stuntman Posted March 4, 2008 Share Posted March 4, 2008 Hello everyone, I've managed to get a hold of a new motor - 200 tdi disco - goldblock engine. It runs like a bag of spanners, but it you lift the revs to 3K + it settles down. Leave it at 3K for a little while and drop it back to idle and it's ok, then it eventually goes back to running like a dog - really rough. I have taken the metal plate off the fuel pump (where the start wheel lives) and found oil coming in through the pipe in the top plate. I also have steam/ smoke coming out of the oil cap and filler plug. The water in the coolant is clear of oil - ie a nice orange colour and the oil is black. Please please help everyone I really would like to save this engine! Regards Quote Link to comment Share on other sites More sharing options...
discojmz Posted March 4, 2008 Share Posted March 4, 2008 oil starvation? oil pump had it? i assume you're not getting any such warning lights up on the dash? Quote Link to comment Share on other sites More sharing options...
stuntman Posted March 4, 2008 Author Share Posted March 4, 2008 Hello Jim, nope no oil lights. Could this be a head gasket problem?? Quote Link to comment Share on other sites More sharing options...
Comical Engineer Posted March 4, 2008 Share Posted March 4, 2008 This could be a piston ring failure perhaps. If you take the filler cap off with the engine running is there a lot of smoke coming out? Broken piston rings mean that the crank case will get pressurised - the gas getting past the rings is more than the crankcase breather can cope with and hence smoke from the oil filler cap. It won't affect the colour of your oil because there is no significant amount of water getting through. The rough running symptom is typical of ring failure on one or possibly two cylinders because you lose compression on the affected cylinders. Used to be a common problem on Triumph 1500 petrol engines at about 80k miles but Disco engines aren't prone to ring failure. The easy way to check used to be to put a couple of squirts of engine oil down the bore and then run the engine or do a compression check (easy when you can remove the spark plug). If compression was good after the oil squirt then it was almost certainly piston rings. More difficult with a diesel..... Quote Link to comment Share on other sites More sharing options...
stuntman Posted March 4, 2008 Author Share Posted March 4, 2008 Thanks for that - the engine is coming out to have new rings fitted! Quote Link to comment Share on other sites More sharing options...
petrolhead63 Posted March 4, 2008 Share Posted March 4, 2008 I had a 2.5FSD Ford in a boat with a simlar problem in that when it built its revs up it ran better......it was I am sure compression because at higher revs the compression increased to a point the diesel fired ok. Ours bore/ring problems had been caused by serious back inhalation of salt water....oooher Quote Link to comment Share on other sites More sharing options...
JimAttrill Posted March 5, 2008 Share Posted March 5, 2008 You mustn't squirt oil into a Tdi engine when you do a compression test, for the oil will just fill the combustion chamber in the top of the piston. It is ok to do it with petrol engines with domed head pistons, for the oil will go to the cylinder walls which is what you want. With a Tdi you stand a good chance of hydraulicking the cylinder, and that will bend the rod, even on the starter. Quote Link to comment Share on other sites More sharing options...
lynall Posted March 5, 2008 Share Posted March 5, 2008 Both my last 300 tdi cracked the oil ring on number 4 cyl, never ran any different just a tadge more smoke than normal. But in your case if it runs fins at 3k and for a while at idle afterwards i would be looking at a fuel problem. Dont forget all engines breath and there is always oil present in the inlet pipework on every turbo diesel i have ever worked on, even new ones! Lynall Quote Link to comment Share on other sites More sharing options...
Comical Engineer Posted March 5, 2008 Share Posted March 5, 2008 You mustn't squirt oil into a Tdi engine when you do a compression test, for the oil will just fill the combustion chamber in the top of the piston. It is ok to do it with petrol engines with domed head pistons, for the oil will go to the cylinder walls which is what you want. With a Tdi you stand a good chance of hydraulicking the cylinder, and that will bend the rod, even on the starter. Quite right Jim - but only if you put too much in - a couple of squirts is sufficient. That said, I wasn't recommending it for diesels (about 20:1 compression ratio as against 9:1 for petrol engines means that the combustion chamber is much smaller). Hopefully, stuntman's problems will be sorted with new rings. I'd also recommend getting the valves re-ground while the head is off. Quote Link to comment Share on other sites More sharing options...
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