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

[James & Son]

Eddif, There has been no discussion on #5 bearing. Get realistic. You mentioned, not to terribly long ago you would be interested in knowing the forces on the cam and thats what I presented ( facts as I see it, not a discussion). I was able to do this now because i measured the tension on the injector spring in the closed position along with the rocker ratio.

After pulling my cam shaft to look at my lifters and bearings it was the appropriate time to state my findings in regards to #1 journal wear location and analyze the spring forces and there effect on edge loading.

http://forums.tdiclub.com/showpost.p...postcount=1484
Face reality. I have. [1]Removal of lower bearing material by itself on #1, #2, #3 bearing increases wear. [2]SbAjjetta stock bearings were still functioning at 39000 miles even though his cam shaft was worn.

I think your oil location at 3:00 is spot on for DIY. Getting oil to the pulley edge of #1 bearing is spot on and will provide lubrication when future oil blockage of the #1 stock position oil slot becomes blocked but the only problem here is under heavy loads the stock oil slot kills the wedge and oil patch area. I assume you are expecting the different oiling will stop this progression.

Heavy loads means more bearing area is required. The soft underlay bearings automatically provide this by the soft copper yielding to generate more bearing support area. I am sure this is why SBA stock bearings were still doing a reasonable job and the oil slot was not blocked on #1 yet.

The first sign of copper is usually on number one bearing, and is caused by edge loading and bearing distortion.

It is obvious now to me that VW way of addressing the edge loading and the distortion was to use the soft copper underlay bearings. They work under the right conditions and the conditions must remain as stable as possible.

To improve number #1 and #5 stock bearings from being excessively distorted and to comform as quickly as possible( less chance of copper break thru), the reliefs should be put on the top bearings not the bottom bearings. This balances the compressive forces ( crush ) so that the top bearings compress the same amount as the bottom bearings which are not supported sufficiently.

As you know I have a beef about the aluminum head being unsuitable, for those who are in the warm up zone a lot, due to expansion and the effects on bearing crush and follower clearances. I do not doubt you see different wear due to southern temp and operating conditions.

I have provided the means in my previous posts to envision or chart how the spring forces affect the tilt of the cam about #1 bearing. In one cam revolution the stock valve spring forces( see previous posts for which ones) and #4 injector edge load the #1 bearing three different times.

I look forward to seeing the condition of your #1 bearing with 20,000 miles or more the better miles. This is the only proof I need.

 

[James & Son]

Doesn't Franko6 have a fix for this problem...? Seems to me he has a cam, bearings, and lifters to fix the problem with the BEW & BRM camshaft issue(s).
df

Jnitrofish had a good reply to dieselfuel, "each method is an experiment"


These are the only pictures of Franks experiment that I am aware of.

brm_km_006


http://pics.tdiclub.com/data/500/brm_pd_006.jpg

These are Black Knight's worn stock bearings and cam shaft. I do not know the mileage but the bearings look good except for #1 which does not seem to have much edge loading but is evenly worn thru to copper. The uppers look clean with very little contact.


10k_km_002


http://pics.tdiclub.com/data/500/10k_km_002.jpg

This is 10,000 kilometers.
Since these pictures Frank has reduced outer injector bolt torque and reduced upper groove width. This may have helped improve what otherwise seems to be massive upper bearing contact.

I have just worked through the loads that would cause edge loading. How is it possible that the upper bearings are showing almost full rubbing contact. Yes i am aware that a central circumferential oil slot cuts the load capability of a bearing in half( eddif showed this long ago). But the upper bearing loads are next to nothing with the compensating injector spring preload tension. Lets check the effective bearing capacity.

The groove seems to scale .16 to .18 wide. Thus bearing capacity is half of .980 less .17 = .405.
Just to compare my upper cut bearings capacity is .18 per side removed or .98 - .36 = .62 or 50% greater effective width.

The sudden extreme reduction in effective upper bearing load capacity post injection firing towards 7:30 could be causing an oscillation known as whil-a-whip( unstable loads in the bearing). I can think of no other explanation. The pictures leave a lot to be desired and it is hard to tell the wear progress of the lower bearings.

If these bearings are working so well why has Frank not posted pictures. I guess the bearings are the last thing to worry about. If the cam and followers last then the bearings are working whether they wear out or not.

Anybody else have another way of looking at this.

Was going to edit but decided against a note regarding number 5 upper bearing. If others have pictures of a successfull Franko experiment please post. I am interested in any known improvements.

 

[James & Son]

Allow me to compare the original 98k mile bearings from that car with the bearings I modified that went 25k miles.

Using software, I have reoriented the upper bearings into the third lower row to be a direct comparison to the modified picture. Don't worry the lower shells and the upper shells are oriented correctly for comparison, even though the oil slots don't match up in the second picture. I flipped the lower shells in the second picture around when I ran them in the engine.

Here is a quote from my thread when I surprised everyone.



I decided to throw in a new set of unmodified Glyco bearings with the cam I was installing.

