Go Bottomkubota B6100HST 4WD engine knock
 | chris leesmann
Join Date: Posts: 1 
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2002-12-25 46560
I had recently purchased this with a bad engine,#2 rod bearing failure. purchased used crank and totally overhauled the rest of engine.now it runs fairly good but, lots of black smoke on start up and pretty much goes away at wot and after warm up can here slight miss or (like lean miss in gas engine).at wot.at idle a very distinct knock noise and as throttle is opened noise disapates.With stethescope the loudest spot is fuel line from pump (fuel)not injector). oil pressure good,injectors overhauled,I think fuel is good #2 diesel.all air appears too have been bled.I don't believe it too be engine noise or bearing failure.I double checked valve adjustment.Head was not milled and clearence appears ok.Then after a cople of days of running and checking all of a sudden trans oil starting foaming or bubbling out of shifter boot only when stationery.Now with brake applied seems to have stopped.3ph goes down very slow with pushing but comes up very fast.I looked for lever under seat but not there.Engine seems to run good when driving and trans performs normal.Can anyone disifer this problem? sorry so long. Thanks chris Marthasville Mo.
Link: B6100 HST 4WD knock
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| buckmaster
Join Date: Jul 2003 Posts: 5 marthasville,missouri.usa
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2002-12-25 46572
This is my original message.I have since joined the club.Didn't no was this easy.So I hope now someone will read and help.I can almost fix any kind of car problem but havn't had much experience with diesels if at all.
thanks buckmaster ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley 
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2002-12-26 46585
Sounds like several problems.
Since there was a recent engine overhaul, I wonder if the engine timing can be assumed correct? Usually that's a matter of matching marks on gears under the timing gear cover, which would take some tear-down to verify visually. Injector pump timing is another matter and the timing should be verified. A manual should give procedures. Some procedures may require an injector to be removed and use of a dial indicator. Valve clearances affect injector spill timing and I guess we're assuming they're correct.
I'd describe my Ford as having moderate gray smoke at startup and some smoke until it's warm. There is knocking right at startup that diminishes within a minute. I think these things are normal for diesels. I can't tell from the description if what is experienced might be normal or not.
I'd check the TX oil level. An overfilled TX is a possible explanation. Another possibility is water or other contamination in the oil, so changing it on general principal isn't a bad idea. It's also possible for obstructions or leaks in the hydraulic pump suction line to introduce oil into the oil that could produce froth that bubbles out around the shifters.
There often are two o-ring seals on shifter shafts, so it might take a lot of frothing to bubble oil out the top if the seals are in good condition. If seals and boot are in bad shape and the tractor sat outside, then that's a good way for rain can get into a TX, so maybe that's an explanation.
Many tractors have a flow control valve somewhere under the seat. These valves adjust the rate of fall of the 3ph but doesn't affect the lift rate. It sounds like a flow control valve is fairly closed--as would be normal when using a heavy implement.
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 | Art White
Join Date: Jan 2000 Posts: 6898 Waterville New York
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2002-12-26 46592
For what's been done I think Tom has some good points to begin with. ....
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| buckmaster
Join Date: Jul 2003 Posts: 5 marthasville,missouri.usa
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2002-12-26 46602
Thanks Tom for responding!I checked and double checked the timing marks because I performed the overhaul.The reason I checked so many times is this!When I disassembled the engine there is a total of 5 gears;oil pump,not timed,crank gear one mark,idler gear 3 marks injection pump gear one mark,and camshaft gear1 mark. the injector pump gear and idler gear never were removed and stayed mesched the timing marks on these gears never would line up always fell 2 teeth short every 3rd revelution ie: 3cylinder.I removed the idler gear when reassembling to turn shaft to allow all 4 timed gears to line up.This was a concern when assembling and I checked all the resources availible to me to double check alignment.Is it possible the injector pump has a problem that could have started the original #2 rod bearing and cylinder pitting and now still exsists.And the noise could have been covered up by the rod?
thanks, chris {buckmaster} ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2002-12-27 46617
On my Ford 1710 there is an adjustment for something called the injector spill time. That's the one I especially wondered about. Adjustment requires positioning the engine and removing a delivery valve and then loosening a coupling between the pump and its drive shaft. The pump is rotated until it just starts delivering fuel at the correct engine position. I know that a spill time that is off will make an engine smoke.
I also know that the mounting position of a pump affects the spill time and procedures for removing and replacing a pump often require making an index mark across the pump body and engine so it can be replaced in the same position. Mounting a new pump usually requires a spill time adjustment. However, some old Ford farm tractors have a scale on the pump calibrated in degrees and owners sometimes just changed the settings to see what worked the best.
I'll think through the knocking buz some, but I'm mostly gas engine experienced and diesel engine theoryed myself. When I've rebuild gas engines, I'd check the crank journals with micrometers to see if the diameters and out-of-rounds were in tolerance. I'd also check the bearing clearances at 90-degrees with plastigauge. I don't know if something like that was done, but it would eliminate a possible explanation for knocking.
Bad injectors or nozzles can cause knocking. I've heard of people identifying problems by slightly loosening injector line fittings while the engine is running. If the knock disappears, they've found the problem. But since this is theory for me, I don't know what else the test might reveal. Of course extreme care must be taken when working around a running engine. In addition to the usual hazards, loosening injector lines (running or not) exposes a person to fuel under high pressure. If it gets injected under the skin, amputation is a usual cure. Same goes for testing for hydraulic line leaks with fingers. Nobody can recommend that somebody else carry out this type of procedure.
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| buckmaster
Join Date: Jul 2003 Posts: 5 marthasville,missouri.usa
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2002-12-27 46625
I also read about cracking the injector lines to isolate wich cylinder I think I'll try that tonite to see if it might be #2 cylinder again.And yes I plastigauged every bearing after micing all journals and all checked ok because I only wanted to do this once.I'm thinking the black smoke at start up and the knock are the same problem but also at wot there is what I would call on a gas engine, a lean miss with a small puff of black smoke each time.At all other throttle setigs engine purrs as if no problem.and really atwot it sounds good.The noise is at idle only and slightly to about 1/4 throttle then you don't hear any noise. ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2002-12-28 46641
Sounds like the right sorts of things were done. I'd guess the wrist pins etc. also were checked. Some manuals don't specify hot or cold for valve settings, but I think cold is more common for diesel tractors.
In terms of the knock, a comparison with the sound of another engine would be very helpful. The sound might be normal, but I don't think that puffs of black smoke are normal.
Diesel trouble shooting often distinguish between black, gray and white smoke (blue is oil like in gas engines). When I hear 'black smoke' I usually think of too little air or overheating, which is the same thing. Too much fuel also is black if it's ignited or white otherwise. A diesel usually puffs some gray until it comes up to operating temperature and many continue puff a bit while rmp is increasing when a lot of throttle is added. I think I'd change the air filter and check for obstructions and maybe give it fresh fuel and make sure it's coming into the normal temp range just to check these things off. I'd also verify the spill-timing, although it it's a little off it should make gray smoke, or white if it's really off, rather than black.
I guess this is a flock of little things that are pretty to check before turning to checking out more difficult problems. There could be a bad injector, compression loss, a governor problem that gives poor fuel metering at low rpm, and the ugly list could go on and on.
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 | Peters
Join Date: Feb 2002 Posts: 3034 Northern AL
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2002-12-28 46653
I guess my post here did not show up. Some of what I said has been covered now.
Last year a friend of mine got a Chev diesel crew cab that had the engine damaged. The owner had taken it to Mr. Goodwrench to set the injector timing (spill timing). When we took it apart it had burned completely through one cylinder and damaged the rod and head. The timing is critical to performing correctly and you need to know what you are doing to set correctly.
It ran fine once we had it back together.
Peters ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2002-12-29 46670
Eventually the net on this problem will start closing and we'll figure it out. Still a pretty wide net though but some things will start being checked off pretty soon I imagine.
Peters: I was harping on the spill time setting because as you noted, the procedure is complex and could produce some of the problems. The procedure for my 1710 requires taking off a valve stem keeper so the valve sits on top of the piston and then using a dial indicator on the valve stem to set the piston to a speced degree BTDC. Chris hasn't described doing something like that but maybe he has or maybe there's another way of setting it on his Kubota.
A couple of things that I guess are still widening the net are: Weak compression on one cylinder can make an engine run cool for that cylinder. It may puff exhaust but may warm up enough so that it wouldn't puff if running under load. A compression test might show something.
The injectors were overhauled. I hope that a good assumption is that they're OK and the pressures were set. Puffing on one cylinder sure could be an injector. I don't know if the injector overhaul included the delivery valves that are usually thought of as part of the pump. Delivery valves are mostly check valves, but they do produce a sharp pressure drop at the end of injection. Without that drop the injector nozzle dribbles, and I'll bet a dribbling injector would make exhaust puffs at low rpm. I don't know how commonly delivery valves fail though or how to check them. I guess that's why diesel shops have test gear.
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| DH83
Join Date: Posts: 1
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2002-12-29 46686
BUCKMASTER,injection timing is very important and early
timing can cause premature rod bearing failure but I think
you have a single injector problem,try moving around a
couple of injectors to different cylinders to see if the
knock moves too. Just because you might have installed
rebuilt or remanufactured injectors doesnt mean they
are working properly.I have installed leaky or bad
reman injector nozzles before.I'm not impressed with some
of the reman companys out there.Just a tiny bit of dirt
in a injector will make it fail also....good luck ....
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| buckmaster
Join Date: Jul 2003 Posts: 5 marthasville,missouri.usa
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2002-12-30 46704
Thanks guys for all of the ideas,I've been trying too check things when time permits.I was also concerned about the timing,due too the fact when reassembling engine the pump to idler gear would not line up had too remove idler and turn shaft and reinstall.Note these two gears were never removed.So these 2 marks were off when original owner was running engine and #2 rod failed.So the procedure too check injector pump time or spill time is this;Remove injector lines at pump,after thourogly cleaning area,Pull throttle to wot,pull decompression lever,turn engine very slowly until wetness is noticed or fuel starts too move,view timing mark through inspection hole on clutch housing.And after this test I found mark to be off.At the top of the inspection window no center.So the adjustment is too remove pump and add or delete shims under pump.add too retard delete too advance so the IT manual says.So my fuel was being delivered late.And after studying the pump operation I noted that if you add a shim the pump moves further away from cam,so therefor the fuel would be later or advance spill time,and visa versa to retard so the manual didnt't make scense.So I deleted 1 shim instead and after reinstalling and bleeding air from system noted mark moved half the distance to center of inspection hole,So I need too remove one more I cleaned the pump and delivery valves replaced o-rings and reinstalled will finish tonite and report back on condition.CHRIS ....
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| buckmaster
Join Date: Jul 2003 Posts: 5 marthasville,missouri.usa
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2003-01-01 46815
Happy new year everyone!Wll fopr some of us.I removed the second shim and reassembled went through the fuel bleeding started the engine only too hear my knock get louder.The spill time is directly on according to IT manual,I really don't have the smoke any more just slight puff on accel,nothing like it was.The noise still disappears when throttle is opened passed 1/4.I cracked the injector lines when running on all 3 cylinders maybe a slight change in noise but,the same on all 3.I still keep thinking back on the gears and the fact that they were off 3 teeth on idler to injector pump and why?I retimed them to match all there marks,now spill time marks are on and still the noise is there and louder.I now this is not a normal noise but why is it there?since the noise isthe same on all 3,when lines are cracked it has to be timing,it's not internal other wise would not disappear when the throttle is opened. ....
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| TomG
Join Date: Feb 2002 Posts: 5406 Upper Ottawa Valley
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2003-01-02 46825
I think my Ford and the 6100 have different type pump drives. A couple of comments about the Ford drive may jog something.
There are three timing marks on the idler gear as well as an external mark and pointer on the crank pulley and a matching mark on the pump and housing. The three marks on the idler gear match with those on the crank, cam and pump gears when #1 cylinder is on a compression stroke. If I recall, the marks don't necessarily line up each time they pass each other, but all three should match when #1 cylinder is on a compression stroke.
The basic orientation of the pump to the crank and cam is set because the pump shaft is keyed into the pump drive gear coupler. The coupler is torqued to the drive gear face by bolts that go through slots. The slots allow a range of rotation of the pump shaft that is independent of the drive gear position. With all gear marks aligned, the pump shaft is rotated to just stop fuel delivery to the #1 injector (That is the spill time adjustment). Index marks are made on the coupler and drive gear for future reference. I have to guess here that the range of spill time adjustment wouldn't be sufficient to allow proper spill timing to be set if the pump gear and idler marks didn't match.
I don't know if this is at all helpful, but I do know that there should be complete certainty that the timing is right before chasing after the knocking. Dang, I've been in situations where I've torn things down again just to gain certainty because I tend to start second-guessing myself. Now that I've got a digital camera, I'd probably take a bunch of pictures just so I couldn't second-guess myself. Not a great way to start the year and I hope you find the answer without much more aggravation.
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