Oil change interval

[sailorryan]

We have twin 8v71N in our 67' Hatt 50MY. We typically run at or below hull speed. I am aware there is an increased potential for oil contamination if you run really slow for long periods ( not necessarily going to happen but theoretically could)

I just changed out our oil on our mains and genset and this got me thinking.

I have not seen how many hours between changes, although obviously most of us casual cruisers end up just changing every year. My questions are:

1) Assuming I could put many many hours on in a year (say a trip to Alaska, many hundreds of hours) - how many hours should I be looking for between changes? I cannot find anything here on Sams

2) Has anyone opted going the oil analysis route instead of always changing oil? ie checking the additives / contaminants and changing when needed as opposed to just every X interval?

3) If I was to go oil analysis route and only change it when the sample was getting out of whack, should I just changed the filter when its determined I need to change the oil or change it at a more frequent interval?

 

[RonNP]

I've always been told to change the oil every 100 hours of use.

 

[SKYCHENEY]

I'd say every year or every 200hrs, whichever comes first.

 

[Glory]

Most commercial applications, including marine, call for 250 hours.

In many applications today services happen beyond 500 hours. That is not likely a good idea for two cycle engines, for one the two cycle oil technology is likely at a stand still, no oil manufacturer is in a rush to cater to the needs of an engine design representing a small part of the market. Some where around '92, Roger Penske, Detroit Diesels President, made some changes to the standards guiding two cycle oil formulas. In '92 the two cycle product was still popular in transit, marine and some construction sectors. Today not so much.

100 hours is to soon, I would say so. Many pleasure boat owners don't make 100 hours. So 250 hours might be three years.

The use of analysis to extend oil changes could save some money, on oil, but at what cost. Oil and it's additive package protect your engine. The additives do things like neutralize sulfuric acid, a byproduct of combustion, prevent foaming and others it's not just slippery stuff.

Change the oil, it is not that big a job.

I change my engine oil, oil filter, coolant filter at 250 hours, trans at 500 hours. Fuel filters as pressure and vacuum indicate.

My 2 cents.

 

[captainwjm]

My $.02; change every year; it is some insurance against bigger problems at a relatively small cost. Spin on fuel filters and a check on the status of the impellers at the same time.

 

[sailorryan]

Most commercial applications, including marine, call for 250 hours.

In many applications today services happen beyond 500 hours. That is not likely a good idea for two cycle engines, for one the two cycle oil technology is likely at a stand still, no oil manufacturer is in a rush to cater to the needs of an engine design representing a small part of the market. Some where around '92, Roger Penske, Detroit Diesels President, made some changes to the standards guiding two cycle oil formulas. In '92 the two cycle product was still popular in transit, marine and some construction sectors. Today not so much.

100 hours is to soon, I would say so. Many pleasure boat owners don't make 100 hours. So 250 hours might be three years.

The use of analysis to extend oil changes could save some money, on oil, but at what cost. Oil and it's additive package protect your engine. The additives do things like neutralize sulfuric acid, a byproduct of combustion, prevent foaming and others it's not just slippery stuff.

Change the oil, it is not that big a job.

I change my engine oil, oil filter, coolant filter at 250 hours, trans at 500 hours. Fuel filters as pressure and vacuum indicate.

My 2 cents.

Thanks this helps somewhat. I have no problem changing the oil when at our home port, we have a reverso setup, its pretty easy. I am big on preventative maintenance. However on a long season (say up to 1,000 hours) I was curious from a provisioning standpoint - obviously changing oil lots of time takes up lots of space.

Oil analysis is pretty cheap and has other benefits (like showing what metals etc are present) as well can show most of the additives and what levels they are at. Sulfuric Acid is a bigger issue when running slow (all else being equal) but with the ULSD (at least here in the US) its much less of a deal then it was pre ULSD - assuming your lubricity and other items are ok etc.

Forgetting the other benefits like monitoring metals in your oil, being easier to just mail off then a change, etc, Oil Analysis has a break even at about a 15% increase in hours used on the oil. (Its like $30 per sample). Double how often we change (I just did it at 10 months and ~100 hours) gives me lots of wiggle room on oil analysis =).

I always heard the 12 months or 100 hours rule as well but my gut said it seemed too frequent from an hours point of view for those people who may put a 1000+ hours on their vessel in a year because thats a ton of storage space for provisioning. Most of the local boats heading into Alaska for a prolonged period assume they can't get much but fuel and keep everything aboard. Obviously you would add oil as its used during the normal course of cruising a quart or 2 here and there, but not a full on change.

