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Old 24th August 2013, 02:16   #46
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Default Re: Long Service Intervals: Pros & Cons

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Originally Posted by Jeroen View Post
Diesel oils are very different from Petrol oils, there is a specific thread out on the forum on this very topic with lots of very good information. I'm not familiar with the term "long drain", but I assume its similar to long life.
Jeroen
Hey Jeroen,

Thanks for sharing the sea of knowledge and wisdom attained through your experience over the years.

I am sure you must have studied the long term effect of excessive engine oils on modern turbo charged diesel engines. I am raising this point since my Swift Vdi was recently filled by at-least 500 ml excessive engine oil over the maximum mark of 3.1 liters. The car was already driven for some 1200 km before this goof up came into notice. After draining the entire 3.6 liters of diesel oil, new diesel oil (3.1 liter) along with new oil filter were put in. Is there anything for me to be concerned about as I am planning to keep the vehicle for 10 yrs or 2 lac kilometers at-least.

Regards
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Old 24th August 2013, 08:18   #47
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Default Re: Long Service Intervals: Pros & Cons

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Originally Posted by Sutripta View Post
@Jeroen,
Any views/ opinions on using TAN/ TBN as a guide to oil changes for medium size (20000cc - 40000 cc) diesels?

The controlled tests: Any of these engines without a roller cam follower? All crosshead piston designs?

Would be interested in knowing how the source of the bearing failure was arrived at. Forensic examination of bearing (fatigue failure?)/ correlating with major operating mode => leading to reexamination of all design calculations?
These were tugs, or off shore/ oil platform supply and support vessels? Who bore the cost? Of actual repairs. Of loss of profits.

Regarding balance and forces, I was just thinking that we are lucky that in India we don't have mainstream engines with balance shafts (except for a few motorcycle engines). So thankfully no balance shaft discussions here. (Going by what I see written about balance shafts in a few foreign forums, these discussions would have driven you up the wall!)

Regards
Sutripta
TAN/TBN test are quite relevant for these larger engines. As a rule the larger the engine the more combustion by pass product end up in your oil. There is another very relevant factor; what type of diesel are you using. Some of these medium speed diesels can be run on heavy diesel oils. By sheer definition those come with much more problems for the lub oil. On the Werkspoor TM410 the engines would be equipped with different set of pistion rings to handle the heavy diesel (and of course a whole host of other stuff in the fuel system). If anything they used a lot more oil then the ones we ran on regular marine diesel.

Anchor handling and supply tugs usually don't run on heavy fuels, some ocean going tugs did. But I sailed on a small container vessel using the identical TM410 as we used in the offshore world. Our range was determined by the amount of lub oil we could carry, not the fuel bunkers!

In those days we carried a few very simple lub oil test on board as well. Viscosity checks were carried out regularly. Most auxiliary engines would receive an oil/filter changes based on hours. On the main engines it was all done based on lab test results. So we sent in lub oil samples on a regular bases , and head office would tell us what to do. On these main engines, the lub oil gets filtered by means of separators, so more advantaged then just a filter. In all large marine engines, water contamination is a real possibility. The separators filter in the traditional sense (i.e. particles), but also take out the water. (most would be equipped with a water detection alarm).

Here's a little video of a Werkspoor TM410 and you get some idea of the tappet/valve operation.



No cross heads on these engines. Crossheads are mostly found on slow speed two stroke engines. There are exceptions to the rule; a Dutch Diesel Manufacturerer Bolnes produced two stroke, medium speed, cross head engine, sort of. The cross head is actually a piston as well and is used to boost air inlet pressure in combination with a turbo charger. See: http://books.google.co.in/books?id=R...ection&f=false

I've sailed on a few ships that used these Bolnes engines for their main propulsion and also the drive the bulk cargo discharge compressors. Interesting story on this one with respect to lub oil; All these sort of engines have separate cylinder lub oil system. A little pump injects lub oil directly into several ports in the cylinder liner to lubricate the piston rings. As part of the engineers normal 'watch rounds' you are expected to verify the correct working of this system on a regular basis. In this particular case they failed and within hours the engines developed some serious problems. They limped home on one main engine, sacked the engineer in charge and I got a frantic call from head office and to get myself on a plane to Aberdeen asap. This was a V16 configuration and we had to replace each and every cylinder liner and piston. Interesting job, although when you've done 8 and there is still 8 sets to go it gets a bit tedious!

