Snagger Posted November 5, 2020 Share Posted November 5, 2020 I may be mistaken, but I understand the perception to be that the 200 is the less refined but more robust engine, though the 300 has a better oil pump. Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 5, 2020 Author Share Posted November 5, 2020 (edited) I thought I would double check the valve clearances and found one rocker very loose. I've found this. Only one is bent so I believe that this happened on reassembly, I remember taking the rocker assembly off after the rebuild to check something and when I retightened, one of the pushrods was not seated in the cup. I did not think it would have bent but I can now see that they are very soft. Edited November 5, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
steve b Posted November 5, 2020 Share Posted November 5, 2020 you definitely need to check the valve timing and then check the tappet clearance too . They are not soft at all and that amount of bending is from a significant amount of valve/piston contact Steve 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 5, 2020 Author Share Posted November 5, 2020 (edited) 3 hours ago, steve b said: you definitely need to check the valve timing and then check the tappet clearance too . They are not soft at all and that amount of bending is from a significant amount of valve/piston contact Steve I've solved it. Power is back up, there's no trace of smoke, there's no more diesel leaking through the exhaust. There's hardly any blowby when warm. Jobs done! All I did was replace the bent pushrod and readjust all the valve clearances. That one bent rod was the one that I crushed when reinstalling the rocker assembly. When I cranked the engine over by hand I felt resistance and stopped and then noticed the rod off the cup. I guess that was enough to bend it but I did not notice at the time. Thank you everyone for all the help! Edited November 5, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
Peaklander Posted November 5, 2020 Share Posted November 5, 2020 Brilliant. It was diesel then, so @Red90 was on the money. How did that push rod get bent? Do you have any idea? 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 5, 2020 Author Share Posted November 5, 2020 (edited) 25 minutes ago, Peaklander said: Brilliant. It was diesel then, so @Red90 was on the money. How did that push rod get bent? Do you have any idea? I bent it reinstalling the rocker assembly. The rod cup was not seated correctly onto the rocker ball end and when I torqued it down it jammed up. Thankfully I did not start the engine and opted to turn it over by hand. As I turned the engine over I felt resistance and stopped. It must have been enough to bend the rod. Edited November 5, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 5, 2020 Share Posted November 5, 2020 Can it be, the valve didn't close anymore? That could be the only reason for Diesel in the exhaust. 1 Quote Link to comment Share on other sites More sharing options...
Ex Member Posted November 5, 2020 Share Posted November 5, 2020 (edited) I assume this was an inlet valve. What happens is you partially starve that cylinder but the fuel rates stay constant. The downside is that you have probably damaged that cylinder from excessive fuel washing. It does not take long. Edited November 5, 2020 by Red90 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 5, 2020 Author Share Posted November 5, 2020 6 minutes ago, Red90 said: I assume this was an inlet valve. What happens is you partially starve that cylinder but the fuel rates stay constant. The downside is that you have probably damaged that cylinder from excessive fuel washing. It does not take long Possible. I did less then 3 miles, pretty much up and down a local road. Quote Link to comment Share on other sites More sharing options...
Peaklander Posted November 5, 2020 Share Posted November 5, 2020 1 hour ago, youngengineer said: Thankfully I did not start the engine and opted to turn it over by hand. As I turned the engine over I felt resistance and stopped. It must have been enough to bend the rod However you did run the engine after that though. I'm a bit confused and feel as though there's something for me to learn here. 😀 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 5, 2020 Author Share Posted November 5, 2020 (edited) 55 minutes ago, Peaklander said: However you did run the engine after that though. I'm a bit confused and feel as though there's something for me to learn here. 😀 I ran the engine after I reseated the pushrod. I did not see it had bent at the time. I did not run the engine when the pushrod was unseated and jammed under the rocker arm. Not sure if I am explaining well. Edited November 5, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
monkie Posted November 5, 2020 Share Posted November 5, 2020 I'm not sure I understand how (assuming the timing was set correctly) that not having a pushrod seated correctly on a rocker arm did that damage. Surely it would just lift the rocker, just not fully. I've made this mistake before and the engine ran like a bag of spanners before I realised why. When I took the push rod out to check, it was not bent so I just reassembled and the engine ran fine. 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 5, 2020 Author Share Posted November 5, 2020 4 minutes ago, monkie said: I'm not sure I understand how (assuming the timing was set correctly) that not having a pushrod seated correctly on a rocker arm did that damage. Surely it would just lift the rocker, just not fully. I've made this mistake before and the engine ran like a bag of spanners before I realised why. When I took the push rod out to check, it was not bent so I just reassembled and the engine ran fine. The valve hit the top of the piston as I cranked the engine over by hand. The pushrod was sitting on the edge of the cup which would give it much more lift. 1 Quote Link to comment Share on other sites More sharing options...
