In frame honing of good bores.

[William1]

Can you explain a bit more about the step mid-bore? My understanding of the flex-hone is that it doesn't remove appreciable material at all unless you spend hours hanging onto it. Maybe you are thinking of a bar hone?

If the piston is still in the bore at BDC and you hone from the top of the piston up, the area the piston is sitting in does not get cleaned/honed. Resulting in a step.
Generically speaking, a used bore has the sharp edged of the original honing worn off, and the 'grooves' filling with glazing (fuel/oil/by-products). The 'glazing' and wear will go to the top/tdc of the barrel where the rings ride to the bottom/BDC. Honing restores the 'sharp edges' of the cross hatch. When run, again, the edges go away and the result is the bore above the piston is larger and a step results.
You must remove the piston and hone the entire barrel.
I often do not hone if the cross hatch is still visible and no marks on the barrel. A good scrubbing with a scotch brite and solvent.

 

[kubotafreak]

Valves lapped with both coarse, and fine compound. Head cleaned.

 

[Deleted member 47704]

The beauty of flex hones is they follow the contour of the bore. If the bore is barrel shaped, out of round, tapered the ball hone will magnify those issues.

 

[Donystoy]

I hope everything works out with this engine. Over the last 50 years I have worked on numerous engines from large displacement auto engines to lawn mower engines and have always at a minimum if having compression or blow by I have always removed the pistons. I would replace the rings and inspect the cylinder walls and bearings and repair as required. If bearings were fine the only extra cost was for the rings and gaskets.

 

[kubotafreak]

William1,
What color scotch bright?

I hope everything works out with this engine. Over the last 50 years I have worked on numerous engines from large displacement auto engines to lawn mower engines and have always at a minimum if having compression or blow by I have always removed the pistons. I would replace the rings and inspect the cylinder walls and bearings and repair as required. If bearings were fine the only extra cost was for the rings and gaskets.

So you removed rods without replacing big end hardware? Did you atleast measure their stretch? You didn't mention rod bearings. Most lose a large percent of their crush when run in for any amount of time. Heck most fall out trying to push a piston out of the bore. Just curious how you avoid lower end issues after your work? If you are, saying rings only. You must work for free. Because your time is assumed to be free in your analysis. Most mowers require the engine case to be split in half to remove the piston.

I keep the post updated as I go for this specimen.

 

[Donystoy]

William1,
What color scotch bright?

So you removed rods without replacing big end hardware? Did you atleast measure their stretch? You didn't mention rod bearings. Most lose a large percent of their crush when run in for any amount of time. Heck most fall out trying to push a piston out of the bore. Just curious how you avoid lower end issues after your work? If you are, saying rings only. You must work for free. Because your time is assumed to be free in your analysis. Most mowers require the engine case to be split in half to remove the piston.

I keep the post updated as I go for this specimen.

I was not talking about Kubotas. I was talking about engines in general. I am aware that considerably more work is involved in disassembling to gain access to the bottom end on these engines. On mine I would have to remove an entire subframe as well. Just I would never consider honing out a cylinder without removing the piston so the walls are true all the way to the bottom. I hope it works for you and you don't have to open it up again.

 

[BAP]

How are you keeping the fine metal filings and oil from running down around the piston when you hone? Any minute amount that gets around the rings is going to instantly cause wear when you start it. If you are lucky it will be only to the rings and not score the bore or get into the bearings.

 

[hagrid]

I think I remember grease being mentioned but no idea if its soap based or if its moly based is it 3% or less.

 

[kubotafreak]

How are you keeping the fine metal filings and oil from running down around the piston when you hone? Any minute amount that gets around the rings is going to instantly cause wear when you start it. If you are lucky it will be only to the rings and not score the bore or get into the bearings.

