Anything wrong with rebuilding?

[Yetii]

Thanks A64. To the OP, I don't know if you have done an engine rebuild before. It was a little intimidating my first time, but definitely not rocket surgery. I agree with Zee, do a rebuild! Not only will you save money, but you will know your engine much better.

[jimbunyard]

Or you could order the parts from a tractor outfit and do it yourself...

KU19200 D950 Kubota Engine Overhaul Kit---Standard Pistons with Liners


Includes: Pistons & Rings, Liners (Sleeves), Wrist Pins, Wrist Pin Bushings
Circlips, Main Bearings, Rod Bearings, Thrust Bearings, All Seals & Gaskets

We will need your bearing sizes to complete this order

Fits: B7200D , B7200E , B7200HST-D , B7200HST-E , B8200D
B8200HST-D , B8200E , B8200HST-E , B1750D B1750E , B1750HST-D
B1750HST-E , B20 F2000 , F2100 , F2100E , KH41 , KH61



Total Price: $699.00

[Lepke]

I've rebuilt many engines, mostly bigger diesel, but originally learned on radial aircraft engines. My first diesel overhaul was a Detroit with a manual and I guy I could call on the radio. If you're careful and have a good service manual, any mechanically inclined person should be able to do a good job.
Cranks that never had an oil failure, blown rod, usually are not worn. I've mic'ed several hundred to form this opinion. Your bad cylinder could have cracked rings from too much ether, who knows. But it's a possibility that all you need are new rings and a slight honing to restore the cross hatching. See pic. These are Detroit sleeves. Youtube probably has a video of how to do x-hatching.
With the engine apart, I'd change the bearings. If you want to check clearances there is a product at most autoparts stores called plasti-gauge. It's small plastic pieces that go between the bearing and crank before putting the rod or main cap on. Then torque the rod or main bolts, withdraw the now flattened plastic and compare to printed guide on the package. Probably have the valves done, too.

[GILow]

I'd go the rebuild of the known quantity engine over a swap to an unknown.


Sent from my iPhone using Cruisers Sailing Forum

[MBWhite]

Those Kubota motors are also used in Bobcat skidloaders, the D950 was used in the Bobcat 543. Here's a link to a remanufactured engine:

Reman - Kubota D950 Engine to replace Bobcat OEM 6563734

I suspect there may be some slight differences in manifolds, etc but you might want to ask around and see if there is a local forklift company that might quote you for rebuilding your engine as another option.

[Terra Nova]

Originally Posted by a64pilot

...there is no good reason not to overhaul.
Like everything else if done correctly, it will be better than new...

Though I agree that there's no good reason not to overhaul, it is common knowledge that an overhauled engine is NOT better than (nor equal to) new.

[ozarkshark]

I have been a mechanic since 1974, and now teach engine rebuilding at a local technical college. Nothing wrong with rebuilding an engine if it is done correctly. To help you ask the right questions, think about the following.
First a proper rebuild means a mechanic cleans and measures every piece of the engine, compares those measurements with specifications and then decides if each part can be reused as is, machined to specification, or replaced. You should ask what kind of machining capabilities the shop has or who they sublet those operations to. And next where do they get their replacement parts from, are they OEM quality or they using off brand parts. next what kind of warrenty, and don't be afraid to ask for names of customers, a good shop will have plenty of former customers willing to promote good work. Next ask for a time frame for the job, if they sublet the machine work, that usually drags out the job. I am always concerned when a shop gives an estimate without having the engine apart for inspection. Unless they have x-ray eyes they are giving you a worst case scenario price. Ask what the estimate covers, and what it does not before they start work. For example, new rings in a worn cylinder will raise the compression for a while, new rings in a fresh bore will last many years. Valve guides are another thing I see that some shops don't repair correctly, again a new valve will last much longer if the guide that holds it, is tight compared to loose and will cause oil consumption as well. I usually spend the money and have bronze guides installed they last better than OEM.
I joined the forum to learn more about sailing, but engines I know about.

[Briandownsouth]

All rebuilds are not equal. Some high-end machine shops basically do a 90% remanufacture. The cost came out close to a factory remanufacture but the level of screwing around seemed to be higher. I would go with an outfit like Foleys over having a local shop do the work next time.

Some rebuilds are not much better than what you would do under a coconut tree in Honduras. I would avoid that method, unless of course, you are under a coconut tree in Honduras.

