I recently acquired a 50 hp V2203 engine. I had spent the last six months sitting outside. The crank shaft would rotate only 270 degrees. Tonight I pulled the cylinder head and found rust on one of the cylinders. After about 5 minutes of rubbing Marvel Mystery Oil into the cylinder walls and gently rotating the flywheel, the engine did a full rotation. I spent another 20 minutes cleaning all the cylinders and piston heads with MMO. The engine now rotates very easily with no resistance anywhere. Should I just slap the engine back together and run it or should I pull it apart and have a machine shop run a hone thru it? The engine has about 12,500 hour on it and Kubota says it is good for about 30,000 hours.
rust in cylinders
- Thread starter sidwell50
- Start date
30,000 hours? Who told you that? 15,000 hours is the close to the high end with religious maintenance. If it wouldn't turn over that means the rust was down in the region where the rings travel so that cylinder is shot. The rust alone makes a case for renewing the cylinders but combine that with the hours? I wouldn't slap that back together. Plus you have no way of knowing what sort of maintenance it's had before you found it. Rebuild it, do it right or you'll be kicking yourself later.
Re: sticker shock
I just priced a rebuild kit. $1306. I found out the cylinders are not replaceable. That means the cyliders will need to be bored and there is no assurance all the rust pits will be gone.
Do I spend the money on having the engine overbored and hope the cylinders are rust free?
I just priced a rebuild kit. $1306. I found out the cylinders are not replaceable. That means the cyliders will need to be bored and there is no assurance all the rust pits will be gone.
Do I spend the money on having the engine overbored and hope the cylinders are rust free?
Re: sticker shock
Are you sure? It would be unusual for a Kubota let alone a diesel to be built without replaceable cylinder liners.
By the way I came across the workshop manual for free. I'd download that before it disappears!
The manual mentions liners exactly once so you may be right but I'd double check with a different dealer or with someone who rebuilds those regularly just to be sure.
Are you sure? It would be unusual for a Kubota let alone a diesel to be built without replaceable cylinder liners.
By the way I came across the workshop manual for free. I'd download that before it disappears!
The manual mentions liners exactly once so you may be right but I'd double check with a different dealer or with someone who rebuilds those regularly just to be sure.
Re: Checked the Manual
If it makes you feel any better you'd have needed a trip to the machine shop even if it had liners due to the design Kubota usually uses.
I looked up that section in the manual and you're absolutely right this thing doesn't use liners. I think the only thing to do is take it to an engine shop and have them evaluate the block. They'll be able to tell if a rebore can remove those rust scars.
If it makes you feel any better you'd have needed a trip to the machine shop even if it had liners due to the design Kubota usually uses.
I looked up that section in the manual and you're absolutely right this thing doesn't use liners. I think the only thing to do is take it to an engine shop and have them evaluate the block. They'll be able to tell if a rebore can remove those rust scars.
Hey Stumpy, The kit for that 50hp engine is pretty close to the cost of the kit/parts for these little 18-25hp engines we are usually talking about isn't it?
Possibly. I've lost track of what I've paid for everything since I kept doing it in installments as I found more damage. I know the pistons, rings, and liners were about $130 a cylinder but those kits also appear to come with gaskets, bearings, lifters ect.
Sidwell,
I'd pull it apart as advised and have the block checked.
Don't forget, the bad cylinder can also be sleeved if necessary by the machine shop.
I have a D-722 that also does not use liners. I did some homework and found a sleeve that will fit it so that is the plan of action with it rather than junking the block.
I also COMPLETELY agree that you should be rebuilding it with that many hours on it.
Good luck,
Steve
I'd pull it apart as advised and have the block checked.
Don't forget, the bad cylinder can also be sleeved if necessary by the machine shop.
I have a D-722 that also does not use liners. I did some homework and found a sleeve that will fit it so that is the plan of action with it rather than junking the block.
I also COMPLETELY agree that you should be rebuilding it with that many hours on it.
Good luck,
Steve
<<<I also COMPLETELY agree that you should be rebuilding it with that many hours on it.
Good luck,
Steve>>>
Steve and the others are correct, a complete rebuild is in order, putting it back together now is just inviting another tear-down quickly. do it right this time and put another 10,000 hrs on it. a diesel is under such pressures that to much tolerances is asking for failure and the purchase of additional parts you may not have needed the first go around.
Good luck,
Steve>>>
Steve and the others are correct, a complete rebuild is in order, putting it back together now is just inviting another tear-down quickly. do it right this time and put another 10,000 hrs on it. a diesel is under such pressures that to much tolerances is asking for failure and the purchase of additional parts you may not have needed the first go around.
Now I am confused. If there are no liners, how do you insert a sleeve? I thought a sleeve and liner were the same thing.
