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| I Like Chips Member Since: 25 Jun 2017 Location: Ascott Under Wychwood Posts: 1540   
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Nodge I am surprised that the valves and rockers are not case hardened. Maybe it would make the metal brittle. |
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9th Aug 2022 4:51 pm |
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| bernie7sk Member Since: 23 Aug 2015 Location: bratislava Posts: 12  
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I think that it doesn't fluctuate much from side to side. Because the pressure of the hydraulic valve lifter presses the roller of the rocker arm against the cam and thus it is balanced. according to the photo, the lubricated pairs of rocker arms and valves are fine, and the others in the same engine are completely worn. I also think it's because the worn valve stem and the hole in the rocker arm are visible first, and when they are too much together, then the rocker arm of the spring plate starts to touch. now I like chips gave me a thought when he mentioned the unfortunate venting of the valve block. By chance, there won't be a problem with engines that let a lot of gases through the piston rings? Maybe the robust flow of gases through the oil drain holes of head is pulling the oil off some rockers. But I don't think so mutch... |
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9th Aug 2022 6:20 pm |
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| I Like Chips Member Since: 25 Jun 2017 Location: Ascott Under Wychwood Posts: 1540
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I see you are thinking that the flow of engine sump gases goes up through the holes in the cam cover rather than down to the cam. Now I am unsure of the direction of gas laden with oil droplets is it up and out through the PCV or down into the sump? |
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9th Aug 2022 7:13 pm |
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| bernie7sk Member Since: 23 Aug 2015 Location: bratislava Posts: 12
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ideally, the exhaust gases should be routed from under the pistons through a "maze" into the head vent, where oil vapors should be added and vacuum from the intake manifold should suck it all up. in fact, exhaust gases are pushed everywhere. but I can't imagine that drained oil from critical rockers would do it. but on the other hand I have not seen Mondeos and Transits with this engine with a worn valve and rocker arm. I really don't know, it's just speculation. in any case, when the place has oil, it can resist. the photos from the crashed engines always had some rockers with almost unmeasured wear and the cylinder two intake valve went down to the piston. otherwise heavily worn valves and rockers are always as polished - dry rub/no oil. less worn rockers have a matte finish - mixed friction.
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9th Aug 2022 9:24 pm |
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| Nodge68 Member Since: 15 Jul 2020 Location: Newquay Posts: 2082
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It's normal for high stress components to be hardened, as it reduces surface wear. What I was surprised to see was the variation in wear across all the valves and rockers in the same engine. Some valves and it's paired rocker had zero wear, yet the valve and rocker next-door had messes of wear in both components. The valve and rocker with the wear also had a rocker which would be free to wobble from side to side when touched, but the wear free valve and rocker remained firmly secured in place. On my old head, there was a huge variation in wear across all 16 valves and rockers, which was a surprise as wear rates should really be the same across the engine. I've noticed that 1 of the tappets is beginning to tick in my new head, which considering it's only done 5k miles, I'm surprised to hear. Could this be that valve wear is taking place already?, quite likely, but as the rest of the valve train is silent, I'm not overly worried about it. Hyundai Ioniq 5 Ultimate. The family car. 2009 Rimini Red SE TD4. Gone. 2006 Tonga Green i6 HSE. Gone. Audi A5 convertible, my daily driver. 1972 Hillman Avenger GT, the project. |
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10th Aug 2022 6:23 am |
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| Lucx Member Since: 11 Jul 2022 Location: sud of italy Posts: 26  
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Where does the oil go first? first and second piston? It would be interesting to understand how many euro 3 engines have happened ... c1 oil has a different viscosity from a5. Has the Nodge cylinder head been rectified or new? |
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13th Aug 2022 7:11 am |
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| Nodge68 Member Since: 15 Jul 2020 Location: Newquay Posts: 2082
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The oil pump is on the timing belt end of the engine, bolted to the side of the balancer shaft assembly, and driven by a chain from the crankshaft. The oil then passes through the filter, then up a drilling in the block, which again is at belt end of the engine. The rockers for the cylinders at the gearbox end of the engine will be the furthest away from the oil pump, but on a correctly designed oil supply system, that shouldn't matter at all. My cylinder head was damaged at the same time the piston was. I made a quick and dirty repair of the head, as at the time a decent replacement wasn't available for a sensible price. I drove it for about 12 months and 6k miles with a leaking inlet valve, as I couldn't cut the seat well enough for a good seal, but the engine ran well enough. Then last May a low mileage (8k) SD4 head came up complete with cams at a spectacular price, so I bought it, cleaned it up properly, then installed it last October. The engine was lovely and quite when the new head was installed, but I can definitely hear 1 tappet is now tucking, which is annoying, but I'm putting it down to engine design. Apart from the crank sensor failing twice, and an occasional misfire under full throttle when cold, the engine runs beautifully. I suspected I've a slightly iffy injector, but because it only misfires when cold under full throttle, it's pretty impossible to tell which injector is at fault, so I've left it, hoping it'll get worse one day. I've a replacement injector waiting to install, when I know which one it is. Hyundai Ioniq 5 Ultimate. The family car. 2009 Rimini Red SE TD4. Gone. 2006 Tonga Green i6 HSE. Gone. Audi A5 convertible, my daily driver. 1972 Hillman Avenger GT, the project. |
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13th Aug 2022 9:52 am |
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| Lucx Member Since: 11 Jul 2022 Location: sud of italy Posts: 26
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My idea is that a part of the engine is not properly lubricated, probably in the ignition cycles, the engines with dpf use low viscosity oil therefore a fast flow but which in the shutdown phase makes the oil flow quickly into the sump ... .is just an idea |
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13th Aug 2022 10:48 am |
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| Nodge68 Member Since: 15 Jul 2020 Location: Newquay Posts: 2082
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All the DW12 engines use the same grade of oil, which is a 5w30 fully synthetic.
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13th Aug 2022 7:36 pm |
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| Lucx Member Since: 11 Jul 2022 Location: sud of italy Posts: 26
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yes it is true but between c1 and a5 the hths index often changes |
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13th Aug 2022 11:55 pm |
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| Lucx Member Since: 11 Jul 2022 Location: sud of italy Posts: 26
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14th Aug 2022 10:47 pm |
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| jules Member Since: 13 Dec 2007 Location: The Wilds of Warwickshire Posts: 5017 
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Just wondering if at 146K miles under its belt, the engine was getting a bit worn and oil pressure was on the low side and causing oil starvation in the cylinder head.
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15th Aug 2022 7:11 am |
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| Lucx Member Since: 11 Jul 2022 Location: sud of italy Posts: 26
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When disassembling the engine, I was able to check some play in the oil pump due to wear of the gear. |
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15th Aug 2022 9:19 am |
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| I Like Chips Member Since: 25 Jun 2017 Location: Ascott Under Wychwood Posts: 1540
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Live values on a code reader will give you the oil pressure, but of course the engine needs to be running |
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15th Aug 2022 8:32 pm |
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