singh_robbie
01-07-2017, 05:51 AM
Hello everyone,
I am Rabsimran Gulati from Formula Manipal, a team from India. We recently participated in the Formula Student Germany and Formula Student Czech Republic events. We faced issues with the engine’s lubrication system in both the events.
Before I describe the events, I will explain the system we are using.
We are currently using a Honda CBR 600RR PC37 (2005 - 2006 model) engine and running a dry-sump lubrication system with it. The previous year was the first time we had implemented the dry sump system. Also, we currently use a Motec M400 ECU, which was also implemented in the previous year. We have designed the intake, exhaust and cooling systems with internals being stock.
The lubrication system includes -
Honda CBR 600RR PC 37 engine with a Dailey Engineering scavenge pump , 2 stage pre ’07 model (04-99-2220), without an air-oil separator and 2 scavenge ports, externally mounted reservoir with a running capacity of 3l (Oil being used, Motul fully synthetic 4T 300V 10w40).
Lubrication Plumbing:
AN -10 scavenge lines (from dry sump to scavenge pump inlet). Scavenge ports oriented transversely w.r.t the car, one of either side.
AN -12 scavenge line (from scavenge pump outlet to reservoir inlet)
AN -6 line pressure feed line (from reservoir outlet to engine pressure pick-up port).
Before running in the event, we had the engine running on this setup for almost 50km on a rolling road dynamometer, and about a 150 km of testing. We were always logging data such as the engine coolant temperatures and oil pressures. We made sure that these values never crossed their limits, knowing the desired oil pressures for various RPM ranges.
However, during our pre-competition testing phase in Germany, the engine started making an abnormal ‘tick-tick’ noise that we had never heard before. Soon after the engine stopped cranking, kind of getting locked internally. Assuming this was a block-related internal issue, we switched to our spare block and continued with the testing.
At FS Czech Republic, in the dynamic test area before the Autocross event, the engine started making screeching sound and we went directly to autocross. During the Autocross, the engine failed with the oil cooler flange separating away from the block. The connecting rod of the 2nd cylinder broke and flew out of the block leaving a hole behind. Also, smoke was observed, probably because of the oil burning up by coming in contact with the hot exhaust pipes. Due to this failure we could not compete in the rest of the competition. Upon checking the logged data we observed that the oil pressure values dropped severely below the desired value during failure.
It was suspected that choked flow rate due to the small ID of the -6 line (from reservoir outlet to engine pressure pick-up port) caused loss of oil pressure at high revolutions causing the failure. We then replaced the pressure feed line from a -6 to -12 size and the tested the system. The overall pressure values were higher than that obtained previously, with occasional momentary unexpected pressure drops still occurring.
We managed to fix the issue before the start of the Acceleration event at FSG and competed in the Acceleration and Autocross events. Could not complete the endurance event due to a leak in the fuel tank (not related to the issue being discussed)
Once we were back home we opened up the engine which was making the noise (which was replaced with the spare engine during testing) and we noticed that the journal bearings of cylinder 2&3 were severely damaged. Find the attached pics.
Pic 1: Bearing of 2nd piston. 1086
Pic 2: Bearing of 3rd piston. 1087
Pic 3: Crankshaft journal of 3rd cylinder. 1088
We are confused as to why this sound (tick) and failure was observed at the competition and not when we were in India, during our 3 months of testing with the system. The only variable being, the change of oil brand from Motul to Repsol fully synthetic 10W40 (which has a higher viscosity at 100oC).
We believe that this was due to insufficient supply of oil to the crank journals due to the -6 line. We continued testing with the new system and we ran the engine for about 170 kms. The oil pressure values were within the desired range.
But the engine recently failed with the exact same symptoms. There was a rattling noise heard during testing and the engine was immediately shutdown. Very fine metal powder was found in the sump and at flywheel. Unfortunately, we did not have the oil pressure values this time as the sensor was faulty and did not log any values. We immediately opened the engine and observed a similar failure. The journal bearings of the third cylinder failed in a similar fashion. Find the attached pics.
Pic 4: Metal powder in sump. 1089
Pic 5: Overlapped bearings of 3rd piston. 1090
Since we observed a similar failure, we understood that our engine issues have not been solved by changing the size of the feed line from-6 to -12.
I hope that the experts in this forum can help solve our issue or at least give us a lead on where we might have gone wrong.
