Where can I find the metal shavings from a worn BRM cam?

So at 147,000 miles, the original camshaft in my 06 BRM Jetta finally got bad enough that I heard the telltale bad cam engine sound. I am in the middle of replacing and repairing not only that, but several other things as well, but am now wondering where all the metal no longer on the camshaft went.

Some have said it all went into the oil filter, but I got curious, and with the cam and rockers off, I stuck a couple small magnets into whatever pools of oil I could see in the head. Bingo, iron shaving came up. I have a magnetic drain plug, and of course, it had some as well, but there is a huge percentage of cam wear metal unaccounted for. Where else might I look for more in the head? The valve cover and oil pan are both still removed, is there some way to clean out wherever these shavings might be hiding? Is it worth removing the head in order to insure there are no more shavings that will cause future problems? I pulled off the oil pan and much to my surprise, did not find any shavings there at all. (I have only ever run the specified Pentosin oil, with changes at or less than 10k miles.)

It has not occurred to me until now that I perhaps should have been checking all my oil filters for metallic iron. That might have let me know to have checked my cam prior to it wearing a hole in one of the exhaust lifters.

Per Franko6's suggestion, my refurbishment is including an oil pump replacement. Sure enough, the original oil pump had some scoring on all of the expected surfaces, but it still actually looked pretty good.

Looks like the magnetic drain plug is useful if it reduced oil pump scoring. Now that you are putting in a new oil pump I see why you want to eliminate metal shavings. I went the oil bypass filter route to make sure oil was clean. I think this helps more by reducing nose wear on follower over the long run. That is a lot of work.

If you are using a parkerized cam you will want to also get rid of the manganese phosphate after the 20 minute break in.

As I have been working on this, I have been thinking a lot about what I should have done instead of waiting until the engine actually quit running well to address the problem. I have had the magnetic drain plug on it for years, and have also been finding metal on it for years, but since both this time and all the others there was not much on it, did not take action earlier. In retrospect, I think that was dumb on my part. The tiny magnet on the plug is only ever going to have a tiny percentage of whatever metal is in the oil. ANY metal on a magnetic drain plug now means to me that further investigation and remediation is required as soon as possible. That has probably already been observed and stated by one or more contributors to this forum, but I must have missed it or not taken the message seriously enough.

In section 17 of the Bentley manual, on page 98, it states "Finding metal shavings or a large quantity of small metal particles during engine repair could indicate that the crankshaft bearings or conrod bearings are damaged. To prevent this from causing further damage, perform the following repairs:
Thoroughly clean oil passages.
Replace oil cooler.
Renew oil filter element."

Replacing the oil cooler and filter element I can and will do, but how am I supposed to thoroughly clean oil passages without dismantling the entire engine? I will take this to mean that the passages I can locate should be cleaned. I intend to take only the oil cooler off and blow both a solvent and compressed air only through passages between the oil pump and the filter housing, plus through the oil line to the turbo. The oil pan is still off, as is the turbo. I solicit suggestions as to both the locations and safe methods of cleaning the oil passages that Bentley inadequately specified.

Franko6 gave me detailed assembly and break in directions with the cam replacement kit I bought from him.

Well there is your answer. Check to see if you have any scoring of your bearings. If not then there is no need for further cleaning. The filter is doing its job. As far as cam shaft breakin instructions provided.

I have noticed that Franko 6 requires bringing the engine to operating temperature and then bringing rpms to 2500 rpm and holding them there for 20 minutes. First, this does not make sense since most breakin will take place while you are waiting for the engine to warm up.

second, why would you use a 10w-30 as a breakin oil. The base oil is a 10w and uses polymers to reach a 30 wt at 100 C. A straight 30 wt oil as Amsoil uses as a breakin oil makes more sense as it has a higher flash temperature with no polymers to break down at the highly stressed metal to metal contact during breakin.

A Brm reaches maximum oil pressure even at operating temperature by 1800 to 2000 rpm. There is no advantage of breaking in the cam shaft at 2500 rpm.

Most or all scientific studies I have read which are numerous that want to compare materials use a a procedure of measuring friction. They usually start at 300 rpm and run it until friction drops, then up it to 400 rpm and do the same, then up to 500 and so on.

Which bearings?

James & Son said:

Well there is your answer. Check to see if you have any scoring of your bearings. If not then there is no need for further cleaning. The filter is doing its job. As far as cam shaft breakin instructions provided.

I have noticed that Franko6 requires bringing the engine to operating temperature and then bringing rpms to 2500 rpm and holding them there for 20 minutes. First, this does not make sense since most break in will take place while you are waiting for the engine to warm up.

second, why would you use a 10w-30 as a breakin oil. The base oil is a 10w and uses polymers to reach a 30 wt at 100 C. A straight 30 wt oil as Amsoil uses as a breakin oil makes more sense as it has a higher flash temperature with no polymers to break down at the highly stressed metal to metal contact during breakin.

A Brm reaches maximum oil pressure even at operating temperature by 1800 to 2000 rpm. There is no advantage of breaking in the cam shaft at 2500 rpm.

Most or all scientific studies I have read which are numerous that want to compare materials use a a procedure of measuring friction. They usually start at 300 rpm and run it until friction drops, then up it to 400 rpm and do the same, then up to 500 and so on.

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I do not understand some of what you are telling me, but greatly appreciate what I do understand. First, as you have suggested, Franko6 has already suggested to me that the filter would have contained most or all of the metal. Second, I do not understand enough about break in to be able to compare what it is that you are suggesting as compared to Franko6's instructions, so based on the enormously positive assessments in this forum as pertaining to Franko6's contributions to our keeping our VW TDI cars running well, I will be completely following his recommendations, especially since he is guaranteeing his cam contingent on doing so. Third, the instructions I have received do not suggest keeping the RPM at 2500, rather, at 2000. I will be inquiring of Franko6 further clarification as to when to change the RPMs from the initially required 2500.

