My old (1980's) dependable JCB 1550 just developed a serious knock in the engine (Leyland 4/98NT). Is there any way to remove the oil pan to take a look without pulling out the motor? The oil pan seems to be integrated into the machine frame and not removeable while the engine is in place. Any tips on pulling the engine if it must be removed?
Not a lot of JCB experts on here unfortunately. What's the history of the machine? how fast did the knock develop? anything else happen at the same time? has the oil been kept up? changed, ever? I'd loosen the injector lines one at a time to see if you can isolate the knock to one cylinder. If it goes away, swap injectors, or just pull them all to get rebuilt?
Good questions ...I have owned the machine since 1987 and did the maintenance regularly. The recent history goes like this. The machine overheated and shortly after that blew the head gasket. In the process of replacing the head gasket I had the head resurfaced and the valves redone. I had the injectors tested and/or rebuilt. I reassembled the machine and then changed the engine oil. On the end of the oil drain plug magnet I found a piece of metal about 3/16 in diameter. I thought that's not good but continued. I fired the machine up adjusted the valves and it ran like a champ. After about 2hrs of use it developed a significant knock. I towed it back to the barn and that is where it sits. Because I found that large piece of metal in the oil I'm thinking a rod bearing. I guess it could be injector knock if one of the new injector sleeves is leaking coo lent into the head. But I see no evidence of that.
When the head gasket failed did coolant get into the oil? Take the oil filter off and cut it open if its a spin on filter use a filter cutter or tubing cutter if you have one or can borrow one. If not cut the the threaded end off with a hacksaw. Remove the element and cut the pleated paper out of it with an razor knife staying a couple inches away from the end if you used a hack saw on. Lay the pleated paper on the bench with the outside facing out and cut a piece out the width of your vice and by about three inches. Put the pleated paper between the vice jaws and squeeze the pleats together with the vice and catch as much of the oil as you can with rags. When you release the vice the paper should look dry. Now you can see any particles in the filter. If you have a bearing failure it should contain a lot of metal.
Any pictures of this 3/16" piece of magnetic metal? How did the oil pressure look? My impression is that is a heavy slow low powered engine, so not likely to hurt the bearings by overheating it.
Was stuck to his magnetic drain plug verses being magnetic itself. Personally, I have no idea but am watching with interest as I also have a 1550b.