YM336D - Started knocking loud while tilling

[westcliffe01]

Were you able to figure out the condition of the small end bearings in the rods ? I had a Toyota 22RE where all the small end bearings were toast. It had a weird sound for a gas engine.

The timing of the diesel pump can have a big impact on how it runs. Retarded and it may start nice but have no power. Too advanced and it may knock like crazy. Any idea if anyone had been poking around inside the diesel pump ? The metering system is typically driven by a rack and if one of the plungers is out of sync it will not get nearly the right amount of fuel.

But working on the pump is not something to be taken lightly.. I think, provided you can remove the injector nozzles, you can have them tested. They are mechanical parts that see lots and lots of cycles and are in a pretty extreme environment so they do wear out, clog, break etc. The back pressure of the spring in the nozzle (cracking pressure) is a key part of the timing since it determines when fuel starts flowing and how it is atomized. I don't think they are too expensive and by having them checked you can pinpoint the problem. A new nozzle is a lot cheaper than an injection pump.

 

[Garybake]

Domush, I am only at post #36 and can see your head gasket was shot on the left of cyl hole #2. It appears you may have been burnning antifreeze from the cleaned off piston top. Antifreeze smokes white. Water in high compression deisel combustion will expand as steam and in knocking loose carbon and discoloring your cylinder below TDC combustion area and cause excessive blowby or crancase vent pressure. It can also cause a piston skirt to collapse which can cause knock especially when cold (before skirt expands fully towards wall) and may foul the injector over time sitting damp.
Just my $.02 worth as your last posts seems it is not resolved. I will try to read rest of thread tomorrow night. I may find by the end of this thread I am talking foolish. (I can handle that if on chance I am not).

 

[Neat 1500]

usually if an engine that has just been rebuilt is shut down midflight then tried to be restarted it is extremely difficult to get it to spin at a speed which it will restart. you will have to wait for it to cool before attempting to start it again. i found this with several petrol engines i rebuilt, let alone a high compression diesel. even 2 batteries in parrallel wouldnt turn one of them over fast enough, it turned out to be a ripper engine once it was run in so dont get all bent up over it just yet.

 

[bruce1966us]

It sounds pretty normal to me. Your timing might be slightly advanced though.

 

[Car Doc]

Domush,

Quoting you- "it is a mostly solid, two bladed ring with a bunch of holes between them and that weird spring thing on the inside."

So its one piece with a spring in behind it rather than a 3 piece? A 3 piece where you put the expander in and then wind the scrapers in one at a time? EDIT: I went back and blew up a pic of #2 piston and I see its a solid so disregard the folded ring theory thats a good thing!

Did you have trouble getting any of them in smoothly? If so that would be the one I would be looking up into the sleeve with piston up and looking for a scratch forming in the bore. Fact all of them are suspect at this point but any known ones pay close attention too!

I am just not remembering what mine was so pic of an old one would be nice so we can file the folded ring theory.

To me (also as noted by 284) it still has a hitch in its get along while cranking meaning a low/high cylinder for some reason. That doesn't 100% mean anything is wrong with fresh rings old pistons but it is odd I did not expect to hear that. Praying it isn't a bent rod.

How does the fuel flow from #2 injector line at both ends equal to the rest critical info here? hth

edit: You can do your own pop testing just pull the injectors re-attach them upside down and crank it. Switch a bad one to a line that is working to isolate injectors/plungers you have at least 2 known runnable now. May not be perfect but thats not the concern at this point. Compression test also if you have the tool.

Oh btw it wont make any difference what order the pistons went in however the orientation of front and back is on most engines though. fwtw

edit: one exception is if one was bent and got in another hole the miss will follow and if there is still a fuel problem well you can add those odds up.

edit #2388.5 Rod checking from outside the engine.

Just throwing this out use it if you can but with the injectors out and the pre-chambers also a person who was very careful and accurate with their measurements could feasibly find a bent rod w/o tear down.

This would be the procedure-with pre chambers all out and a socket on the crank bolt and a long screwdriver or rod turn every piston slowly up to TDC (a dial indicator would be so nice for this) and mark the rod in such a way as the same measurement could be made in the next cyl if you are following me? Any measurable difference and that piston would need to come back out. Recheck and recheck to make 100% sure there is a difference and go from there.

One more thing if you still have all the old bearings lay them all out side by side with the bearing surface up twords the camera and take a pic I can tell you if there is a bent rod by that and they dont have to be in any order either unless you still have them in order that would be real nice!

 

[clemsonfor]

I have had a very slow coolant leak (1 cup every 1 hours or so) above my water pump which I have not been able to stop. I wonder if it is caused by a water blockage, and the pressure is building until it leaks? Probable? Wouldn't that affect the temp gauge reading, though?
.

Thats a lot if you ask me!! Is the bearing bad, does it come out of the weep hole, i guess not as thats easy?

 

[Kyle_in_Tex]

Great thread, well documented. Lots of advice. The thing I've learned from this is to change my dang oil.

I believe the sludge clogging your pickup is what put the final nail in the coffin.

I haven't read your previous threads where you fixed it up, but I can see the before and after pics. Somebody somewhere didn't do jack squat for maintenance on this poor tractor.

 

[scoops]

I've had two 3 cyl yanmars, and they both sounded like yours.

I don't have a trained ear, but I listened to that video, and yours sounded just like the ones I had.

As for it shutting down on you, did you verify you are getting enough fuel?

 

[jonyyuma]

Domish, I had a bad injector in MY Mercedes... It put too much fuel into the cylinder and made it knock..Plus it can puddle up on top and make a lot of noise when it runs...Glad you made it thru the cylinder caper...

 

[Car Doc]

Domush, I am only at post #36 and can see your head gasket was shot on the left of cyl hole #2. It appears you may have been burnning antifreeze from the cleaned off piston top. Antifreeze smokes white. Water in high compression deisel combustion will expand as steam and in knocking loose carbon and discoloring your cylinder below TDC combustion area and cause excessive blowby or crancase vent pressure. It can also cause a piston skirt to collapse which can cause knock especially when cold (before skirt expands fully towards wall) and may foul the injector over time sitting damp.
Just my $.02 worth as your last posts seems it is not resolved. I will try to read rest of thread tomorrow night. I may find by the end of this thread I am talking foolish. (I can handle that if on chance I am not).

You are on the right track no doubt I pointed the head gasket out also good catch!

I believe by his skirt measurements they are fine at least they are consistent put it that way he does however have a bit excessive top ring groove clearance which is what it is a repair not a new engine it will be fine he did the absolute necessity parts the head and sleeves fuel system may be next. :thumbsup: