B-6100e engine smoking

[LittleJim]

I recently just purchased an older B6100e and I'm in the process of trying to fix it up to a nice useable tractor. I believe it needs a clutch, sheet metal work on the fenders, tires, so that is all on the to-do list it but the first issue I want to tackle is I have some white smoke coming out the exhaust. It's not billowing out clouds of smoke but when its idling at a low rpm the crank case breather tube will smoke a little, then give it some throttle and it will go away and come out the exhaust. Next thing I'd like to try is take the valve cover off and let it run and see if the smoke is coming out the valves. If it's not I assume its a leaky injector, does that sound about right? Thanks in advance for the help!

 

[85Hokie]

How many hours are on the engine?

I think you have a "worn" engine - that blow-by is coming from the combustion getting by the worn/stuck rings.

The crankcase is what is getting the blow by and thus it vents back through the valve cover.

Is it somewhat hard to start? Do you have to glow it a bit to get it to start?

This may sound a bit crazy - but fire her up and run it .....run it hard - work it hard, see if the smoke slowly goes away, if the rings are stuck, running it will hopefully allow them to free up a bit.

Something you can do - remove the glow plugs or injectors - which may be fun - and drop about two tablespoons of marvel mystery oil in each hole ......... let it sit for a week .......... and then add two more....... another week.

If you have a compression tester - now would be a good time to test the compression of each cylinder, it would be a good thing to test before the MMO is placed in, that way you have a benchmark to go by - then after to see IF that helped at all.

Then spin the engine and allow any of that to blow out. Then replace glow plugs/ injectors and start her back up - expect a good deal of smoke at first, then it should get a bit better as it runs.

Change the oil once completed.

Whatever you do - report back as to what you do and find.

 

[LittleJim]

How many hours are on the engine?

I think you have a "worn" engine - that blow-by is coming from the combustion getting by the worn/stuck rings.

The crankcase is what is getting the blow by and thus it vents back through the valve cover.

Is it somewhat hard to start? Do you have to glow it a bit to get it to start?

This may sound a bit crazy - but fire her up and run it .....run it hard - work it hard, see if the smoke slowly goes away, if the rings are stuck, running it will hopefully allow them to free up a bit.

Something you can do - remove the glow plugs or injectors - which may be fun - and drop about two tablespoons of marvel mystery oil in each hole ......... let it sit for a week .......... and then add two more....... another week.

If you have a compression tester - now would be a good time to test the compression of each cylinder, it would be a good thing to test before the MMO is placed in, that way you have a benchmark to go by - then after to see IF that helped at all.

Then spin the engine and allow any of that to blow out. Then replace glow plugs/ injectors and start her back up - expect a good deal of smoke at first, then it should get a bit better as it runs.

Change the oil once completed.

Whatever you do - report back as to what you do and find.

It does not have an hour meter on it, I guess a compression test would be the best thing to do next. It is hard to start all the time and does need the glow plugs every time starting even when warm.

 

[Mark_BX25D]

I guess a compression test would be the best thing to do next. It is hard to start all the time and does need the glow plugs every time starting even when warm.

Yep. Sounds like time for a compression test.

Not everybody's cup of tea, but to get a few more years out of a worn engine, consider this:

Follow up a year later:

 

[LittleJim]

Are these little diesels worth rebuilding? Does anyone have any good links to guides or rebuild kits? Looked on ebay and seems to be a pretty wide variety of prices for what looks like the same kits.

 

[85Hokie]

Are these little diesels worth rebuilding? Does anyone have any good links to guides or rebuild kits? Looked on ebay and seems to be a pretty wide variety of prices for what looks like the same kits.

Before you jump into the rebuild ............ eat the elephant one might at a time. Don't let "some white smoke" make you jump into the rebuild RIGHT off the bat. I had one that would smoke for 15 seconds and then clear up and then puff again when I opened her up - she still runs well..... smokes yes - but does a good job over all.

And IF you are going to make use of this tractor - sure it is worth a rebuild. But I think you have other problems to address first. YOU said it needs a clutch, have YOU adjusted it yet?

 

[North Idaho Wolfman]

If it hard to start then it's more than likely low compression caused by wear and bad ring seal.
A compression test will tell you a LOT.
Bad injector/s can cause it to smoke out the exhaust but not out the breather pipe.
Yes the engines are worth rebuilding, but they are not cheap to rebuild.
Good kit will run you in the $750 range.
You'll need a machine / engine shop to remove, install and bore the sleeves, it's not something you can DYI, and that will run you $450 to $1K depending on the shop.

 

[LittleJim]

Ok just an update on the tractor. I started it and ran it today for a while and all the smoke out the exhaust cleared up, unless you revved it and black/little bit of grey smoke would come out which is correct I believe. When idling real low it will still have a steady stream of blow by out the breather tube. Will be checking the valve lash this week and see if that is all correct.

Last item that has me concerned is that I checked the exhaust manifold temps at each cylinder and at the time 2 & 3 were around 170 and 1 was at 135/140ish. I have ordered a compression tester, just don't have it yet. I need to get the injectors tested and also I need to test the glow plugs. Would a bad injector possibly cause it to not fire? Or is it more likely a compression issue?

Thanks for the help this far.

 

[North Idaho Wolfman]

Both low compression and a bad injector can cause a cool cylinder.

Swap the injectors and if the cool follows the injector there is your issue.

Valve lash has nothing to do with blow by, that's all rings.