Eddif and James will have to comment if what I did was good, as for me it was driven by the question of "why not? I know what the stock bearing is going to do, and that's boring."

Your modified bearings needed the copper underlay to deform more than the stock bearings. This was probably due to you being more aggressive with the colt stage II cam.

I think the #1 modified lower bearing is edge loading when #4 injector fires. The rpm determines the injection pressure, the volumn of fuel injected has no effect on the injection pressure only rpm. Volume determines how long the pressure duration lasts.

You may have broken your cam in properly but I think you were to aggressive early in the bearing break in.

Each heat cycle copper goes through it becomes harder. New bearings are soft and may not be able to handle aggressive injection loads.

The cam bearings will have to be part of a progressive type break in procedure.

I am not sure how the introduction of oil at 10:00 affects the lower #1 bearing. There seems to be no test information.

The interesting thing about Franks bearings is for 6 months on his thread he said he was going to provide oil at 10:00 but when they came out the oil slot ended up at 2:00. I don't think there was ever an official test compared to stock bearings showing increased oil flow.

 

[cdutton]

I have copper streaks on 3 lobes of my cam, Car idles fine and runs good until u accelerate then not much power and has black smoke, can hear noise like air from intake,but on hiway runs great. from what I read sounds like cam. It is getting worse now. I started by thinking maybe timing was off to bad injector to cam. Belt looks fine and is due cause I have 80,000 miles on it but think it is cam or hoping injector. I have pics but could not get them on post need help with that too.
Please help

 

[Richptl]

Here is an interesting tidbit. When I bought my car a year and 40,000 miles ago I pulled the valve cover and checked the cam bearings, they looked good. I've been using Pentosin HP2 (now I hear the Mobil 1 TDT actually has more Zinc) but lately the idle has been getting rough. VCDS stabilization #'s going more and more negative on 1 and 4, approaching -1.0. Slightly positive at +.40 approx on cylinders 2 and 3.

Pulled valve cover again last night, cam lobes still looked good. This time though I spent more time rolling the crank and got a look at the lifters (I ordered a USB scope camera on eBay for $50 today, that is the tool you need!). Low and behold, #1 exhaust lifter was dished and #4 lifter has a slotted wear pattern.

So in my case it appears that the lifters are wearing but the cam is largely intact. I ordered a Colt Stage 2 cam and installation hardware, will get a better look at the old cam, lifters, and bearings when they come out.

 

[James & Son]

1656, new learning experiance, and 1657 needs to post pictures as words are vague.

Here are my pictures. My cam is finally broken in.



83000 km cam replaced under warrentee

128000 cam lobes had oval smoke rings on nose of lobes from center wear of the black followers.

128-135000 , TDT and additives(I tried some unusual combinations here that just did not work) but did not help and had follower center scoring at 135000. Cam lobes not broken in but had slight lobe wear of tenths of a thou.

138000 put in new set of Ina black followers. Rotella T6 5w-40 with no additive.

143000 and cam nose much better but some wear and center scoring of follower although not affecting steel substrate yet. Decide to go to a group II oil to stop follower wear thinking it needed heavy viscosity during warm up of motor. Used Petro Canada 10w-30 and 15w-40 CJ4 group II for winter and summer respectively.

173000, take pictures and change to Petro Canada 5w-40 synthetic CJ4 for winter. The cam nose is fully broke in with no indication of further follower center wear although I will need to remove the cam to compare to previous pictures taken at 143000 and around 148000

Modified bearings and oil delivery mods installed and made at 135000.

Made some bearing and oil treaks at 143000 as well as changed inner valve springs to a 15 % overall reduction in spring force (had custom automotive quality springs made).


Opinions, Since cam took a minimum of 10,000-20,000 kilometers to breakin on the second set of lifters it is necessarry to have lots of viscosity in the warm up zone of the motor/oil and a group II is ideal for this. Now that the lobe is smooth and mated a 5w-40 synthetic will do.

See James and Son photo album for documentation and dates will correspond to posts in this thread.

 

[GoFaster]

Your nemesis/counterpoint (me) is closing in on 400,000 km having never touched the cam bearings and on the original camshaft and lifters.

Having said that ... the car needs work (leaky EGR cooler, rattly DMF, T-belt change interval is coming up) and a Franko6 camshaft and new lifters and bearings are under consideration for the powertrain's mid-life freshening.

 

[James & Son]

Sell that car to anyone else and it will fall a part in less than a year but I will take it off your hands if you want to sell it.

All my major costs have happened under warrantee.

VW is putting out for 2500 in rust repairs and i will be getting my cost back on the drivers side wiring harness( maybe).

So far the other things that go wrong somebody has come up with a fix for and I am lucky enough to be able to fix them at little cost. I dread the firewall side of the motor which so far I have had not a problem. My luck may not hold out for very much longer. I always keep my cars until they die a slow painful death and my local garage I think loves me.