Delo 100 40 wt - what we all should use in our 71s has a TBN of 7.3 which helps neutralize acids and is much lower then what used to be used in 8v71s. (Note there are 2 methods to measure this that result in different numbers, this is higher then what you might see from a virgin sample sent to an oil analysis shop)

Per Chevron re: TBN and oil change for others who might find it useful-

--How much TBN do we need to protect the engine?
The old rule was to change the engine oil when 50% of thenew oil TBN had been consumed. Because of the virtual absence of fuel sulfur today, much less is needed.Chevron now sets the TBN guidelines for all of its diesel engine oils as follows:

FOR ALL OILS when using ULSD
• Severity 1: 50%-44% of new oil TBN or 3.5 to 4
• Severity 2: 43%-36% of new oil TBN 3 48 to 2.9
• Severity 3: <35% of new oil TBN < 2.8 to 2
• Severity 4: less than 2 <2

Other parameters of engine oil are now more important to engine durability and extended service protectionthan TBN. These are parameters such as oxidation stability, wear control, effective soot dispersancy. ----

 

[SEVEN]

Once a year. Always have always will.

 

[sailorryan]

Once a year. Always have always will.

Regardless of hours? I mean if you do not put many hours on, sure - but if you are putting 1000 hours on you will not change them?

I am looking for 12 months or X hours whichever comes first. What is X?

 

[Avenger]

RTFM! There's a good chance the answer is in there.

 

[bobk]

I have 6V92 TA's at 425 hp each. The Detroit manual says change engine and trans oil at 150 hours, which I have pretty much stuck with over the last 11 years. I typically operate at hull speed, 1000 rpm with the occasional run up to 'blow out the carbon'. Occasionally I have let it go to 180-190 hours and oil analysis always looks good, except the viscosity begins to increase. All else has always been OK. I run 300-400 hours per year. No way would I consider 1000 hour change interval unless I had some sort of extra ordinary filtration and backed it up with analysis. Even then, viscosity is likely to be increasing regardless of filtration methods.

If you are cruising the US, NAPA has a good oil for our engines and most towns have one. I even saw a NAPA in the Bahamas yesterday.

Bobk

 

[sailorryan]

RTFM! There's a good chance the answer is in there.

Thanks for that insight. Ill chalk it up to you not knowing.

I have a manual, its 50 years old. Diesel (ULSD) and Oil (additives/mixes/etc) have changed since it was written.

The point of this forum is to read between the lines of what the manual says and get practical advice from others.

 

[sailorryan]

I have 6V92 TA's at 425 hp each. The Detroit manual says change engine and trans oil at 150 hours, which I have pretty much stuck with over the last 11 years. I typically operate at hull speed, 1000 rpm with the occasional run up to 'blow out the carbon'. Occasionally I have let it go to 180-190 hours and oil analysis always looks good, except the viscosity begins to increase. All else has always been OK. I run 300-400 hours per year. No way would I consider 1000 hour change interval unless I had some sort of extra ordinary filtration and backed it up with analysis. Even then, viscosity is likely to be increasing regardless of filtration methods.

If you are cruising the US, NAPA has a good oil for our engines and most towns have one. I even saw a NAPA in the Bahamas yesterday.

Bobk

Thanks Bobk - I have read over many of your past comments regarding oil changes (like don't fill to fill) but could not find an hour related comment that was semi recent. That's why I posted this.

I would never run 1000 hours between changes, just trying to figure out from a provisioning standpoint how many changes to account for in a long cruising season. Most people just say 12 months but that assumes they don't put many hours on.

If I was running in an area with "high" sulphur diesel (compared to ULSD) I would obviously need to change it more often relatively speaking, sulphuric acid and all.

I could not find for the life of me hour recommendation for our 2 strokes that took into account ULSD and the relatively new formulation for Delo 100 and then stated a recommended hourly change interval. It all predated that by considerable time, if you have a source I would love to know where you get yours from so I could read it myself as well.

Re: Analysis - that is extremely helpful. That all else being equal - watch/measure viscosity as well so that it does not increase too much.

Re: Filters - For the mains oil we use Baldwin B95s, For the tranny we use Baldwin BT 274s, and for fuel we have dual Racors with a secondary of a Baldwin 5810 I believe (off the top of my head, not at the boat atm).

 

[SKYCHENEY]

If you want to extend intervals, put on some bypass filtration

 

[bobk]

If you want to extend intervals, put on some bypass filtration

X2. Check out the web page for Gulf Coast Filters. They have a good reputation. Interestingly they describe a truck with a Detroit that reached 1,000,000 miles with just one 'unnecessary' oil change. No mention of viscosity change. I wonder if their subject oil is more stable than the NAPA Valvoline?

