B7000 Z650 engine

Hi All,

I need to replace the engine in my B7000 kubota.. Cracked block etc..this one is hopeless..It uses the z650 but I cant find that engine anywhere. Does anyone know if another 2 cyl engine will fit in this tractor?


Thanks,

Damon

Vic,

My neighbor had the kabota field tech over to fix his tractor so I had him look at mine. He knew a few things I didnt. He said there is some water in the engine oil..not just water in the radiator like I had thought. He says most likely its a cracked block and I might as well look for another engine. I wish it was just a freeze plug but he didnt think so. I may still check that but its not looking good. Im lost without my kubota!


Damon

Guys,

The oil color is cloudy and its about 1/4" above the full level of the dipstick. The radiator has alot of oil in it but I know it floats on water so dont know just how much but if you stick you finger in the fluid it comes out pure oil. The tractor doesnt have more than 10 minutes running since I rebuilt the head and changed the oil as well. Running the tractor does not increase pressure at the radiator opening. I was able to pump it up till I could pump no more..the gauge isnt working on my old stant radiator tester but it held the pressure. There is a pulsating pressure at the dipstick hole increasing with rpm.
I did watch the video on this problem but wasnt really able to get the pressure loss at the cap you discribe.

Somehow I dont think this sounds good..


Damon

Ill start dissasembly tomorrow and report back.
I truly hope that is what it is!

Damon

Ok I did those tests. No bubbles at all around the head/cyl area under pressure. The glow plugs have some fluffy carbon on them but thats all. No sign of oil or water.
Is a compression test in order? Would have done that but I dont have that size adapter for the plug hole. Can get it though.

Once started the tractor idles just fine..nothing out of the ordinary. It is hard to start..much harder than before I had the head rebuilt by the kubota people. WHen it does start it blows out alot of diesel smoke. Once cleared out it runs fine. Its like it piles up in the chambers while sitting.


Damon

Wow I know I must have got some of this right

-The reason for rebuilding the head was this oil in the radiatior problem. I noticed it blowing oil STRONGLY out the overflow tube. Thats what got all this started. Talked to the kubota shop and they said most likely blown head gasket. So I took the head off and had it gone through anyway ( they said it was a mess inside) It did the same thing afterwards with the same intensity.. pressure in radiator and oil out the overflow.
-I did torque the bolts in sequence. New gaskets used. Didnt see any white sealer on the bolts that I recall. I could be wrong though.
I did put the bolts back in the right spot. I photograph everything and every step as I dont trust myself. No I didnt save the photos unfortunately.
-The smoke is black/grey and diesel smelling. Takes about 2 minutes after prewarming to get it going and it clears in about 15 seconds. As I said this was a definite change from its previously easy starting.
Could the valve clearance have changed after settling in?
I could have set that wrong too...but like I said it runs like a champ once its started.

-I didnt have any coolant, water etc in the block after head was removed as the lower rad tube was off. Im in california too with the mild winter temps.
- The water neck was not cracked but badly corroded.
- The radiator always leaked. The shop had to recore it.

I cant find an adapter to fit the glow plug hole in my stuff unfortunately. I have 10mm but the thread pitch kubota uses is different. I also have a leakdown tester but again no adapter that will match the thread pitch.
I hope we can get this problem isolated its really bugging me. I havent taken the tractor apart yet in case there are further tests we can do Rechecked the radiatior pressure at 16lbs..holds solid for 3 min or so. Starting the tractor did not vary the pressure at all and I lowered it to 6 lbs.


Damon