Just so you know the OEM Brm cam( replaced under warrantee at 83000 km) that I have just finished breaking in at 173000 km had 9 equally spaced grooves ground around the cam circumferential surface. I would say it took 4 times longer than normal to wear those ground in grooves to a surface compatable with elastohydrodynamic lubrication and thats where most of my problem came from.

eddif I am sure will be happy to hear you are having cam problems maybe you should PM the good news.

If you buy Franks bearings make sure you have his warrantee in writing although really they work on the placebo effect more than anything.

By the way what is your fuel mileage? Are you still on the same injectors. Do you add anything to the fuel in that regards.

Also maybe you can squeeze another 100,000 from the cam and hit that magic 500,000 km mark that would be more than remarkable!

 

[GoFaster]

I am NOT having cam problems. There is zero external evidence of any issue whatsoever with the original camshaft and lifters. I just don't want any trouble for the next couple hundred thou. I'm not springing for modified cam bearings - just the standard ones - all evidence that I have, is that they are good enough when the correct oil is used.

Original injectors - but part of the mid-life freshening will include replacing them with PD130/150 units.

EGR cooler replacement requires halfshaft removal. Clutch replacement requires transmission removal. Transmission mount is suspect, too. At that point it might as well all get done together.

 

[foobert]

I'm not springing for modified cam bearings - just the standard ones - all evidence that I have, is that they are good enough when the correct oil is used.

Are you referring to 505.01, or ??

What oil do you use?

 

[2footbraker]

Why would you not use Frank's modified cam bearings? IMO, that is much more important than using his or Colt's cam.

 

[James & Son]

Frank will sell you stock bearings or modified bearings, he will sell you chrome journals or non chromed journals and as long as you buy all the parts from him he will still warranty the cam shaft for 3 years. I would not buy bearings without proof that they flow more oil than stock.

There are pros and cons and the main pro is it is easily made at a reasonable price. But ask Frank what the flow is at 4000 rpm through a .010 depth oil groove at 60 psi flowing against journal rotation 14 cst

Or how much flow you get with TDT through his .010 deep oil groove at 93 cst at 40 degrees C. at 1800 rpm against cam journal rotation at 60 psi.

I would be surprised if he has any test information which is normally the next step after using a formula that takes into account "flow through capillary spaces with moving boundary"

Frank has never said he would guarantee more flow than stock but he has said "it can't hurt".

One other thing I find surprising. Yesterday he explained on his thread in the Vendor section how to break his cam in. After changing to Joe Gibbs oil you were to start the no load break in proceedure after bringing the motor up to operating temperature. So what was happening to the cam while you were bringing it up to operating temperature. Zddp does not start to do anything until 95 C. It was probably scoring the follower no less than any other oil for the 5 to 15 minutes it takes to get both the motor and the oil to 95C.

Does he have written instructions that come with the cam that explains in more detail how to prevent scoring during this warm up period?........These are all issues that should have been addressed before selling product. Maybe he can show me where he has done so.

 

[2footbraker]

Maybe I am biased, as I am closing in on 250k km on a stock cam, but why are you guys spending so much of a short life obsessing over a hunk of metal? There's much more important things in life to be concerned with.

If a cam design is messing up your life so bad, why not sell your heap and buy an ALH car?

 

[James & Son]

Maybe I am biased, as I am closing in on 250k km on a stock cam, but why are you guys spending so much of a short life obsessing over a hunk of metal? There's much more important things in life to be concerned with.

If a cam design is messing up your life so bad, why not sell your heap and buy an ALH car?

On the contrary, I am loving the challenge, but there wouldn,t be much fun if you don,t challenge. I love factual information and testing and retaining the big picture, like a jigsaw puzzle that has fixed boundary's and you fill in the pieces.

So far Frank has helped a lot with those pieces with good technical information but he is not one for testing I guess.

Design wise Frank can improve the oil flow if he maintains a .015 to .020 deep oil groove to improve the situations that I have pointed out where he has minimal flow.

But his #1 bearing will wear just as fast as stock no matter even if there is an improved oil flow to the lifters and to the 4:30 wear position. I am refering to cars that drive under 20,000 miles a year mostly

Until, if and when, someone comes up with a method to keep #5 bearing journal in place #1 bearing will wear more than the others. If copper shows then all lower bearings must be replaced.

It is the low milage cars that are hurting. Ol'Rattler was pissed when he only got 80,000 miles out of his cam about 6 months ago. Those like myself putting on less than 20,000 miles a year will replace cam, followers and bearings on a regular bases.

The solution to both the cam, follower and bearing wear is to get #5 journal to sit flat and then make sure there is still enough [excess flow to the lifters(e.g. Franks upper oil groove)]. eddif method got the wear pattern to wear evenly on #5 but the edge loading is still on #1 because certain valve spring forces are lifting #5 journal at 2 other times during one cam rotation. He solved one, I solved another with my 15% lighter valve springs. Does that mean the cam, lifters and bearings will go 2/3 longer or 140,000 miles, obviously that is still not good enough, I need to get to the next belt change so we need the last 33% life expectancy potential.

