Need help with our semi fleet cam problems.

[TiredTrucker]

True, enough, Doug. But we have no evidence here that the OP is abusing the engine is such a manner with the engine brake. And we have no evidence that overhead adjustments are not being regularly done. But since all commercial heavy diesels are equipped with engine brakes in the U.S., it would show a similar pattern as the OP is having, if engine brakes are the primary issue. Since most commercial trucks are operated by mechanically ignorant folks, many of whom could give a rip about how an engine is treated since they don't pay the bills in relation to operating it, we should see a industry wide pattern of engine brakes causing issues. We don't. And the vast majority of commercial heavy diesels in N. America are using a mineral based 15w40 CJ-4 oil in them.

The source of the problem could be as you suggest, but the odds are against it. I can't speak in regards to how they do things down under, but while fleets and OEM's make recommendations regarding operation of heavy trucks here, in reality, things that actually occur are quite different. After 40 years of watching these morons operating commercial trucks, I can attest that many drivers have little regard to the things we are discussing. While telematics is making inroads into watching driver performance in operating commercial trucks, no one is watching engine brake applications. That is, except the local LEO who tries to catch commercial trucks using an engine brake in a restricted area so that he can generate some more revenue for the city or county.

 

[Silverado12]

That and the engine brake cuts out on its own once it hits low RPMs. If that was a problem (I've been driving 20 years and this is the first I ever heard of that) it would have happened with older engines.

 

[Doug Hillary]

Hi,
Snowjw - tell us more about the operational aspects of your Fleet

 

[TiredTrucker]

I concur with Silverado. The jake brakes are designed to cut off at below an RPM threshold, usually 900-1000 RPM. At least on US spec'd trucks. Which is only around 2-300 RPM lower than most of them run around the country at highways speeds with the latest engine designs and gearing being utilized. If that isn't enough, then the local LEO will confiscate some of your hard earned cash in the form of fines if you don't turn it off when going thru some of those urban areas where speeds and subsequent RPM's are lower.

I have owned and run Detroit Series 60's, Cummins N-14's, and Cummins ISX's. I have never heard of jake brakes causing this. Now to be fair here, one thing wasn't addressed by Doug, is those that have the jake on while shifting and they are floating the gears. Engines undergoing rapid deceleration from the jake on the shift, essentially braking the engine while it is not under load between the shifts. I have heard of damage being caused those situations. Haven't seen it myself, but I have heard of it.

 

[Doug Hillary]

Hi,
TiredTrucker - You said this;

"I have owned and run Detroit Series 60's, Cummins N-14's, and Cummins ISX's. I have never heard of jake brakes causing this. Now to be fair here, one thing wasn't addressed by Doug, is those that have the jake on while shifting and they are floating the gears. Engines undergoing rapid deceleration from the jake on the shift, essentially braking the engine while it is not under load between the shifts. I have heard of damage being caused those situations. Haven't seen it myself, but I have heard of it."


I get the impression that it is thought that OZ is a back blocks location for trucking - it isn't! It has a very sophisticated National road transport system! It runs from areas of almost Ant-artic to Tropical locations. On good and bad roads and sophisticated well built Motorways. It is a mix of large Fleets and Owner Drivers

OZ has long been used as a pre-production testing ground for most US and European Heavy Vehicle Manufacturers - and still is! This ranges from Cabins to Chassis, Engines to Drivelines and all in between! I have been part of that with four Manufacturers - three US and four Euro - vehicles, drivelines and suspensions - and BPW (axles/suspension) and ZF (driveline) have a long history in that regard here in OZ - so does Thermoking!
This also includes lubricant testing - my involvement over many years was with both Castrol and Mobil, and Shell many years ago

The reason OZ is used is simply because of its culture, professionalism of the Industry and of course the geographic diversity. IMO a very wise choice indeed!!!

Jacobs Brakes are designed to be most efficient at an engines rated speed (say 2100>) and become increasingly inefficient as the revs decrease. The problems of excessive wear are typically caused by shifting as you state and use in urban areas at low revs - especially with a cold lubricant! And some other malpractices!!

