Oil Change I(~ 15 KVA) nterval

[Flywest]

Hi Guys.

I am running a small 4 cyl lister petters air cooled genset (~ 15 KVA)on an island as our power supply - have been doing so for couple years now, and it has 20,000 hours on it.

We do oil & filter changes with Castrol CS6 every 250 hours (10 days continuous) running.

Does that seem like a reasonable oil change interval to you guys?

It's just that when I did a rough mental exercise - same engine in a vehicle traveling 100 kph on the highway for 250 hours - I get 25,000kms per oil change which seems a bit long without sub micron bypass filtering and UOA's etc!

(Most diesel vehicle manufacturers since 1994 at least suggest 10,000 Km change intervals and prior to API 4 oils before 1994 it was commonly every 5000 km's).

So I guess a stationery engine rated at maybe 80% of capacity operating as a genset can go longer than a equivalent vehicle engine between oil changes huh? 2.5 - 5 times as long?

Reason I am asking is - I have a new 4 cyl Diesel water cooled Perkins gen-set (40 KVA) just arrived that is due to commission tomorrow or next day, and have no idea what oil change interval to work on?.

Anyone know the answer to these mysteries?

Cheers and thanks in advance.

 

[deeter16317]

Cummins and Cat are a 250 hour change in some HD equipment IIRC...

15000 miles/55mph = 272 hours...this is a typical OCI for a Cummins-powered Dodge truck.

 

[Doug Hillary]

Hi,
Flywest - There are a number of reasons for the variance!
Constant speed running and load being but two

Over many years I was involved in the development of refrigeration systems in the Transport Industry - both here in OZ and with ThermoKing in the US. Part of the development process was developing an auto stop/start system - this was dependent on a number of operating criteria
Starting with Benz engines and working thru Isuzu and on to Yanmar and Kubota one thing became obvious - constant speed/load and the use of a suitable lubricant ensures that at least the maunfacturer's OCIs were always accurate (and very conservative)!

So, starting with a 250hr OCI (with Interstate trucks in OZ the average speed is 80kmh)and using UOAs we eventually got to 2000hr OCIs. This was using a suitable synthetic lubricant!
2000hrs of course equals 160 000kms but really constant speed engine are MUCH easier on their lubricants than road vehicles
The maximum we allowed an engine to go to was 3500hrs without an oil change and the oil was still servicable - maintenance management processes detrmined that we settle for the conservative 2000hrs across the board

Finally we settled on UOAs at 500hrs, 1000hrs and 1500hrs. The next was at 1750 as a lead in to the planned OC at/around 2000hrs
We did a mid point filter change on some engine families

I settled on this practice on a wide range of engines (Onan, Kubota, Isuzu, Benz) and we had engine life way beyond 20000hrs in most cases. Many Isuzu engines were good for 30000hrs (2.4m kms)! There were/are around 150 engines in the mix!

The synthetic lubricants used were/are Castrol's 10w-60 and Delvac 1 5w-40

The reduction in running costs from the 250hr OCI to the 2000hr OCI was enormous!

I hope this is of some assistance
Regards
Doug

 

[Flywest]

Thanks Doug,

Thats enormously useful information, so thank you ever so kindly!

Anyone had experience specifically with the 4 cyl Perkins diesel in a stationery engine environment such as genset as to Oil Change Interval?

I am thinking with our extremes of temp (48C yesterday - thats 118+f)... that Castrol 10 W 60 Synthetic would be the ducks nuts!

Cheers!

 

[Doug Hillary]

Hi,
Flywest - Castrol's 10w-60 should have a suitable diesel rating (SM/CF) and I would be doing a UOA at 150hrs to see whta it is like and stage the next UOA from that point. 10w-60 may be a little too viscous but it is a great lubricant - and cheap in OZ too!
If using the likes of Delvac 1 5w-40 I would do the first UOA at 200hrs as this lubricant tolerates soot and high operating temperatures better than most other diesel specific lubricants

Soot may be an issue but I found that on extended OCIs with diesels the soot and iron levels reached condemnation levels at around the same time. I never experienced any issues with TAN.
I always obtained both TAN & TBN at each UOA. I always used 25% of the virgin TBN as a baseline in small diesel engines

Regards
Doug
Regards
Doug

 

[Lawrence Richards]

25% of the first TBN. Did you ever get acid #s higher than the TBN on that schedule? I always like a TBN to be at least twice the Acid #. Any smaller gap and I like to get it out. I have a 95 Chevy Kodiak with the Cat in it.

