Okay I need the masters analisys #2 rod bearing failure & #4 blown HG failure
05-30-2012, 04:29 PM
#46
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So, it sounds like we have consensus on the #2 rod bearing.
There is the rotating movement of the crankshaft journal inside the rod bearing - as this rotational speed increases, the likelihood of bearing damage increases. E.g. at 0 RPM it will last forever; at 12,000 RPM it will last for only a very short amount of time.
Since these two parts are moving against each other, oil lubrication prolongs the life of the bearing. At very high oil pressure and volume, the protection is great. At low pressure and/or volume, the protection is minimal, and in some cases, inadequate.
If one was to plot this in a graph, with likelihood of failure on the vertical and RPM on the horizontal, it would start out as a flat horizontal line, then start curving up until it's a nearly vertical line. At the tightest point on the curve, the inflection point, that would be about the "upper limit"... depending on if you're a gambling man.
Of course the safest course of action is to park it in the garage.
There is the rotating movement of the crankshaft journal inside the rod bearing - as this rotational speed increases, the likelihood of bearing damage increases. E.g. at 0 RPM it will last forever; at 12,000 RPM it will last for only a very short amount of time.
Since these two parts are moving against each other, oil lubrication prolongs the life of the bearing. At very high oil pressure and volume, the protection is great. At low pressure and/or volume, the protection is minimal, and in some cases, inadequate.
If one was to plot this in a graph, with likelihood of failure on the vertical and RPM on the horizontal, it would start out as a flat horizontal line, then start curving up until it's a nearly vertical line. At the tightest point on the curve, the inflection point, that would be about the "upper limit"... depending on if you're a gambling man.
Of course the safest course of action is to park it in the garage.
05-30-2012, 06:13 PM
#47
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I have a customer with a 450rwhp race car lots of engine work and a dry sump in his last race @ willow back in April he spun # 2, okay Einstein so much for your answer, I believe there is another thread two other guys with accusump also had #2 failure we know accusump is not as effective as dry sump but still better than stock.
05-30-2012, 10:40 PM
#48
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I think some of it may be due to so many people running higher (than necessary) viscosity oils, resulting in lower flow and higher oil temps. Add high rpms, and you're likely spending quite a bit of time with your oiling system in relief as well. None of it good for bearings...
05-30-2012, 11:04 PM
#49
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I think some of it may be due to so many people running higher (than necessary) viscosity oils, resulting in lower flow and higher oil temps. Add high rpms, and you're likely spending quite a bit of time with your oiling system in relief as well. None of it good for bearings...
Don’t imagine that it’s like molasses in the middle of Winter. By having a 0w/40 it will be watery thin at high race temps offering very little film protection.
05-30-2012, 11:12 PM
#50
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I've actually heard that overfilling the oil can be problematic - as the oil level gets higher to the crank, it's more likely to be whipped into a foam - and foamy oil does not lubricate well.
05-31-2012, 12:05 AM
#52
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Yeah, my powerband is between 6500-7300rpm...what should I do?
05-31-2012, 12:15 AM
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05-31-2012, 12:17 AM
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05-31-2012, 12:23 AM
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I think some of it may be due to so many people running higher (than necessary) viscosity oils, resulting in lower flow and higher oil temps. Add high rpms, and you're likely spending quite a bit of time with your oiling system in relief as well. None of it good for bearings...
05-31-2012, 03:31 AM
#56
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05-31-2012, 09:38 AM
#57
So with speaking with Mech Engineers at work general comments about bearings were:
1. Dirty oil and contamination of the bearing area inhibiting oil path within the bearing.
2. overheating the oil
3. oil supply issue...so find reason why #2 is getting less oil
4. Need to increase oil supply to bearing # 2
These are just general comments without looking at the engine design.
1. Dirty oil and contamination of the bearing area inhibiting oil path within the bearing.
2. overheating the oil
3. oil supply issue...so find reason why #2 is getting less oil
4. Need to increase oil supply to bearing # 2
These are just general comments without looking at the engine design.
05-31-2012, 10:53 AM
#58
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So with speaking with Mech Engineers at work general comments about bearings were:
1. Dirty oil and contamination of the bearing area inhibiting oil path within the bearing.
2. overheating the oil
3. oil supply issue...so find reason why #2 is getting less oil
4. Need to increase oil supply to bearing # 2
These are just general comments without looking at the engine design.
1. Dirty oil and contamination of the bearing area inhibiting oil path within the bearing.
2. overheating the oil
3. oil supply issue...so find reason why #2 is getting less oil
4. Need to increase oil supply to bearing # 2
These are just general comments without looking at the engine design.
1. Dirty oil and contamination of the bearing area inhibiting oil path within the bearing.
2. overheating the oil
for turbo cars oil the thicker the better, also here is something I learned while disecting 951 engines, about 70% of the engines with rod bearing failure had dirty/burned oil,
05-31-2012, 01:02 PM
#59
Some of those cars with dirty oil could just be from being old cars. This almost makes me want to run a quart of ATF fluid for about 100 miles to make sure my engine is all clean on the inside then switch back to Brad Penn which has been great oil.
06-01-2012, 01:23 AM
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for turbo cars oil the thicker the better, also here is something I learned while disecting 951 engines, about 70% of the engines with rod bearing failure had dirty/burned oil, I changed my oil every 2k miles i personally have never experienced a rod bearing failure and ran high boost but I have always been very conservative when driving as you can see in the next video
If the factory nominated 20w/50 for most average climates I doubt that’s correct. Even 60w oil in a race track is going to flow perfectly fine.
Don’t imagine that it’s like molasses in the middle of Winter. By having a 0w/40 it will be watery thin at high race temps offering very little film protection.
Don’t imagine that it’s like molasses in the middle of Winter. By having a 0w/40 it will be watery thin at high race temps offering very little film protection.
Same comment for the "turbo cars thicker oil is better" crowd.
The higher you go in viscosity the lower the flow, the higher the temps, and the more time you'll spend in relief. Dont know why that is "better" if you can minimize that and keep necessary shear and coking resistance.