"Not addressed by me" ? That is why I asked the OP to provide more info on the actual operation of his trucks. Hauling gravel as the OP states suggests to me that they are on short haul and probably urban use. Perhaps he will tell us

Bad practice with engine brakes is well known! So are some of the consequences and I have been in the trucking game as a Technical Consultant (including Driver assessment and training) and Fleet Owner, since 1973. My first Technical involvement with Heavy trucks was with Bedford, Austin, Morris and GMC commencing in the 1950s

 

[Silverado12]

On the times I had to use the jake when shifting (think going up a steep hill, loaded with a 9 or10 speed transmission) I turned it back to the lowest setting, because the dang thing will slow the engine down so fast on high that I couldn't shift fast enough. I wouldn't think that would harm the engine, as it's turning at 1700+, then slowing to about 1200+.

 

[TiredTrucker]

Problem is, Doug, very few heavy truck engines made in the last 5 years can even run over 2100 RPM, and many are governed to 1800 RPM. Check the latest spec sheets on U.S. spec'd Detroit DD15, Cummins ISX, Volvo/Mack D13/MP8, Maxxforce 13, and Paccar engines, which are what is being used today in trucking. 12.7L Series 60 was discontinued in 2003 and 14L Series 60 got discontinued in 2010 and Cat has been out of the OTR trucking game for the last 5 years. The old days of revving to 2100+ are long gone. At least in the U.S. The newer engines are not rated at the RPM's you are suggesting, but at their max RPM's governed setting before they get there. Ratings are generally in the 1450-1600 for max HP and 1000-1200 for reaching peak torque. Max efficiency of the jake is reached at the max rating of HP. At stated, that is considerably lower than the 2100> you mention. At 2100 RPM on many newer engines, the graph is dropping like a rock in both torque and HP. To compare what is done down under with engines to what we have for offerings in the U.S. is not an apples to apples comparison. In the U.S. if you take a modern engine over 2100 RPM (and some brands even less), it most likely will throw warning lights and go into derate or shutdown sequence.

 

[Doug Hillary]

Hi,
TiredTrucker - There are obviously various ratings for various engine families in diverse applications. We don't all live in the US - or North America - but many Technical issues exist without geographical boundaries!

In my own case with my on highway vehicles I used 500hp @ 1800 Max rpm and Max Torque (1550 lb/ft) at 1200 (full torque rise from 1500 rpm) - optimised for fuel efficiency via Computer route simulation in consort with DDA

We have a large number of quad trailer Road Train operations in this country that run around 130t (290000 US lbs). These are typically specced with higher speed ratings!

Back to the OP's topic - we don't know the OPs modus operandi but it doesn't sound like on-highway to me. Perhaps he will respond

As I write this I have heard a Jake being used to almost stall speed as the driver approached a nearby roundabout - at least the ambient temp is around 33C today!

 

[artificialist]

Since you have non-DPF engines, you might be able to get CI4+ oil from a specialty company. CI4+ does have higher ZDDP than CJ-4, and that might help cam life.

That in mind, I suspect something else is going on. As some have already mentioned, Cummins made some failure prone cams on the ISX, and no oil can solve a flawed part.

It is risky to quickly rev up a cold engine with heavy oil. In Canada, Shell makes a 0w40 CJ-4 oil, but they don't make one for the USA. I don't understand that, because Montana and several other states have similar weather to Canada.

 

[TiredTrucker]

And to the OP, I used a Delo 400LE 15w40 in a 12.7L Series 60. At 15,000m / 300 hrs OCI's, the oil was shearing out of viscosity to a 30w. No fuel dilution and no reasonable explanation. I moved the engine over to a Schaeffer 700 15w40 syn blend that has is now taking the engine to 25,000m / 500 hrs and staying well within viscosity. And wear metals are similar or lower at 25,000m / 500 hrs on the Schaeffer as was the Delo at the lower OCI. You might want to give the Schaeffer a try. Bulk pricing is around $1019 for a 55 gallon drum as per my last order. And orders are shipped free to your location and they toss in free oil sample kits and analysis.

http://www.schaefferoil.com/documents/222-700-td.pdf

Salesrep in the vendor section should be able to turn you on to Schaeffer if you choose to give it a shot. Else, I can refer my rep to you.