 

[Doug Hillary]

Hi,
Lawrence - A quick summary of my UOA database (on my heavy diesel engines - high Interstate utilisation) shows TBN (D4739)readings as this;

Highest TAN 7.7 & lowest TBN 2 (Delvac 1 @ 100kkms - 62k miles)
One reading was TAN 6.7 & TBN 0.3 (Delvac 1 @ 105kkms - 65k miles)- suspected wrong reading. This engine was later "tear-down" inspected at 1.2m kms (745k miles) and all parts were reusable with excellent "hone" patterns on all liners

Average numbers at oil change point all engines(Delvac 1);
TAN 6.67, TBN 2.41 (Virgin TBN 11)
Average OC interval all engines = 99kkms (56k miles)

Detroit Diesel's limits for these engines is;
TBN 1 (D4739) or 2 (D2896)

A representative sample on a typical DI diesel Isuzu fridge engine shows this;
Hours on lubricant (Delvac 1) = 2445hrs (196kkms - 121k miles)
TBN = 6.90
TAN = 3.30
Soot = 0.6%
Viscosity = 109cSt (sb 72 to 119)
Iron = 87ppm
Alu = 9ppm
Chrom = 19ppm
Cop = 8ppm
Lead = 4ppm
Sil = 10ppm

In this case the lubricant was changed due to the viscosity increase from new (85Cst)

I hope this is of interest
Regards
Doug

 

[Flywest]

Doug,

The info is enormously helpfull...and not just for the gensets (we have 3 turbo diesel engines in family vehicles all on Delvac 1)

My only issue is price, here in the Pilbara a 20 litre (5 US Gal pail) drum of Delvac 1 last week was $800 smackerooneys..

Back in the city we were getting it trade price at half that!

We have been changing it every 5000kms (one vehicle uses 18 litres and the other 12litres / change).

At that $800/ pail price ($40 a litre) each 5000 kms we are dumping $720 and $480 each worth of oil thats not worn out bye a longshot.

Mobil need to get real about their costs if they are serious about staying in the oil bidness, these prices are ridiculous ludicrous..even.

Yes we COULD go longer OCI's but really just wanted to run the best oil available for the manufacturers recommended OCI.

Converting those costs 5.29US Gallons is costing us $US716.24
Thats $US135.39/Gallon

What would Mobil USA head office say if they KNEW their product is being retailed abroad at those sorts of prices - maybe they would realize why they aren't selling much volume, it's just plain stoopid to gouge customers that way, it creates resentment of the company that could flow on to their other products fuel etc that might lose them a LOT of market share and potentially a whole lot more profits than what they are going to gouge out of some sump oil.

Sorry had to have my rant about Delvac 1, I like it and its s'posed to be good but I am getting weird UOA results back from CAT on two last UOA samples questioning high oxidisation levels of the oil...from the one vehicle.

If the oil is particularly good at resisting oxidisation and I'm getting such high oxidisation levels then whats causing that in a vehicle that APPEARS to be running at normal operating temperatures?

Cheers

 

[Shannow]

Flywest,
Here Delvac 1's $65 for 5 litres. Last I checked a "44" of Delo 400 could be got for a grand.

Cost split is incredible.

 

[Flywest]

Shannow - where is here? $13 / litre is a lot better than $40 / litre.

And yes - I remember! ;o)

Cheers!

 

[sprintman]

I used to buy 20-litre D1 drum for around $200. $800 is wrong. I'll see what my local disty is asking for a drum

 

[Doug Hillary]

Hi,
sprintman - Your D 1 prices are about spot on - between $220 and $285!

Regards
Doug

 

[Shannow]

Flywest, local Repco Garage in Lithgow.

You could probably drive over here, fill up the ute, drive back and still make a profit.

 

[Steve S]

Dougs advice is as usual the way to go.