fatforbes Posted August 22, 2009 Share Posted August 22, 2009 I didn't know where to put this topic so I thought I'd post it in the defender forum and hope for the best! I've got a Case cx50 digger with a 4cyl OHV Kubota engine and its got some problems. A few months ago it badly overheated and just kept dieing, so I removed the head to find that it was had very bad water damage and was cracked in a few places. So I purchased a second hand complete cylinder head and fitted all new gaskets. After fitting this it will now run and doesn't overheat but it has a nasty knocking noise and won't idle smoothly, it dies back and every time it knocks puffs of smoke come out of the exhaust in time with the knocking. It will run for about 10minutes then the revs will die right back then pick up again, it will do this for a while then eventually stall. The knocking sounds very metallic, its almost more of a tapping/slapping noise but very loud (if that makes sense) and to me sounds like its only coming from 1 cylinder but im not too sure. Ive removed the head to try and see if anything looked wrong but couldn't see anything obvious. The tappets are all adjusted correctly, so im a bit stuck so any help would be greatly appreciated! Apologies for posting in the wrong Forum/ website Quote Link to comment Share on other sites More sharing options...
steve b Posted August 22, 2009 Share Posted August 22, 2009 Hi , Have you checked the pistons all rise to the same hieght with the head off ? a bent con-rod ( due to water in the cyl. with the bust head ) would give these symptoms, might be worth popping the valves out of the replacement head as damaged valves will make the engine sound really rough cheers Steveb Quote Link to comment Share on other sites More sharing options...
Happyoldgit Posted August 22, 2009 Share Posted August 22, 2009 Not strictly Defender so I'll move this to the International. Quote Link to comment Share on other sites More sharing options...
fatforbes Posted August 22, 2009 Author Share Posted August 22, 2009 I did check the height of the pistons when I had the head off and noticed that the 2nd and 3rd piston noticeably protrude more than the 1st and 4th when at TDC, but didn't think much of it because it wasn't a problem with the old head. Is this the likely cause? and if so whats the solution??? Many thanks Quote Link to comment Share on other sites More sharing options...
errol209 Posted August 23, 2009 Share Posted August 23, 2009 I did check the height of the pistons when I had the head off and noticed that the 2nd and 3rd piston noticeably protrude more than the 1st and 4th when at TDC, but didn't think much of it because it wasn't a problem with the old head. Is this the likely cause? and if so whats the solution??? Many thanks New con rods all round; and since hydraulic lock in an engine can bend the most unlikely things, you may need new pistons and gudgeon pins to replace the ones you can't get apart. It is also possible that you have bent the crankshaft, which might explain 2 and 3 sitting high if there isn't a middle bearing. In summary, take the bottom to bits! For the worst that can happen, see Post #16 in this thread Quote Link to comment Share on other sites More sharing options...
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