Should I walk away?

[rofish59]

Been in the market for a convertible for awhile and we've finally found one we like at a price we can afford. It's a '84 46c with a galley-up layout. The boat shows great and except for a few minor issues (that I can live with) everything seems to be in good shape. Nothing unexpected on the hull survey or sea trial. The boats 8V71s ran great. Mechanical survey is pending. So far so good.

I got the results of the engine oil analysis yesterday (no comparisons available) and I'm somewhat at a loss in interpreting them.

The starboard engine (1450 hrs) showed an iron level of 59; the port 139 with a recommendation to "monitor" the engine.

The starboard gear's iron level was 83 and again higher on the port side-172.

Should these numbers frighten me? Should I cut my losses and cancel the mechanical survey with these numbers? I realize this is a breezy post and I appreciate any advice you can aim my way.

 

[GJH]

Not sure what trans you have, but DD specs 150 as "max" iron count on 71 series engines and 250 for marine applications. Do you know when oil was last changed on any of these? Are you sure these are "clean" samples?

Doesn't sound like a deal breaker to me; not sure I'd walk away, have your surveyor look at them, check the trans strainer for metal shavings. Hopefully, Karl (Genesis) will pipe in on this as well.

 

[MikeP]

Oil samples are useless unless there is a "history" of them. A single one cannot tell you anything that is of real value for evaluating the engine. Use it, if possible to get a reduction on the price, but I would go by how the engine acts, not on that oil sample.

If there is a series of samples over time that show increasing iron amounts, THAT is useful info. Otherwise, don't even worry about it.

 

[Bugsy]

When my purchase survey showed excess metal, I was advised to change oil and then run engines at varying RPMs for 20 hours and re-do samples. I followed that advice and eliminated engine issues.

Cap'n Ned had some knowledge re oil samples.

 

[SeaEric]

I sold a 2001 boat last spring with 800 hour Cummins QSM-11's in it. The surveyor pulled oil samples, one of which showed major issues. After we had huge (gu)estimates of what may be wrong, we pulled more samples and re-tested. Second time around, everything was fine.

I'm with Mike P. A single test has little value.

 

[Boss Lady]

Detroit Diesel warning levels for iron are 150 PPM.

Your lab needs to use Direct Reading Ferrography to distinguish the ratio of small particles to large particles. This will determine if the iron originates from oxidation (small particles) or wear (large particles).

How many hours of operation on the oil?

The type of fuel will influence the alkaline level of the oil which causes oxidation, higher sulfur fuel will require more frequent oil changes since the it will become acidic quicker.

What viscosity, type and brand of oil has been in the engine?

This is important, using the wrong oil in a Detroit can be hazardous to your pocket book. Detroits are old school and require oil with specific properties. If they have been running multi-viscosity oil I would walk away immediately. With the gear having high iron levels as well, this would be my first conclusion. Multi-weight oils cannot support the film sheer needed for the cam shaft lobes and you get high wear. This cost DD millions in warranty repairs when they experimented with multi-weight oils years ago.

 

[Brian Degulis]

Without knowing any history those #s are witin range. In other words when you do a single oil analysis as part of a survey the only thing that should frighten you is a reading that's way out of spec. You don't have that so based on the oil alone there is no reason to be afraid.

Oil analysis is only use full when there is a history of it. That will show a change or problem before it results in a failure. For a one shot survey analysis you can only go by the specs and even then it's not really telling you very much. If the oil was recently changed then you #s are high. If it hasn't been changed for hundereds of hours your #s aren't high.

I would go ahead with the rest of your survey and base your decision more on that and less on the oil.

Brian

 

[captddis]

Agree with the other posts that nothing alarming. I would pull the screens on the allisons and look for metal if not already done.

 

[Boss Lady]

I would still find out which specific oil has been in the engines and gears.

You need to run the engines to temp and then pull the samples. The filters remove particles larger than 10 microns, so any reading will not show sever wear particles. This is why you need to do ferrography.

One sample is not conclusive, but it can alert you to look closer though.