Looks like Hagrid actually read the posts. (Polyura) As far as contaminates it would be minimal to none. The grease fillet is substancial, and creates a contaminate seal. The contaminated grease is wiped off. Any trace grease is also dissolved by the wd40. As far as lower end contamination. That has been what ive been saying the whole time. Over disassembly leads to more possible failure. None of the pressurized lower passages have been disturbed so filtered oil only goes in. That would be a concern only for the times you tear the lower end apart. The amount of cleaning required when lower end components are disturbed is substantial. Everything I dissassemble goes in a solvent bath and scrubbed down. If you don't at least do that you are asking for trouble.

 

[Lil Foot]

I'm also a little skeptical about this method, I've built lots of gasoline engines, but no diesels. I hope it works out, and if it does, I will be pleasantly surprised. However it works out, either you, or all us us, are going to learn something new.

 

[BAP]

Looks like Hagrid actually read the posts. (Polyura) As far as contaminates it would be minimal to none. The grease fillet is substancial, and creates a contaminate seal. The contaminated grease is wiped off. Any trace grease is also dissolved by the wd40. As far as lower end contamination. That has been what ive been saying the whole time. Over disassembly leads to more possible failure. None of the pressurized lower passages have been disturbed so filtered oil only goes in. That would be a concern only for the times you tear the lower end apart. The amount of cleaning required when lower end components are disturbed is substantial. Everything I dissassemble goes in a solvent bath and scrubbed down. If you don't at least do that you are asking for trouble.

Obviously you think you know more than anyone else on here who has probably a lot more engine repair experience than you. I asked a question and you appearantly don’t like it. Regardless how careful you are there is a chance of error which can be expensive. I hope it works for you and I expect that if it doesn’t, you will never come back and post that it didn’t. You seem more interested in getting everyone to tell you how great your idea is than to listening to what the great people who have a lot of experience have to say. Have a great day!

 

[kubotafreak]

Obviously you think you know more than anyone else on here who has probably a lot more engine repair experience than you. I asked a question and you appearantly don’t like it. Regardless how careful you are there is a chance of error which can be expensive. I hope it works for you and I expect that if it doesn’t, you will never come back and post that it didn’t. You seem more interested in getting everyone to tell you how great your idea is than to listening to what the great people who have a lot of experience have to say. Have a great day!

I enjoy the dialog, and challenge. Do you not think I understood this would be met with resistance to norms. For me there is no feelings. I only expect that those who reply have actual meaningful pro/cons, and back them up with more than “because we always do”. You wont learn if you dont fail. I am not a cookie cutter individual. What part of the proccess have I left out for you? It is in work and a living post. But, I guess you made your mind up before the end…

You sir do seem to have a chip off the shoulder.

 

[Henro]

I enjoy the dialog, and challenge. Do you not think I understood this would be met with resistance to norms. For me there is no feelings. I only expect that those who reply have actual meaningful pro/cons, and back them up with more than “because we always do”. You wont learn if you dont fail. I am not a cookie cutter individual. What part of the proccess have I left out for you? It is in work and a living post. But, I guess you made your mind up before the end…

You sir do seem to have a chip off the shoulder.

My impression is that what Kubotafreak is doing becomes a short term VS long term question.

Could be that by doing what Kubotafreak is doing he might prolong the operation of the engine for a while. How long is the question, as compared to a traditional rebuild. AND how much time and money is saved for that increased period of use.

I assume, but do not know, that eventually the engine could be rebuilt in the traditional manner. What is the probability of this? Is this a reasonable assumption?

Almost looks like it turns into a "pay me now, or pay me later" scenario.

 

[foobert]

I wonder how many of the naysayers here have actually cut open a used oil filter and really inspected it? Ever held a magnet under the unfolded pleats and seen the oil "dance" a little in the reflection? The oil filter is not there just in case a little external dirt finds it's way into the oil -- it's there because even a perfectly healthy engine sheds metal and any bits that are larger than the oil-film thickness cause a cascade of greater shedding.

Regardless how careful you are there is a chance of error which can be expensive.

Of course, this is self evidently true and absolutely irrefutable. In fact, it seams to be a philosophy that some people live by. <sarcasm> It's best to cower in fear of messing up than to try anything new. </sarcasm>

I thought OP laid it out very reasonably that this method was clearly going against convention and had justifiable reasons for doing so.

