youngengineer Posted November 2, 2020 Share Posted November 2, 2020 (edited) I have quite a considerable amount of oil coming out the exhaust ports of the 200TDI I recently rebuilt. The head does have cracks between the inlet/exhaust valves however the seats are intact. I could not find a suitable replacement head so refitted the one I had although I know, not ideal. The valve's have all been lapped in and new valve stem seals fitted. I made sure that they seated correctly by using a socket to push them into the valve guide indent. They all felt very firm when installed. I did the water leakdown test and all the valves passed after lapping. New pistons and rings were fitted and the bores re-honed but not re-board as still in spec. There is a small amount of blow-by from the breather, however the engine has not been broken in so I would expect the rings have not seated yet. The head gasket is the new Multi-layer steel style and was torqued down in the right sequence. Any ideas? Edited November 2, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
western Posted November 2, 2020 Share Posted November 2, 2020 After a previous head gasket replacement where I used the laminated steel gasket, I had oil in the cooling system, so head off, replaced the gasket with a elring composite type, problem cured, I don't use the laminated gasket now, think they are trash. Also check your turbo oil seals & associated hoses, it could be getting past the turbo seals & into exhaust 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 2, 2020 Author Share Posted November 2, 2020 (edited) 7 minutes ago, western said: After a previous head gasket replacement where I used the laminated steel gasket, I had oil in the cooling system, so head off, replaced the gasket with a elring composite type, problem cured, I don't use the laminated gasket now, think they are trash. Also check your turbo oil seals & associated hoses, it could be getting past the turbo seals & into exhaust Good to know. It's a 300tdi gasket. I wonder if It may help to torque the central bolts a further 20 degrees such as the manual suggests for the 300. Edited November 2, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
Ex Member Posted November 2, 2020 Share Posted November 2, 2020 If the manifold gasket is leaking, fix the manifold gasket...... 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 2, 2020 Author Share Posted November 2, 2020 (edited) The nuts were finger tight when I took the photo. They are now torqued correctly. But oil now flows further downstream. The egt blanking cover for example. Edited November 2, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
Ex Member Posted November 2, 2020 Share Posted November 2, 2020 It is just exhaust leaks. With the engine cold idling, half burned diesel will come out the exhaust. It is not oil. Put it together and drive it. Cold idling destroys the engine. If you just rebuilt it, you are ruining all of that work. It is critical to get load onto the rings immediately. 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 2, 2020 Author Share Posted November 2, 2020 (edited) 17 minutes ago, Red90 said: It is just exhaust leaks. With the engine cold idling, half burned diesel will come out the exhaust. It is not oil. Put it together and drive it. Cold idling destroys the engine. If you just rebuilt it, you are ruining all of that work. It is critical to get load onto the rings I had it idle for no more then a few minutes since rebuild only to check for leaks. I took it out today and gave it a good run with decent load and achieved full boost on several passes. I am also using sae30 break in oil. I assure you that this is engine oil and not diesel. The leaking has subsided since it's been run on the road today, possibly since the oil has now dried solid around the egt port and manifold and provided a seal. I will pull the valve cover tomorrow and check the stem seals Edited November 2, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
Ex Member Posted November 2, 2020 Share Posted November 2, 2020 I will guarantee it is not engine oil. There is no way for engine oil to get into an exhaust port. I can explain if you wish. 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 2, 2020 Author Share Posted November 2, 2020 (edited) I trust your opinion. Maybe I am misunderstanding the concept however. If the valve stem seals have failed or lifted from the valve guides then surely oil from the head would enter the combustion chamber and be pushed out the exhaust port since it would be uncombusted? Alternatively if the headgasket had failed between and oil way and cylinder then would oil not also be introduced into the combustion chamber? Edited November 2, 2020 by youngengineer 1 Quote Link to comment Share on other sites More sharing options...