Please feel free to ask any questions if I have missed out on any essential information.
I am Rabsimran Gulati from Formula Manipal, a team from India. We recently participated in the Formula Student Germany and Formula Student Czech Republic events. We faced issues with the engine’s lubrication system in both the events.
Before I describe the events, I will explain the system we are using.
We are currently using a Honda CBR 600RR PC37 (2005 - 2006 model) engine and running a dry-sump lubrication system with it. The previous year was the first time we had implemented the dry sump system. Also, we currently use a Motec M400 ECU, which was also implemented in the previous year. We have designed the intake, exhaust and cooling systems with internals being stock.
The lubrication system includes -
Honda CBR 600RR PC 37 engine with a Dailey Engineering scavenge pump , 2 stage pre ’07 model (04-99-2220), without an air-oil separator and 2 scavenge ports, externally mounted reservoir with a running capacity of 3l (Oil being used, Motul fully synthetic 4T 300V 10w40).
Lubrication Plumbing:
AN -10 scavenge lines (from dry sump to scavenge pump inlet). Scavenge ports oriented transversely w.r.t the car, one of either side.
AN -12 scavenge line (from scavenge pump outlet to reservoir inlet)
AN -6 line pressure feed line (from reservoir outlet to engine pressure pick-up port).
Before running in the event, we had the engine running on this setup for almost 50km on a rolling road dynamometer, and about a 150 km of testing. We were always logging data such as the engine coolant temperatures and oil pressures. We made sure that these values never crossed their limits, knowing the desired oil pressures for various RPM ranges.
However, during our pre-competition testing phase in Germany, the engine started making an abnormal ‘tick-tick’ noise that we had never heard before. Soon after the engine stopped cranking, kind of getting locked internally. Assuming this was a block-related internal issue, we switched to our spare block and continued with the testing.
At FS Czech Republic, in the dynamic test area before the Autocross event, the engine started making screeching sound and we went directly to autocross. During the Autocross, the engine failed with the oil cooler flange separating away from the block. The connecting rod of the 2nd cylinder broke and flew out of the block leaving a hole behind. Also, smoke was observed, probably because of the oil burning up by coming in contact with the hot exhaust pipes. Due to this failure we could not compete in the rest of the competition. Upon checking the logged data we observed that the oil pressure values dropped severely below the desired value during failure.
It was suspected that choked flow rate due to the small ID of the -6 line (from reservoir outlet to engine pressure pick-up port) caused loss of oil pressure at high revolutions causing the failure. We then replaced the pressure feed line from a -6 to -12 size and the tested the system. The overall pressure values were higher than that obtained previously, with occasional momentary unexpected pressure drops still occurring.
We managed to fix the issue before the start of the Acceleration event at FSG and competed in the Acceleration and Autocross events. Could not complete the endurance event due to a leak in the fuel tank (not related to the issue being discussed)
Once we were back home we opened up the engine which was making the noise (which was replaced with the spare engine during testing) and we noticed that the journal bearings of cylinder 2&3 were severely damaged. Find the attached pics.
Pic 1: Bearing of 2nd piston. 1086
Pic 2: Bearing of 3rd piston. 1087
Pic 3: Crankshaft journal of 3rd cylinder. 1088
We are confused as to why this sound (tick) and failure was observed at the competition and not when we were in India, during our 3 months of testing with the system. The only variable being, the change of oil brand from Motul to Repsol fully synthetic 10W40 (which has a higher viscosity at 100oC).
We believe that this was due to insufficient supply of oil to the crank journals due to the -6 line. We continued testing with the new system and we ran the engine for about 170 kms. The oil pressure values were within the desired range.
But the engine recently failed with the exact same symptoms. There was a rattling noise heard during testing and the engine was immediately shutdown. Very fine metal powder was found in the sump and at flywheel. Unfortunately, we did not have the oil pressure values this time as the sensor was faulty and did not log any values. We immediately opened the engine and observed a similar failure. The journal bearings of the third cylinder failed in a similar fashion. Find the attached pics.
Pic 4: Metal powder in sump. 1089
Pic 5: Overlapped bearings of 3rd piston. 1090
Since we observed a similar failure, we understood that our engine issues have not been solved by changing the size of the feed line from-6 to -12.
I hope that the experts in this forum can help solve our issue or at least give us a lead on where we might have gone wrong.
Please feel free to ask any questions if I have missed out on any essential information.