Synthetic oil in genset

[Mike in GA]

I have a Powertech 10kw generator which came with straight 30 weight oil. I ran it that way for the first 10 years. About 6 years ago I switched to Rotella T6 full synthetic.
       Here's my question. The factory recommended interval change on the straight weight oil is 100 hours. My gut tells me that on full synthetic I ought to get double that before needing to change, but I thought I'd come to the Forum and see what the masses say.
       Any thoughts?
Mike in GA

[Geoff]

Just check how dark the oil is at 100 hours.  I run 15w-40 in my Isuzu generator @ 100 hr changes, but it holds 2 gallons and is dark when changed.  I run syn in my pickup and go 7500 miles but it stays fairly clean.  You should not have run 30wt unless it was for diesel engines.

[buswarrior]

With our modern high tech oils, it isn't so much the oil, the issue with extended drain intervals is filtration.

Getting the dirt out is key.

At what point during the cycle does the filter give up and bypass everything?
For the high milers, it is common to do a filter change and make up the loss at the half life.

And quality filters, not the box store cheapies...

Oil analysis is your guide to extending. Anything else is blind?

Your guiding thought: Oil is cheaper than a rebuild?

happy coaching!
buswarrior

[Geoff]

Good news.  Walmart Supertech oil filters are made by Wix.  And no, they are not cheap knock-offs.  Google the question.

[buswarrior]

Careful, made by WIX to walmart's price point.

I wouldn't put my name on them either...?

Run 'em, see how soon, or how long, before the fresh oil starts carrying colour/dirt.

Use a different one everyoil change, save 'em up and then cut 'em open and compare notes with the amount of material inside.

And then buy your preferred manufacturer by the case from the supplier to save some retail cash.

Size for a past auto, the cheapy Defender line go on sale for $1.75 a piece at the wholesaler,total crap, luberfiner were $6 at the same time. Store shelf prices quad and triple.

I am partial to Amsoil, WIX, Donaldson and Luberfiner, Baldwin when I get stuck. Absolutely NO Fram thank you.

Happy coaching!
Buswarrior

[belfert]

Diesel oil is going to start looking black after just a few hours of use no matter what filter is used.

I use Bosch premium filters on the small diesel engines in my riding mower and diesel generator.  I use WIX for my car.  My bus is whatever the bus garage uses.

[chessie4905]

Trouble is, is that mfg., because of competition, or improving the bottom line, can change the efficiency of any oil filter at any time. You could see if they offer a larger filter with more capacity for that engine. Otherwise, if you extend oil change hours, and are concerned, change filter halfway through interval.

[luvrbus]

This so easy all you need to do is pull a oil sample send it in and the sample will tell you how long you can run the oil,? what engine is in the Powertech didn't the Cat call for straight 30 w on some of those small engines 

[Geoff]

I reread the original post, and see Mike has already been running full synthetic oil for 6 years and changing it every 100 hours.  So, Mike, does the oil look black or not?  Black/brown indicates combustion particles that the 20 micron oil filter won't pick up.  You can do an oil analysis that will tell you how the oil is holding up, but it would cost you as much as an oil change.

[Mike in GA]

Thanks Geoff. Yes the synthetic oil does look black around 100 hours, but I presumed that all oil used in diesel engines goes black quite quickly, and that is not a reflection of its useful lubricity.
     I had thought about sending off a sample, but that costs about the same as a jug of synthetic for my 4 cylinder Kubota powered PowerTech.
      Thanks everyone for the input. The irony I see is that the diesel generators that run the refrigeration units on reefer trucks are screaming 24/7 for weeks and weeks at a time and that's probably a thousand hours instead of 100. Go figure.
Mike in Georgia

[luvrbus]

The refer vans are 500 hour oil change but they have a different filtering system they have 2 filters the standard and a by pass,the Lubefinder by pass filter does keep the oil clean 

[chessie4905]

You can get an idea of how dirty or soot saturation level is by putting a drop in your finger, and lightly rub between thumb and finger. Then wipe off with rag. If it comes off and finger and thumb are relatively clean, the oil is good yet. If it stains, it's saturated with soot and should be changed Feel the lubricity when you lightly rub thumb and finger. When it is soot saturated it doesn't feel slippery. You may think I'm crazy, but I noticed this from years working on Olds diesels. The oil in them quickly became soot saturated, especially in 1980 models, when they recirculated some exhaust back through engine to reduce nox numbers. Check your shortly after changing, then down the road, then right before you change it. Excess idling will mess this up, as fuel dilution will make soot in oil less likely to stain, but oil will be less slippery feeling.

[DoubleEagle]

       The irony I see is that the diesel generators that run the refrigeration units on reefer trucks are screaming 24/7 for weeks and weeks at a time and that's probably a thousand hours instead of 100. Go figure.
Mike in Georgia

Not really, the reefer units cycle on and off as needed, just ask any trucker that is parked next to one when they are trying to sleep. 

[buswarrior]

The size of the oil sump is EVERYTHING.

Bigger the sump, longer the drain interval.

Truck engines have big sumps and long drain intervals. Bus engines have shallow pans, much shorter oil change interval.

Same can happen for aux power units, generators, Reefers, etc.

For fun, see if a bigger oil pan is available for your particular engine, andwhether you can accomodate it?

Then you can brag/complain about howmuch oil it takes to change the oul?

Happy coaching!
Buswarrior

[Geoff]

You can get an idea of how dirty or soot saturation level is by putting a drop in your finger, and lightly rub between thumb and finger. Then wipe off with rag. If it comes off and finger and thumb are relatively clean, the oil is good yet. If it stains, it's saturated with soot and should be changed Feel the lubricity when you lightly rub thumb and finger. When it is soot saturated it doesn't feel slippery. You may think I'm crazy, but I noticed this from years working on Olds diesels. The oil in them quickly became soot saturated, especially in 1980 models, when they recirculated some exhaust back through engine to reduce nox numbers. Check your shortly after changing, then down the road, then right before you change it. Excess idling will mess this up, as fuel dilution will make soot in oil less likely to stain, but oil will be less slippery feeling.

I agree, and would like to add that when the oil is so dirty it stains your skin it means the oil is past its point of being able to hold contaminants and is basically wearing out your engine.  If full synthetic oil gets black in 100 hours you might as well run 15w-40 diesel oil.  I think the syn oil is great for the newest engines, but no better for older engines that don't run as clean.  Also, personal testing of T-6 vs 15w-40 dino oil with lab analysis shows the viscosity of the T-6 breaks down sooner than 15w-40 oil in identical 50 hour tests.