From my calculations I am very close with the 15% reduction in valve spring force. It might not take much to finish this.

 

[James & Son]

Cam Edge Loading Solution

For me the following will solve my cam lobe, follower and bearing wear.

(1) reverse bearing top and bottom and activate 10:00 position oil slot.

(2)15% oal valve spring tension force reduction. ( reduced valve spring force prevents overcoming injector spring preload keeping cam flat )
I have turned 4500 rpm with 15w40 with these springs but this is got to be on the ragged edge)

(3)add .095 inch shims to #2 #3 #4 injector springs to balance tension of cam belt on #1 cam bearing.


I have done #1 for 30,000 km and #[was 3] (edit to#2) for 20,000 km but I need to do #3 asap and I may do that this Fri.

Stock, without the #2 and #3 mods, the valve springs can over come the injection springs pretension of 60 lb per spring and cause the cam to lift up and down 4x per revolution of the cam shaft. ( the rocker ratio increases pretension x 1.2 or to about 72 lbs.)

And along side of this during this one cam revolution each injector fires.

Because of the 275 lb tension of the cam belt #1 bearing is most effected with the #1 bearing acting as the longitudinal fulcrum and #5 journal bearings acting as a ralatively loose containment of this orbital motion.

So by allowing the injection spring pretension to hold the cam flat, bearing edge loading will be eliminated.

This should also solve the center follower wear. You need follower bore clearance to allow the follower to stay flat against the cam lobe if the cam is moving around. When the aluminum head is hot you get plenty of clearance but there is always what eddif has termed as friction climbing(side forces). There is plenty of side forces from the opening lobes to unbalance this balancing act of follower trying to stay flush to the cam lobe as it is pushed against its bore housing by lobe forces and friction while it is pushing upwards all while the cam centerline tilts down at #1 bearing and up at #5 bearing about .0002 inch per inch. This is happening 4 time per revolution of the cam shaft.

As you can see getting the cam to remain pressed down against the cam journal bearings keeps everything on center and the followers square in their bores against the cam lobes.

Now the only forces that are a problem that may skew the cam momentarily is #4 injector which seems to push that end of the cam to the 7:30 position. I think if the cam is forced to sit flat that the lobe friction force may help it stay in place. If not then ediffs method to increase journal friction climbing away from the 7:30 position may be necessary to prevent this.

Now with the cam journals sitting flat at 5:00 and not moving around it may be oil to the followers may be reduced. This can be countered by introducing oil at 10:00.

I have done the above and just need to add the injector shims. Will it be worth it. Yes only if I can get to 250,000 kilometers. Unfortunately my cam and followers did not get a good start partially due to a very roughly ground cam that took a long time to break in.

 

[GoFaster]

Are you referring to 505.01, or ??
What oil do you use?

The car has seen various oils through its life. First the Castrol 5w40 505.01 that the dealer used during the warranty period, then various Elf, Motul, and other 5w40 505.01 oils, then Mobil 1 Turbo Diesel Truck 5w40 for the last 100,000 km or thereabouts. Never had a drop of anything other than 5w40 in there.

Why would you not use Frank's modified cam bearings? IMO, that is much more important than using his or Colt's cam.

400,000 km on the original setup. IMO all this discussion concerning the cam bearings is about a non-issue. It's rather normal, and is not a cause for concern, to get shiny spots on plain bearings. In all the photos in this thread, I have yet to see a truly trashed cam bearing.

One other thing I find surprising. Yesterday he explained on his thread in the Vendor section how to break his cam in. After changing to Joe Gibbs oil you were to start the no load break in proceedure after bringing the motor up to operating temperature. So what was happening to the cam while you were bringing it up to operating temperature. Zddp does not start to do anything until 95 C. It was probably scoring the follower no less than any other oil for the 5 to 15 minutes it takes to get both the motor and the oil to 95C.

Does he have written instructions that come with the cam that explains in more detail how to prevent scoring during this warm up period?........These are all issues that should have been addressed before selling product. Maybe he can show me where he has done so.

You are missing something here. The traditional camshaft break-in procedure - which is really no different than what Frank suggests - is to start the engine and IMMEDIATELY bring it to 2000-ish rpm and hold it there for 20-ish minutes, this 20 minutes INCLUDES the cold start and warm-up period. Keep in mind that when the oil is cold, its absolute viscosity is higher, so it should be BETTER at holding film thickness when it is cold. The intent is to get it running as close to hydrodynamic lubrication as possible with only any excessive surface asperities in contact (and wearing away, and polishing against each other).

Idling is the worst thing possible for camshaft and lifter wear.

By the way, I highly doubt that the camshaft break-in procedure was followed at VW when the engine was new.

 

[James & Son]

#159

We recommend this break-in procedure:

Change oil filter and oil to the Joe Gibb's BR oil. The initial break-in is done with the engine brought to temperature, no-load and varying the RPM between 2000-3000. If you are going to install large springs, the internal spring should be removed. We wait for the engine to reach 95c and start a 1/2 hr break-in. After the 1/2 hr break-in period, shut down, drain the oil and change the filter and refill with more Joe Gibbs BR oil.