monkie Posted November 5, 2020 Share Posted November 5, 2020 6 minutes ago, youngengineer said: The valve hit the top of the piston as I cranked the engine over by hand. The pushrod was sitting on the edge of the cup which would give it much more lift. Ah right, I see. I had pictured the push rod just sat under the rocker arm, unlucky that it didn't just pop into place. As I understand it, the push rods are designed to go first to protect the valves and rocker. Good to hear its sorted. 1 Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 5, 2020 Author Share Posted November 5, 2020 (edited) 3 minutes ago, monkie said: Ah right, I see. I had pictured the push rod just sat under the rocker arm, unlucky that it didn't just pop into place. As I understand it, the push rods are designed to go first to protect the valves and rocker. Good to hear its sorted. I also thought they might be a sacrificial piece as they seemed quite soft. I bent the old one back straight with ease. I'm also shocked that I managed to bend it in the first place by turning the engine over with a 1/2" Ratchet. Edited November 5, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
Snagger Posted November 6, 2020 Share Posted November 6, 2020 They are sacrificial for just that reason, though the rocker arms can still snap if valve to piston contact happens with the engine running. Quote Link to comment Share on other sites More sharing options...
Sigi_H Posted November 6, 2020 Share Posted November 6, 2020 14 hours ago, Red90 said: I assume this was an inlet valve. What happens is you partially starve that cylinder but the fuel rates stay constant. The downside is that you have probably damaged that cylinder from excessive fuel washing. It does not take long. better explanation than mine Quote Link to comment Share on other sites More sharing options...
cackshifter Posted November 6, 2020 Share Posted November 6, 2020 Glad to hear it is solved - and so simply and cheaply. Quote Link to comment Share on other sites More sharing options...
Snagger Posted November 6, 2020 Share Posted November 6, 2020 22 hours ago, Red90 said: I assume this was an inlet valve. What happens is you partially starve that cylinder but the fuel rates stay constant. The downside is that you have probably damaged that cylinder from excessive fuel washing. It does not take long. Yes, it really needs the head off again to check for scoring. If it only did three miles, it might have got away with it. There is the possibility it’ll need honing again and another set of rings on that bore. It’ll need new oil for sure, as diesel will have contaminated the current oil. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 6, 2020 Share Posted November 6, 2020 That explains the 'oil', it was indeed unburnt diesel chuffing out the exhaust, also why it was leaking past the manifold joints so readily. Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 6, 2020 Author Share Posted November 6, 2020 (edited) 3 hours ago, Snagger said: Yes, it really needs the head off again to check for scoring. If it only did three miles, it might have got away with it. There is the possibility it’ll need honing again and another set of rings on that bore. It’ll need new oil for sure, as diesel will have contaminated the current oil. I think I will just live with it. I'm certainly not replacing pistons or re-honing. There's very little blow-by when hot and virtually no smoke at all if any. If its scored then its scored. The engines in a much better state then it was pre rebuild. I suppose I could have a look through the injector hole with an inspection camera. Down the line I will test compression on all cylinders once I have a functional compression tester. Edited November 6, 2020 by youngengineer Quote Link to comment Share on other sites More sharing options...
cackshifter Posted November 6, 2020 Share Posted November 6, 2020 May I ask how much bore wear was there? Quote Link to comment Share on other sites More sharing options...
youngengineer Posted November 7, 2020 Author Share Posted November 7, 2020 12 hours ago, cackshifter said: May I ask how much bore wear was there? The bores were still in spec according Haynes. The first cylinder had scoring. Quote Link to comment Share on other sites More sharing options...
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