Bobk

 

[Glory]

Thanks this helps somewhat. I have no problem changing the oil when at our home port, we have a reverso setup, its pretty easy. I am big on preventative maintenance. However on a long season (say up to 1,000 hours) I was curious from a provisioning standpoint - obviously changing oil lots of time takes up lots of space.

Oil analysis is pretty cheap and has other benefits (like showing what metals etc are present) as well can show most of the additives and what levels they are at. Sulfuric Acid is a bigger issue when running slow (all else being equal) but with the ULSD (at least here in the US) its much less of a deal then it was pre ULSD - assuming your lubricity and other items are ok etc.

Forgetting the other benefits like monitoring metals in your oil, being easier to just mail off then a change, etc, Oil Analysis has a break even at about a 15% increase in hours used on the oil. (Its like $30 per sample). Double how often we change (I just did it at 10 months and ~100 hours) gives me lots of wiggle room on oil analysis =).

I always heard the 12 months or 100 hours rule as well but my gut said it seemed too frequent from an hours point of view for those people who may put a 1000+ hours on their vessel in a year because thats a ton of storage space for provisioning. Most of the local boats heading into Alaska for a prolonged period assume they can't get much but fuel and keep everything aboard. Obviously you would add oil as its used during the normal course of cruising a quart or 2 here and there, but not a full on change.

Delo 100 40 wt - what we all should use in our 71s has a TBN of 7.3 which helps neutralize acids and is much lower then what used to be used in 8v71s. (Note there are 2 methods to measure this that result in different numbers, this is higher then what you might see from a virgin sample sent to an oil analysis shop)

Per Chevron re: TBN and oil change for others who might find it useful-

--How much TBN do we need to protect the engine?
The old rule was to change the engine oil when 50% of thenew oil TBN had been consumed. Because of the virtual absence of fuel sulfur today, much less is needed.Chevron now sets the TBN guidelines for all of its diesel engine oils as follows:

FOR ALL OILS when using ULSD
• Severity 1: 50%-44% of new oil TBN or 3.5 to 4
• Severity 2: 43%-36% of new oil TBN 3 48 to 2.9
• Severity 3: <35% of new oil TBN < 2.8 to 2
• Severity 4: less than 2 <2

Other parameters of engine oil are now more important to engine durability and extended service protectionthan TBN. These are parameters such as oxidation stability, wear control, effective soot dispersancy. ----

I pretty sure where you fuel up you will be able to by oil. And for a fee dis guard waste oil. You will not get a great deal, but you will get it.

 

[sailorryan]

X2. Check out the web page for Gulf Coast Filters. They have a good reputation. Interestingly they describe a truck with a Detroit that reached 1,000,000 miles with just one 'unnecessary' oil change. No mention of viscosity change. I wonder if their subject oil is more stable than the NAPA Valvoline?

Bobk

Lots of help from both you guys re: bypass. Curious what pricing is, I called and left message. Do you guys have one?

Interesting enough - on their website they specifically mention how often to change an 8v71 without their filter. -- 250 hours, unless you are burning more oil then normal and consistently add new then its longer.

http://www.gulfcoastfilters.com/Frequent%20Questions.htm#9

 

[krush]

Why not get some data before coming up with crazy ideas. Do oil analysis...blackstone is a good/fair price one.

If I ran my boat every day...or nonstop, I'd definitely go 500+ hours before oil change. I run synthetic, though. Changing it so often is a waste of money if it isn't needed....and the lab will tell you if the oil is still good. Do a sample every 100hrs.

 

[bobk]

Why not get some data before coming up with crazy ideas. Do oil analysis...blackstone is a good/fair price one.

If I ran my boat every day...or nonstop, I'd definitely go 500+ hours before oil change. I run synthetic, though. Changing it so often is a waste of money if it isn't needed....and the lab will tell you if the oil is still good. Do a sample every 100hrs.

Krush,

I thought synthetic was a no-no for two stroke Detroits??

Sailorryan,

I do not run Gulf Coast filters. Simply change the Dinosaur oil as described.

Bobk

 

[jim rosenthal]

Krush has 4 stroke Cummins. Which synthetic are you using? I am using Mobilgard SHC 1, I think it's called, in mine.

 

[krush]

Krush,
I thought synthetic was a no-no for two stroke Detroits??

Krush has 4 stroke Cummins. Which synthetic are you using? I am using Mobilgard SHC 1, I think it's called, in mine.

I usually run Rotella T6. Easily available from walfart.

rSmith has been running synthetic for like 30 years in his detroits.