THE 2020 CBI 6800Ct...OUR OVERHEAT TESTS

Overheat test before software update

This test was performed in front of the CBI tech who came to do the software update. He was a witness to this before software update test and the after software update test. On this test grinder was tricked into thinking it was overheating but this time by actually boiling coolant on a camp stove with the coolant sensor connected to the ECM. The sensor was placed in the boiling coolant. It still would not disengage the clutch and idle down at CBI's factory setting of 221 degrees. The screen indicated a alert in Celsius but also at 221 F however it was not until the grinder hit the CAT preset 232F hard shutdown did the grinder completely turn off without cooling down. This is what caused the catastrophic engine failure. Unknown to us this happened (11)x's beginning at <800 machine hours.

Overheat test after the CBI software update

Only after 7 months of engine rebuild and many attempts to get CBI to fix the programing did we learn about the heat gun overheat test by another grinder manufacturer. Otherwise CBI was perfectly willing to let us burn up another grinder engine.

After the software update in April 2023 the grinder did disengage the clutch and idle down. The software update allowed us to also change this procedure to our preferred temperature. We choose 205 degrees at this time however we would again lower it to 195 degrees out of precaution. Since the machine ran 98% of the time under 190 anything above this should be a warning to inspect the machine.

PSR downloaded at the CAt dealer

Additional Information

This PSR was downloaded at our local CAT dealer when they were trying to diagnose the engine problem. We were not aware of PSR's prior to this time and how valuable they can be. Since then we now have purchased the software from CAT and are pulling our own PSR's on a regular basis.

The red ovals indicate the (11) times the engine performed a "hard" shutdown without disengaging the clutch and idling down to cool the engine.
RED oval SHM First shows that the first time this happened was when the engine had only 774 hrs...well within warranty time period.
RED oval RTC First indicates the date of the first 'hard' shutdown which occurred at the 774 hrs or just a few months from the machine being new.
RED rectangle indicates the last time the machine performed a "hard" shutdown. We believe at this date is when all the final damage occurred however we were not alerted about it until the oil scan the following month.
Blue rectangles were the dates we actually first started to suspect damage as the engine was blowing coolant out of the side of the engine. This is when we began trouble shooting. We suspected a head gasket and took the machine to the local CAT dealer.
The local CAT dealer still could not diagnose the problem and asked us to haul the machine into the field so that they could see the problem under full load. This went on for a month and required hauling the machine in and out of the dealer 3 times for a month until the dealer decided that opening the engine would be the only way to properly diagnose the issue.

Oil scans

While not common in our industry we take oil samples to our CAT dealer to perform an oil analysis.

These were some questions we presented to CBI/Terex Executives early on looking for answers as to why the engine failed? The oil scans indicated a minor issue with the coolant within a month or 2 after the last "hard shutdown". It took 6 months and many out of State trips and emails to finally come up with the answers however none of the answers came from CAT or CBI.

· From the complete engine PSR/ histogram, I see no indication of extended periods of extreme overheating, what would explain the condition the engine was in?

· *11 total overheat shutdowns in 4800 hours?

· Visual inspection of the turbos seemed ok – Not sloppy. Good oil scans with no signs of failure or imminent failure. No high metal counts in the oil scans.

· Charge air/boost pressure were in range during testing under a load. Mid 20’s psi on screen.

· No performance loss, or tattle tail white smoke or rough running engine to indicate one injector failure leaving the high carbon deposits on one cylinder.

· Telematics is very difficult to navigate and report alarms or send alerts...We were finally provided access to telematics however much data seemed to be deleted or missing.

· We followed the manufacturer recommended service intervals of 250 hrs on engine oil changes and used only CAT filters for fuel and oil.

· Known issue with C32 engines outside our serial number range that has service letters.

· Is there a programming error on CBI’s side that set temperature limits of least severe at 228* and 232* moderate severity (turned off – when it should have signaled to disengage clutch and reduce engine to idle speed to cool down with fan still running) and then Highest severity at 232* which would kill the engine in a complete shutdown? This seems to be a problem, because the temperatures would continue to climb with no air flow and oil circulation and cause even more damage? NOTE: This is the question that we would later on learn the answer from our heat gun experiment.

· High and moderate exhaust temperature settings look to be turned off?

· Would like to see manufacturer’s recommended temperature operating ranges (coolant, fuel, exhaust, etc), and what are temperature procedures for CAT vs CBI?

· Why is a “D” rated engine acceptable in a horizontal grinder especially in the Southern US and even more so in Texas?

· As the current machine design exposes the engine to direct Texas sunlight I have requested that the CAT dealer paint the engine white to aid in cooling. I am not sure why this or sunlight protection was not originally considered.