Cylinder Liner Trouble

[Stumpy]

Hello guys.

I've run into a big snag rebuilding my L175 and was wondering if I could get some advice. I don't know how I missed it before other than carelessness but as I was cleaning the deck to reinstall the head this afternoon I noticed the liner on Cyl 1 was sunk farther into the block than on Cyl 2. I have no luck with this machine.

Cylinder 1

Cylinder 2

You can see where the old carbon build up used to be and where it's been scraped clean by the rings. The exhaust valve guides were loose in the head so can infer that it was overheated hard and I imagine that's when this liner shifted. Another concern is the connecting rod having impacted the bottom of the liner though I heard no knocking so I think I'm good there.

The correct path is obvious, renew the rings and liners (probably the pistons too with my luck). I'm already well over budget for this rebuild and parts (including pistons) would be $400 at Messicks plus whatever the machine shop costs. On top of that it'd mean stripping down and removing all of what I just put back together and then some. I could just kick myself for not noticing it before. I just can't figure out how I missed it.

The pistons still move freely. I don't know about the compression ratio but it seemed to run ok before it was disassembled and I don't see any serious scars in the liner walls. My fiscal sense is sorely tempting me to find a way to tap the liner back into place and put it back together with my fingers in my ears. My inner mechanic is screaming just as loudly that even if that worked it's going to cause more problems later and there is only one way to do it right.

What do you think I should do here? If I do the renewal I can probably get the liners out but I lack a press large enough push in the new ones. I've read Aquaforce's thread and understand the liner needs to be bored out to the piston size and the deck surfaced. Is there anything else that needs to be done? Is there a better (cheaper!) way to do it then sending the block off to a machine shop? Can I reuse the old pistons (though the top lip on #1 doesn't look good)?

Thank you in advance for any help,

Matt

 

[Kubota Newbie]

Your worst case scenario is the best option for a good repair. New liners/pistons/rings.
However, you might be able to pull that liner back up into place and get by if you're carefull. Start by first pulling the pan and checking the liner positions at the bottom to make sure it wasn't a short liner in the first place. If #2 is lower than the rest you could try to pull it up with a sleeve puller. You'd have to remove the piston/rod assembly for that hole, install a puller, and hope you can move it without messing up the bottom edge. The top counter bore will need to be cleaned of all carbon first.
Regarding re-using pistons etc.... If you're going to keep it, never combine new & used pistons, rings, and/or liners. If you're going to peddle it off and don't care about the next guy then..........
I've never done a Kubota, but plenty of others. A lot of dry sleeve assemblies are pre-sized (no need to re-bore or hone after installation). They generally come as matched sets. Not sure if Kubota does it that way or not. It's odd that your sleeve moved. Most have a rim at the top of the sleeve or a ridge at the bottom of the counterbore to prevent that from happening.

 

[Apogee]

Hi Matt,

Sorry to hear of your troubles.

My advice it to bite the bullet and take it apart. You can buy a new liner, piston and ring set on ebay for $135 each including shipping.

You will kick yourself down the road for not doing it right the first time.

Also, I'd say you're correct about it being overheated. Likely the grabbed the liner at some point and that is how it moved. The point is, the liner likely isn't round any longer and even if you put new rings in, there is no guarantee they will seat properly.

Remove and reinstall the sleeves by packing them with dry ice. It will usually shrink them enough that they will come right out. Be sure to not get the dry ice in contact with your skin.

Finally, not sure of the extent of your rebuild or if you have already put new rings in it, but looking at the pics of the sleeves there is not enough cross hatching in them to properly seat new rings anyway. If you put new rings in and try to run it, based on what I see it will likely use lots of oil.

Bitch, moan, and curse at it for a few minutes and then just bite the bullet and get it done.

Best of luck,

Steve

 

[Orange Tractors]

I hope you didn't glue the new gaskets in place so well that you can't reuse them.

I have never been that deep into an engine that has a liner, but my concern if you just pulled the old liner back into place would be: what is going to keep it from moving again?

One way to look at it is that after you put new liners, pistons, etc. (might as well do all the crank and rod bearings while you're at it) is that you will have what is essentially a new tractor that will last another thirty to forty years without having to do anything other than routine maintenence to it.

Robert

 

[Stumpy]

Steve, thanks for the idea about ebay! That cuts the parts cost considerable. I agree without you about the cross hatching but I believe that's because the liners must be sized to the pistons. If they are presized I'm naming my first born after you! If that's the case I've got a cylinder hone and I'll add my own if theirs is insufficient. I'll call them shortly.

Robert, I agree about the rods and the mains if I've got to take the crank out. You're absolutely right I'll kick myself for not doing it right and I'm above slapping it back together and selling it. I guess I'll just have to wait til the money is available. This is turning into a $4000 tractor and that's before I've done any sheet metal work or painted it!

KN I can't remember why they don't come finish bored but I think that was explained in AquaForce's thread.

 

[Apogee]

I agree without you about the cross hatching but I believe that's because the liners must be sized to the pistons.

Hi Matt,

The cross-hatching has multiple functions, only one of which has to do with the bore sizing. You are correct that honing (which generates the cross-hatching) is how they get to the final bore size. However, the cross-hatching also assists with seating the rings to the bore, and is also there to better hold an oil film in the bore to prevent galling a piston (that's how your liner likely moved).

The likelihood of the liner arriving in finished size is small. The reason is, the liner will distort when driven into the block. The manufacturers know this and plan for it. They are designed to do this and then be machined back perfectly round once installed. I would budget for having the block hot tanked, bored, power honed, and decked once the new liners have been installed. Shouldn't be too expensive since it's only a two cylinder. Hopefully I'm wrong, but don't be surprised if that is what ends up being needed.

