Another BRM Cam victim

[eddif]

So a different opening and closing ramp such as with a BEW cam doesn't really address the root problem, it might just buy you a little more time because the ramp up/down loads are perhaps gentler causing less cam to lobe wear but not less bearing wear.

Your implication seems to be that lobe/follower wear is a result of reduced oiling caused by bearing wear.

Could you expand on:

• Cam bearing oil slot coverage (and thus follower oiling) takes place at different mileages for different people.
• The cam bearings do not have enough support under them and experience cocking from cantilever forces (both balanced and un-balanced)
• (BRM)Cam position is worse. The belt end climbs a lot and very early copper release can happen. Cam position can possibly contribute to failures.

Lack of oiling to the lobes/lifters could be supplemented easily enough, but I don't quite understand the dynamics of the bearing oiling.......................

First the oil slot coverage

The inner circle is of course the camshaft bearing journal. The clearance is exaggerated for it is actually only about .003".

Then looking at a photo that shows the bottom row (beginning position of the cam wear at low mileages). (BEW) Center row at 105,000 miles US. The top row is the top cam bearings with 105,000 miles US.

The bottom row is the beginning position. Plenty of room for oil to exit the oil slot and get to the bearing wear spot, and the followers.

How long it takes for the cam to move to cover the oil slots (shown in the middle row at 105,000 miles US) depends on:
Oil
driving conditions
OCI
percent of WOT driving
etc.

This picture will show how the extra oil gets to the follower tops.

Right out of the bearing to be slung around to hit the followers. It is not a direct path but in the area. The oil goes about 35 degrees from the oil slot to the follower top and may be hitting about right (I do not know it is the correct rotation direction to do this). It does not have to go straight there but there is plenty of oil flow when everything is new.
++++++++++++++++++++++

This photo shows the head and its lack of support for the cam bearings. A wide bearing is placed over a narrow amount of metal support. Hydrodynamic oil film actuall forces the cam bearings to bend and stay permantenly deformed a tiny bit. It only takes .0001 deformation to show a wear surface pattern change. Not one thousanths but one ten thousanths.

++++++++++++++++++++++
BEW cam position. Even cam position except for cocked flywheel bearing making it look strange, but all other bearing wear patterns show cam to be in line.


BRM wear pattern showing the cam position. Cam actually starts to show it is not in line very well. IMHO it is the increased oil flow from the oil pump drive combined with the end bearings cantilever (pry bar effect that causes the poor position.

++++++++++++++++++++++

The eddif cam bearings oiling thread has all this. You got a mini version.

eddif

 

[Ol'Rattler]

The eddif cam bearings oiling thread has all this. You got a mini version.

eddif

Ya, your right. Like we tell the newbies, search is your friend...............

 

[hid3]

OP: any updates on detailed oil usage history?

 

[TonyJetta]

Oil changed to 5W30 on October 4, 2007, at 50,172 miles.

Also something else I noticed in my data, was the MPG graph. Over the next year, it drops from a 37.4mpg average, to 33.0mpg average. What confounded the data analysis, was the fact that the wife's commute changed from 80mile per day 50-50 heavy traffic, to 20 mile per day, strictly city. When we moved to Tucson, 2 months ago, I expected the MPG to come back up, but it never did.

From here on out, I will be using Lubro Moly 5W40/505.01. Yes, the 5W30 was Castrol SLX OE, spec'd 505.01

I will also be looking into a ZDDP Additive.

Tony

 

[eddif]

Oil changed to 5W30 on October 4, 2007, at 50,172 miles.

Also something else I noticed in my data, was the MPG graph. Over the next year, it drops from a 37.4mpg average, to 33.0mpg average. What confounded the data analysis, was the fact that the wife's commute changed from 80mile per day 50-50 heavy traffic, to 20 mile per day, strictly city. When we moved to Tucson, 2 months ago, I expected the MPG to come back up, but it never did.

From here on out, I will be using Motul 5W40/505.01. Yes, the 5W30 was Castrol SLX OE, spec'd 505.01

I will also be looking into a ZDDP Additive.

Tony

I sure wish you the best on this. I hope you can share some information with us as time goes on.

I am waiting to see the wear you experienced. Too bad it came at the time it did. I would also be interested in tracking cam bearing wear over time. It would help to see your cam position by seeing your bearings as they wear (1,000 ; 2,000; 5,000 ; 10,000 miles etc.

I really want to see if the BRM cam position can be changed with bearing modification. I am pretty sure it can.

Take photos of the process.

eddif

 

[hid3]

From here on out, I will be using Motul 5W40/505.01. Yes, the 5W30 was Castrol SLX OE, spec'd 505.01

I will also be looking into a ZDDP Additive.

Tony

Thanks for sharing the info.