Ok thanks for commenting. The first sentence to me is written as an over view.

"The initial break-in is done with the engine brought to temperature, no-load and varying the RPM between 2000-3000."

Then he details the procedure.

We wait for the engine to reach 95c and start a 1/2 hr break-in.

You can see that it is written as if the warm up period is not part of the break in as you must reach 95 C before break in begins?

I would like to see his written instructions before declaring he actually counts the warm up as part of the break in.

I agree the warm up period could be and should be part of the break in but I think unless you pre-pressurize the oil you will not have a good start up.

There is a problem with the initial start in that the lifters are collapsed and make a racket and may take 5-10 minutes before things start to quiet down. Its hard to tell if its the cam and lifters are just breaking in or a collapsed lifter(s) is making the noise.

JNitroFish has had this problem and I know when I started my motor with 5w-40 at room temperature I had a lot of noise and wasn't sure what was causing it and it took quit a while to get to a point where you wanted to even try continuous high rpm.

Its just to easy to say immediately take it 2500 rpm. I think Frank just counts the warm up zone as a variable and do what you want.

 

[Jnitrofish]

Excuse me if I speak out of turn here, I like that you two are having this discussion, and I mean no offense.

Idling is the worst thing possible for camshaft and lifter wear.

I agree with this, and I also think that it is generally a poor decision to use normal oil over special break-in oil if given the option. However GoFaster, one of my cars presents just as much of a challenge to this idea as your car does to BRM cam wear. I idled the replacement cam it on TDT and didn't change the oil until a full 10k miles interval, and it now has nearly double the miles of the original cam with a remarkable fraction of the wear. So while it may be the worst thing you could do, it doesn't equate to guaranteed failure.

One other thing I find surprising. Yesterday he explained on his thread in the Vendor section how to break his cam in. After changing to Joe Gibbs oil you were to start the no load break in proceedure after bringing the motor up to operating temperature. So what was happening to the cam while you were bringing it up to operating temperature. Zddp does not start to do anything until 95 C. It was probably scoring the follower no less than any other oil for the 5 to 15 minutes it takes to get both the motor and the oil to 95C.

Does he have written instructions that come with the cam that explains in more detail how to prevent scoring during this warm up period?........These are all issues that should have been addressed before selling product. Maybe he can show me where he has done so.

Remember that the Joe Gibbs BR he has people using is a 15w-50 conventional DINO oil. It is old school Delvac 1300 on steroids. Do you think that is not enough to limit wear to a certain extreme under cold start conditions? I am assuming there there is a oil film on the lifters to begin with here, but wouldn't the ZDDP protection also depend on an oil film be present to deliver the additive?

And yes I am still running Delvac 1300 15w-40 in my car year around at the risk of many a costly repair.

 

[James & Son]

You are missing something here. The traditional camshaft break-in procedure - which is really no different than what Frank suggests - is to start the engine and IMMEDIATELY bring it to 2000-ish rpm and hold it there for 20-ish minutes, this 20 minutes INCLUDES the cold start and warm-up period. Keep in mind that when the oil is cold, its absolute viscosity is higher, so it should be BETTER at holding film thickness when it is cold. The intent is to get it running as close to hydrodynamic lubrication as possible with only any excessive surface asperities in contact (and wearing away, and polishing against each other).

Actually I had a chance to break in a replaced lifter last weekend and used your warm up method and break in although after 15 minutes I just drove around the block in 4th gear. I added an ounce of ZDDPlus to the oil to bring it up to 1533 parts per million ( prior to break in) and then will see how the addition to the oil will help the new lifter as well as the rest of the lifters which are not quit worn through the black coating at 33000 km.

I have had 3 scored lifters. 2 from sand entering the filler neck #1 exhaust and #2 exhaust. This last one was on #2 exhaust as well. All this has been caused by changing the oil thru the filler neck( I see no other way).

Reason for going in is this lobe, although all the rest looked very good after the 33000 km break in on second set. See below for look at lifter taken out of #2 exh.( center)

Row 1 is cylinder 1 & 2 and below the center follower is cylinder 3 & 4. These are the start set with this cam or set #1 and set #2 replacing this set is shown below.

The above and the other pics here show the condition of the other followers in the set#2. The picture of cam with green tape is of the #2 exhaust lobe after polishing. Can just make out the gouge that caused all the follower damage.
Now Set #1 ( back to pic of 9 followers)has got the two followers that were scored by sand getting in through the filler neck. The lifters are #1 exhaust and #2 exhaust, you can make out extra radial marking from the circular marking on these followers.

The circular marking is not grooves but is still flat as I have a precision square and up to the light it shows no scoring on the rest of the followers and I guess they would still be usable.

But here is a problem

This album shows the followers that are scored in set #1 and the above which showed up after the #1 exh and #2 exh lifters were scored.

The circular marking on all the lifters could be caused by the closed dwell side of the cam when the injector ramps and fires. The compression( in cylinder) would prevent any give of the valves no matter what the force.

