New engine Installation.

JohnnyD · Feb 10, 2003

Getting ready to put a new engine in my 1998 B-21 with approx 2450 hours. Low compression, alot of blow-by, very difficult/impossible to start when cold and begining to see loss of power under load. Since I cant do the rebuild itself due to lack of time and experience, I had two local dealers price the job. Both were in the $3000 + tax range with doing everything. However, I can mail order a new (not remanufactured) engine (complete includes injection pump, injectors, water pump, clutch, flywheel...) for $3200 which includes shipping. Of course, I have to due the swap myself. The servive manuel does not look like the job is as straight forward as the last 69 Camaro it did 20 years ago! Any advice would be apprecitated. Thanks, John

JATO_RaT · Feb 10, 2003

Hard to imagine it being that difficult. Not being familiar with the B-21 I would still not be afraid of tackling it myself.

Hoeman00 · Feb 10, 2003

2500 hrs doesn't seem like the old motor should be worn out.
It may pay to tear down and see what happened,could be
a single cylinder or head trouble.
If u wanted to save money pull the old motor out and
take it to dealer or another rebuilder to do the work.
U get the <font color="red">fun</font> of pulling and installing.
A new motor may be the way to go if machine is in good
shape and u plan on keeping for a while.

littlediesel · Feb 10, 2003

I would consider this a low hour engine. I know of many Kubota engines with over 4500 hours and no rebuild. Are you sure that those are the right hours? How did you care for the engine? What oil, how often? You should not need a rebuild at 2500 hours!!!!

Jon

JATO_RaT · Feb 10, 2003

I would think the number one reason for early engine failure when the obvious reasons are complied with (oil in the engine) would have to be allowing dirty air into the intake. That doesn't mean installing a new and/or cleaning the air filter frequently, in fact, that can be in itself the cause of it. You really need to pay extra attention when removing an air filter(s) on a tractor. Its easy to let small amounts of dirt into the intake manifold unintentionally. This will easily wear the cylinders. As hard as the little diesels on tractors work, the loss in power is noticeable quickly.

DK35vince · Feb 10, 2003

I agree with Rat,
If low compression at those hours my bet would be dirt getting in the intake.
Rings don't last long if dirt gets through the intake.
I would look over all the intake hoses and clamps for leaks,cracks,or a hole rubbed through.
Hate to see the same thing happen to the new motor !

kubmech · Feb 10, 2003

Hey John, I know alot of guys don't like to hear it but, I have rebuilt/replaced more than a few Kubota engines at the 2000-3000 hour mark. Before you tear in to yours take a look at a few things, to prevent your new engine from suffering the same fate; Pull the rubber intake hose where it attaches to the intake manifold, take a look inside the hose, run your finger around the inside, do you notice dust or dirt build-up? Do the same with the inside of the manifold. If you see build up/does'nt take much. You have verified the cause of the failure and your cylinder walls are most likely "dusted". Inspect the intake hose connections and the hose itself, check for proper air filter element (there is two different ones).
Another way to verify dirt contamination is to take a look at the intake valve faces (go ahead and pull the head, you have nothing to lose at this point) If there is a noticeable groove in the faces this also indicates dirt contamination. With the head off, you can inspect each cylinder and see what condition they are in. If they are darkish grey with no or little cross hatch and a noticeable ridge at the top, this also indicates dirt ingestion. If you see staining, uneven wear patterns such as some cross hatch on the side of the cyl walls adjacent to the piston pins, this indicates overheating and or excessive engine lugging. Alot of carbon build up with some cross hatch still showing and it may have been overfueling. If you remove the pistons and find cracked rings and ringlands, that is a sure sign of ether use. Now depending on the condition of the cyl's and pistons a re-ring just may be the way to go, I have had good luck with honing a good cross hatch back into the cyl's Maybe removing .0001 or .0002 out and installing new std. rings. Kubota engines tend to have quite a bit of meat in them before hitting overbore size. Replace the connecting rod bearings, do a valve job, test injectors, clean flush and pressure test radiator (do this one no matter what) re-assemble and it 's good to go.....This can usually be done with the engine still in the machine which is a big plus labor wise.
However the price you got for a new engine sounds real fair, if it comes with new injection pump, injectors, starter, water pump etc. If you are going to tackle the engine replacement. Have a good place to dissasemble it, I would highly recommend a good half inch air gun with a good compresser, 17mm. 3/4or19mm, 7/8, and 15/16 swivel impact sockets for getting all the blasted subframe and loader frame peices off. Check the hyd pump drive out good for partial sheering, take a good look at the clutch and flywheel, be patient and if it helps, take pictures along the way, 'cause you're gonna have a heck of a pile of parts halfway through. When re-assembling the frame pieces, keep EVERYTHING loose till all the bolts are back in, then apply down pressure on the loader on a level surface, lifting the front wheels off the ground while tightening everything back up as far as the frame pieces go. Good luck however you go, and as always, we are here to help you through it........................

JATO_RaT · Feb 10, 2003

Hey man, are we lucky or what to have Kubmech here? My vote goes to Kubmech, MVP of TBN! /forums/images/graemlins/grin.gif Rat...

JohnnyD · Feb 10, 2003

Thanks for the great replys. My local dealer stated that the "pattern" of compression loss - measured values = #2 - 100 psi, #1 or 3 (cant remember exact order) approx. 300 psi, and remaining cylinder approx. 400 psi are charactoristic of a "dusted engine" as several of you guys have suggested. I bought the tractor about 10 months ago with only about 100 hrs less on it. Yes, it did have some blow-by, but I was told that although this was a sign of some internal wear, overall the engine was still pretty strong and probably would last a while before it eventually needed rebuild/replacement. The rest of the tractor was and still is in great shape. Thus, at the time, the $12,000 for a TLB did not seem to bad. Over the 100 hrs this past year that I put on it, despite getting the best and most frequent maintainece the tractor has had its entire life, it progressively began to deteriorate both in engine performance and cold weather starting. (hence some earlier posts on "cold starting problems back in Oct/Nov). I quickly inspected the engine when I got the tractor back from the dealer today and have not been able to find a definitive source of dirt entry. However, the gasket on the inside rear of the air cleaner housing looked dirty as if there is not a good seal between the primary element and the gasket. Over the next day or two I will pull the hose between the cleaner and the intake just to confirm what I allready know. As far as actually pulling the motor, most of my questions revolve around things like frame removal, how to support it, removal and supporting FEL. Should the ballast be removed from the rear tires before removing them to make them more easily managed. The questions go on and on. .......As far as tearing down the existing engine and rebuilding it, there is a time and definitly knowledge issue if trying to do it myself. Plus the new engine at $3200 includes a new injection pump, injectors, water pump, clutch, etc - alot of parts that I probably would not opt to replace if I choose to rebuild the existing engine. If nothing else, Ill gain alot of pease of mind.

Thanks. Keep the suggestions, questions and advise coming! John