I have been lurking for a time and most impressed with quality of posts and information.

I am Service Manager for a pump company in Melbourne Australia, my focus is on the servicing of fixed fire pump installations and most of these units are diesel engines, from some single cyl Lombardini to 6v 92 Detroit and 6CTA Cummins.

These engines accumulate very few total hours but lead a very hard life, they are tested for a nominal 10 minutes per week under no load at maximum horsepower RPM, dead cold to duty revs as quick as they can get there and shut down just as quickly.

Particularly hard on turbochargers, and if long exhaust runs [multistorey buildings] are not adequately drained they will accumulate water in the crankcase.

We service them once a year, and change all fluids and filters with the exception of air filters [every second year].

Last month we bought 1000 litres of Penrite "Pro 15 Plus" [not for the Detroit 2 strokes, Penrite Mono 40 for them].

Given that the application seems suited for a multigrade, and the harsh duty, is there anything we could be doing better?

We get bore glazing and high oil consumption from the high RPM/ no load running which occurs 51 weeks out of 52, where we can pump back to storage tanks we open valves and load up the pumps to cure this, 30 minutes or an hour under load does wonders.

The engines are almost universally heat exchanger cooled, only via the water jacket, very few have oil coolers are fitted.

I think we are doing our best, we religously change oil and filters but quite often come across engines that have not had an oil filter change [and probably an oil change] for 10 yrs or more.

Water contamination of crankcase oil has been known to be sufficient to allow stray current from mains battery chargers to eat the sacrificial anode material out of the main and big end bearings, massive pitting.

Apologies, the Penrite Pro 15 plus is a 15/40 mineral oil.

Tiger,

I am employed at a large opencast coal mine where we utilize the CUMMINS 6CTA, B and C series engines for in-pit pumping operations.

These engines are also started at full revs, under cold conditions, similar to your application. We get approximately 5000 hour service life out of them and the main failures are usually dust / drowning.

The glazing and oil consumption is indicative of top end (piston & liner) wear and cold start-ups. Glasing can lead to fuel dilution and several other associated problems.

I would suggest you consider one of the following;

Fitting a pre-lube system to provide oil pressure to the main oil galleries etc before starting. This system comprise a small oil pump at the back of the starter (your CUMMINS agent should be able to source pre-lube starters) and when the engine is started oil is pumped and as soon as the pressure reach a preset value the starting circuit kicks in. This takes only 5 to 10 seconds out of your starting time.

Fitting a high capacity sump (OEMs have these options available) thereby utilising the oil as additional cooling radiator. It will also assist in reducing / delaying oxidation severity due to the water ingress.

Ensuring that the oil you use is at least API-CH4 compliant or higher.

Air filters is a crucial item and will deplete your oil additives by causing excessive soting etc and put unnecessary strain on the whole air induction system - turbo chargers etc. Consider fitting a vacuum gauge indicator on the suction line immediatelly after the air filter, this will indicate air filter blockage and you can rather change the filter on-condition rather than on a calendar based schedule.

Some OEMs and aftermarket suppliers sell what is commonly refered to as "Turbo Protectors". These devices accummulate a sufficient volume of oil and when the engine shuts down gravitational flow provide lube to the turbo during the crucial period.

Consider running the engines at slightly reduced revs during the testing, until operating temperature is reached, and then ram it up to full rpm.

If you have a problem to get to all the engines and some are "skipped" with regard to drains contact your OEM and enquire about the CUMMINS Centinel system. This system works on the principle of burning "used oil" and sweetening the sump with lube from a prefilled reservoir. I am however not sure if this is available for 6CTA engines but it is usd on KTA50 and QST30s.

Have a GREAT day.

Also look at installing a <2micron bypass oil filter that can catch water contamination. The filters are relatively cheap to replace - and may allow you to implement an SOS included oil life extension.

