Repair ? or do a total rebuild ?

[Kabota]

I am buying a L1801DT with a cracked head and 1100 hours on a working tach. Engine was sucking water from the head and blowing it out the exhaust and was hard to start. Oil is black so no water (anti freeze) getting into crank case.
Previous owner had a friend who worked at a Kubota dealership so he looked at the tractor (being gray market the tractor is not allowed to be serviced or repaired at a Kubota dealership). The liners are not pitted but one liner worn more than the other... in fact one cylinder worn .030 more than the other. The Kubota dealer employee said that this wear is what you would expect on a tractor with 1100 hours and he thought that just putting on a new head was a reasonable solution.

Sooooo what do you think .... should I pay $500 for a complete rebuild kit or should I just repair this engine. Tractor will be used to farm one acre of specialty crops and for occasional loader work and snow removal. I am 65 and in good health and plan to keep farming for at least 10 more years.

Also down the road if I need to sell rebuilt at 1100 hours would make the tractor more valuable. I doubt I would be putting more than 100 or so hours per year on this tractor.

So if you had this tractor ... what would you do .... repair or rebuild ?

 

[Fordtech86]

.030 wear on one cylinder and not the other, and “kubota” mechanic says put a head on it and roll? You must be buying pieces of a tractor if it’s torn apart enough to know one hole worn more then the other.

 

[Fordtech86]

And a cylinder head doesn’t have anything to do with cylinder bore wear

 

[Kabota]

The man who is selling the tractor bought it only knowing that it was hard to start.... so he took off the head and discovered it was cracked so he bought a new head... he was thinking he might just go ahead and rebuild it and then he had this dealership employee look at it and he measured the wear and said that if he owned it he would not rebuild because the wear was what you would expect on a 2 cylinder engine with 1100 hours.

The cracked would not have anything to do with cylinder wear unless maybe water inside cylinder would cause pitting..... and there is no pitting.

The man I am buying this tractor from intended to totally restore it inside and out .... just because that is the way he is .... he has a few rare very small cars that he restored inside and out .... he is what you would call a perfectionist. Reason he is selling is he lives in the city and the city would not allow him to put an addition on his garage for the tractor because it would be too close the his neighbors property line and then in the meantime he developed and is currently being treated for prostate cancer.... so he decided he had better sell it.

So I was was just asking for advice ... should I rebuild or repair

.... and no.... the tractor is not split and in pieces.... just has head removed. and still has loader on it.

 

[Fordtech86]

I’m sure wolfman and other tractor experts be around to chime in,but having one cylinder with that much more wear then the other isn’t good, yes the head could have cause the wear on one cylinder if it was cracked and washing it out but just putting a head on it isn’t going to fix it. Rebuild will be in store.

 

[Beaudeane]

Rebuild. Then good to go 10 years easily I’d think at 100 hours a year use

 

[North Idaho Wolfman]

.030 is a ton of wear on one cylinder, Its never going to start and or run right,
I would do a complete rebuild with new liners, pistons, and bearings.
Also consider new glow plugs and injectors.
I would also throw a new clutch, pressure plate, throwout bearing, and pilot bearing in there while you have it apart!

 

[CobraTom]

I agree with wolf.
I also guarantee that tach is not working with .030 of wear, or someone does not know how to measure the bore correctly.

Years ago when I was young and stupid (still, stupid, just old now), I was rebuilding my Honda single cylinder ATV and accidentally purchased the wrong piston after assuming the motor was never bored or rebuilt before, it most certainly was and .020 difference between the right piston vs the smaller one was enough to pivot the piston in the cylinder on the rings. That is a lot of play and you would hear some piston slap.

 

[D2Cat]

Tom, that's a good point. The OP should measure the cylinder for himself before proceeding too far.

 

[Kabota]

Well I am not a diesel mechanic
(but I did sleep at a Holiday Inn Express !!!)

Well the thickness of a sheet of newspaper is about .003 or three thou,
so thirty thou would be thickness of ten sheets of news paper...

If the bore is actually .030 difference then there is .015 more worn off of the side wall of the worn cylinder ... or the thickness of 5 sheets of newspaper.

I am not so good at measuring bores.... I can read calipers and micrometers accurately. So I will have a friend help me measure the wear in each cylinder.

As for 1100 hours.... the tractor has a bushhog quick attach loader which a previous owner installed..... there is no wear on the loader cutting edges and there is zero play in the steering sector..... so I see a possibility that the actual hours could be 1100.... except that someone indicated that .030 wear would indicate more hours.

QUESTION : would water vapor in a cylinder affect lubrication of that cylinder ?????

 

[Kabota]

Well maybe that dealership employee is the delivery man aka gofer.... like gofer this or gofer that

 

[Kabota]

Well before going any further I think I need to verify the wear.

And you all have made good points .... now that I think of it...

I have a bit of Kohler engine experience and over bore kits come in .010, .020 and .030 oversizes

SOOOOOOOOOOO Wolfman you must be right .... if .030 is verified then that is a ton of wear.

 

[North Idaho Wolfman]

QUESTION : would water vapor in a cylinder affect lubrication of that cylinder ?????

Most definitely!

