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2G Odd worn rod- and main bearings?

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Ben-Stian

15+ Year Contributor
131
29
Aug 23, 2006
NORWAY, Europe
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Hi,
I dont drive my car very much, mainly just street legal/drag events. Normally I change the oil and filter after the season, (running E85) but I didnt do it last as I had used the car very little. I ran with it some events and thought I would pull the bearings to check and was surpriced how bad they looked... Both mains- and rodbearings did look strange. I am running Castrol Edge Titanium 5w40 with oem clearances (just with Plastigauge when I built the motors years ago) and ACL race bearings. I have now put in bearings with extra clearance and Castrol 10w60.
Could it be the Ethanol that have contanimated the oil/tearing the bearings? Or is it just wear from poor lubricating? I have a deeper oil pan/pickup with doors and have logged oil pressure when launching and was fine when I installed it some years ago. I havent checked lately if oil pressure is still fine while launching...
 
There was dirt that took those bearings to that place, maybe sand left over from a sandblasted engine part, maybe just trash from inside of the crankshaft that was hiding? it looks also like the journals on either the crank or the bearing caps themselves were not machined round, there are iron particles embedded on those bearings too, so those came from something made of steel unless you have another reason for them being there because it doesnt look like its worn that far down to the base metal, it looks like its down past the low friction coating in most areas...how many miles are on those? are your grounds from your engine to your frame very good? I would recommend running 20w-50 or something around that weight, race bearings with excess clearance need the added viscosity, remember that race bearings will wear with any dirt in the oil, they are not designed to embed dirt like stock bearings, I would for sure check your crankshaft journal diameters after seeing that.
 
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There was dirt that took those bearings to that place, maybe sand left over from a sandblasted engine part, maybe just trash from inside of the crankshaft that was hiding? it looks also like the journals on either the crank or the bearing caps themselves were not machined round, there are iron particles embedded on those bearings too, so those came from something made of steel unless you have another reason for them being there because it doesnt look like its worn that far down to the base metal, it looks like its down past the low friction coating in most areas...how many miles are on those? are your grounds from your engine to your frame very good? I would recommend running 20w-50 or something around that weight, race bearings with excess clearance need the added viscosity, remember that race bearings will wear with any dirt in the oil, they are not designed to embed dirt like stock bearings, I would for sure check your crankshaft journal diameters after seeing that.
Ok thanks for the reply. I have not sandblasted anything, and have no idea how something have come inside the motor. I dont know how many miles, a wild guess max 1000 miles. Why 20w-50? I always believed that the 10w60 are thicker when hot vs the 20w50? Should I drain the fresh 10w60 and fill 20w50?
 
Oil can be a controversial subject, but what I can tell you is that nowhere in the owners manual does Mitsubishi recommend 10w-60 as a suitable oil, they do recommend 20w-50 though in warm temps above 70 degrees, there are lots and lots of us that run 20w-50 with hundreds of thousands of hard miles on our cars without problems if that speaks of anything to you.

If I were you I would run the Valvoline VR1 20w-50 because of the added zinc level in it, oil manufacturer's due to pressure from the government have been deleting zinc from off the shelf oil for decades without notice to the public and our engines were designed at a time when zinc was more plentiful in shelf stock oil, therefore they were designed to have zinc in them and might explain the crankshafts not being hard enough to deal with todays crappy oil, the 6 bolt crankshaft were nitrided on the bearing surfaces to add hardness, for some reason Mitsubishi decided to save money by not nitriding the 7 bolts in the 2g and the iron they used was obviously not quality enough on its own to prevent wear with the added pressure from a heavy aftermarket pressure plate.

I can tell you that it was a major issue on small block GM engines for years when the camshaft lobes would wear completely away causing a misfire due to a lack of zinc and camshafts that were not designed with the hardness for low zinc oil.
 
Oil can be a controversial subject, but what I can tell you is that nowhere in the owners manual does Mitsubishi recommend 10w-60 as a suitable oil, they do recommend 20w-50 though in warm temps above 70 degrees, there are lots and lots of us that run 20w-50 with hundreds of thousands of hard miles on our cars without problems if that speaks of anything to you.

If I were you I would run the Valvoline VR1 20w-50 because of the added zinc level in it, oil manufacturer's due to pressure from the government have been deleting zinc from off the shelf oil for decades without notice to the public and our engines were designed at a time when zinc was more plentiful in shelf stock oil, therefore they were designed to have zinc in them and might explain the crankshafts not being hard enough to deal with todays crappy oil, the 6 bolt crankshaft were nitrided on the bearing surfaces to add hardness, for some reason Mitsubishi decided to save money by not nitriding the 7 bolts in the 2g and the iron they used was obviously not quality enough on its own to prevent wear with the added pressure from a heavy aftermarket pressure plate.

I can tell you that it was a major issue on small block GM engines for years when the camshaft lobes would wear completely away causing a misfire due to a lack of zinc and camshafts that were not designed with the hardness for low zinc oil.

Thanks yes I feel oil can be difficult... Problem regarding what Mitsubishi recommends for my stock 265 hp engine, I feel doesnt apply that much anymore regarding my 700 hp engine with a non-Mitsubishi 100 mm crank and much higher redline running extra bearing clearance as well...
I think I will try to source the Valvoline oil you recommend:)
 
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