Was this a one time event and was caused by the unfortunate circumstances of sand scoring the followers that this resulted on. Not an easy question to answer.

EDIT- maybe the reason ( is this coincidence or what! Remember this is set #2) #2 exh. scored. Look at the chunk missing from #1 exhaust this could have happened to #2 but resulted in scoring as well, but was only lucky the follower on #1 was not scored.

 

[James & Son]

What is the problem?

The first set of lifters( replaced with set#2), F-46516 83 EF measure .724 inches for both #1 exh. & #2 exh. collasped

The lifter ( #2 exh. )that was scored and from set #2 part no. F-46516 83 F measures
.724 inches fully collapsed. Note it takes a long time to remove all the oil which is necessary.

Oil is introduced into the follower at some time in its stroke. If this happens in the closed dwell portion of the cam the oil pressure at 60 psi would garrantee the oil filling all chambers and the lifter would have zero clearance against the cam dwell.

My cam rides on the lower portion of #1 cam bearing and the #5 cam journal rides against the upper bearing half of #5 bearing. This is because the cam belt and injection springs are preloading the cam but there is a set of valves opening and closing every 90 degrees of rotation so there is leverage to lift #5 cam bearing end. This happens very quickly at high rpm. But what about low rpm?

Would there not be time for the hydraulic follower to actually track the up and down #5 journal end cam movement. Valves push up and then as they are closing the injector pushes down. The cam would now be forced against closed valves and followers which if held closed by cylinder compression would have hundreds of pounds holding the valves from moving( besides the valve spring). This is where I think the circular center marking on the follower is coming from. You can see here what I am talking about.(These lines would translate to circular lines on the center of follower).

 

[GoFaster]

Crossed 400,000 km today. You know the story - Never touched camshaft, lifters, or cam bearings.

edit: Also, it's at 925 km on this tank of fuel and it's not on low-fuel yet, so there's no indication of distress from that front, either.

 

[James & Son]

Crossed 400,000 km today. You know the story - Never touched camshaft, lifters, or cam bearings.

edit: Also, it's at 925 km on this tank of fuel and it's not on low-fuel yet, so there's no indication of distress from that front, either.

I would like to see pictures of the parts when you change the bearings,cam and followers and keep track of your total cost CA.

Make sure you remember to check the rocker shaft plugs are not coming out.

from Jnitrofish- I agree with this, and I also think that it is generally a poor decision to use normal oil over special break-in oil if given the option. However GoFaster, one of my cars presents just as much of a challenge to this idea as your car does to BRM cam wear. I idled the replacement cam it on TDT and didn't change the oil until a full 10k miles interval, and it now has nearly double the miles of the original cam with a remarkable fraction of the wear. So while it may be the worst thing you could do, it doesn't equate to guaranteed failure.

Since I have measurements of the cam shaft I thought I would check the surface speed of the lobe at idle and compare it to a white paper I have that simulates EHD lubrication of the cam and followers. The tip of the lobe is on a 1.4 inch radius that equates to .22 meters per rev. of cam. At idle the cam is rotating 450/60 = 7.5 rev/ sec or 1.65 meters per sec.
According to the white paper with an oil visc of 14 or 15 cst. border line full film support vs. partial with some contact of asperies is around 2 to 2.5 m/sec.mostly depending on roughness of the surfaces. Zddp only works when you have contact anyways but has to be above 80 or 90 C. So idling to warm up especially at break in is a concern( like you said if the oil is very thick at room temp. might not be to bad). By the way 1800 rpm of the engine equates to 3.3 m/sec. of the cam.

Further to this the white paper also tested DLC coating at various rotating/slide ratios. They determined that the DLC speeded the break in process up for the 5100 bearing steel because of its rougher( ralative) and harder surface compared to steel on steel.

Another thing they pointed out was that the DLC promoted droping in and out of the full EHD contact at higher entrainment speeds do to a rougher surface( note this rougher surface does break in as well at some point) and possibly also increased EHD contact temperature.

So far with the wear progression on my followers I have not been able to go from DLC to nitride substrate on #1 exh and #2 exhaust( the rest were ok). Another 10,000 km the coating will wear through again and I am hoping the extra Zddp is all that is needed this time.

Eddit I want to make it clear that my cam was installed in Sept. 2009 using all OEM parts under warrantee. The lobes are smooth and measure #1 int 2.4298, #1 exh 2.430, #2 int 2.430, #2 exh 2.430, #3 int 2.4296, #3 exh 2.4292, #4 int 2.4297, #4 exh 2.4299. Order is not based on order in engine .

All modifications were made after I started having #1 #2 exh follower issues.

Eddit has any one noticed it is the followers associated with the lobes with the least wear that are giving me the problem with pickup and scoring???

 

[James & Son]

Your nemesis/counterpoint (me) is closing in on 400,000 km having never touched the cam bearings and on the original camshaft and lifters.