The conclusion on the bearing was derived after visual inspection by various experts from the manufacturer and a marine surveyor, in combination with talking to the captains/chief engineers on operational procedures. The manufacturer then redid some of the design calculations to verify the findings.

These ships with variable pitch propellors are designed with 'one handle' operation. Meaning engine RPM and propellor pitch are controlled jointly for both ahead and astern operations. The correlation between RPM and pitch is something that is cleverly designed but also extensively tested in labs and tanks to the get the most efficient combinations. In those days, no clever electronics and computers. Just cams and followers and pneumatics. However, you can also control engine RPM and pitch individually.

Several captains found that for continuous precise maneuvering (which for an AHT is pretty normal, you could spend 24 hours maneuvering close to an oil rig at a time!) they would put the engine RPM on a fixed settings and just control the pitch. Gave them better response. They were running the rpm on approx 50 - 60% of max settings. Still, this led to the problems. I do believe that Werkspoor did adjust their design on the bearing seatings (that's where they had some of the damage as well) after this finding.

I don't know who paid for the cost. But I can imagine there must have been a few heated debates. I do remember that the manuals did show the fixed rpm mode as one of the operating modes. No limitations were mentioned. After these findings the first thing what happened is no operational procedures were issues and lot of placards everywhere on the bridge and engine control room about not using 'fixed RPM" mode during maneuvering.

As a rule of thumb, western companies will never accept contractual liability for loss of revenue of their customers, in any industry I'm aware of. If anything there might be performance penalty, bonds or such. Again, I wasn't privy to the financial settlement on this one.

With respect to the balancing shafts; I agree whole heartedly!

Quote:
Originally Posted by Grr7 View Post
Hey Jeroen,

Thanks for sharing the sea of knowledge and wisdom attained through your experience over the years.

I am sure you must have studied the long term effect of excessive engine oils on modern turbo charged diesel engines. I am raising this point since my Swift Vdi was recently filled by at-least 500 ml excessive engine oil over the maximum mark of 3.1 liters. The car was already driven for some 1200 km before this goof up came into notice. After draining the entire 3.6 liters of diesel oil, new diesel oil (3.1 liter) along with new oil filter were put in. Is there anything for me to be concerned about as I am planning to keep the vehicle for 10 yrs or 2 lac kilometers at-least.

Regards
Thanks for your confidence in my 'research' experience, but just to be clear, I'm no research guy at all. The experience I wrote up were a one off, in which I happened to be part of a particular program and got the change to talk and interact with some real research buffins who were helping us out on some of the validations and modeling and also were kind enough to share their findings on a similar program on car engines.

So I have no in depth view or experience on overfilling, but I do have an opinion: When an engine gets overfilled with oil there are several possible things that can go wrong.

One is the main shaft seals could get damaged. As long as you see no oil leaking I would not worry. Either it got damaged or it did not.

The other thing is a bit more tricky. What happens with too much oil in the crankcase is that the oil could be whipped up into a froth by the crank shaft dipping into the oil all the time. And that is bad news indeed, because air bubbles don't lubricate. So such a scenario could and would lead to pretty severe bearing problems.

The only way to check if you have any bearing problems now is to drain the oil again and check for metal shavings in the oil and or on the magnet. Take the engine pan off too, because when you drain the oil that's where some will end up! It will look like a sort of silvery sand.

Jeroen

Last edited by Jeroen : 24th August 2013 at 08:33.
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Old 24th August 2013, 21:32   #48
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Default Re: Long Service Intervals: Pros & Cons

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Originally Posted by Jeroen View Post
Anchor handling and supply tugs usually don't run on heavy fuels, some ocean going tugs did.
LDO only?
Another question - do the bunkers/ fuel suppliers give any test report of the fuel you are buying?

Quote:
Our range was determined by the amount of lub oil we could carry, not the fuel bunkers!
Old lube mixed with fuel and burned in engine?

Quote:
Here's a little video of a Werkspoor TM410 and you get some idea of the tappet/valve operation.
Thanks. That is essentially showing startup using compressed air.
Was wanting to know if you have come across any largish engine in which the cam does not operate a roller follower.

Quote:
No cross heads on these engines.
Actually was wondering whether the stuffing box has any special lubrication requirements.