Finally, since the oil pan is off and I can access the rod bearings, I will be following up on your suggestion to investigate the condition of some of these other bearings. Since I cannot locate any posts in our forums indicating that cam failure has precipitated main bearing or similar failure(s), I anticipate finding nothing alarming.

I have seen many of your posts and I greatly appreciate your contributions to the collective knowledge about how to keep these wonderful cars on the road.

I agree with what you say.
No where have I seen posted that bearings were damaged by a cam failure.

I also agree that Frank is forth coming with information on maintenance issues or maintenance trends. Yes Frank feels the standard oil filter is adequate for his cam.

I am not suggesting you do not follow his break in procedure. For some reason no one is willing to provide a pdf of it. Your instructions say 2000 rpm. He has stated in a post warm engine and then bring to 2500 rpm, if that has changed, fine.

Yes, you should question him as to what rpm you should run during this warm up period.

http://forums.tdiclub.com/showthread.php?t=364637

note: Go Faster states you should at no time idle the engine during the break in. May be the written instructions include this? Idling will be part of the break in but should be minimized.

To know what the ideal rpm is. One needs to know, force on cam nose, oil viscosity, and required surface speed to generate an oil film without generating excessive heat during the initial metal to metal contact and resulting smoothing and friction reduction.

Once a cam is properly broke in the cam nose mating conditions allow for oil film separation even at low idle rpms. Of course a high viscosity index 5w-40 oil would be the ideal for a brm cam shaft.

Sorry for being of topic. If your question was is it worth replacing the oil cooler, and blowing out lines etc. If your replacing the oil pump and cleaned your sump and head of chips then I would also replace the oil cooler.

The bearings are fine leave the caps alone, you will do more harm then good. It takes awhile for the cam problem to surface so every oil change you are collecting the particles in the filter when it's changed. The filter will catch all the fine particles. I had Crower cams weld up my cam and regrind it for $120 plus shipping, runs fine. I can see cam break in when it's metal to metal, but if you got the black tappets, I think it"s diamond like coating. The cam should be the only thing that can wear. I didn't replace the oil pump, oil pressure is in spec.

The cam should be the only thing that can wear.

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Anybody see a problem with this statement.

Ya. On a PD engine cam bearing wear usually accompanies cam lobe/lifter wear and may even contribute to the cam lobe/lifter wear because of localized low oil pressure from a worn cam bearing.

This wear, metallic particle damage and possible consequence resulting conversation is interesting, especially to me, when combined with my circumstances and current car status. So the cam and the lifters took a dive, but the turbo, which is super sensitive to lubrication, appears to have escaped completely unscathed. This means that the oil filter must have saved the day by preventing whatever metal was removed by the failed cam from making its way into the oil system downstream of the filter. Now, as I have have found virtually no metal shavings in the oil pan or the oil cooler, I am beginning to believe that the oil filter design must actually have trapped all the metal and has been very effective in preventing dispersion of the cam disintegration metal into other areas of the engine, which in turn, perhaps also means that the main bearings almost certainly remain relatively unscathed. The oil pump did appear damaged by scoring, but the measurable component tolerances were still only 0.003 in. maximum.

Cam wear, cam bearing and lifter wear most likely appear to be concurrent, but damage elsewhere seems to have been prevented by the highly effective oil filter. I will be continuing with my rebuilding work by assuming this to be the case.

I am thinking that I should probably invest in an oil pressure gauge instead of relying on the oil pressure idiot light, since these cars are so dependent on adequate oil pressure. Perhaps additional status monitoring gauges should include vacuum and boost?

James & Son said:

Anybody see a problem with this statement.

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There is no problem with this statement. Read it again, this is referring to break in wear. IE: cam lobe friction against lifter at initial start up. If it is DLC the cam should only wear. Just use assembly lube and it is fine.

Now, as I have have found virtually no metal shavings in the oil pan or the oil cooler, I am beginning to believe that the oil filter design must actually have trapped all the metal and has been very effective in preventing dispersion of the cam disintegration metal into other areas of the engine, which in turn, perhaps also means that the main bearings almost certainly remain relatively unscathed.

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I have a number of questions.

Did you remove the oil cooler and found no steel particles? If so then this must mean wear particles are very small and not dropping out of suspension.

The Bently repair manual says the oil pump pressure relief is 12 bar( 175 psi) and I know for a fact that my engine reaches about 55 psi at 1800 rpm at operating temperature and then holds that pressure constant at increasing rpm.

The only other relief is in the filter cap which I would think means this is a full flow filter.

This does not make sense. The 12 bar must be wrong or you would have oil by passing the filter directly to oil gallery through the oil cap relief.

https://www.crower.com/media/pdf/cam_book.pdf

Page 15 has break in procedure if you want to do it.

Nissans coating is non nitrogen and is designed to work with nissans oil and I think they patented the combination.

The Tdi coating is aprox. 20% nitrogen. The dlc coating is sacrifical( friction and heat causes graphite to develop) and can wear through rather quickly, if the cam is not ground with the proper finish and profile.

VW used the DLC coating to get cams passed the warranty period when the cars were new and then the follower and cam would wear out very quickly.

The follower dlc coating will prevent galling until the coating wears through, then the cam will gall and tear metal because the dlc coating surface fractures and a proper oil film will not develop on this fractured surface.

If all your stars align and you get through this dlc wear through period without galling the cam should get to 200,000 miles otherwise 50,000 to 150,000 is quite common.