The level of sanctimonious reactions to this thread is astounding.

But, the implicit character attacks -- wow, I'm really glad some of you folks are NOT my neighbors.

 

[Henro]

The level of sanctimonious reactions to this thread is astounding.

Wow! I sure have a way to go to get beyond my four letter vocabulary!

LOL

 

[RCW]

I enjoy the dialog, and challenge.

For or against, I've certainly enjoyed the dialogue, and learned a lot.

Personally, I appreciate kubotafreak sharing this project.

After seeing his posts over the last few years, he seems to be quite savvy with Kubota tractors, and very helpful on OTT. He's not guessing when he offers help.

I've never honed a cylinder. Know the processes, more or less. Never knew there were different types of hones...

If Fordtech would ever show me how to do those memes or gifs or whatever those things are, I would have done the "Eating Popcorn"-type thing to just watch the dissertations......

Many of us seem to have two interpretations of a project...My way and the wrong way....

I'm no different for certain subjects. A few years ago, a member ticked me off big-time about a simple chainsaw repair....I used bad words to him/her, and some stuff was deleted by NIW.....

It was my way or the wrong way...(by the way, my way was right....)

 

[Deleted member 47704]

In the good old days there were boring machines for boring flat head Fords that bolted to the deck and allowed reboring in the frame, but the pistons had to be removed.

 

[kubotafreak]

My impression is that what Kubotafreak is doing becomes a short term VS long term question.

Could be that by doing what Kubotafreak is doing he might prolong the operation of the engine for a while. How long is the question, as compared to a traditional rebuild. AND how much time and money is saved for that increased period of use.

I assume, but do not know, that eventually the engine could be rebuilt in the traditional manner. What is the probability of this? Is this a reasonable assumption?

Almost looks like it turns into a "pay me now, or pay me later" scenario.

Henro,
I believe your response is a very logical summation. You are correct that at any time the engine can be “fully” rebuilt if this type of repair fails, or does not produce the level of results wanted. Your loss would then be time, and a gasket or two.

I find the removal/cleanup of a cylinder head to be one of the major lines of effort, next to the lower end. Keep in mind that if the cylinders still dont seat well, that all the effort redoing the cylinder head was not lost.
The magic question of how long, or how good the “fix” is, really depends on the starting point. The actual measured dimensions. The amount of time/cost willing to impart on the candidate. This small tractor I'm using as an example cost me $200. Its not a newer tractor, or higher hp build like my ford lightning, or vette. This engine I know succumbed to a non existent oil change schedule. I believe it was never changed… The oil on this model is supposed to be changed every 50-75 hr. It has 4xx hr on the clock still ticking on, so no foul play suspected. The in/ex passages were completely clogged with oily soot. The valve stem seals were hard as a rock, and spun around. The convection flow only cooling system didn't help either. But to my surprise, it measured out almost build spec. So if this works, it will be more than adequate. I will be happy if i can be in service spec. I will hypothetically save $400-600 in parts, as well as time.

 

[kubotafreak]

RCW,
I love that you brought up chainsaws. Bet some have never seen someone sand, or chemically melt seized aluminum off the jug. Its like someone designed, there might be a chance in a chainsaws life it will be run dry. Almost like it was made to be rebuilt. A Nickasil cylinder is amazing stuff!

 

[RCW]

RCW,
I love that you brought up chainsaws. Bet some have never seen someone sand, or chemically melt seized aluminum off the jug. Its like someone designed, there might be a chance in a chainsaws life it will be run dry. Almost like it was made to be rebuilt. A Nickasil cylinder is amazing stuff!

This subject was a simple oiler line leak on a little modern Stihl. Bought it that way used. A $14 part (almost theft for that 3" tube) fixed it all. Common with many Stihl saws.

As the oil line was leaking, the saw was covered in oil and all the sawdust that sticks to bar oil.... real simple stuff.

I was admonished for the "poor" condition of my saw, it was trashed, and needed new sprocket, bar, chain, etc.

I blew up...