I'd suggest you to find and consider this Motul oil: http://www.motul-oil.co.uk/pdfs/synthetic-engine-oil/8100_X-clean_5W40_TDS_(GB).pdf

It's a long-life one (ACECA C3) so no worries it will deplete too early. Besides, it is 100% synthetic with high Viscosity index and 14.1 Viscosity which makes it fairly "40" oil among the 505.01 oils. Also, the oil meets MB 229.51 which many members here believe to be superior to VW 505.01. It also meets many other manufacturers approvals so I think 'it must be good'. This is what I personally run. When I buy a 5 L jug, I pour exactly 35 ml of ZDDPlus there and mix well. I drain the oil every 6215 miles (10'000 km).

 

[TonyJetta]

Old cam & lifters are out. Exhaust lifters on 1, 2, and 3 were dished badly. #1 was eaten through the top, into the plunger below the top. #1 exhaust lobe was also significantly worn down as well.

Bearings all looked OK. OK, as in, not as bad as some I have seen here. Mostly, the bottoms were worn. #1 also had some copper showing.

I have pictures...just need to find the cable for the camera. Will have pictures up later tonight or sometime tomorrow.

Oh, well, break time is over...back out into the heat & humidity.

Tony

 

[hid3]

Please post the pics of what you have taken out!! The pictures would be so useful!

 

[TonyJetta]

Pics:
It's late and I'm too tired to bother trying to figure out the new photo posting. Pics are in my gallery; I just uploaded them.

A few observations:
1) The oil supply hole in the head seems to line up on most (if not all) of the bearings
2) The bearing bottoms had all the major wear, which is reprentative of the PD injector loading

Tony

 

[eddif]

Pics:
It's late and I'm too tired to bother trying to figure out the new photo posting. Pics are in my gallery; I just uploaded them.

A few observations:
1) The oil supply hole in the head seems to line up on most (if not all) of the bearings
2) The bearing bottoms had all the major wear, which is reprentative of the PD injector loading

Tony

If you could, please, line up the bearings so we can see the wear marks at the oil supply slots (post #31 as guide). If you arrange them that way we can see how much the camshaft position was blocking your oil supply. The top row of bearings can be matched with their lower worn running mate.

Thanks
eddif

 

[Jnitrofish]

TonyJetta, I personally would be interested in knowing how your injector rocker adjustment pins and rollers held up. Like still smooth as a babies bottom or worn. Thanks.

PS. those lifters look rough bro, #1 exhaust has had a hard life.

 

[hid3]

#1 always has got hard life. Not sure why. Maybe it lacks oil there? Maybe it is the farest point from the oil pump?

 

[Jnitrofish]

#1 always has got hard life. Not sure why. Maybe it lacks oil there? Maybe it is the farest point from the oil pump?

Probably both, and the timing belt pulling that end of the cam down and slightly forward--to where what friction is there from the lack of oil allows the cam to ride up the bearing and block the source of oil more--doesn't help either.

 

[hid3]

I need to admit I've never seen a complete cam/follower failure whithout the #1 exhaust follower failed even more more completely than others...

Seriously, I wonder how the hell VW tested those engines if such identical failures are happening from early 2001 models till the most recent? There isn't a chance VW hasn't seen such a failure...

 

[eddif]

Probably both, and the timing belt pulling that end of the cam down and slightly forward--to where what friction is there from the lack of oil allows the cam to ride up the bearing and block the source of oil more--doesn't help either.

You are getting the senerio down pretty good on what happens. Then this TonyJetta failure allows us to see the cam friction walking on the worn follower tops too. The ultimate position of that cam is right against the oil slots, causing a circle of events (friction movement, less oil, heat generated, etc) and the final closing off of the oil supply, (bringing about sudden death of a cam).

Now if you begin to see the reason for all the eddif bearing modifications. You will see the a partial solution to the PD delimina. Get oil to that high friction area on #1, belt end bearing, lower the friction and cantilever forces causing #1, belt end bearing to have high frictional contact right next to the belt during deceleration (light injection loading)....etc.

Hyper aren't I. I will shut up.

eddif

 

[eddif]

#1 always has got hard life. Not sure why. Maybe it lacks oil there? Maybe it is the farest point from the oil pump?

Come on hid. The first link on the first page of the eddif oiling thread describe friction climbing of a shaft in a bearing, and the oil slot being covered just shows that much more why the trouble is there. There is no great mystery, unless you just want it to be one. Sure distance from oil gallery entrance port makes a difference, but it is not the major cause of failure.
TDI Pumpe Duse PD Cam Bearing Oiling and Related Wear (eddif)
http://forums.tdiclub.com/showthread.php?t=241279

post #12 on the oiling thread
Snip: "The cam belt itself may pull the cam slightly to the front of the car, or the increased loading at the belt end may cause more friction ,climb toward the front."

post #21 on the Oiling Thread refers back to the link on the first page
Snip:"8.. Cam walking due to friction (see first links + follower friction walk)"


eddif

 

[eddif]

Understanding the eddif oiling thread
TDI Pumpe Duse PD Cam Bearing Oiling and Related Wear (eddif)
http://forums.tdiclub.com/showthread.php?t=241279

If the thread has been a mystery to you all this time I think I finally see why.

