I repeated the compression test because I didn’t record the numbers before. In order to perform a compression test (using the injector holes), you will need to remove:
Air Filter Housing
Metal Injector Lines
Fuel Overflow / Bleed Line
Metal OverFlow / Bleed Line Rail
Injector Nozzles (make sure to remove the copper gasket from the bore for each one as well)
At this point you can test the compression of each cylinder. While cranking the engine, be sure to pull and hold the engine shutoff rod, so the injection pump is not squirting diesel fuel.You can optionally disconnect the glow plugs power wire to conserve battery as well.
The values I read for each cylinder was from back of engine to front (dry): 80 PSI – 160 PSI – 160 PSI
Since the #1 cylinder was especially low, I squirted some oil in the cylinder and repeated (wet).The value rose to 150 psi, which is a good indication the issue is with the piston rings, and not a valve issue.
The service manual spec for allowable range on compression is 337-448 psi, so all three cylinders are well below spec.
At this point I pulled the head to check for any signs of damage to either the head, valves, or the pistons.
To remove the engine head on this tractor, you will need to (starting with parts already removed for compression test above):
Drain Oil & Coolant
Remove Air Filter Bracket & Fuel Filter Mounting Bolts
Remove Firewall Mounting Bracket Bolts to Head
Remove Exhaust Manifold (optional)
Disconnect Fuel Supply Hose to Injection Pump
Remove Air Intake Manifold
Remove Glow Plugs
Remove Top Radiator Hose
Remove Top Mounting Bolt on Alternator (and swing alternator out of way)
Move Fan Belt OfF Pulley
Remove Valve Cover
Remove Valve Rocker Arm Assembly
Remove Push Rods (inspect to make sure they are all straight)
Remove Head Bolts
Lift Head Assembly from Engine
The engine is quite crusty with carbon deposits, but I don’t seen any signs of head, piston, or valve damage yet. I will post a follow up again once I have pulled the valves apart and cleaned everything up for a more thorough inspection.
Getting back into this project. We have moved since I started this project and now have a garage bay I can use to continue working on the tractor. I was never able to get it to fully fired up. It would sputter and almost catch but never quite start. I finally did a compression check and was seeing low compression on all three cylinders, with one very low. I am guessing there was some engine damage due to overheating issues it was having back when it was running last.
Since it is going to need a rebuild of some sort, we loaded it up on my trailer and brought it back to my house where I can work on it in the garage.
Once back at my house, I needed to figure out a way to raise the bucket and hold it there so it wouldnt guoge the concrete. Many of the hoses are leaking, so I needed an external way to hold it up. I used a floor jack to lift the bucket off the ground, and a scrap board placed into the linkage to prevent the hydraulic cylinder from collapsing back down worked very well!
Safely in the garage so I can start the engine tear down.
She has definitely seen some wear, and sitting outside has taken a toll too. These pics will hopefully serve as some good “before” pics once I get it back up and running and cleaned up!
Update: I have tires and wheels on the Kubota B20 and aired up. Was able to get 3 of the 4 to hold air with some tire slime. Front left still has a slow leak that I am hoping will seal up once I get it rolling.
Changed the engine oil, oil filter, air filter, fuel filter and radiator fluid.
Engine was completely seized and would not turn over. Removed the injectors and squirted sea foam and engine oil into the chambers to let sit for a couple days. Still wouldn’t crank over with the starter so I used a wrench on the flats of the crankshaft / hydraulic pump shaft coupler to work it loose.
Also needed a new fan belt. Side-note – Not an easy job on these machines. If I ever need to do a belt on a machine set up like this again, I am using one of these:
Engine now cranks over and after lots of working the air out of the injector lines sounds like its firing on one cylinder, but not enough to start. It was in the low 40s (F) when I was attempting, so I plan to give it another try on one of the upcoming warmer days.
A friend of mine has this tractor that was been sitting unused for several years. It ran when it was parked, but at the time it was having some overheating issues, as well as we suspect at least one of the injectors was leaking down causing a surge of heavy smoke for a few minutes when it would first start up.
I am going to go through it and get it back up and running. Once I get it back operational again, I may also consider setting it up to run on waste fuels such as used vegetable oil, motor oil, etc.
First up is get the front tire back on it (was borrowed to be used as temporary spare for a different tractor),new battery, and get the supplies together to change out the motor oil, and coolant.
It definitely has been sitting for a few years!
The hours meter has definitely turned over at least once. I am also not sure what the expected lifetime is on these Kubota 3 cylinder diesels.
The engine compartment isn’t too bad. There is a mouse nest in the coolant overflow bottle though!
Should be a fun project! Click here for part 2 on the Kubota B20 project.