Engine Break-In RPM

[robertm]

I've had several tractors and never saw the "do not exceed 2500rpm in the first 50 hours" notice. Have you all observed this? Granted, I'm not working the tractor hard, only mowing.

For years and many, many trucks, I drive them off the lot, hit the interstate, and pegged the cruise at 68 for a six hour ride home, never varying speed and rpm advised by the manufacturer... With no problems on any with over 85k to 120k each. Again, not really working the engine... Unloaded.

 

[David_Kb7uns]

The Super Mini's in the BX tractors run at 3000RPM at full throttle which is fast for a diesel. Best not to lug at idle and not go to full throttle and vary RPM until the rings seat in and everything else settles in.

Kubota knows their engines well and you can either have a 5000 hour engine if treated correctly or you can have 1200 hour failure, it is up to how the engine is treated and serviced. Have 4 Kubota engines, and other than a design flaw on one hydraulic pump drive holder, have had no problems with over 2100 hours between all.

David

 

[robertm]

The Super Mini's in the BX tractors run at 3000RPM at full throttle which is fast for a diesel. Best not to lug at idle and not go to full throttle and vary RPM until the rings seat in and everything else settles in. Kubota knows their engines well and you can either have a 5000 hour engine if treated correctly or you can have 1200 hour failure, it is up to how the engine is treated and serviced. Have 4 Kubota engines, and other than a design flaw on one hydraulic pump drive holder, have had no problems with over 2100 hours between all. David

Great point! Thank you.

 

[MHarryE]

This is on a Kubota? Surprising. So many jobs require full engine speed on diesels. All 3 of the machines for which I was design responsible during my career had 2 engine speeds - high idle and low idle. Fifty hours at low idle to break in an engine before going to work? Incredible. Think also of a generator - we need to run 50 Hz AC for the first 50 hours to break in the engine before we step up to 60 Hz.

 

[oosik]

My Kubota OP manual lists no specific procedures for break in of the engine. However - it does list two specific procedures to always be followed - don't lug the engine and don't put the engine under full load until its up to operating temperature.

 

[brown40]

I always operate under the assumption that a new engine gets handled with kids gloves until the first oil change is under its belt--especially with avoiding settling into a steady rpm and letting it go. I don't go over 1/2 throttle until its warm, I don't exceed 80-85% WOT, and new or old--lugging is always bad. I don't know any engine I have has experienced WOT except pushmowers, weedwhackers and chainsaws. I don't know if its made any difference, but I've never had one consume oil taking the time--could be luck, but I'll keep doing it.

 

[David_Kb7uns]

Same here no problems and no oil consumption between changes on the Kubotas.

I have never thought that wide open throttle on any new engine was good.

Did take the 2005 Dodge RAM Cummins 5.9 about 30,000 miles until everything got seated in and started getting better mileage.

David

 

[buickanddeere]

Break in is much over rated. Just don't idle it, don't run it cold , don't do short start stop putting around jobs and don't lug it.

 

[bdhsfz6]

The manual for the new MX5800 simply states "Do not operate the tractor at full speed for the first 50 hours." I'm not sure what "full speed" means but the manuals for my previous 3 Kubotas had similar statements. The exception was the B7100 HST which did recommend keeping the RPM under 2500 for the first 50 hours. I remember it made for slow going while mowing with the Woods RM59 3 pt mower.

The maintenance manager at the dealer is a bit conservative and makes a verbal 2500 RPM / 50 hour recommendation to all his compact tractor customers.

IMO, common sense says to take it easy on any new machine.

 

[oldballs]

I'm in the "kid gloves" camp for the first 50 hours. I like to run it for awhile at the lower to higher rpms ( up and down the rpm range) and then let it get back to the ambient temp before running again. Have done it on all my trucks, cars and small tractors. .....don't know if it made any difference, but never had an engine failure during my possession, and I keep them until.....almost forever.

 

[PHILIP8N]

The Super Mini's in the BX tractors run at 3000RPM at full throttle which is fast for a diesel.

David

3000 rpm is not fast for a diesel engine that only has a 2.90" stroke Think mean piston speed. Philip.

 

[mjw357]

Run easy till it's warmed up, then use it.

 

[sandyc]

If you have a tractor that has to regen that will mean that it has to go wot in order to maintain the heat needed to burn the crud out of the filter. If you do a parked regen the computer runs the RPm's at wot in violation of the manuals instructions.

 

[David_Kb7uns]

3000 rpm is not fast for a diesel engine that only has a 2.90" stroke Think mean piston speed. Philip.

Some versions are governed at 3600RPM, John Deere has made an issue of the faster speeds in marketing their tractors against Kubota.

David

 

[PHILIP8N]

Some versions are governed at 3600RPM, John Deere has made an issue of the faster speeds in marketing their tractors against Kubota.

David

OK, still, 3000 rpm is not fast for a diesel engine that only has a stoke of 2.90", think mean piston speed. You said it, not me Kubota Super Mini series engines are rated for continuous duty at 3600 rpm, I would think mainly for gen-set applications. Anytime you can run an engine at a slower speed within its operating range it will generally last longer, but you also get less horsepower, which means larger engine (more cost) or a turbo charger (more cost and higher cylinder pressures) to do the same job. I bought a Kubota over a John Deere because I wanted a larger naturally aspirated 4 cylinder engine over a 3 cylinder turbo charged engine, even though my Kubota's rated horsepower was 100 rpm higher than the Deere. I still think I won Philip.

 

[CADplans]

The JD dealer in Richmond VA had a dyno. This was in the 1970's,,
For any machine that they sold that they knew was to be used for light duty,,, they would put it on the dyno @ 80% of max HP rating for 8 hours.
There was a tractor out back screaming many times when we went for parts.

I asked about the procedure.
The service manager told me they had too many old guys buy a 70HP tractor, tale it home, pull a hay rake for the first week, then have engine problems.

He said this was almost a sure fire cure for those early engine problems.

My BIL purchased many dozens of new tractors. When new, ALL the tractors were parked until they could be put in the field doing heavy work.

He had great success with tractors, but, he was a fanatic about clean fuel, and scheduled oil changes.