Oil sampling is treated like voodoo. This is due to general lack of understanding the finer points. It is not a cure all, but is and can be an invaluable tool in the right hands. The quality of the analysis is controlled by the lab technician. You need to have a relationship with one of them to get good information out. They do so many fleet analysis that almost nobody does a good job anymore. If you really want good info you have to get the guy who gives a crap and not the flunky they normally have processing samples. The lab is not going to call you up and tell you that you need to check out a leaking head gasket, unless the numbers shout that a problem exists, everyone uses the gross numbers, looks at a chart and says I don't see any problems, and misses the point of why we do analysis. Over time you can calculate exactly how much wear material and what type it is. Nobody cuts filters apart anymore either, ignorance is bliss. Give your engines the respect they deserve ($50K-$150K each).

Ignore it at your own peril.

P.S. Unless I know exactly what I am buying, I discount the engines considerably in my offer price. That way if you have a problem you can build them and not be upside down on the boat. There are plenty of horror stories about engines. You did not provide any other details on the history, original, supposedly rebuilt, in-frame repair, etc.

 

[Genesis]

Those numbers are high but not ridiculously so.

What do you know about their operating history, when was the oil last changed, and how much have the engines been run since the last change? Total time on the motors and any claimed overhauls? If so, what documentation were you presented on them?

When engines sit you will get oxidation and then gets "scrubbed" and can produce high iron numbers. I presume copper, tin and the rest are ok? No glycol, fuel, water or sodium contamination? How are the soot numbers?

The high reading in the gears are suspicious (as in potentially a BAD READING) as usually problems in Allisons will show high copper or silver (bearings), not iron. It is VERY RARE to see high iron in an Allison if there's no water present or other contaminents. It can happen, but its uncommon. Was the oil in the gears ok color and smell-wise (that is, didn't smell burnt and is not black?) If black its likely contaminated due to a leaking rear main seal. This is not a serious operational issue but its a pain in the butt and VERY EXPENSIVE (like $3k/engine!) to fix - the seal is cheap and changing it once you have access is easy, getting to it is another matter, and most of the time its not worth doing.

How was the viscosity? In range for a 40wt? If there was a multigrade in there that explains it in both cases and it ain't good, but I doubt you did serious damage so long as its changed NOW.

Need more info - I wouldn't run away but I would ask more questions, and I'd pull a second set of samples and use a different lab.

PM me if you want to chat on the phone.

 

[Red Hatt]

Their are some nice 45 Hatts in Near or in Orange Beach Al. I saw several and you can buy them cheap and the ones i saw had rebuilt engines. You might want to take a look a them.

 

[REBrueckner]

Lots of good advice is posted already.

Regarding multiweight oil:
As I have posted before, when I was in Nova Scotia boating in 2002 I vistied aboard a number of commercial boats with DD 71 series engines while awaiting fog to clear....turns out everybody there uses multiweight oil and never gives it a second thought!! I decided to change my own oil since I had plenty of spare time...A big supplier with at least 1500 pails of oil sitting on the floor had just the two pails of straight 40 in stock "Nobody uses straight" here he told me....he almost did not find it....

Regarding oil samples: when I first had my 8V71TI's oil sampled around year 2000 I had a reading for chromium that was not flagged but which was actually out of spec, I found years later. About 2007 I again sampled oil as a routine and this time the chromium was considerably LOWER (after perhaps 1200 hours of running) and by gosh a different lab flagged the level to "monitor".

Also, DD oil standards are apparently set at 150 hour intervals (based on previous threads in this forum). So if your oil was smapled at 300 hours your actual readings mean one thing; if sampled at 100 hours may mean something else. If the former, cut your absolute readings by 50%; if the latter double them for comparisons with DD standards.

Finally, DD oild analysis specs are proprietary...many (most??) labs do not have them but make informed judgements typically based on truck fleet comparisons from experience. Call whatever lab is used and talk with them....The one time I did this I got a wealth of feedback, and posted it here at Sam's...Specs are different from different manufacturers and also four vs two cycle engines....

I've read that multigrade oil can foul DD turbos...sounds like yours are naturals so even with multiweight oil I'd not be concerned about that issue.

 

[Bugsy]

Now I'm worried but my ignorance as to lubricant classifications may be showing. I have DD692s and I am using Rotella T SAE 15W-40 for engines and transmissions. This was actually recommended and is in my manual.

