Oil analysis findings

[Larry]

I am hoping some of you guys with some more diesel experience then me can share your thoughts on this oil analysis, this is on a 1998 48 Ocean with 6V92TAB's w 700 hrs, 625 hp that a buddy of mine (and fellow current Sea Ray owner) is looking at. Some background on this boat, it has sat with the same oil for the last 2 years due to lack of use as the PO was very ill and eventually passing away, but the boat has been Capt maintained by the same Capt for the past 10 years and he says he would fire up the motors periodically but the boat was not really taken out and run hard for almost 2 years, so I don’t know what effect this would have on the oil samples but the Port engine is showing high Iron (301 PPM). What is wearing that the Iron levels are high or could this be from lack of use and old oil? There was a full mechanical inspection from a Detroit mechanic (besides a full hull survey) that spent almost a day on these motors checking everything out, he says that the motors are fine and performed at spec during the sea trial.
Would any of you more experienced diesel guys be concerned with this number??

Thanks!

 

[fwebster]

Ordinarily, a 301 ppm iron reading would be cause for alarm. These are 2 stroke engines and have a relatively short top end life compared to 4 stroke so their iron readings are higher than Cat, Cummins, etc., but normal iron for a 6V92 is less than 125ppm, and anything over 175 ppm is considered critical and needs immediate evaluation. high iron comes from liners, rings pistons wrist pins, etc and can be caused by high operating temps, degredation (old) of the oil, fuel or coolant contamination, stuck or broken rings etc.

However, samples on 2 year old oil, particularly in a boat that has been sitting, are almost worthless.

This is a hypothetical for instance, but remember that the engine crankcases are vented. That air comes from a source very near the sea and it contains some salt (high sodium). Then during the idle periods, suppose some surface corrosion forms on anything metal in the engines. Rust is ferrous oxide which is oxidized iron (high iron). Or, cranking and letting the engines idle extensively with oil moisture contaminated oil causes liner and ring wear.

The only way to make any real sense out of oil sampling on those engines is to service them.....change the oil, oil filters, crankcase filters, etc.....and run the engines under normal loads for about 20-25 hours, then re-sample the oil.

If your friend is a serious buyer, then I would stop the survey process right now and do just that.....make the deal contingent upon re-sampling after the hired captain runs the boat. My bet is that the samples will come back normal since 700 hours is well under the normal time that most Detroit owners get the bad news they need a top end rebuild.

Hope that helps...........

 

[BlewByYou88]

I do an oil analysis on my truck which has the 6.7l Cummins. I do it every 10,000 miles, and change every 20,000. I run good oil and a bypass system.

I checked my last three reports, bare in mine I change basically once a year, I'm averaging about 60-90 PPM.

That oil should be changed!

Do you know what oil was in it? WHen the oil analysis was done they should have a TBN (total Base Number) for the oil that was in it to compare to what the oil was like new.

The fact that the oil is two years old would deffinatley have an effect on the amount of iron in it. Depending on the conditions, how often is periodically run? Rust will start to form on the counter weights and big ends if not run often enough in humid weather. Good Luck!

 

[Larry]

Guys, thanks for the quick and detailed info, this really helped! This boat is very clean and a very good deal ($100K less then all others on the market), if we can get past the oil findings...

 

[paulswagelock]

Without the TBN and TAN numbers, it is hard to say what is going on. Oil sitting for a year or two is fine, in the bottle, but not in an engine that was run for short periods of time. Without getting the oil up to temperature to drive off all the nasties, oil life shortens quickly. A single bad UOA is not always indicative of a problem, a series of bad UOA's would be. I agree with the others, do an oil change, run it for a bit, and re-test.