 

[torch]

Like others have said: 0.030" is a LOT of wear. And I can guarantee it won't be evenly worn -- a cylinder with that much wear will be out of round and/or tapered top to bottom. I would also expect a massive ring ridge at the top of the cylinder.

On the other hand, if the mechanic actually said it was 0.03 millimeters, then I wouldn't worry too much. (Given that the tractor specs are actually metric, this is a reasonable possibility.) In that case, slap a head on it and see how it goes.

If you have a friend that can help measure the bore, then great. OTOH, it doesn't take a lot of skill to measure 0.030" difference. If your friend can't make it, buy a set of telescoping bore gauges. Even a cheap Chinese set will be good enough for this application.

 

[Kabota]

Ahhh...well ...... hmmmmmmmmmm

I called the man selling the tractor to me..... seems there was a lot of communication over the short 30 minutes that I shared with him when I inspected and agreed to buy the tractor.

So the information must have gotten scrambled in my mind after I left there...

Sooooo

The seller knew a man who worked at a Kubota dealership but this man did not examine the tractor. The seller knew another man who had a transmission shop and also repaired other equipment like hydraulic pumps or equipment that had sleeves. This man had a son who worked for him and this son also rebuilt some Kubotas on the side (at his home) .... so it was the son who examined this Kubota and concluded that it was not necessary to do a total rebuild ????

The wear somehow turns out to be .010 to .020 and not .030.........
Seems like a lot and I know you all will be advising to rebuild so ..... I will rebuild.

The head is pitted more on the cracked side but also some pitting on the other side and they believed there was some cross leakage through the head gasket.

I will have the old head and send some pics in a week.

The seller of this tractor bought it not running. The owner previous to him said it was using water and hard to start but they kept using it till it got so it would not start.

The man I bought tractor from has a theory that originally the head gasket started leaking and water level would drop and they would add cold water to the running tractor and maybe that caused the head to crack ????????

So sorry about the misinformation. I drove 3 hours to look at this tractor and my mind got overloaded as I was simultaneously inspecting the tractor while listing to him explain what he did. I prefer to take another knowledgeable person when tractor buying but I was first to answer the CL add and there were 25 others who responded to the ad that day so I had to move on it quickly.

BTW tractor is equipped with a Bush Hog brand quick attach loader with wobble stick control valve and the loader its self would be worth what I am paying for the tractoir with attached loader..... So I think I got a deal
(paying $1475 for this rig and includes newer tires still showing nubs)

 

[torch]

I think, given the confusion and chain of potential misinformation, you would be well advised to take your own measurements.

That said, I would guess that the wear limit is probably something like 0.005", so if the current info is accurate then yes, it's time for a re-build.

You have the tractor in your possession? The head is off? Can you feel a ring ridge with your finger?

 

[Kabota]

Thanks torch.... Today is Sunday and the tractor is coming home next Saturday so until then no new information or pictures.

But I am inclined to rebuild at this point....

So the next question I have is to decide how much of the rebuild I can do with the skills that I have. I do have neighbors who farm and rebuild their own tractors and so I can lean on them for help or otherwise if I am getting over my head then I will split the tractor and give the engine to a qualified person. My engine skills are limited. Once I bought a John Deere 2 cylinder vintage gas tractor. It was using oil so I tore it down and discovered the rings were stuck so I measured the wear on the cylinders and a decided to hone and put in new rings. The connecting rods were on babbit bearings so I used plastic gauge to measure the clearance and dropped some shims to bring it back into tolerance. I used feeler gauges to adjust valves and had the head done in a local shop. Put it all back together torquing the bolts. I also do the same with small engines ....usually Kohler brand K series.

Sooooooooo my skill and experience is limited and so should I attempt to do this rebuild ? With me I always have more time and less money so I tend to do what I can mechanically to keep pickups and tractors running... and I am not too afraid to take on this rebuild unless others convince me otherwise.

Also might mention that I have a metal lathe and series 1 Bridgeport milling machine... not that I would need to use these machines in the rebuild but I just decided to mention this to ya. I have taken some machining night classes at local tech schools. So I use calipers and micrometers.... I have a machinists tool box full of tools.

 

[torch]

I won't attempt to say if you have the skill to rebuild your tractor. Clearly you don't have experience, but nobody does when they first start. People with experience got it by doing -- and making mistakes in the process!

I will say that honing is not the same as boring. If the cylinder is out of round or tapered, then it needs a rebore to bring it back into true. Honing will not correct the shape of the cylinder, it just follows the existing surface. Honing is done to prepare that surface for new rings.

The Bridgeport is of course the ideal tool for reboring. Coupled with a boring head and the appropriate metrology -- internal micrometer set such as a Starrett 124 set or telescoping gauges such as the Starrett S229 set. I know last night I suggested a cheap Chinese set might be OK, but that was for rough verification. If you are assembling a home machine shop and plan to do precision work in the future, then the difference is significant and worth the extra money. Keep an eye on eBay. If you are patient you can still find good deals on quality equipment.

In the meantime, if you are still taking the classes, maybe you could bring in your block for a re-bore using their tools and expert assistance?

 

[Jim L.]

At age 65 you should do everything to this tractor to keep it running for 10 years.

It will become a chore at age 70, and at age 75 you won't feel like messing with it.

 

[D2Cat]

So what happens when one turns 80? Does he need to do additional work to it now to make it there?