created, but it would be relatively expensive.

In the mean time, the top shell oiling will let a relatively small but important amount of oil through exactly the right place; at the top of the cam. It will be slung directly onto the lifters and that is a good thing.

A controlled oil slot going out the sides of the top bearing was brought up again today. I don't know how much it is needed or if I like the idea of an idle pressure drop caused by opening up a bearing like that. I've left that for future consideration.

I'd be interested to see a set of bearings run for 5,000 miles or so. Eddif has done such tests. I believe they will still be looking brand new!

I'll chip in and also offer that the original proposal can't hurt. I'm not so sure that you want to have an oil slot going out the sides of the top bearing shell. There is some loading on this bearing (during the valve opening period when the injector is not being activated). I'd be concerned that by making it too easy for oil to get out this slot, it might starve the bearing or the rocker pivot.

I'm tempted to do the oil gallery drilling mod on mine, but not do the modifications to the bearing shells and not do the modification to the #1 journal. This way I shouldn't have to remove the camshaft. I'm at 249,000 km without any apparent issues.

That's what I was concerned about too -- oil starvation to the rockers...

Now a few questions to GoFaster:

GoFaster, you have impressive mileage on your PD and you have zero cam wear. Unfortunately you're not in 505.01 army anymore. I (we) know you do a lot of towing and have used only 5w40 oil. But I'd like to know a few more facts:
-Did you follow DBW's break-in procedure step-by-step?
-How often do you do italian tune-ups and for how long? (at what RPM, for how long?)
-How do you travel highway? How long does your commute take? Constant speed? Constant RPM? Varying RPM, varying speed? Also please mention the numbers.

Thanks in advance.

After reading this thread it reminded of looking through the oil fill hole on one of my Mercedes , probably the 500SL, it had a copper tube above the cam with a hole pouring oil on each cam lobe. The thing that makes VW's failed cams such a big deal is the crazy high price for parts.
I am about to label my Passat the money pit.

There were some people asking about reversing the direction of the bottom cam bearing. The reasoning was that it would block the hole feeding oil to the 'wrong side' and make a better transition for the oiling on the correct side.

My feeling is that reversing the direction will absolutely no good.

The reason is that the lower bearing is being oiled just past the point of greatest pressure. The direction of travel is away from the point of pressure, so reversing the bearing, if it does anything, would be interrupting the oil flow as it goes into the lower bearing.

The cam turns in the same direction as the wheels. The oil galley hole made by VW is in about the 8 o'clock position when viewed from the passenger side of the car. There is oil flow coming from that hole, albeit, a small amount. It will not adversely affect oil pressure to leave it alone. If the bearing is reversed to the other direction, it serves no good purpose at all

Are you offering your bearing mod for the CAM wear fix?

Bushy II said:

Are you offering your bearing mod for the CAM wear fix?

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Yes, I am making annular oiling slots into the top bearing shell.

I am also providing reusable rocker and cam cap bolts to replace the expensive torque to yield OEM bolts; all $100 worth of them. The reusable rocker and cam bolts I have are $50 per set.

Frank have you thought about using one of the top brands of non synthetic break in oil as a part of the fix?

I think it's well worth the money.

Frank, supposedly, the BEW cam is holding up better than the BRM. What is your thought about using the BEW cam in a BRM? There has been some discussion about other cams also. Anything on that front.

Rod Bearing said:

Frank have you thought about using one of the top brands of non synthetic break in oil as a part of the fix?

I think it's well worth the money.

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Using the non-synthetics is what I recommend... better then that, use racing oil for break-in. The initial break-in is, in my opinion, critical.

After installing new cam and lifters, I recommend running the motor 1/2 hr with a 40wt. racing motor oil like Reline, Brad Penn, Joe Gibb or equivalent, varying the engine speed between 2000-2500 rpm. Dump the oil and filter. Refill with racing oil and run for 500 miles. Again at 2500.

If you like, resume the synthetic oils at that time. I prefer 5-40 over 5-30. Motul, Pentosin, Elf, or Lubro Moly are good synthetic choices. I'm not against the Mobil 1. I personally use Lubro Moly in everything up to the 2009's. School's still out on that, so far as I am concerned.

The reason for the track oil is that lubricity. Regardless of API, the 'off-road' oils are only concerned with what makes it work in a performance situation.

You probably make a case for continuing with such hi-grade oil. It is more expensive and not particularly a grade for diesels, which is made to hold a lot of soot in suspension. I still think I'd move to a diesel grade synthetic after break-in.

Frank I should of just typed everything you told me on the phone today and posted it to save you time - ha

Bob S. said:

Frank, supposedly, the BEW cam is holding up better than the BRM. What is your thought about using the BEW cam in a BRM? There has been some discussion about other cams also. Anything on that front.

