Blue smoke, B7100 HST

[521]

A few years a go i bought a B7100 HST D 4wd. Had 400 hours, used very little. R1 Ag tires, MMM.

400 hours later from a few years of use mowing, plowing, discing, hauling and pretty much anything else needed or asked of, never fail, never saing "i dont wanna" - from the breather tube under the engine - blue smoke pretty steadily flows.

When starting - white smoke or a mix of white and black. Once running and warmed up a bit - no firther smoke from exhaust.

As far as starting - when cold it takes so long i usually have to plug in a battery charger because i ended up running down the battery trying to warm the gp's. Cold im talking below 30*. Last week we had a few 10* mornings - had to wait a few hours before being able to start.

Maintenance has only been oil changes every 100hrs. Aur filter was replaced once since i have had it and has a new battery.

 

[CountryBumkin]

Blue smoke indicates your burning oil. If the smoke clears up after running a little, that usually indicates that oil is getting past the valve seals. What happens is that a little oil leaks down the valve stem when the engine is shut off and then when you start it, blue smoke. If you see blue smoke all the time it is generally an indication that the piston oil ring is worn.

Regarding you hard starts cold, I would first test the glow plugs. I'll bet either the plugs or the relay is bad. A cold/long-cranking startup with faulty glow plug system would also explain the black smoke.

 

[521]

Mike - thanks for your thoughts!

For the glow plug issue - what parts would i need to order for a complete go replacement? Glow plugs for sure and a relay?

 

[North Idaho Wolfman]

Blue smoke out of the breather tube to some extent is semi normal on these old engines.
If excessive it's most likely bad rings or worn / damaged cylinder walls, also excessive blow-by can be a cause of a hard starting motor (low compression).

Pull the glow plugs and glow plug indicator, do a compression test while you have the glow plugs out, test the glow plugs and indicator for resistance.
Your tractor does not have a relay to run the glow plugs it's all done via the switch.

If you don't have the WSM yet got to Kubotabooks.com and download the three part copy, it will give you the testing and specs for the glow plugs and indicator.

 

[sitdwnandhngon]

I would assume the valve seals on those engines are kind of a failure point.

After I fixed my cam plug I started getting some blue smoke under load that wasn't there before.

We figured that because it went so long with low oil pressure the valve seals are likely worn and now with oil getting pumped strong all around more of it is finding it's way into the cylinder.

Still starts and runs fine, so no biggie. I see plenty of older larger machines blowing a little blue under load and running for years.

When it comes time to do the rings and head gasket I will do the seals at the same time.

 

[OldeEnglish]

I get some smoke out of my olde gal when the engine is cold, once it warms up it's not so bad. It also tends to smoke more while in high range, especially going up a hill. Throw it in low range and it doesn't smoke. It's an old tractor with over 1200 known hrs on it so I expect to get some smoke out of it. Actually I can't recall seeing any type of old diesel equipment that doesn't smoke.... The tractor runs like a bear, it has amazed me how much power it has for a low hp small tractor .