Oil Filter Change Interval

[Dockhead]

Originally Posted by Wotname

More thread drift
Why do you hold this view?

Because no one designs engines specifically for sailboats. Yanmar engines are used in tractors, other land-based equipment, and in fishing boats and motor boats. Those are the primary uses, and these uses are similar -- many hours in a short period of time, much use at 70% to 80% power, etc., etc. 100 hours a month or more -- even 200 hours as month -- is usual for some of these uses.

Our use pattern is very different from this, and many sailors don't even put on 100 hours a year; many not even 50 hours a year, in fact. Besides that, most of us almost never run at as much as 70% of full power; typical sailboat use may be 30% or even less.

[Panope]

I am in the "Dry start is not an issue" camp. I believe that it is the viscosity (thickness) of the oil that prevents metal to metal contact. The oil that is present on bearings and other parts does not immediately disapear when oil pressure is zero. Also consider that one of the highest loaded (in terms of psi) components in a four stroke engine is the camshaft lobes - a component that by nature of its shape (and the shape of the tappets), cannot be lubricated with pressurized oil.

Steve

[Hudson Force]

Originally Posted by Panope

I am in the "Dry start is not an issue" camp. I believe that it is the viscosity (thickness) of the oil that prevents metal to metal contact. .................. Steve

I'd like to stand in this camp with Steve and it causes me to speculate about my best practice, I have 6,562 hours & 25 minutes on my Yanmar. I don't have this figure from reading an engine log. I have this because I've written down every start time and stop time in my engine log and kept an accumulative count since the installation of my engine 14 years ago.

Do I have more "dry" starts because I run my engine for a half hour every week even at times when I am not underway and cruising?

....or.... Do I have fewer "dry" starts because I run my engine every week and the viscosity of the oil leaves me with a coating for every start?

I'm not going to claim to know which answer best describes my condition, but I do observe that my oil remains a fairly clear amber color when I change it every 200 hours and it's not black like I often see among some others.

I'm only one data source, but some compulsive behavior allows for some accurate observation.

[Stu Jackson]

If you think about it, you have a dry start every time you start your engine.

The advice to use the engine stop lever or solenoid has great merit if you are concerned about this. I'm not, and we have 2,830 engine hours on a 1986 Universal M25. Our oil filter is side mounted, so no real way to fill it up before installation. There's always some oil inside, as mentioned.

[sailorboy1]

way too much worry about nothing, have any idea how many starts a car engine must have after 10 years .............................. I don't but I bet is a lot more than a sailboat's

[Hudson Force]

Originally Posted by sailorboy1

way too much worry about nothing, have any idea how many starts a car engine must have after 10 years .............................. I don't but I bet is a lot more than a sailboat's

....and what is the typical time interval between car starts and sailboat engine starts? I'd say most cars start twice a day and most sailboat engines may start as much as once every two months.

This factor has relevance to the oil coating of the critical moving parts.

[Wotname]

Originally Posted by Stu Jackson

If you think about it, you have a dry start every time you start your engine........

I guess I have a different idea of what a "dry start" is...

To my mind, a dry start is time running the engine with no oil pressure. When I start my Yanmar normally, I have oil pressure within moments say less than a second. It is almost simultaneous with the start.

However after an oil and filter change, oil pressure is not developed for about 5 or more seconds. This is when I have a concern as the engine has started and running with no oil pressure for that time. This is why I like to develop oil pressure after a filter change by turning the engine over with the decompression levers pulled until oil pressure is obtained.

Yes there is residual oil in the bearings etc but no pressure...

[sailorboy1]

Originally Posted by Hudson Force

....and what is the typical time interval between car starts and sailboat engine starts? I'd say most cars start twice a day and most sailboat engines may start as much as once every two months.

This factor has relevance to the oil coating of the critical moving parts.

Just how long do you figure oil just stays put? My vote is for something like 3 seconds after turning off the engine as that is about how it takes for the low pressure alarm to come on.

BTW - I would say on average my car starts at least 12 times a day.

[Stu Jackson]

Originally Posted by Hudson Force

....and what is the typical time interval between car starts and sailboat engine starts? I'd say most cars start twice a day and most sailboat engines may start as much as once every two months.

