Do L3450s have bad engines?

[SPYDERLK]

After several years and 2000hrs on an L2550 we upgraded my wifes tractor to an L3450 with 1700 hrs bought on eBay. The 3450 engine did not sound good like the one on the 2550 always had thru years of rough treatment. We wanted the greater power on the familiar platform, while retaining the 2 speed PTO dropped from later models, so we bought the 3450 with plans to put the engine right - it sounded like a wrist pin or piston slap, and there was excessive blowby at the breather. The tractor performed acceptably for the 126hrs we used it before putting it in the shop.
It turned out the cylinders were ovaled and tapered - #4 especially. Nothing else seemed amiss. Nevertheless, along with all liners and pistons, the bearings and valves were replaced. The rebuilt engine does not have blowby but still has the same knock/tap quality that put it in the shop. The tap is a good bit quieter, but knowing what this sound turned into in 1700 hrs has me real worried. Does anyone know of problems with the 3450 engines?
Thanks,
larry

 

[rbargeron]

Never heard of chronic engine weakness in specific Kubota models. But there are engines that get damaged by their owners (or prior owners). If running on old contaminated oil, and/or running hot from a fouled radiator screen, the rings/sleeves/piston skirts/bearing shells can give it up. Some engines sound different than others depending on how the fuel is injected. And diesels make a racket anyway. Maybe it's really ok now and all it needs is proper maintenance.
As always, prompt cheerful refund if info is bogus. Take care, Dick B

 

[Leejohn]

I have had a L3010, L3130, have a B7800 and L4240 Kubotas and they all have had the same noise that sounds like 2or3 marbles in a glass jar.jumping around. The best I can tell it's coming from more to the rear then from the front. I ask the dealer's service manager if they new what it was and he said they didn't, but he new what I was talking about. I also had a Johndeere 950 and it didn't do it.
Does anyone else hear the same or I'm going nuts? All the Tractors ran great. Maybe you are hearing what I am?

 

[SPYDERLK]

I have had a L3010, L3130, have a B7800 and L4240 Kubotas and they all have had the same noise that sounds like 2or3 marbles in a glass jar.jumping around. [[[The best I can tell it's coming from more to the rear then from the front.]]] I ask the dealer's service manager if they new what it was and he said they didn't, but he new what I was talking about. I also had a Johndeere 950 and it didn't do it.
Does anyone else hear the same or I'm going nuts? All the Tractors ran great. [[[Maybe you are hearing what I am?]]]

[Maybe.....?] What Im worried about is that the noise in the completely rebuilt L3450 engine sounds just like the horrible sound it made before being rebuilt -- only quieter. The degeneration to the loud hammering didnt happen under my watch so I had been expecting that some abuse caused it and a rebuild would totally fix it. The way it sounds now I can just imagine it happening again. My L2550 has been beat to crap with marginal preventive maintenance and sounds sweet. - I guess Im looking for knowledge of some trouble area in this particular engine model that must be correct, or it beats its cylinder walls up.
larry

 

[rbargeron]

........It turned out the cylinders were ovaled and tapered - #4 especially. Nothing else seemed amiss. Nevertheless, along with all liners and pistons, the bearings and valves were replaced......

In your latest post you mention "hammering" - which makes me think about the crank, not the pistons. Piston slap is a somewhat lighter knocking noise - but a crank that's loose in its main bearings (especially at the flywheel end) can sound like a heavy hammer. Do you know if the crank journals were measured when the engine was worked? Could the crank be egged too - so there's still too much clearance in the main bearing shells? One way to get an indication is to replace the oil pressure switch with a gage and watch how it acts with a warm engine. Bad bearings tend to show changes in oil pressure going from power on (pulling) to power off (compression braking).

 

[MessickFarmEqu]

I can't say we've notice one Kubota engine being better than any other. They are all simply great. That being said, there may have been a reason that tractor was sold, who knows what the history was, or why it was on ebay. Alot of stuff that goes there has questionable backgrounds.

 

[SPYDERLK]

In your latest post you mention "hammering" - which makes me think about the crank, not the pistons. Piston slap is a somewhat lighter knocking noise - but a crank that's loose in its main bearings (especially at the flywheel end) can sound like a heavy hammer. Do you know if the crank journals were measured when the engine was worked?

Thanks for the idea. It was not a heavy knock and also seemed to be up top. Imagine Mighty Mouse inside with an 8 oz ball pein hammer - LOUD violent tapping. I will specifically ask the mechanic about the condition of the main journals. Im expecting he was thorough. He didnt do the liner/piston fitting tho and Im curious as to the clearance set up, esp at the rear. - Also, the liners are quite thin. Im assuming theyre not wet. Wondering whether the bores that they fit in may have been misshapen.
larry

 

[SPYDERLK]

I can't say we've notice one Kubota engine being better than any other. They are all simply great. That being said, there may have been a reason that tractor was sold, who knows what the history was, or why it was on ebay. Alot of stuff that goes there has questionable backgrounds.

I hear ya. After my experience w the 2550 thats what I thot. I figured I would set the 3450 right and have a Kubota engine. The problem is it still sounds wrong in the same way it did before a total rebuild. Just lighter tapping - same exact throttle, speed, related characteristic. It even still taps as it coasts to a stop. Could the block be damaged in some way that is not apparent even with total disassembly?
larry

 

[Baby Grand]

Larry,
You need a control. Any chance you can listen to another 3450 and decide for yourself if it's just typical noise or something that needs tending to?

-Jim

 

[dfkrug]

Thanks for the idea. It was not a heavy knock and also seemed to be up top. Imagine Mighty Mouse inside with an 8 oz ball pein hammer - LOUD violent tapping. I will specifically ask the mechanic about the condition of the main journals. Im expecting he was thorough. He didnt do the liner/piston fitting tho and Im curious as to the clearance set up, esp at the rear. - Also, the liners are quite thin. Im assuming theyre not wet. Wondering whether the bores that they fit in may have been misshapen.
larry

Whether the mechanic miked the journals, or used plastiguage, it requires
more work. Esp the latter measurement, which requires one more assembly/
dissassembly. He prob did not do it.

Anyway, I have not had a Kub diesel apart yet, and I am curious if they
have wet liners. All my Kubota engines have been great (even on ex-rentals),
so I have not had to rebuild one yet. One thing changed around 2000: it
seems all the engines got quieter.