Ex Member Posted November 2, 2020 Share Posted November 2, 2020 (edited) The pressure in the exhaust ports is always higher than the pressure in the valve cover. This forces exhaust gas to flow into the valve cover if there is a valve stem leak. There is no way for oil to flow counter to this. As to oilways, there is only one oilway through the head gasket and it is not near any combustion chambers. In addition, any oil entering the combustion chamber (more likely via the rings) will be burned. If so much was entering that it could not be completely burned, the engine would run on the oil and it would not be possible to shut the engine down through normal means. Edited November 2, 2020 by Red90 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 2, 2020 Author Share Posted November 2, 2020 (edited) Thank you for the explanation. That makes sense. However, Would a failed valve stem seal on an inlet valve not allow oil to be drawn into the combustion chamber since the inlet port would be under vacuum? If the oil is not "Atomized" then surely it would fail to burn and be released through the exhaust port. Edited November 2, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
Ex Member Posted November 2, 2020 Share Posted November 2, 2020 The inlet is not a lot different. There is still higher pressure in the inlet port versus the valve cover. The difference is not as much as the exhaust. Any oil coming in here will be burned as well. The whole valve stem leak issue is not really a problem with diesels. It is a hangover from petrol car experience where the the inlet ports run at high vacuum. Oil consumption if it happens is almost always rings or turbo seals. 1 Quote Link to comment Share on other sites More sharing options...
steve b Posted November 2, 2020 Share Posted November 2, 2020 He is not wrong Have you done a compression check since the refurb? Steve Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 2, 2020 Author Share Posted November 2, 2020 (edited) I bought one of those Ebay diesel compression testing kits but it read 0 on all four cylinders and since the engine runs reasonably well and starts on half a crank I assume that the gauge is faulty. Either that or I cannot get it to seal correctly. I am using the adapter which fits into the glow-plug thread. Surly compression testing a newly rebuilt engine would not be accurate as the rings would not yet be bedded in? Edited November 2, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 2, 2020 Author Share Posted November 2, 2020 (edited) Edited November 2, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
western Posted November 2, 2020 Share Posted November 2, 2020 2 hours ago, youngengineer said: Good to know. It's a 300tdi gasket. I wonder if It may help to torque the central bolts a further 20 degrees such as the manual suggests for the 300. No fit as per 200Tdi manual, the bock is a Discovery 200tdi going by the oil filter & vacuum pump locations, where is the fuel lift pump ? oil filter type & thermostat housings are wrong for a 200tdi 1 Quote Link to comment Share on other sites More sharing options...
steve b Posted November 2, 2020 Share Posted November 2, 2020 For the time and cost I think a composite HG would be worthwhile , I've not used one , but there seems to be some basis for doubt of the effectiveness of MLS HG's? Very tidy work fella Steve 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 2, 2020 Author Share Posted November 2, 2020 (edited) 15 minutes ago, western said: No fit as per 200Tdi manual, the bock is a Discovery 200tdi going by the oil filter & vacuum pump locations, where is the fuel lift pump ? oil filter type & thermostat housings are wrong for a 200tdi You are correct on all counts. I use an electric faucet style pump and decided to blank off the mechanical pump due to several previous failures. The electric pump has proven far more reliable. I am using a series radiator so the I have no capacity for the oil lines of the TDI filter housing. As for the thermostat, I modified a series one to accept a TDI thermostat. Edited November 2, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
Troll Hunter Posted November 3, 2020 Share Posted November 3, 2020 Some very good photos, but a little text explaining what you are trying to demonstrate in each would be useful! Mike Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 3, 2020 Author Share Posted November 3, 2020 1 hour ago, Troll Hunter said: Some very good photos, but a little text explaining what you are trying to demonstrate in each would be useful! Mike The photos show the progress of my series 3 TDI/LT77 conversion. I thought they would be self explanatory but they aren't really relevant to the thread. I posted them just to show the progress of my work. Quote Link to comment Share on other sites More sharing options...
western Posted November 3, 2020 Share Posted November 3, 2020 Ah now that makes more sense. Where do you propose to connect the cyclonic breather to? & that's not the correct oil Gill cap for a Tdi engine. Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 3, 2020 Author Share Posted November 3, 2020 38 minutes ago, western said: Ah now that makes more sense. Where do you propose to connect the cyclonic breather to? & that's not the correct oil Gill cap for a Tdi engine. I made a breather from parts I had. Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 3, 2020 Author Share Posted November 3, 2020 (edited) This is the oil or possibly diesel? leak displayed clearly. As you can see it's quite considerable. Edited November 3, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
western Posted November 3, 2020 Share Posted November 3, 2020 Got you with the breather, looks like oil to me, diesel fuel can't get to that point. 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 3, 2020 Author Share Posted November 3, 2020 (edited) 25 minutes ago, western said: Got you with the breather, looks like oil to me, diesel fuel can't get to that point. Yes as I thought. It's oil no doubt. I can only assume my bores or rings are damaged? I gapped the rings to specs on haynes manual. Could this be due to new unseated rings? It never leaked oil like this before the rebuild. And the oil and middle rings were stuck on all pistons but one so something's not right Edited November 3, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
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