This is all interesting discussion, for me it would be interesting to tear apart several 100k mi + CRDs, mine for example has been running delo 15-40 since 30k with no EGR, if wear is a mitigating factor, how would an engine with 120K worth of 15-40 oil have compared to an engine using factory oil specs this whole time.

If my engine bites it one of these days, I'll donate to the cause. I'm at 112K miles and I've only ever used 0w 40 oil at 6-9k change intervals. I've had the GDE tune since around 65k.

hey sam, you run a bypass filter?

Yup, I've been there with multiple engines, but what I can tell you is that each one of those engines experienced sudden failure, and both were 15-20K overdue for a timing belt change. I've also noticed all of these engines have the exhaust rockers fail worse than the intake rockers.

I think it has nothing to do with the rockers being of poor quality or design, and everything to do with the rockers failing INSTEAD of the valves bending.

Like I have said before I think the failure method is the belt slipping at the crank, pistons hitting valves, rockers taking the brunt instead of the valves, and the belt being pushed back.

I can think of no other reason that 16 rockers would fail simultaneously. Plus think of it this way, if it is enough force to break the rockers, it is enough force on a slackened belt for it to get pushed back on the correct tooth at the crank.

Give me a reason that 16 rockers will simultaneously fail on an overdue belt, with exhaust rockers always being a little bit worse than intake, and yet always still have the engine timed correct via the pins, and I will listen to it. Because I just don't see how any bearings could wear bad, not have any symptoms, and then suddenly, ALL 16 fail bad enough that the engine barely runs, backfires out the intake, etc.

That wear is NOT from a single event....



here's a question:

I understand how EGR absolutely craps all over the intake manifold, but how exactly does it contaminate the oil?


Exhaust ---> intake it's a pretty simple route it takes...

I'm planning (in my head so far) a remote oil filter w/ bypass filter and remote oil cooler somewhere between the trans and the diff...

http://www.amsoil.com/catalog.aspx?groupID=56
http://www.summitracing.com/parts/der-15850/overview/


would solve all the world's problems.....

that's IF I decide to keep this thing...
I want proof that it's fixable permanently...

Didn't someone on here install a centrifuge at some point? If I remember right it was quite effective at removing the soot and the oil was squeaky clean. Did this ever go anywhere?

For CRD owners with rocker arm failures. GDE would be very interested in having the failed parts for analysis. GDE would cover the shipping costs of the failed rockers and oil. The oil type, brand, etc. would be required along with maintenance practices.

For the oil, a little plastic bottle (clean) about 6-10 oz should suffice. We can get the oil tested locally and have the parts shipped to Italy for analysis. Some time under the microscope should help determine the wearing characteristics on the inner bearings.

Ideally, it would be nice to have a seized rocker, fully worn rocker, partially loose bearing and a decent one from the same engine. Varying degrees of this on a few engines would be helpful.

If you are interested and have an oil sample, please call us at (248) 977-9531 and we can work out the details.

Just a thought, but have any of you checked the torque on the camshaft bolts to the camshaft pulleys after a failure like this? If I remember right, the belt doesn't have to slip, the pulleys actually rely only on torque of a bolt to hold them lined up correctly, the manual has you loosen them when doing the belt change and retorqueing them. If they were to slip rathern than a belt slip on a cog it could have the same effect.

For CRD owners with rocker arm failures. GDE would be very interested in having the failed parts for analysis. GDE would cover the shipping costs of the failed rockers and oil. The oil type, brand, etc. would be required along with maintenance practices.

For the oil, a little plastic bottle (clean) about 6-10 oz should suffice. We can get the oil tested locally and have the parts shipped to Italy for analysis. Some time under the microscope should help determine the wearing characteristics on the inner bearings.

Ideally, it would be nice to have a seized rocker, fully worn rocker, partially loose bearing and a decent one from the same engine. Varying degrees of this on a few engines would be helpful.

If you are interested and have an oil sample, please call us at (248) 977-9531 and we can work out the details.

you are correct, except: when we get to these motors, the pins fit in.

if the pins fit in, that means everything is in time.

A friction slip on the crank / cam sprockets would cause a permanent shift out of "time" and the pins wouldn't be fitting when we go to work on these engines.

That's why we have the two competing theories of "belt slipping a tooth but somehow slipping back" and "the rollers just wear so bad that the valve-train @$#% itself"

how you solve the problem perminatly depends on what theory you subscribe to...

if it's the belt, you change em' at 100,000 kms
if it's the rollers, you delete your EGR (eco tune), use a different than spec'ed oil, and install a bypass filter.

we all know which theory I subscribe to, so we know what I will be doing.
and Keith, I can ship you my entire valve-train if you like....

If it all lines up correctly I agree it hasn't slipped. It would take alot to jump a tooth, the belts fit pretty tight. Oil passages being clogged with soot seems more likely in this case. I'd send your drivetrain to Keith @ GDE and some of the oil if you still have it.

Just got my rockers out and was surprised at:

-the variability of the wear. #1a exhaust had slight wear, but #2b exhaust was heavily worn and sloppy. I need to look at the wear and see if the lifters on the heavily worn ones are carboned or springy to see if there is any correlation. May also try checking the relevant oil passages.

-the amount of soot and sludge in the top end of the motor. I have about 11k miles on this buggy since I got it, mostly highway miles, and with Mobil 1 5w-40 lube oil, and I would have thought that my frequent oil changes would have abated this issue. WRONG!

- the amount of soot deposited in the air passages in the cover.

- Given the wear on the rockers, I was also surprised to see no scuffing of the lifters. I may mike those and see whether there is any wear compared to a new set.

How much wear is acceptable? I saw nothing in the 2005 FSM on that subject in the rocker section.

Do you have any kind of tune or EGR delete on your CRD?