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The cam profiles between the BEW, BRM and BHW are very close. The Valves for the BRM are .5mm shorter. I think there are issues with the valve guides in the BEW/ BHWs... the guide is way too short. It is lengthened in the BRM.

Comparing the BRM to the BEW, the lobe for the unit injectors is longer duration at the peak. Valve lobe height is marginally higher. I haven't had the BHW in the shop, so I don't know. But I understand that you could swap any of the cams out and be safe, so far as usability goes.

The end result... the BEW is slightly less torque than the BRM. Can the swap be done? Yes. What are the biggest advantages? Longevity? Maybe.

I think the biggest advantage is that I am currently able to get a quality BEW camshaft at a much better price then the BRM.

nic_a_bod said:

Frank I should of just typed everything you told me on the phone today and posted it to save you time - ha

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Heh.. yeah... It's not like I haven't thought about it 10x a day...

I think I need a website not to create more business... but to save time by saying, "Go to my website and read the post concerning.... "

sometimes your isp lets you post a website for free... just a thought... would be a good way to showcase the work you do as well

Has anyone with this mod driven XXk miles yet? Seems meaningful, would like to see if wear (on bottom bearings or followers) patterns have changed after performing this mod.

Unfortunately I have had my camshaft replaced in the beginning of this year. Sadly the mod wasn't available at that time

Here is the method for cutting the top bearing shell I have chosen. It is the same manner that the top crankshaft bearings are cut.

Note the #5 lower journal bearing has a center cut between the oil hole with a space to allow oiling to the top shell. I am not sure there is enough allowance to properly oil the top bearing. I still drill a pathway to the rocker galley to more directly oil the top bearing.

Here is a small modification to the bottom bearing shell to help oil 'climb' into the lower bearing shell.

I don't know if this is a reasonable improvement to warrant the time spent.

This last picture is typical wear pattern. Rotation of the cam is the same direction as the car moving forward. From the passenger side, rotation is clockwise. Both bearing shells have the oil slot toward the back of the head.

I have been approached with the issue that the annular oil slot in the top bearing shell would be going against the rotational force of the cam. This is not so.

Looking from the passenger side of the engine, the re-engineered oil galley hole would enter at about the 10 o'clock position. The top bearing shell has been cut to a .020" depth.

The purpose of the annular ring cut in the top shell is to allow oiling at the point of greatest clearance, which would be at the opposite point of the greatest wear on the bottom shell, which is about at the 7 o'clock position.

Rather than cutting an oil path in the bearing cap to the correct location for oiling, the annular ring cut gives full range for oil flow and the 2 o'clock position, which is the best location to insert oil, is automatically covered.

Also, the other nagging problem with the PD motors are the expense of the cam cap and rocker shaft bolts. It's about $100 for the set of TTY bolts.

The engineering for the set of cam hold down bolts is completed. A grade 12.9 high chrome steel with rolled threads is now being stocked. It is a reusable set.

The 8mm rocker bolt is torqued, dry, to 44 ft lbs. If installing with engine oil, reduce to 34 ft lbs. The 6mm cam cap bolts are 22ft lbs dry and 18 ft lbs oiled torque.

The set of bolts are $50. The set of top cam bearings are cost + $50 for the annular grooving.

As a judgement call, look at the top bearing shells in the pictures above. There is virtually no wear on the top bearing shell. All of the loading force is onto the lower bearing shell. If customers desire, I will replace only the bottom set of bearing shells as needed and cut the annular rings into your top shells. The top shells and the bearing cap bolts are under no force. They are only 'holding location'. Given that, there is no reason I know of that they could not be reinserted and used. I would recommend they be used in the same position they came from and marked accordingly.

Frank - did you ever figure out if there is non synthetic redline racing oil anymore? I plan to pull the valve cover in the spring to take a peak at things since I performed your mod.

so are their any pics of bearings with some miles on them? really hate to cut into my head if it isnt gonna change. I'm open to it if it shows improvement.

05_new_jetta said:

so are their any pics of bearings with some miles on them? really hate to cut into my head if it isnt gonna change. I'm open to it if it shows improvement.

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x2.

I asked that already two times but got response that 'it just works'. Isn't there any enthusiast who would like to try this out and share the results with us?

I like what Frank is doing to create an oil galley in the upper shells and the small mod to the lower to aid the entry of oil there. I will opine that the upper cut could be twice as wide and not create any issues, and that the lower mod he is doing could also be wider and carry as much as .250 further onwards out into the load area on the lower surface. I like these mods very much.