Quote:
As part of the engineers normal 'watch rounds' you are expected to verify the correct working of this system on a regular basis. In this particular case they failed and within hours the engines developed some serious problems.
No built in monitoring/ alarms? Strange.

Quote:
Just cams and followers and pneumatics. However, you can also control engine RPM and pitch individually.
Within limits, cams allow implementation of arbitrary functions. (Would love to get my hands on a working American WW2 bombsight!)

Regards
Sutripta
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Old 25th August 2013, 17:37   #49
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Default Re: Long Service Intervals: Pros & Cons

Quote:
Originally Posted by Sutripta View Post
LDO only?
Another question - do the bunkers/ fuel suppliers give any test report of the fuel you are buying?


Old lube mixed with fuel and burned in engine?


Thanks. That is essentially showing startup using compressed air.
Was wanting to know if you have come across any largish engine in which the cam does not operate a roller follower.


Actually was wondering whether the stuffing box has any special lubrication requirements.


No built in monitoring/ alarms? Strange.


Within limits, cams allow implementation of arbitrary functions. (Would love to get my hands on a working American WW2 bombsight!)

Regards
Sutripta
On the bunkers, I can remember exactly what was on the paperwork. Certainly differed from place to place. But one thing was identical the world over; during bunkering samples get taken. Depending on the total volume and from how many different tanks on the fuel barge. Those samples got sealed and signed off by the fuel barge crew.

Old lub no. It just used a lot of oil!

Roller follower: Can't think of any right now.

Lubrication requirements for the stuffing box; no nother special as far as I recall

Alarms: Depends a little on whether the engine room was designed and certificied for unmanned operations. If so, you will see much more alarm then when it is manned 24/7 during sea operations.

Most of the AHT and ocean going tugs were designed and certified for unmanned operations. However, in practice the engine room was always manned at sea. Anchor handling, towage, supply work is just not safe without having somebody in the engine room all the time.

Jeroen
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Old 12th October 2014, 11:37   #50
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Default Re: Long Service Intervals: Pros & Cons

[quote=SS-Traveller;3205578]I have mixed opinions on whether extended service intervals should be considered a scam or not.

I agree with your viewpoint that most cars can do with shorter oil change intervals than the 15k or 20k km that manufacturers recommend, given that they are used in less-than-ideal / harsh conditions as you describe...."

All BMW owners please note that all N47 diesels,(fitted on the 3 series) are extremely prone to timing chain failure. This was due to the CBS based long periods of oil change and the design of the chain. Informed Owners in the west are changing their oil 10k miles / 1 year whichever is less. I am not sure that BMW India is following the yearly service policy (they have issued a bulletin in the west for the same) but their India website still talks of CBS. Furthermore, as compared to other cars, the changing of timing chain in N47 engines requires engine removal along with the gearbox, making it a fairly expensive and complicated process. This is because of the design of the engine. The engine otherwise is great with regular oil change and service. However, for long term owners, changing the chain at around 150k is prudent, otherwise in case of failure the engine will be a total write off.
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Old 13th October 2014, 18:35   #51
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Default Re: Long Service Intervals: Pros & Cons

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Originally Posted by mike_vwworld View Post

All BMW owners please note that all N47 diesels,(fitted on the 3 series) are extremely prone to timing chain failure. This was due to the CBS based long periods of oil change and the design of the chain. Informed Owners in the west are changing their oil 10k miles / 1 year whichever is less.
The way I read this bulletin is that it is still CBS based, just with a lower base mileage compared to before, So its the computer that decides based on a number of parameters it monitors when you will get the notification. So they changed the 15000 km to 10000 km.

I have owned a number of cars with these CBS indicators, VW, Audi, BMW etc. in those days I drove high mileage, upwards of 80.000 km a year, so a lot of highway kilometers. my experiences was that the CBS system usually advised me at least 10% above the base line. Which make sense given the high mileage and long fast drives. For city driving I would expect it to stay well below the base line.

I also recall having far higher baseline on my last cars, somewhere around 30.000 km or so?

These long service intervals were really relevant to me. Having to take in your car for a service every 5000, 15000 or 30000 km at a yearly mileage of 80.000 means anything from every third week to just twice/three times a year.

Still, conditions here in india are very different from Europe so from that point of view different intervals can be expected I guess.

Jeroen
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