New owner of Z482 engine.

[dieseldude]

Hello,

I was refer here by someone on another forum who said if I have Kubota questions this is the place to go. I will say right off I'm new to servicing Kubota products but am no stranger to the name, reputation or engines in general (gas or diesel) and mechanical things.

I recently picked a well used (and maybe abused) Z482 at a swap meet. On first sight its missing a lot of parts, thermostat housing, 1 glow plug, dipstick, filler cap to name a few. and to top things off, today I discover the exhaust valve on the number 2 cylinder is leaking. Such a shame to see good machines going to waste. On a more positive note, it cranks well, no binding, both of the injection pumps are working, good oil pressure, and injectors spray (kind of) ok.

As far as the history pf the engine, it supposedly came from a carrier refrigerator unit where the truck was crushed by a tree. Serial numbers put it made in January '06. First question of what I fear to be many, If I invest time and money to get this running again, are the worthwhile and dependable engines?

Thanks for reading.

 

[Kytim]

First off welcome. Secondly, what purpose do you intend to operate this engine for, i.e. what type of service?

 

[dieseldude]

Thank you Kytim.

I'm not 100% sure yet, but thinking about a small (3 - 5 KW) back up generator. If not that maybe a garden tractor repower.

 

[Apogee]

Should be very reliable and would be perfect for that application.

Also fuel efficient.

Good luck,

Steve

 

[dieseldude]

Thanks steve,

Which application were you refering too? The garden tractor or generator?

Dave

 

[Kytim]

I think it would be best for a genset type application being s it was a spec-ed engine for that type of constant run use. I'm not knowledgeable enough to know if it would make a good candidate for tractor work.

 

[dieseldude]

That's sort of the way I was leaning on going. Thanks for the input.

Another question, if no one minds. The fuel circuit. I'm lost as to where the return goes. All the picture and discriptions I have seen show the following:

supply from tank through filter to lift pump.

lift pump to injection pump input.

Here's where I get lost, return from injection pump and injectors tied together and NOT going back to tank??


on a side note, new glow plugs on the way, so maybe get to see if it will start this weekend.

Thanks

 

[Kytim]

From the Inj. pump to injectors then back to the tank s what you need to do.

 

[Apogee]

Hi Dave,

I was also referring to the genset angle. If it was originally spec'd that way, it should be a fairly easy project. You'll be very happy with it in the long run.

Good luck,

Steve

 

[dieseldude]

an update with dissapointing news. Received the new glow plugs today, installed and tried to start, no good. Just cranking away with little puffs of whitish smoke. Also noted as much smoke from the intake and from the oil fill cap (another missing part)

Seems like I'm losing compression, but the thing that has me most concern is that blowby. I guess this weekend I'll be pulling the head back off to see whats going on. I wanted a winter project, well it looks like I got one.

 

[dieseldude]

Quick update

Played around with it a little this morning and though I ran the battery flat. No problem, put on another battery, same thing. On a hunch I took the starter off and checked it in a vice. What do you know it's not spinning up all the way. Opened it up, thoughly cleaned and re lubed it, then installed. When I went to see how it would spin the engine, clack clack clack away it went. It finally fired on it's own, no ether, no WD40, no glow plug power.


Now that I know it will run, I wonder what to do to it next. any suggestions to bring it back to full working order?

 

[aquaforce]

It finally fired on it's own, no ether, no WD40, no glow plug power.

I hope you would NEVER use stuff like either. WD-40 is good for starting up a diesel and under extreme conditions maybe the vapors off a gas soaked rag. Anything more than this is almost a guaranteed damage situation.

Modern production diesels have intake heaters which will cause either to explode if used on those applications.
I don't like either at all !!!!!!!!

White smoke on a diesel also indicates a shortage of fuel in the cylinder.

 

[dieseldude]

I'm sure ether / starting fluid has its place. As for me personally, I don't like it. I have seen first hand the damage it can do. Luckily this was on an engine destine to be scrap anyway.

as for the smoke, I was thinking something fuel related since as of yet it has no cooling system so obviously it can't be coolant related. When it did start it filled my shop pretty quick with dense smoke. I hope this is just from unburnt residue from previous attempts to start, Though I do know as a fact the nozzles could use replacing, but that's down the road.

 

[dieseldude]

a question arose today that has me confused. Why would an injector not be firing / opening? I had my 482 running for a few minutes today, then suddenly it started missing then died. Re-bled the fuel lines thinking air, no good. Pulled the injector and put on the pop tester, one bad as ever (new nozzles on the way, bad spray pattern and leaking), one not opening at all even at almost double pressure.

It's not a real big issue as I plane to rebuild both anyway, but it does peak my curiosity.

 

[aquaforce]

a question arose today that has me confused. Why would an injector not be firing / opening? I had my 482 running for a few minutes today, then suddenly it started missing then died. Re-bled the fuel lines thinking air, no good. Pulled the injector and put on the pop tester, one bad as ever (new nozzles on the way, bad spray pattern and leaking), one not opening at all even at almost double pressure.

It's not a real big issue as I plane to rebuild both anyway, but it does peak my curiosity.

That no fuel condition would explain the white smoke.
Sudden no fire... rust in injector? An injector tear down would tell the story.

 

[dieseldude]

Might see this weekend if the new nozzles come in. Rust in the injector, I never though of that. Thanks for the tip. I'll keep me eyes open for specs of anything when tearing them down. Will also assemble in clean fresh fuel.

I also read somewhere about coating the nozzle retainer with a thin layer of anit-seize after getting the pressure adjusted so it can be open again in the future, good idea or not?

 

[aquaforce]

Might see this weekend if the new nozzles come in. Rust in the injector, I never though of that. Thanks for the tip. I'll keep me eyes open for specs of anything when tearing them down. Will also assemble in clean fresh fuel.

I also read somewhere about coating the nozzle retainer with a thin layer of anit-seize after getting the pressure adjusted so it can be open again in the future, good idea or not?

If there was any way that the anti-seize would be exposed to the internals of the injector fuel pathway I would not do it. The abrasive nature of anti-seize is not well enough represented by some of the biggest supporters of that stuff. On a machined surface anti-seize will cause wear and if tolerances are involved then wear means failure.

As far as the retainer holding the injector in the head, anti-seize could be beneficial when the engine is going to be in the weather.

 

[dieseldude]

quick update for anyone interested.

installed, adjusted and air bled the new nozzles. Tried to start, no luck. Tracked down to the starter failing by dragging a second time, this time the rear bushing almost worn in two pieces. Made and installed a new brass temporary bushing. What a difference in the way it turns the engine over. Starts much easier with less glow, and cranking time. Still grayish (not as white as before) smoke, good oil pressure around 60ish.

I never noticed until today that the copper gaskets and heat seals are missing from under the injectors. That's probably where my loss of compression is going so needless to say they will be the next items purchased.

Aquaforce:

looked for rust specs..nothing very clean inside. Apparently it had seized the needle in the nozzle. It took vice grips, a vice, and a torch to seperate the two pieces. The new one however moves silky smooth and freely.

 

[aquaforce]

Good. Sounds like progress.

 

[dieseldude]

Well, The last of the parts have been ordered to bring it back to runnable condition. So at the end of next week, I should have the correct overflow pipe, new injector gaskets and heat shields, both water pipes and fuel pump. With word of a possible lay-off coming, this could be something to do for a couple days.

I fear that to get this little kubota to useable condition, I may have to fix a stuck ring, or just re-hone the bores (just enough to remove the glazing) and new rings, head gasket and maybe valve guides. Anyone have any expierence with this level of repair? I have never done honing and rings.

Time will tell