M diesel engine

I have an M diesel which sounds like it may have an engine knock. You can hear it easier when someone else is driving it than when you are on the seat. I pulled the pan and all the bearing caps. I seen minor scratches but no catastrophies. I did find a little bit of brass or bronze thin flakes in the oil pan. Where could these have come from? None found in the oil pump. The engine has about 200 hrs on since a frame out overall. Maybe I am paranoid. Any suggestions would be appreciated.

Nathon, I had a 706 ger. diesel that way. Put about 4000 hrs on it that way and never had a problem.

steveormary

Fuel knock probably...

If the pan is still off of it, Plastigauge the bearings that you can get to. If OK, run it. JimN

Someone else mentioned fuel knock. How do I get rid of it?
Thanks

OK, this is kind of off the wall, and somewhat embarassing to have happened to an experienced tractor mechanic, but I have to throw it out there.

My Dad's Farmall 400 gas tractor developed what sounded like a slight engine knock. It wasn't loud, but it was there and didn't seem to vary with load. You could hear it the most when the engine was idling, but it was there all the time. I had done a complete stem-to-stern reconditioning of this tractor about 600 hours prior to this, and everything in the engine was brought up to new specs. I ended up pulling the pan off and Plastigaged all the bearings and found nothing wrong, so I put the pan back on. My Dad wasn't using the tractor that much, but I told him he could keep using it just as long as the knock didn't get worse until I had any new brainstorms. One day he was out using it and the wiring going to the regulator melted and the regulator started smoking. He got it shut down and the battery disconnected before it burned things up too bad. After checking things out, I found the bushing at the back of the rebuilt generator that I had gotten from the local Carquest had gone bad from lack of lubrication because nobody had bothered to drill the wall of the bushing and install the oil wick. It had run dry and wore enough to drop the armature down into the pole pieces, then rubbed through the insulation of one of the brush wires, causing the electrical short. I rebuilt the generator myself and reinstalled it. After I got the engine started and verified the electrical system was working OK, I realized the engine knock was gone. Then I realized the cause of the knock had been from the armature hitting the pole pieces, and the noise was telescoping in such a way that it sounded like a slight knock. That was 4 years ago, and the knock hasn't returned, so I guess that was it.
Just some food for thought.

Well, it's dieseling. It will quit when you shut it off

They all rattle a little, of course.

Now if you have had the tractor for some time and it didn't make the sound you are hearing before the rebuild you may have a problem. It would be good to try to find another diesel M and listen to it run, maybe at a show if you don't have any neighbors with one.

I can relate to that story! I have a Farmall M. My son was using it one day, and when I started to take it home, I said "Have you noticed this knocking sound and slight vibration that didn't use to be there?"
Not completely to my surprise, he answered "WHAT knocking sound?"
I took it the short distance home, all the while fearing the worst. When I got off and listened to it, the noise was louder on the right side of the engine, and seemed to be toward the front. The bearing in the front of the generator had gone bad, and lost most of the ball bearings. How it was still turning and charging, I don't know! I decided that was a good day to convert it to a 12 volt system with an alternator.

When I got my original M gas years ago, and was running it for a couple months, I noticed (felt more than heard) a noise midway up the block or so. (dialed in location with a long screwdriver used like a stethoscope.) I pulled the engine down, and found a wrist pin bushing on its way out. No one else heard it, but I felt it. It pays to get to know your tractor. I'd check the wrist pins if I were you. Also, you may have excessive skirt clearance, causing piston slap. Good luck.