Following instructions
The first page gave two links. If you did not read the links you were lost from day one. The first link laid out the principles needed to understand the oiling and position of the camshaft.

It is just like a class. If you are told to read chapter 1, and you chose not to read the assignment, you are lost in the class. If the teacher chooses not to re-teach the chapter then you have no idea what is being said.

I spent about 25% of the first post setting the scene to read this post.
http://www.zddplus.com/TechBrief11 - Internal Combustion Engine Lubrication.pdf
It is a ZDDTPLUS Technical Brief. If you did not read this link or comprehend the writing you were lost from day one.

I went back and mentioned a few things from it (from time to time), but if you did not do the homework you were, and probably are still, lost.

A partial quote from Jnitrofish let me know what is going on. I have said read the link on the first page no telling how many times.

Read the link on the first page of the eddif oiling thread.
http://www.zddplus.com/TechBrief11 - Internal Combustion Engine Lubrication.pdf

If darkness covers your understanding ask questions. When anyone understands the hydrodynamic oil film development and effect of moving a rotating shaft then the eddif thread should make sense.

There is no great mystery. The mystery of PD failure has been posted for months.

I still am a jerk from Mississippi and will help if I can.

eddif

 

[eddif]

Why do we see this so much? Poor design and using the VW parts counter oil.
#1 belt end

#1 cylinder exhaust valve follower usually is the first cylinder to have an oiling problem. The oil slots on #1, timing belt end, are usually the first to be covered.

You did get the good out of your followers. I wish we could see some black followers with some just beginning wear.

Any progress?

eddif

 

[TonyJetta]

Any progress?

Work is getting in the way!

I have covers back in place; just need to install the EGR, ASV, boost tubing, and start break-in. Maybe tonight.

Tony

 

[hid3]

Tony, can you describe shortly the climate your Jetta was driven in?

What was the max outside temp you've seen? What humidity? How hot is now at the moment there?

 

[aja8888]

Tony, can you describe shortly the climate your Jetta was driven in?

What was the max outside temp you've seen? What humidity? How hot is now at the moment there?

Tucson area is hot and dry with summer temps as high as 105 F (day) and 75 F (night). Humidity averages around 40%. Winter temps average 60 F (day) and can get to 30 F at night. Elevation is 2600 FT above MSL.

It's actually a great climate compared to a lot of other US areas.

 

[TonyJetta]

aja hit the nail on the head, for Tucson. For the prior 4 years, we were in metro Phoenix. Summer highs to 110+; winter lows into the low 30's. Humidity averages in the lower range, 5-25%.

Tony

 

[hid3]

Tell me if I'm wrong, but I still believe HIGHer IATs have something to do with those cam failures.

Besides, there's another thread saying that turning on A/C adds about 20 *F (~7 *C IIRC) to the IATs (Intercooler becomes interheater due to A/C condenser being vented). So 110+20=130(+)...

 

[TonyJetta]

hid, I disagree...exhaust is going to be a LOT hotter than the intake. All the cam followers in my engine that failed, were on the exhaust.

Couple exhaust heat with oiling issues, mostly on Cylinder #1, and the reduced ZDDP in oils over the last few years, I would say the failure mode for the BRM cams is the oil.

Tony

 

[hid3]

Any ideas why did they make exhaust valves smaller than the intake ones?

 

[Windjammer]

Any ideas why did they make exhaust valves smaller than the intake ones?

Seriously?

 

[hid3]

I mean, with such a redesign (injector rullers, etc) they could have redesigned the valves too IMHO...

 

[eddif]

Wonder where your pictures fit?
Your cylinder #4

Then your cylinder #2

Your cylinder #3

You can look back a few posts to see cylinder #1

+++++++++++++++++++

These followers came from all over. But they tell a progressive story of failure.
1... you have a new Black follower

2... You get a little fracture going. It might be a timing belt error, or a carbon strike, or an over rev, or a tapping follower, or who knows. By nature the black followers are brittle.

3...And then a little wear. You have one of those

4... And finally a lot of wear. You have one of these too.

eddif

 

[hid3]

Still black followers are the updated ones and must be better than the silver ones.

 

[eddif]

Still black followers are the updated ones and must be better than the silver ones.

You might want to condider this.

VW put out 5W-40 oil that did fair, and then replaced it with 5W-30 oil, and some consider 5W-30 is too thin and caused failure even on BEWs. Mine was a BEW that had marks on the followers at 105,000 miles US.
..........................AND.....................

Those are silver followers sitting beside the failed black followers.
The silver followers are in BETTER shape than the black followers beside them.
...........................So......................

Being brittle are the black followers any / always better..............????????

You have to keep and eye on things.

IMHO the silver followers are tougher, and if kept oiled live a long time. The black followers are low friction, but brittle. If the black followers never fracture they are great. IF................!

eddif