If you decide to pull the liner up and put new rings in what you've got and just run it, then you really should use a ball hone to put the proper cross-hatch in the bores. Otherwise, the new rings likely won't seat and you will have wasted your time and money. Just Google "flex-hone" and you will see what I'm talking about. You will need to buy the proper size one for the bore as its not a one-size-fits-all deal. Yes, you can use one of the cheap 3-stone hones from the auto parts and they will work, but the flex hone will do a much better job.

http://www.brushresearch.com/

With the liner down like it is the compression in that cylinder will be significantly lower than the other one so definitely pull it up if you decide to not install new ones.

Lastly, since you're going to have to pull the pistons anyway, at the very least, I'd put new rod bearings in it while I was at it.

Best,

Steve

 

[Stumpy]

Whoops, miscommunication on my part. Somehow I thought you were referring to a picture of a new liner when you were talking about cross hatching in your first post. Thanks for explaining that clearly, that sounds like the reason that was given in AquaForce's thread.

You're still right though I'll kick myself for not doing it right now. We'll just have to suck it up and put more money into the machine than we were planning. May have to wait a while before finances allow it again. In the mean time I'll have to start stripping down the block once finals are done at the end of the month. How far down do I have to go? I'm guessing the crank probably has to come out (not looking forward to that) but do I need to take the cams out too?

 

[Apogee]

If you're planning on doing a full rebuild, then yes everything needs to come of the block.

You do this mostly for cleaning purposes to ensure you don't have any trapped metal shavings on reassembly.

You will be glad you did this in the long run!

;-)

 

[Kytim]

Kubota Newbie,if you know is there a machined "puck" that would fit the sleeve in the bottom to allow it to be pulled up or is it a more generic tool? I've never done a sleeved engine, a bunch of SB chevy's and fords.

Oh, a ball hone, the only way to go!! I can still remember when I saw the first one, WOW what a nice finish.

 

[Kubota Newbie]

If you can find someone with a sleeve puller set they'll have a few "pucks" of varying sizes. If they have the size you need is a good question. For a few bucks a local machine shop could likely make one from a chunk of scrap.
Regarding the pre-sized sleeve and piston kits, again I don't know about Kubota specifically but you can buy pre-sized matched sets of dry sleeves/pistons for stuff like Deere and IH all day long. Press-em in and assemble, that simple!
To aid in pressing in dry sleeves you should throw them in a freezer over night. Be sure to mark them so you know what piston goes in what hole if you're buying a matched set.
To help pull that sleeve back up in the block, assemble your puller, seal up the bottom real good so it will hold liquid, heat everything up REAL GOOD, cyl block hot as you can get it reasonably, then pour the liner full of ice water. Should help shrink it enough it will move

 

[Stumpy]

Ok sorry for the delay in getting back to everyone, I've had an interesting week. Busy at school and Friday we had a HVAC company come and assess and do some maintenance on the boiler and AC (while I learned over their shoulder) and lo and behold the this morning the house is about 58F. Fancy that! A little poking later and I find that while the ignitor (hot surface type) looks fine it has infinite resistance and is getting power. The company did not seem interested in taking responsibility for it and I wasn't in a fighting mood plus it's a $20 part. I called around til about 2pm when most places closed but noone seems to have one. Everyone said they could order one Monday and have it Tuesday so I'll do some more calling Monday. Til then we're heating via fireplace and blankets.

Anyway I did talk with the machine shop that did my head, the ebay company that sells that liner kit, and Vic through a PM conversation and they all said those liners have to be machined after installation for just the reasons Steve said. It appears that due to their thin wall dry liner design they warp unlike their thicker wet liner cousins. There are dry liners that don't exhibit this phenomena but they're of different construction. Now the machine shop told me he wouldn't give an estimate without having a chance to look at it but looking around at prices on the net it doesn't seem to be as bad as I'd feared.

The bad news is he voiced his concern that the liner should've had a lip preventing it from sinking into the block like that. I don't see one on any of the pics of the liners but he was concerned the block may have cracked. In light of that I'll be yanking the pistons and liners before I take anything else apart and giving it a good inspecting. If the block looks ok I'll remove it and let the machine shop examine it. If they think it's good I'll haul it home, strip it, install new liners (unless they need to bore and install oversize liners) and then let them have their way with it. This is going to have to wait til at least mid May when I've got the time though.

I think I'll try the thermal expansion method before I goto the trouble of making a puller but we'll see if the sunk liner feels like cooperating.

Matt

 

[Toyboy]

The "ball hone" is marketed as Flex Hone

 

[Stumpy]

Oh yeah I forgot about that. I have used a ball hones before but not for engine cylinder honing. I'll have to see what this shop uses in their final hone and see if I need to run one of those through it when I get it back.

 

[Apogee]

Stumpy,

I only recommended the flex hone in the event you decided to put it back together and run it without replacing the liners.

If you have a shop do the work (which you should), then they will power hone it to size. Don't do anything to the bores after you get it back from them because they will have the correct finish and be the proper size.

For the record, you might seriously consider having them remove the old ones, and install the new ones as well. They are used to doing it and know the tricks. You'd be very bummed if you screwed up and junked the block or destroyed a new sleeve during the learning process.

Perhaps it might be worth asking if they'd be willing to let you watch while they do it so you can learn. However, don't be disappointed if they tell you no as lots of shops won't allow it.

Good luck,

Steve