(cracks knuckles) As I just learned some of this myself a little while ago take it with a grain of salt but it should be fairly accurate.
[wall-o-text]Liner and sleeve are interchangeable to laymen (us). I believe sleeve refers to thin wall dry liners as I call them and liner is reserved for wet liners. There are 3 types of cylinders in common use these days.
-A bare cylinder where the piston and rings physically touch and run in the block. Common on engines that don't usually get rebuilt, i.e. car engines. Though the engineers are usually able to leave enough 'meat' in the bore that they can be bored out (.015 of an inch or so) and oversize pistons installed. It's cheap and easy but makes rebuilding annoying and can result in higher cylinder wear as the metal used is an engine block material first and a cylinder material second.
-The next is a thin wall dry liner. This is a thin cylinder of metal inserted into a bore in a block and the pistons run inside of this. The liner is slightly oversized and is inserted by heating the block and cooling the liner (expanding the bore and shrinking the liner respectively). The cylinder still takes a lot of the stress of combustion but wear is limited to the liner which is made of materials better suited to the cylinder environment than engine block cast iron. One cylinder block can be used almost indefinitely by just changing out liners. Heat is passed from the liner to the walls of the block and from there to the coolant in the jacket.
One very important advantage is the block doesn't have to be redesigned to use them. In fact almost nothing except the piston and ring size must be changed. I read somewhere Ford on one of their tractors changed mid production to dry liner construction when they started having problems with porous block castings. In this manner a machine shop can also prep an engine bore to accept liners that previously didn't use them. The only disadvantage is the piston is usually smaller and thus so is the displacement so the engine must be derated. This is what Kubota seems to use (for sure in the Z series and several D series) when their engines use liners.
The primary disadvantage is then when the temperatures of the liner and block normalize the liner is under a lot of stress and tends to warp slightly. Enough that after installation the liner must be rebored round and to size and then honed before the piston can be installed. Thick wall dry liners may exist that don't exhibit this problem but I haven't come across them in my reading, plus I think they would have cooling problems.
-Wet liners are the last type and are found in many (if not all) large diesels including those found in semi tractors. They are similar to many respect to dry liners except that they are much thicker and have coolant physically touching the liner hence the wet designation. The block must be designed for it and a means of sealing the top and bottom of the liner well must be designed but the thicker construction avoids the remaching procedure. They're pretty much drop in and go. I think there's also some benefit to cooling but I'm not sure on that.[/wall-o-text]
[wall-o-text]Liner and sleeve are interchangeable to laymen (us). I believe sleeve refers to thin wall dry liners as I call them and liner is reserved for wet liners. There are 3 types of cylinders in common use these days.
-A bare cylinder where the piston and rings physically touch and run in the block. Common on engines that don't usually get rebuilt, i.e. car engines. Though the engineers are usually able to leave enough 'meat' in the bore that they can be bored out (.015 of an inch or so) and oversize pistons installed. It's cheap and easy but makes rebuilding annoying and can result in higher cylinder wear as the metal used is an engine block material first and a cylinder material second.
-The next is a thin wall dry liner. This is a thin cylinder of metal inserted into a bore in a block and the pistons run inside of this. The liner is slightly oversized and is inserted by heating the block and cooling the liner (expanding the bore and shrinking the liner respectively). The cylinder still takes a lot of the stress of combustion but wear is limited to the liner which is made of materials better suited to the cylinder environment than engine block cast iron. One cylinder block can be used almost indefinitely by just changing out liners. Heat is passed from the liner to the walls of the block and from there to the coolant in the jacket.
One very important advantage is the block doesn't have to be redesigned to use them. In fact almost nothing except the piston and ring size must be changed. I read somewhere Ford on one of their tractors changed mid production to dry liner construction when they started having problems with porous block castings. In this manner a machine shop can also prep an engine bore to accept liners that previously didn't use them. The only disadvantage is the piston is usually smaller and thus so is the displacement so the engine must be derated. This is what Kubota seems to use (for sure in the Z series and several D series) when their engines use liners.
The primary disadvantage is then when the temperatures of the liner and block normalize the liner is under a lot of stress and tends to warp slightly. Enough that after installation the liner must be rebored round and to size and then honed before the piston can be installed. Thick wall dry liners may exist that don't exhibit this problem but I haven't come across them in my reading, plus I think they would have cooling problems.
-Wet liners are the last type and are found in many (if not all) large diesels including those found in semi tractors. They are similar to many respect to dry liners except that they are much thicker and have coolant physically touching the liner hence the wet designation. The block must be designed for it and a means of sealing the top and bottom of the liner well must be designed but the thicker construction avoids the remaching procedure. They're pretty much drop in and go. I think there's also some benefit to cooling but I'm not sure on that.[/wall-o-text]
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