I was interested in this discussion on another post but did not want to hijack the topic.
It would seem logical as engines have developed over time and tolerances decreased, the 'running in period' should have also decreased.
Have the manufacturies change their instructions over time?
I have followed the instructions running in three motors this year. (two 2 stroke and one 4 stroke). All were 10 hours.
What is the running in period for diesels ?
If you consider a motor vehicle where the manufacturer might specify a running in period of 10,000 klms. At 100 klms/hour this equates to 100 hours of running.
Therefore a running in period of 100 hours for a marine diesel would seem to be appropriate.
Select to expand quotecisco said..
If you consider a motor vehicle where the manufacturer might specify a running in period of 10,000 klms. At 100 klms/hour this equates to 100 hours of running.
Therefore a running in period of 100 hours for a marine diesel would seem to be appropriate.
I spent around 25 years working in Toyota and various other dealerships I can't remember any actual running in period specified by Toyota or the others but just to drive it as you normally would
I would contact the manufacturer of the engine in question and see what they say
Regards Don
A modern engine that has been manufactured by CNC machinery to exacting tolerances doesn't need any special running in period, in fact it's important that you cycle the engine through its full operating range, but never allow the engine to labour.
Running in was something you had to do when engines were hand fitted with a much wider range of tolerances and you needed to 'bed' all the components. eg. hand honed cylinder bores would all have been at variance from one another by a few thousands of an inch and this is where running in becomes important, the tighter cylinders needs to work their way into balance with the more loose cylinders.
It's also well to remember that besides the advances in metallurgy the corresponding advances in lubrication qualities all help to ensure that your engine if looked after and serviced will last longer than an engine built 50 years ago. Remember those days, when an engine with barely 30,000 miles on it had to be rebuilt whereas now it not uncommon for an engine to have in excess of 200,000km on it and still be running fine.
Hand fitted engines should still be run in for reasons mentioned above.
Select to expand quotecisco said..
If you consider a motor vehicle where the manufacturer might specify a running in period of 10,000 klms. At 100 klms/hour this equates to 100 hours of running.
Therefore a running in period of 100 hours for a marine diesel would seem to be appropriate.
I would be talking with Kubota about that. Diesel engines love "load".
If you nurse that engine you will surely glaze the bores. This "running in" idea/proceedure is not generally relevant today.
Engine manufacturers have figured it out and no longer make engines to the size tolerances that require a "running in" period. They deliver engines "ready for work".
You are "allowed" to run the engine at whatever load capacity you "choose". Of course running it as the manufacturer recommends is recommended for warranty purposes.
Cisco, I am having a little difficulty reconciling these two statements of your's, which do you think is actually more appropriate here? 
My experience with the Beta I've just fitted is that the handbook that came with it advises not revving
past 2500 rpm for 25 hours. Mechanic Sandy, who aligned it for me reckons " be kind to it" for 20 hours.
The engines max revs are 3600, so it seems there's a good percentage of revs not to use for a few hours.
From my Yanmar manual:
A new Yanmar diesel engine must be operated at suitable speeds and power settings during the break in period to make the sliding parts, such as piston rings, break in properly and to stabilize engine combustion. During the break-in period, the engine coolant temperature gauge should be monitored, temperature should be between 71? - 87?C (160? - 190?F). During the first 10 hours of operation, the engine should be run at maximum rpm minus 400 - 500 rpm (approximately 60 - 70% of load) most of the time. This will ensure the sliding parts break-in properly. During this period, avoid operating at maximum engine speed and load to avoid damaging or scoring sliding parts. NOTICE: Do not operate at WOT (wide open throttle) for more than a minute at a time during the first 10 hours of operation. Do not operate the engine at low idle or at low speed and light load for more than 30 minutes at a time. Since unburned fuel and engine oil will adhere to the piston rings when operating at low speeds for long periods, this will interfere with proper movement of the rings and the lube oil consumption may increase. Low idle speed does not allow break-in of sliding parts. If operating engine at low speed and light load, you must race the engine to clean the carbon from the cylinders and fuel injection valve.
Perform this procedure in open waters: ? With the clutch in NEUTRAL, accelerate from the low speed position to the high speed position briefly. ? Repeat this process five times. Once past the initial 10 hours until 50 hours, the engine should be used over its full operating range, with special emphasis on running at relatively high power settings. This is not the time for an extended cruise at idle or low speed. The boat should be run at maximum speed minus 400 rpm most of the time (approximately 70% load), with a 10 minute run at maximum minus 200 rpm (approximately 80% load) every 30 minutes and a 4-5 minute period of operation at WOT (wide open throttle) once each 30 minutes. During this period, be sure not to operate your engine at low speed and light load for more than 30 minutes. If operating engine at low speed and light load by necessity, just after the low idle operation, be sure to race the engine.
Even now, every time before shutting down, I always give it 5 full range revs in neutral to burn off carbon from the cylinders and injectors.
Select to expand quoteUncleBob said..
Cisco, I am having a little difficulty reconciling these two statements of your's, which do you think is actually more appropriate here?
Which two statements? I made seven. 
Select to expand quotecisco said..UncleBob said..
Cisco, I am having a little difficulty reconciling these two statements of your's, which do you think is actually more appropriate here?
Which two statements? I made seven.
Ah, mabee the two quoted. 
The advice I got when I installed my new beta 25 was pretty much " take it for a run increasing the revs by 500 rpm every 5 mins then when you reach 2500 flat stick it for one minute , then use as you normally would . Or something to that effect. I will let you know if that's correct in a couple of thousand hours
Ok Bob, you win. 
Hey oldboy, two thousand hours is 10,000 miles in a yacht at 5 knots. Near circumnavigate the Island of Oz with that!!
I reckon your and samstudy's engines will out live most of us in this room.
When I installed a new three cylinder Kubota generating plant into my fishing vessel many years ago I filled it with oil and coolant and pressed the starter. Engine started and then run at 1500 rpm for 17,000 hours. There would have been different loads on the engine but it always run at 1500 rpm. There was no running in specified in the workshop manual or handbook.
I agree with oldboyracer's routine and would add that the correct oil be used for the first fill. Having the rings bed in properly is important with new engines and rebuilt engines. Stick with the manufacturers recommendations and don't go higher.
I agree newer engines are not so critical, but I still do it.
My running in of the Volvo Penta was drive it normally, ie: just use it for its intended purpose with no aberrations such as excessively long periods in idle or flat out etc.
Its pretty much common sense Sam, don't run it for 50 hours on the dock in idle, nor do you want to run it flat out for the same period. Just let the engine experience its normal working loads without any excessive extreme periods.
The only real critical part for my run in phase was to religiously adhere to the first service (50 hours) and that is mainly for the oil change. It's a new engine, you want an engine oil flush/filters to get rid of any contaminants, and the first service is that chance.
Advice is sourced from a few diesel mechanics, I'm surrounded by them!
Cheers mate,
SB
