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Diesel Engines A forum dedicated to diesel engines fitted to Volvo cars. See the first post in this forum for a list of the diesel engines. |
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Mar 17th, 2016, 21:34 | #51 |
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[QUOTE=skyship007;2078811]How long the oil bypass valve opens depends on a lot of different factors, but in most cases it's only a few seconds IF the oil is of the correct type. It makes very little difference in engine wear terms unless the oil is too cold to flow around the top end. Just to confuse matters most TD oil filters are in partial bypass all the time at high revs. So the time quoted depends on how you define open.
No normal full flow filter works well when clean, that's why they introduced dual units with an ultra fine secondary. If you ask on Bobs The Oil Guy forum they should have some wear particle rate graphs showing just how bad the first 1000 miles is with a new air or oil filter, although it does depend on if you pre fill a new oil filter. If you do prefill a new oil filter, then the initial efficiency is much better and often turns out to be similar to the efficiency of a dirty filter. Alas it's not possible to prefill a side on spin on oil filter. I have tested numerous engines in endurance testing and field testing with live particle counters on the system post filter and I can assure you that there is no improvement with a dirty or older filter. I'm not sure where your information comes from but it is contrary to all engine trials and field data I have been involved in. I'm interested in how this data been collected we use an ISO particle counter and take live samples at 25hr intervals and send to our own Lab. How has this data been collected to prove a dirty filter improves things? NOTE by a live sample our recommended sample point is fitted on the main outlet from the filters before the main gallery. |
Mar 17th, 2016, 21:59 | #52 |
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Which engines are you testing ??
My local lab does radiometric particle counts, BUT they still use final oil analysis, cos the particle counters only count metal contamination and most of the debris caught by an oil filter is Silicon or small clumps of Carbon. It's those 2 contaminants that cause most wear and often determine when the oil must be changed. Also you might be testing synthetic media oil filters. They can be obtained from the US (Mobil, Amsoil or Purolator) for some newer Volvo engines and will produce better initial figures (U curve rather than hockey stick), but alas Volvo sold mostly petrol and not diesel cars in the US, so they don't make one for my 1.9TD at present. The modern way of testing filters is not radiometric particle counts, as that only works for metals. They use that data mostly to figure out which oil or fluid works best, NOT which is the best oil filter. That's still done with multiple cold starts, redline spikes and sudden shut downs using standard used oil analysis. My own real world UOA results did produce 16 ppm of Si in 10K km, which if I had done a 20K km run would have put the final figure near the 30 ppm limit (Varies a lot with air quality as I got 8 one year), although the insolubles (General dirt, which is mostly Carbon) only reached one third of their limit. The Iron content was no where near the oil condemnation limit, apart from one run of Catrol Edge 5w40 TD (Terrible Acea C3 cat test). It averages about 30 when the limit is 200 ppm before it becomes a long term negative factor. The Si in the second run with a dirty filter has always been lower, as has been the Fe figure. PS: Your post has got my comment and your reply mixed up, if I copy part of something I use Italics to make it more obvious.
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2003 V40 1.9TD Mods: Scratches, bent bumpers, raised REAR mats & internal mud guards. SHELL ULTRA 5/40 & LIQUI MOLY CERATEC. Everyone should DYOR (Do Your Own Research) Last edited by skyship007; Mar 17th, 2016 at 23:42. |
Mar 18th, 2016, 01:54 | #53 |
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Skyship, yes we carry out a full analysis at 25hr intervals and have a live particle counter in the system all the time.