Similarly - if you're running under such extreme conditions - Pro15 (CF rated) is probably the wrong oil. Sure it's nice and cheap - not in comparison to the components it is supposed to protect ;P.
I'd suggest going to a synthetic for enhanced start up viscosity, better temperature stability and should reduce your consumption.

Castrol Magnatec or Wynn's Friction proofing may also be another solution.

Have you conducted an SOS on the system? Probably a good place to start at by getting a clearer picture of the problem.

We use the Pro 15 because the engines do maybe 9 hrs/yr and I doubt that I could justify synthetics, "nice and cheap" it is not, certainly compared to some oils that I am offered.

My small understanding of the subject indicates to me that the synthetics are not at their best in situations where water condensation/contamination in the crankcase is an issue ?

There are dozens of engines, all different sites and differing ages, re-read my original post. Some have never been serviced.

We do SOS frequently, all on ruined engines to prove a point, engines that we maintain from new survive.

We know what the problem is, "we don't need no stinkin SOS".

Stefan, I would appreciate any feedback re oil reservoir for turbochargers, I thought through the application and would prefer something commercially available.

Regards Tiger

Hello,

We run our detroit diesel 72 and 92 2 stroke diesel fire pumps monthly for 20 minutes or more but not at full load.
Also our engines are fitted with stand-by water heater to keep engine temperature relatively warm.
Above this and as per manufacturers recommendation we use SAE40 CF4 oil and is replaced annually with filter.

Best regards

Good input guys, received with thanks but the Australian std for fixed fire pumps prohibits "aids to starting" such as block heaters etc, also prohibits any form of overtemp or low oil pressure shut down.
Engine speed is fixed and usually at max HP RPMs, the pump set builders use the smallest engine they can get away with.
Between the time of my original post and now we have had to replace one turbo and overhaul another on the same pair of engines [duty and standby].

Hallo Tiger,

The reservoir I referred to is actually in essence an accumulator and is OEM fitted and supplied on most of our engines e. g. KOMATSU SA6D170 and SA12V140, some of the CUMMINS 6CTA, KTA38, 1710, K1800 ... and CAT 3304, 3306, 3412.

The principle it works on is basically; It is "T"-ed off on the pressure line to the turbo and it charges during operation (filling up with oil and being pressurised - to system pressure). In a shutdown situation the pressure, in the pressure supply line, falls away and the accummulator feeds the turbo through a release of oil onto the bearings, through an orifice. This will provide protection for the greater part of the "run down" and definitely extend the turbo life.

I am not sure about aftermarket products as they are usually "country specific" etc, the best will be to approach your OEM. In South Africa we have several, most aftermarket products are for commercial vehicles or UTes as you guys say.

Maybe we will meet in the near future as I am relocating to Moranbah, Qld in Jan/Feb '05.

Have a great day.
sminnaar@mhs4.tns.co.za

Thx Stefan, you have answered a couple of important questions.

I had reason to look at the specification of the OEM filter [LF3349] for the Cummins 6BTA today and just checked it again now.

There is no bypass valve in this filter.

And I suspect no anti drain back valve either, that would mean that the Turbocharger starts dry and runs down dry also.

Bloody frightening circumstance with a full fuel start and abrupt shut down.

quote:

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We get bore glazing and high oil consumption from the high RPM/ no load running which occurs 51 weeks out of 52, where we can pump back to storage tanks we open valves and load up the pumps to cure this, 30 minutes or an hour under load does wonders.

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You may try and reduce the high oil consumption by adding at least some load to your engine. The piston rings start to "flatter" blowby rises and thus oil consumption.

Good advice Callisa but the blokes who test start these engines on a weekly basis are generally disinterested, and most would call their union if you wanted them to open a valve and read a pump discharge pressure gauge.

I know of one case where I am sure a tester who had been fired and was on his last day loosened an oil filter on a 6CTA and deliberately seized it.

Not all are dickheads by any means but their union protects those that are.