Having said that ... the car needs work (leaky EGR cooler, rattly DMF, T-belt change interval is coming up) and a Franko6 camshaft and new lifters and bearings are under consideration for the powertrain's mid-life freshening.

If your going to keep the car or not I would do the valves and replace the valve springs as I think they are fairly cheap about the same price as the bearing half. The valve seals are cheap. Then you would have no problems in reselling the car on this site. Offer it to me first though.

 

[James & Son]

From post 1674

So far with the wear progression on my followers I have not been able to go from DLC to nitride substrate on #1 exh and #2 exhaust( the rest were ok). Another 10,000 km the coating will wear through again and I am hoping the extra Zddp is all that is needed this time.

There are only 3 things I can think of causing my problem

#1-sand or grinding grit or bits of steel getting onto #1 and #2 exh follower when oil is changed. There is a good chance this is what happened to my 2009 followers as I found sand on the inside lip of the filler opening prior to finding the scored #1 and #2 followers. The recent scoring could be the same issue but I had started blowig the filler cap opening and area of before having the oil changed. I am now doing it myself as I can't take the change.

#2- possibility is expansion closes the gap to less than .724 ( see post 1172)
From checking back to specifications on older mechanical followers on small OHC diesels it is possible to have up to .016 inch expansion. The hydraulic followers have a minimum of .025 to a max. of .030 of hydraulic adjustment. I am going to check the distance between valve and follower( edit- between valve and cam) next chance I have. I am going to look into if I can turn the contact seat down on a follower in the lathe with a ceramic insert as I have the used ones for the trial.

#3- It might be possible at slow speeds and heavy injection pressures that the up and down movement in the cam is allowing the follower to load up in the dwell portion of the cam. See post 1671/1672 for picture of dwell scoring on #1 and #2 exh. I have thought of a way to look after this problem. I will be doing this in the next while as well so will post pictures after.( see post 1671 for more detail on problem)

I have only so much time before #1 follower wears through the black DLC coating. I would say about 10,000 km. when that happens I want to have all of the above solved so I only have at most another month.

 

[James & Son]

I have studied both sets of followers from same cam. #1 exh and #2 exh. They are the first to actually tear material from the center dot upon black coating wearing through. But #1 intake of first set(right) looks almost identical to #2 exhaust of second set(left).

#1 possibility is this is all caused by cam lobe.
#2 possibility is this is all caused by cam dwell
#3 possibility is this is all caused by both

If you study my pictures in James and Son album will will see my attempt at trying to solve this problems[edit: sub album is named Oct 30 2012 Shim Experiment ]. I decided the solution is same.

I replaced 1,2,3,&4 bearing but kept all previous modifications except the .140 in waisting cuts to 1,2 and 4 bearing. #3 and 5 still have waisting as are all of the uppers. The waisting helps to balance the crush or compressive forces between upper and lower bearing halves. Normally the fully supported uppers would shove the lowers into the unsupported regions and distort the bearing. My attempt now is more a compromise to balance wear evenly on the bottom bearing halves.



Eliminate as much up and down movement of the cam shaft by shimming #5 bearing. picture shown was my first attempt as I was going to shim all bearings up. This did not work so I shimed #5 upper down instead. [ #1 bearing not shown as I had already started the install ]


Here is an interesting shot of an attempt to use the shim to balance crush as well as reduce clearance on #5. The center mark on #5 lower is new from the shim install and hand rotation. This was what I saw after deciding shiming all lowers was to tight for comfort. I then took the same shim and put it in the upper #5 bearing half biasing it to the flywheel edge side of the bearing.[ keeps both upper and lower#5 bearing crush from tilting the bearings into the unsupported area of the lower.]

Edit- The shim is incorrectly placed in the below pic. It should be flipped or mirror image and aligned with the right side edge of the distinct center marking so in fact this now allows the left and right to have similar unsupported areas balancing crush and eliminating #5 bearing tilt


I also checked if my valve stems were to high causing an improper distance between valve stem end and dwell of cam. The only check I could do was to put a parrallel across the lower bearings and measure the distance and compare. All were within .005 in. of each other except one was closer to the cam by .010 or .015 depending on which of the other valves you were comparing to. I then found that if I tried really hard and with patience I could get the follower to collapse .100 (yes that is not a miss print). I remember Frank stating the alh had about 1 to 1.5 mm. I feel therefore I have elliminated this as my problem, besides the valve in question was not on the problem followers even.

I have been driving my car for two days now and everthing seems find. No disaster yet.

How much up and down movement have I elliminated. First of all do not use full throttle at 4500 rpm on a new soft copper bearing. The copper must harden up somewhat from many heat cycles to with stand the force. My belt bearing measured .0025 in. greater than journal and my #5 measured .0015. Airbeast has measured .0013 clearance on new bearings. I should have minimal movement to get through the black wear through which will take place in the next couple of oil changes. You must add .00075 to .001 extra clearance on warm up of aluminum head.