I still don't understand how you have established dirty filters are better than clean which was my question and how this has been established. As already mentioned there are to many variables with one engine or duty cycles to establish real effects unless conducted over test conditions. I'm not sure if you work in tribology or the oil industry or are quoting on your own vehicle? I have worked for many engine manufacturers throughout my carear and all practices for each are very similar. Most of the best by German and American manufacturers. |
Mar 18th, 2016, 06:41 | #54 | |
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You can't simulate real life in test conditions, which is why ZF and VW have cars and a bus driving around to check on the Lab results. The big questions are always about how long in both time and distance terms an oil filter can be used safely before it blocks and unless it's a synthetic media or one that can be pre-filled the manufacturers look for the longest figure possible. Oddly enough the limiting factor has often turned out to be the oil filter oil seal, hence the present 2 year limit in the newer OLM units. In particle or UOA test terms they look at 2 points, one just after the filter and the other just before the turbo inlet pipe, as it still seems to be that turbo bearings and head gaskets are the limiting factor, unless it's a larger marine diesel (Much more expensive bearings). ZF also do oil lab work for both MTU and VW, although they don't have to fit the radioactive parts required for some tests. I will try again to explain why new full flow car oil filters work better when dirty (Unless they are pre-loaded synnthetics or you can fill it first due to under sump mounting point). New the Far Eastern cardboard media has lots of tiny holes and the empty filter causes a loss of oil flow on first use. That combination results in new oil dumping extra wear particles into the oil and the average pore size is not good enough to trap the ones that get caught in the bearings (Big particles don't matter so much). BUT once some sludge and other debris has gone through the filter, many of those holes are partially obstructed. That allows smaller particles to get caught by the remaining partial pore holes. The oil flow rate is of no real interest, as it's particles that cause the damage, so unless the filter gets blocked or the pump inlet screen blocks (Or varnish formsin the turbo inlet pipe), the slowly reducing size of those holes increases the filters efficiency. Synthetic media filters are better because the pore size is more random and they use some extra additives soaked into the weave to offset the effects of the higher amounts of active detergents (I think only Mobil 1 filters are doing that at present, as their oil is a tad too effective when new at cleaning). Oddly enough driver style can make a big difference to some oily figures. Blackstone Lab recorded the record a few years ago, with a 16 year old Nissan pick up truck that had never had an oil or any of the filters changed in over 163K miles. The engine was in real good condition due to the following: 1/ It had an expensive factory fill full synthetic still in use. 2/ No one tried to change any of the filters, so both the air and oil filter were nearly blocked. 3/ One of the injectors gummed up or blew a tip out and this really saved the engine, because the detergent additives in the oil had run out, but it had only thickened from a 5w30 to a 15w40. The only reason that it was not off the scale was that the Bio diesel contamination from the failing injector had offset the sludge formation to a large extent. 4/ The air in Montana is very clean and they don't salt the roads, the driver also pre-heated the engine in winter, although he was doing a lot of local trips. That old engineer sure knew how to drive!
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2003 V40 1.9TD Mods: Scratches, bent bumpers, raised REAR mats & internal mud guards. SHELL ULTRA 5/40 & LIQUI MOLY CERATEC. Everyone should DYOR (Do Your Own Research) Last edited by skyship007; Mar 18th, 2016 at 06:48. |
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Jul 31st, 2018, 22:52 | #55 |
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I am going to resurrect this old thread with my observations over the last 9 years - actually much longer than that as I always used Shell in my semis in the US - Shell Rotella (filters and oil change every 10,000 miles which was basically a recurring event every month) The least I got on an engine was 700K miles before a rebuild was necessary.
Every time I buy a new (used Volvo) I do an oil change, a transmission fluid change and often a cam belt change (better safe than sorry). I use Shell Helix Ultra 5-40 and a bottle of Liqui Moly Ceratec according to the recommendations of Skyship007 and a bottle of Lubegard Red . The result? The engines run better, smoother and quieter than when I bought the car(s). Same with the transmissions. My present 2002 V70 D5 163 Euro 3 had 209K on it two years ago when I bought it for silly money - £800. The car now has 233K and the engine (and transmission) is much smoother and runs so well I can't imagine exchanging it for anything. Just passed MOT with flying colors. I just came back from a 2,200 mile trip to Sweden. I changed the oil and filter b4 I left and when back home and parked the readout said 55.8 mpg - and it hadn't used any oil at all - none.
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2008 XC70 D5 Lux Geartronic Polestar, 161K 2005 XC70 D5 SE Geartronic, 203K |
Aug 1st, 2018, 00:12 | #56 |
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Cant go wrong with SHU 5w40 in a euro 3 D5
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Aug 1st, 2018, 07:58 | #57 |
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This technobabble is worse than star-trek.
I fear the point is being missed. Most UK cars are either repmobiles doing lots of main road driving, or are stuck doing lots of short journeys and grinding commutes. The repmobiles are probably fine on long-interval servicing. All the rest are being used to far less than ideal conditions, so need servicing at lower mileages. Servicing is not just an oil change. The long service intervals recommended these days are aimed at the NEW car buyer/user, the fleets. Most new cars are owned by companies, lease- or otherwise. These businesses are interested in costs to run for 3 years, not longevity after 10 or more. When they get to the used market typically after 3 years the vehicles usage pattern often changes, and so should servicing. Those of us with cars over 10 years old should do our best to ascertain what servicing has happened prior to purchase, in the hope of having some clue as to how long the car might remain as worthwhile transport. True, as a previois poster said, we dont see many totally clapped-out bangers grumbling around on knackered engines (remember the ford sierra+pinto), many things have improved over the years; its the increasing complexity and cost of repairs that are scrapping cars. The tell-tale cloud of oily smoke pouring out of the back of a junker is a rarity, thankfully. I am in no doubt that every car I have ever done an oil change on runs better for the clean oil, smoother and less noise. It seems to me highly unlikely that there is some disadvantage in doing basic maintenence.
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Aug 1st, 2018, 11:02 | #58 | |
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Quote:
Yes, of course - your post is spot on as are most of the posts in this thread..
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