Should I be using straight SAE 40 HD weight?

On our recent trip north, my wife reported that the gear oil on the starboard side was "dark" (after just under 200 hours of daily use) while the port side was "honey coloured). Now you've got me worried that I may have a seal problem developing which I went through on my 48MY.

 

[Genesis]

The issue with multigrade oils is film strength and potential cam damage.

The cam pressures involved due to the unit injector design are quite high and these engines were designed for single-weight partially for this reason. Detroit at one time recommended that 10W oil was "ok" for places with cold temperatures but quickly withdrew that recommendation after a rash of premature failures, and went back to "use block heaters".

There is no reason to run multigrade in a Detroit OTHER THAN cold starting (single grade gets THICK when cold.) The other problem is that multi-grade oils typically have much higher TBN than single-weight and TBN and sulfated ash are opposites - getting one up means living with the other being high, and excessive sulfated ash is bad news in DDs over time (thousands of operating hours) as it fouls exhaust valves on these engines.

Use the right stuff.

 

[Brian Degulis]

Now I'm worried but my ignorance as to lubricant classifications may be showing. I have DD692s and I am using Rotella T SAE 15W-40 for engines and transmissions. This was actually recommended and is in my manual.

Should I be using straight SAE 40 HD weight?

On our recent trip north, my wife reported that the gear oil on the starboard side was "dark" (after just under 200 hours of daily use) while the port side was "honey coloured). Now you've got me worried that I may have a seal problem developing which I went through on my 48MY.

Detroit aproved multi weights then changed back to single weight only. I wouldn't worry about it. Just change it to the correct stuff it's very doubtfull you did any harm.

Here's a link to all the coolant and oil specs http://www.detroitdiesel.com/Suppor...lants/OilFuelFilterBulletin_7SE270_010307.pdf

Brian

 

[TopHattandTails]

I second the above on history of samples. Have your mechanic pop the sleeves and check out the pistons, rings and things on the engine - its easily done. He would be looking for any scoring, etc.. Second, pop the strainer on the tranny's and take a long magnet down to the bottom of the reservoir and see if any metal filings (also check the strainer). You can buy a magnet that unfolds from itsself and looks like a pen at an office supplies store for about $3. The tranny strainer is 3 bolts near the opposite side of the dip stick on the tranny's (outboard side). I usually sample trannys, mains, and genny's at each oil change (for me 1 time a year, before storage). Do the engines smoke on a cold start? What color, how long? How do the mains sound (real american power, or bad timing?). Any obvious oil spills / fuel spills in the bilge and on the lower end of the engines (you will see some oil drips, which if land in water can be a little frightening, but you will notice the difference between a split oil line and a drip from the DD's). Is the RPM turning up to rated power (2350) at WOT?

Good luck.

 

[Walter P]

Dark transmission oil color is an indication of a leaking seal from the engine and you are getting engine oil into the transmission. I've been told that it's a problem that we can live with as long as you change the transmission oil and filter each time you change the engine oil. Since I have a similiar situation, I routinely change oil in both engines, both transmissions and generator at least once each year. I believe the interval is fine since I put on less than 100 hrs yr on them. Besides oil is cheaper than engines and/or transmissions. Of course the best thing would be to replace the seals, but that's a hell of a big job and the cost/benefit ratio doesn't make sense.

Walt

 

[REBrueckner]

"On our recent trip north, my wife reported that the gear oil on the starboard side was "dark" (after just under 200 hours of daily use) while the port side was "honey coloured). Now you've got me worried that I may have a seal problem developing which I went through on my 48MY..."

I second Walters comments...transmission oil should stay the honey color of fresh oil thru it's 500 hours or whatever interval used.

 

[Bugsy]

So....switch to SAE 40 (what am I going to do with my supply of 15W40?) for engine and trannie and change oil in both every 75 to 100 hours (my engine change intervals) and I should be okay. Right?
PS...I'm now boating in Lake Huron and the St. Clair River..well....not NOW but "soon".

(And thx.)

 

[chris piazza]

Bugsy
Where are you going to be on Lake Huron, Just curious, I am up at Bay City, not many HOF'ers up here.

Chris
Superior Nights 53C