Edit: just in case there is a misunderstanding I am referring to the clearance on my bearings prior to replacement and shimming. The result is an improvement of reduced up and down movement as well as fore and aft movement of the cam shaft center line.

I am hoping extra Zddp and the reduced cam movement will solve my problem.

Oh by the way I have even and copious oil flow to each follower as described

 

[James & Son]

Ok just to fill in some gaps so I can do another wait and see. Shimming is a radical thought, but I am not using tin foil here but .0005 in. full hard Stainless steel Rc40 shim stock.

If you saw metal pickup on the dwell side of your cam a distant equal to the injector firing cycle duration, as well as the center of the followers on 5,6,7,8 followers showing a perfect circle pattern comparable to the raised ground grooves on the cam dwell and then on 1,2,3 follower not only circles but the center dot and next ring is being tore out and then the cam lobe is riding over the circular scars of 1,2,3 and further scoring and removing the partially tore out pieces and then after observing this and waiting another 1500 miles the followers with this small wear dot distruction start to heal themselves with the gouges starting to smooth over. What would you think or do?



If you have read any of my posts above you know my thinking on the forces and cam movement within the bearing.
I have read Frank say the follower rides clear by .004 and bently says you can have up to .004 thou in the bearings but I am going to have to say I think under the right circumstances this might not be right.

I think my situation and probably others under the right circumstances the cam shaft can rock on bearing #3. #1 and 2 bearing wear quicker and #3, 4 and 5 do not wear or very slowly. When #4 injector fires it raises the belt end of the cam up and leveling it against bearing 3-5 as well as pushing hard against followers 5-8( but 225 lbs of belt tension is reducing this somewhat). The followers 1-4 also follow the cam up because they have 2-1/2 pounds of spring pressure and oil is entering at 50 psi ( at least intermittently).

After #4 injector fires #2 and #1 are next in line. The valves are locked close do to compression when they are on the fire stroke and the compression stroke ( injection pre TDC ). The injection cycle of #4 ceases and the cam drops hard onto the followers and then 2 and 1 fire in concession. Also I think the followers under the light spring pressure and internal oil pressure are rotating at the same surface speed as the cam dwell and these increased rotating sliding loads and suddenly the hot spot becomes even hotter, which is more apt to happen more at low rpms.

If I am correct then shiming number 5 and getting #3 bearing to wear down as quickly as #1 and 2 bearing will put the fulcrum on #4 bearing and under normal injection pressures it can not be lifted against the cam belt tension if #4 is the fulcrum. At the same time this slight wear tilt moves #5 journal closer to the already shimmed #5 upper bearing half. Therefore 1,2,3,4 must wear in a manner that results in #4 being the fulcrum not #3 as I now suspect. This is not perfect as the cam will never be square to the followers. #1 bearing wears to fast.
I am just trying to get pass the point now where as the followers wear thru the black coating the dwell portion of the cam does not load the follower.


PD Cam Wear Riddle Solver

This is one of eddifs pictures I had forgotten about. He showed I believe that the hammering was peening the metal. I think I have convinced myself I have a solution to eliminate all movement, and I get to find out in the next 2 or 3 months.

 

[James & Son]

Update: wear dot wear stopped

Update, read discription on pictures.

 

[James & Son]

Center dot wear stopped

I want to make it clear in case those without access to the picture folders; can see the clear difference from my previous posts 28000 km ago.

54000 km ago I replaced all followers because they broke through the black coating.

These followers had 50,000 km on them( this was not good to say the least).

The cam lobes on this new warranty replaced cam were good so I did the unthinkable and replaced the followers.

The second set of followers looked like the third picture below after 25000 km with the small center dot tore out of exhaust #1 and the coating completely broke through on #2 exhaust( third from left)

I replaced this follower as it was badly torn up. The 2nd picture shows the mark left on the lobe from riding over this torn up metal.

The above posts describe the changes I felt were necessary to get the cam to stop destroying the followers.

After an additional 28000 km( see first picture). The newly replaced follower on #2 exhaust looks as new as the day I replaced the torn up one for it. If you compare the pics. the other followers look exactly the same with no additional wear.

The pictures clearly show that the changes that were made 28000 km ago dramatically stopped follower black wear through and the resulting galling of center dot metal.

The forces that were causing this suddenly stopped!

I

 

[James & Son]

Cam Wear Solution DIY

I am claiming I have solved the follower wear and thus the cam lobe wear and anyone can eliminate the cause with a simple DIY procedure.

Note how the galling takes place on the side that is slipping or being driven against the follower rotation were as the other side is fine because it is the driving side and is not slipping.

Remove about .005 inch of material where the galling is taking place from the the galled area on the closed lobe dwell as shown in pic below and no more galling. I claim this DIY method and allow anyone to use it as long as I am given credit as the author of the solution.

Edit: A picture will do showing your handy work.

Edit #2: I will provide and test a procedure for doing this that even the most incompetent will have a hard time screwing up as well as a similar method for removing minor damage on lobe noses and blending edge radius.

James and Son

 

[2footbraker]

I'd be interested in a step by step DIY.