Load knock Bang Bang Bang part 2

[olink]

Ok guys, The hyd pump and seals look ok, My hyd sys still works, raised and lowered FEL several times and the rear lift /dragbox too. So, Now what? I took the valve cover off, and glow plugs out (my glow plugs are trashed, globs of melted metal on the side of the glow part.) I'm wondering if this could be an early ignition problem? I noticed yesterday for the first time that I have bluish/white smoke from the exhaust. My compression seems to be OK, although I haven't put a compression gauge on it. The engine starts and runs, but I still have the loud knock (bang) that wasn't there before. No water in the fuel, Antifreeze level is still full, no water in the oil, checked the firing of each cyl by cracking the fuel line...each cyl. dropped off line as fuel started to leak from the compression nut...tighten it back up and the engine picked up speed as it should.
Can anyone think of anything else? No metal in the oil, I only ran it about 6 minutes, but no increase in the oil level. I looked for the separation in the old oil (fuel vs hyd fluid) but saw nothing. The old oil did seem really black for having only been run about 6 hours though. I checked for blow-by, don't seem to be getting any unusual crankcase pressures.

I'm guessing either an early ignition problem on one cyl or a bad rod bearing? Any suggestion on how to diagnose these?

Thanks again guys...Oly in the panhandle of Florida...

 

[JimR]

Pull the head and see what is floating around in there. Or you have one real bad rod bearing and the piston is hitting the head. If you have metal on the glow plugs your pistons are disentigrating.

 

[roccon31]

do all of the glow plugs have globs of metal on them? did you just notice the off color smoke? it could be a failing injection pump firing early and frying your pistons. they can sometimes jump time and fire the fuel earlier than it should. that would also give you a horrendous knock,(like starting a large diesel in the freezing cold and having it buck and kick until all the cylinders fire) it would be similar noise and smoke to that.

 

[greg_g]

Gotta play devil's advocate here. But I don't see where any of these alternate solutions account for the the crankcase and hydraulic levels changing as described. Or did that turn out to be a red herring? I think also some of the suggestions were probably made without realizing that it's a low hour engine. And by cracking one hardline at a time with no change in engine noise, doesn't that suggest the noise is NOT coming from an engine part?

Occasional blue-white smoke isn't ordinarily a symptom of engine trouble. HERE is a great article about troubleshooting diesels by the color of the exhaust.

But just because the hydraulics go up and down, doesn't mean you still don't have some fluid bypass through that seal. Or did you try it with a serious LOAD on the hydraulics? If not, it might take a lot of hydraulic pressure to blow fluid past a failing seal.

The glow plug thing is mysterious though. Only one plug? Have you measured the resistance to see if the "glob" affects heating? About 1.7 ohms is typical through a functional Jinma glow plug.

//greg//

 

[bluechip]

Before you pull the head, pull the access cover off the timing cover in front of the drive gear for the injection pump and make sure all is well (tight, no cracked pulley). This could account for a change in injection timing which can cause knocking. Since you do not create a miss when you crack the lines, we can proabably skip the pushrod coming out from under a lifter, but it might be worth pulling the valve cover and making sure you don't have a broken valve spring.

If your oil pressure is good, I would not suspect any lower end problems at this point.

You can remove the hydraulic pump and run the engine if you want to make sure it is not causing the problem. the gears may splash a little oil out the hole so be careful.

It is usually something simple, and even the major stuff is not too big a deal on these machines, so take heart!

 

[F100Panel]

Just a thought.. Could the Glow Plugs have become stuck on & melted dropping a piece of a glow plug into the cylinder? Are the glow plugs intact or does 1 look like a piece is missing? It don't take much of a metal shard dropping into a cylinder to cause the noise you describe. If the glows looks like there may be a piece of glow plug missing, DON'T run the engine anymore. It don't take much of a metal shard/debris to cause the sudden noise you describe. Pull the head/ look into the cylinders for debris. Just another thought as long as we're reaching for ideas...

 

[JohnS]

- I agree with Greg, unless you think it was in high likelyhood you overfilled the cranckcase, and the hyd oil run down from the leaks you mentioned, the problem is still there and waiting.

- If you cracked the injection lines one at a time and the knocking level stayed the same, probably elliminates a bad injector. Agree with Chip, check the timing gear/keyway to injector pump. Sheared keyways are not unheard of.

- the metal on the glow plug sound omonous, and have not seen that reported before. I'd check valve train operation before removing head, but even if you find something, I think you need to pull it to see what the damage is. At that point, it will also be easy to tell if it is a rod.

I am not a believer in numerous things failing independantly, around the same time. I am more inclined to go with cause and effect. One event preceeded and caused another event. My mind keeps going back to the over filled crankcase. /forums/images/graemlins/confused.gif

 

[ToolManRick]

When I first got my tractor only one glow plug was working. Finally the third one failed and I never really used them. I did used to start the engine as stated in the manual which does activate the plugs for a very short time. I now turn the key CCW to start and then to "on" to recharge the battery. My glow plugs also had a glob of metal on the sides of them where the glow wire had shorted out against the can. It wasn't a BIG glob, but looked more like a deposit of metal. BTW, no problems with mine and all three glow plugs work fine after replacing the originals.

 

[ToolManRick]

I agree with greg, there's still the real possibility that the front seal on the hyd. pump has failed. I re-read your first thread and either something is missing or the knock is another problem that's occurred by coincidence. Sounds to me like the fuel injection timing has changed. You stated the engine didn't stall, but you turned it off to inspect the lift arm damage. I'm at a loss as to why it's knocking if it didn't take a hard hit, unless it was hard enough to damage the clutch.

I also think F100 panel has a valid point on the physical appearance of the glow plugs. Is a piece on the end of it missing and banging around in the combustion chamber? Not a good situation. If you don't have your dealer pull the head then that would be my next step. Check the vavle train and have a look inside the cylinder bores for something and side wall scoring. Could even be a broken ring, that could maybe explain the blue smoke.

 

[SPIKER]

I know the replacement glow plugs I have appear to be damaged on the ends BUT in actuallity it is the spot welds that holds the wore in place on the tip of the plug. it appears to be melted metal and it IS as it is the wire melted into the plug.

not sure on the rest though.

MarkM