This factor has relevance to the oil coating of the critical moving parts.

Ever leave your car at the airport for week-long business trip? Or at home when you go on a vacation?

[Glenn.Brooks]

Don't forget to change your transmission fluid when you change your engine oil. Transmissions are often overlooked for years as the drain plug and fill plug are usually buried behind the engine in impossible to get at places. But It is important to run with clean tranny fluid if you want to preserve the life of the pressure cones, shifting plates, and bearings etc inside the transmission- as I recently learned the hard way.



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[F51]

"Dry Start?" Phhhtt! You do warm the engine up before draining the oil, right? So your oil pressure was up just before you drained the oil, right? I have disassembled engines that have not seen oil pressure for years. The bearings still have oil on them. No way I am believing that the 5-10 seconds before oil pressure comes up after oil and filter changes means the bearings are dry.

[Dockhead]

Originally Posted by Hudson Force

I'd like to stand in this camp with Steve and it causes me to speculate about my best practice, I have 6,562 hours & 25 minutes on my Yanmar. I don't have this figure from reading an engine log. I have this because I've written down every start time and stop time in my engine log and kept an accumulative count since the installation of my engine 14 years ago.

Do I have more "dry" starts because I run my engine for a half hour every week even at times when I am not underway and cruising?

....or.... Do I have fewer "dry" starts because I run my engine every week and the viscosity of the oil leaves me with a coating for every start?

I'm not going to claim to know which answer best describes my condition, but I do observe that my oil remains a fairly clear amber color when I change it every 200 hours and it's not black like I often see among some others.

I'm only one data source, but some compulsive behavior allows for some accurate observation.

Of course running your engine every week leaves it with more oil in the moving parts, than would be the case if you let it sitting for a month or more, as many of us do. I think there's no question about that.

It's not a "dry start" when you just crank up your engine. A dry start is when you have an empty oil filter and the enginer runs for a number of seconds without oil pressure.

[evm1024]

I'll toss in my 2 pence. I send a sample of my oil off for analysis at every oil change. I use blackstone here in the usa. Knowing the specifics of my oil is not quite as important as knowing the history of the oil.

Regards

[Hudson Force]

Originally Posted by sailorboy1

Just how long do you figure oil just stays put? My vote is for something like 3 seconds after turning off the engine as that is about how it takes for the low pressure alarm to come on.

BTW - I would say on average my car starts at least 12 times a day.

Dockhead and Wotname have specified a definition for "dry start" as that brief time of running without oil pressure. Sailorboy1, above, also is suggesting that when the sensor alarm sounds at the loss of pressure means that the oil has not "stayed put".

It seems that the question is, does oil pressure always corelate to oil prescence? Among close fitting parts, even less vicous water would remain by capillary action. Certainly oil is present at the start before pressure, but the pressue would be required to move and replace the oil. If the oil does not move then heat would soon vaporize this oil.

So, it seems to me, that the question is, how long does residual oil protect moving parts on a cold starting engine before oil pressure moves more oil among these parts?

I am aware that my horizontal fit filter is not pre-filled at first start after an oil change; however, my low oil pressure alarm sounds for less than one second at start. Of course the location of the sensor can make this less meaningful.

Please notice that I'm not suggesting an answer to these questions, but I am attempting to better identify the questions.

PS: I can't answer that question about how often I leave my car in places like an airport lot without starting. We're fulltime liveaboard cruisers and have not owned a car in well over a decade, , but I understand your point!

[ontherocks83]

My memory is a little foggy but if I remember correctly from when I was going to school to be an A&P (aircraft mechanic) there is an allowable amount of time to see a lack of oil pressure when starting a piston engine on small planes (i.e. 4 or 6 cylinder Cessna's and the like)

When starting the engine you watch the oil pressure gauge and start counting to 10. If by the time you get to 10 you do not see oil pressure you immediately shut down the engine and investigate. I had one instructor forget to put oil in a plane, started it and by the time he got to 8 remembered he forgot to put in the oil and shut it down. Because he stayed under the allotted amount of time he did not have to send the engine out for inspection.

My point in all of this is if an airplane engine which is very heavily regulated and monitored has that kind of allowance on start up, your engine after an oil change will be just fine.