[JOHNMARDALL]

Whatever you do yourself, it will still be an old engine, with another part just getting ready to break or freeze up and let you down. Re-manufactured could be all right, if you thoroughly research the company doing it and if they have a suitable engine in stock, but if you don't want to spend your time being an engine mechanic, I recommend going straight to what will probably be the end of the process anyway, and getting a new engine now. Yanmar and Beta are the companies to talk to for sailboat engines and your main concern should be finding an engine of the required power that fits your engine beds.
Anytime I don't take my own advice and spend time and money repairing old equipment, I end up regretting it, especially fiddling with ancient diesels.
Good luck
John Mardall
Vetus Maxwell Group

[Elie]

A few years ago, I brought a small 2 cyl Yanmar that had a crack(close to the nain fron bearing) to a sort of manufacture that do mainly one thing: Rebuilding large truck diesel engines, and curious a visited the shop, talked to the foreman and looked around. I was amazed to see the process of systematic rebuilding of large V8 Diesels. The dismantle it quickly using powerfull air tools, put all internal part in a bascket that was sent to a cleaning station. Then a specialist checked(mesured) each part and decided to discard, rebuild or take it as is. It was a fast process. Within two hours, crankshaft, block, piston etc where assembled, the cylinder honed, evething was processed using CNC equipement. And the reassembly of the engine would start as soon as all parts where avalable. Very efficient, and the forman told me that they find most of the parts incatalogs (Motors builders just fabricate the block, the gaskets and some special fittings that are specific to their engine. So I was told that a small 4 cyl engine would not cost more than $2k to rebuilt unless crankshaft, camshaft or engine block are really brocken. But the most important is the fact that everything is put back in a perfect and very automatized way. Rebuilding a large V8 diesel cost less then $5k, and often much less!.
You most have rebuider of the same sort in your region. It might be a good idea to pay a visit...

[Matsubob]

REBUILD! Do it yourself. Find a Shop Manual online and download it. You will need a set of socket wrenches, some deep sockets for certain sizes, a torque wrench to use for reassembly, a valve spring compresser, a valve lapping tool, ring compresser, etc.
As a rule, boat engines see a lot less mileage than car engines, therefore, parts that need replacing or attention are generally a result of sitting idle, rather than from running. This is especially true for auxiliary engines on sailing craft.
So unless something traumatic has happened, such as damage from contaminated oil or few or no oil changes, especially on diesel engines, the need for reboring only seldom occurs.
And whether the crank needs to be turned or not can quickly be established by measuring the journals for out of roundness with a micrometer. If they aren't out of round, check clearance with Plastigage to determine whether there is enough wear to warrant changing the rod bearings and main bearings out.
As the engine is disassembled, each part should be marked for which cylinder it came out of, both for later wear analysis as well as better compatibility if it is returned to its original place.
My YANMAR 3GM has two mains that are perfect circles, so must be installed with a press. I prefer having this done at a machine shop to avoid installing them crooked, and at the same time I have the new wrist pin bushings reamed and matched to the piston that it will be installed in.
Because of the low running time, there will be little or no "ridge" on the cylinder walls, so a simple cylinder hone is adequate for cleaning the cylinder up before instaling the newly ringed pistons. The pistons should be closely scrutinized for carbon buildup and the piston lands should be cleaned well before installing new rings. If the engine block has sleeves, and the old sleeves are worn, siimple replacement of the sleeves when the rings are replaced will restore the cylinders to almost new condition)
Take plenty of time for analysis during disassembly, and then follow the instructions closely in the Shop Manual for reassembly, and you will not only be rewarded with a fine rebuilt engine at a fraction of the cost, but you will also be very familiar with your engine should the necessity arise to perform subsequent repairs on it.
Generally, replacing rings, main bearings, rod bearings, wrist pin bushings, all oil seals, valve seals, as well as lapping the valves will produce an engine close to the condition it was in when brand new!
So: why NOT rebuild? (providing parts are available)

[svHyLyte]

Originally Posted by Briandownsouth

All rebuilds are not equal. Some high-end machine shops basically do a 90% remanufacture. The cost came out close to a factory remanufacture but the level of screwing around seemed to be higher. I would go with an outfit like Foleys over having a local shop do the work next time....

Given your limited tenure on this Forum, you are evidently unaware of the poor, if not horrible, reputation of Foley (aka "Dr. Diesel") for mis-information, overcharging, delays, non-deliveries etc. etc. etc. For more on the matter, use the search function, above, and run the name(e).

As for the OP's inquiry, any good tractor shop can rebuild his engine and will likely do so for far less than a "marine" diesel shop but with comparable results.

[Dymaxion]

Suggestion: find a nearby community college that has a diesel mechanics program. See if they will do the rebuild as an exercise if you foot the parts bill and any machining steps. You are on their schedule but once known maybe you can live with it. Biggest part of any rebuild is teardown, cleaning and measuring. Lots of excellent advice in this thread, ignoring the repowering ones. ☺ Your engine sounds like an excellent candidate for a rebuild.

[buzzstar]

carlspackler- please let us know what the final estimated price is. Thanks,

[SouthernPride]

K&K is good but they make more on a straight sale

As well as the complete replacement and install of a new engine. It's also less labor for them if a problem arises after a new install.

Faster for them as well.