ZD221/D782 help

[346ci]

I bought a ZD221 with the D782 engine that had been overheated from not cleaning the radiator. The previous owner took it to a Kubota shop and they said it needed an engine.

I could tell they tried a new head gasket and replaced a bent push rod. I checked the head with a straight edge and could get a .003 feeler gauge under it. I let the local bike shop resurface the head and it's good now. He didn't have the ability to magnaflux for cracks so I had to skip that.

The cylinders look ok but of course I can't check compression yet. The rotating assembly feels good when turning by hand.

My plan is to order a upper gasket kit and try what they did, with a flat cylinder head this time. That kit doesn't come with the head bolts so I'm assuming they can be reused?

Good idea or wasting my time/money? I see reman engines for $4200 and from research, the D782 seems like a odd ball Kubota engine. I'm not willing to put that much in the mower, would sell it for parts as it has very low hours and in good shape.

Thanks

 

[rentthis]

When your bike guy resurfaced the head, did he note how much he took off? That measurement is critical in that there is little to no tolerance between the block and head. Someone here will have the plus-minus on that repair. It may be as simple as using a thicker head gasket but must be addressed.

 

[Sjess12]

Yes as rentthis said that is very critical. Did they do more of a cleaning or actually take a bunch off? And almost all the Kubota engines I've ever seen apart and back together was the same headbolts, only time I've seen bolts replaced was obvious reasons as in breaking or stripping.

 

[346ci]

He replied back today with .008" taken off. I can't find in the service manual where it states at what measurement you need to use a thicker head gasket. Being that there is only one part number for the head gasket, makes me wonder.

I called Country Sales and Service Friday to pick their brain, these guys must reman a lot of the small Kubota motors. They mentioned that I'd only have to worry about a thicker head gasket if the block was decked.

Thanks

 

[Dieselaholic]

He replied back today with .008" taken off. I can't find in the service manual where it states at what measurement you need to use a thicker head gasket. Being that there is only one part number for the head gasket, makes me wonder.

I called Country Sales and Service Friday to pick their brain, these guys must reman a lot of the small Kubota motors. They mentioned that I'd only have to worry about a thicker head gasket if the block was decked.

Thanks

If the .008 removed is acceptable or a metal spacer shim is available why not drop the pan and plastigage all the bearings? Then you will know the crankshaft condition. If they look fine might skip plastigage or do a couple. If no cylinder scuffing you should have a good motor unless the rings are worn out. Any ridge on the top of the cylinders? Can you shake the piston back and forth in the bore excessively. If no ignore the rings. Did you check the block flatness?
I've got the opposite. Good motor and mechanicals but ugly cosmetics I am restoring. Just got the motor running today on my ZD326S and she runs perfect. 3 cylinder D1005 diesel.

 

[Dieselaholic]

He replied back today with .008" taken off. I can't find in the service manual where it states at what measurement you need to use a thicker head gasket. Being that there is only one part number for the head gasket, makes me wonder.

I called Country Sales and Service Friday to pick their brain, these guys must reman a lot of the small Kubota motors. They mentioned that I'd only have to worry about a thicker head gasket if the block was decked.

Thanks

If the .008 removed is acceptable or a metal spacer shim is available why not drop the pan and plastigage all the bearings? Then you will know the crankshaft condition. If they look fine might skip plastigage or do a couple. If no cylinder scuffing you should have a good motor unless the rings are worn out. Any ridge on the top of the cylinders? Can you shake the piston back and forth in the bore excessively. If no ignore the rings. Did you check the block flatness?

 

[346ci]

I might could make a spacer from the old gasket, just would like to confirm it is 100% needed.

Bores are good, no ridges at the tops, pistons don't rock. The block's deck is fine using a straight edge.

The mower has very low hours according to meter; tires, mower deck and other wear items show signs of low use.

Thanks

 

[lugbolt]

I always replace the head.

then there is no questions to it's thickness

most of the overheated engines have cracked heads anyway, there is no saving or milling them once broken.

there is only about .015" (IIRC) between the head and piston crowns when everything is up to snuff. Removing 8 will bring that to .007. That is not enough to account for rod stretch and oil clearance in the rod & crank metals (bearings). that is also why ether, oil, transmission fluid, water, or anything else but diesel sprayed through the injectors only WILL damage the engine in the form of bent rods cracked pistons cracked crank journals and a host of other things that may not be apparent

whats the cylinders look like? Scuffed any? IF so, pull the engine and have a look at the pistons, in particular the ring lands and the ring side clearances. I have 4 or 5 torn down at the moment that all need pistons from overheating.

also anytime the head is off for whatever reason it is wise to check to see how far each piston is out of it's cylinder and compare that to the spec. Bent rods a lot of times will show up as one or two pistons that are slightly lower and bent rods are VERY common. They get a little hard to start, so owner (or operator) grabs a can of starting fluid, gives it a little spritz cranks it and at that point the damage is irreversible. why? 23:1 compression on a 750cc diesel leaves VERY little room for combustibles, but a 16:1 truck engine (6000-15,000 cc displacement) has a much larger combustion space, AND much beefier parts; although it's still possible (ask my dad...7.3, ether, cracked pistons). he wasn't very happy with himself about that and it took almost a year for it to rear it's ugly head, of course murphy's law, only happens at the worst possible time, the day before loading up the race car.

 

[346ci]

Thanks Lugbolt, I measured the bottom layer off the old gasket and it is .008".

Should I even go through the trouble of trying to piece it and the new gasket together? The original 3 layers are held together by a brass looking rivet that was pressed together. I'd have to drill those out and see what could be used in their place.

Cylinders look good, I found the top clearance measurement and will do it next.