 

[LittleJim]

Thanks for the reply, I will wait for the compression tester to arrive and post the number here. I also had a thought that the fan blowing might make a slight difference but probably no more than 10 degrees. In the meantime I'll see if I can't get the injectors tested while I wait for it arrive.

 

[North Idaho Wolfman]

Forget testing them, just buy 3 new injectors, I'll guarantee you it needs them.

 

[LittleJim]

Ok, I know its been a while, but I received the compression tester and did a compression test. All the cylinders were about 250 psi dry and with a tiny bit of oil in them. When performing the test, I hooked it up to the glow plug and cranked on the engine. It did take almost a whole minute of cranking (total cranking time) to get to that number then it stopped climbing on the gauge. Makes me think the rings are just completely gone. I put the glow plugs back in, adjusted all the valves(all were loose by a few thou, one was loose so much so .010 slipped under the rocker easily), and tried to start it. Won't pop off or anything. Just blows lots of white/few puffs of black smoke when cranking. I did also bleed the hard fuel lines. As I'm writing this I' m realizing that I should of checked the compression again after adjusting the valves. Too late now.

So, I decided might as well as pull the head and have a look at this point because why not. Cylinders 1 and 3 were completely soaked and had a little bit of standing diesel in them. Number 2 was dry as a bone and was just carboned up. At this point the cylinder walls look great with no scarring and the pistons look great too. I'm beginning to think that the injectors are bad, which after 45 years is understandable, and the valves being out of spec were my problems. I'm new too diesels, but would this sound like a logical answer. I guess I can always buy new injectors, and a head gasket and see if that helps if not, then do a full tear down and rebuild. Attached are pics of the block and head, on cylinder 3 it is just a oily smudge from where I wiped the wall with my finger.

 

[North Idaho Wolfman]

I think the wet your seeing is antifreeze and not fuel, but could be wrong.
While you have the head off measure the cylinder diameters, I bet they will be out of spec and it's going to need new liners and pistons.

FYI:
With the valves being loose, and you tightening them it will not change the cylinder PSI, if anything it's going to go lower not higher.
It won't start at 250 PSI.
With the compression numbers your posting it needs a complete rebuild.

 

[LittleJim]

After thinking about adjusting the valves, I realized that being loose the valves would be closed anyways. I thought at first it would be antifreeze but it was very green in the few drops that were from around the valves. So concluded that it was straight diesel. I would like to do a rebuild instead of just replacing it because from I've researched the prices are about the same. Does anyone have any good links to rebuild kits? Kumar bros has everything but the sleeves, would it be possible to just use that, I don't have the correct tools to measure the roundness of the cylinder.

 

[Mark_BX25D]

I thought at first it would be antifreeze but it was very green in the few drops that were from around the valves. So concluded that it was straight diesel.

Diesel is not green. Antifreeze is green.

But it's a moot point since it needs a rebuild.

Looks like the coolant had been neglected, anyway. Lots of rust in the water passages.

Nothing a good hot tank won't clean up!

 

[North Idaho Wolfman]

Here is a rebuild kit with liners:

Engine D650 Overhaul Rebuild Kit for Kubota Utility Tractor B6001 B6100 B6100HST

Engine D650 Overhaul Rebuild Kit for Kubota Utility Tractor B6001 B6100 B6100HST

www.fridayparts.com

You are going to need to get a machine shop or an engine shop to press out the liners and press in the new liners and bore them.
It's not something you can do yourself.
They are only semi sized, they are smaller then they need to be on the inside.

You can do everything else yourself.
and buy new injectors!

And yes the green liquid is antifreeze, not diesel.

Make sure you keep all shims that are under the fuel injection pump.
Do not have the deck of the block milled!

 

[LittleJim]

Here is a rebuild kit with liners:

Engine D650 Overhaul Rebuild Kit for Kubota Utility Tractor B6001 B6100 B6100HST

Engine D650 Overhaul Rebuild Kit for Kubota Utility Tractor B6001 B6100 B6100HST

www.fridayparts.com

You are going to need to get a machine shop or an engine shop to press out the liners and press in the new liners and bore them.
It's not something you can do yourself.
They are only semi sized, they are smaller then they need to be on the inside.

You can do everything else yourself.
and buy new injectors!

And yes the green liquid is antifreeze, not diesel.

Make sure you keep all shims that are under the fuel injection pump.
Do not have the deck of the block milled!

Thank you, I looked on Fridayparts and unfortunately that kit is out of stock so the next best thing is ebay where they are a $100 more. It is diesel sitting in the cylinders, the green I was referring too was the few drops that were around the valves. I should of wrote that better.

I talked to one machine shop here in town and he said he gets $100 a hole to punch out liners, install and bore them to the correct size. Is that reasonable? I'll be calling a couple more today to get their prices. Thanks for all the assistance so far, hope to get this tractor back in good shape.

 

[North Idaho Wolfman]

I talked to one machine shop here in town and he said he gets $100 a hole to punch out liners, install and bore them to the correct size. Is that reasonable? I'll be calling a couple more today to get their prices. Thanks for all the assistance so far, hope to get this tractor back in good shape.

Excellent price, it's costs me much more than that to get it done!

Do you have the WSM (aka service manual) for the rebuild?

 

[Joisey]

I'm not familiar with this engine. Does it use replaceable valve guides or are they one piece with the head?

 

[North Idaho Wolfman]

I'm not familiar with this engine. Does it use replaceable valve guides or are they one piece with the head?

All Kubota engines use replaceable valve guides, but you rarely ever see one that needs them replaced.