bottom end blues

[Reg]

I ran one race with my new engine and pulled the motor today to check things out and fix my oil line from valve cover to pan, which fell off after 3 hot laps. I plugged the holes and ran the car anyway. My main bearings at least the 2 main bearing was totally bronze color, my crank has score lines in it and when I turn the top bearing out to look, it was seriously damaged too. it looked like it was even broken at one spot. If anyone has any great ideas what to do I would be greatful. I has extended my pan and put in a high flow oil pump, my pressure stayed above 40 as far as I could tell. can't stay watching the darn thing all the time. I am thinking of throwing in new bearings and running sat. is this crazy or what.

[340king]

I am curious if you had what appeared to be glitter in the oil pan? If so, that is where your babbit material went. This is caused by a lower than required oil pressure/volume. If the pressure/volume was much lower, you probably would have turned the bearings and completely ruined the engine. I would definitely look at the number 2 and 3 rod journals also. They usually get hurt worse than the number 2 main. A quick pressing back and forth on the rod assembly should give a hint to the condition of the bearings there, but definitely look also.

How do I know this? I had it happen on a 340 many years back. When I asked the machinist why this happened, he explained that he had talked to Mr. Carrillo about this and his thoughts were that the slight lack of oil caused a scouring effect on the bearing surface. The babbit is basically sucked off the face of the bearing by the viscous shear of the oil. Sufficient oil is present to keep the bearing from going into total destruction. This is what I learned in 1984. Since then, I have tried very hard to keep enough oil in the system.

Does your pan have baffles? How much extra capacity do you have? Race engines can store as much as two or three quarts of oil in the upper end of the engine during a race. I have filled right side valve covers completely full in the past.

[340king]

I am curious if you had what appeared to be glitter in the oil pan? If so, that is where your babbit material went. This is caused by a lower than required oil pressure/volume. If the pressure/volume was much lower, you probably would have turned the bearings and completely ruined the engine. I would definitely look at the number 2 and 3 rod journals also. They usually get hurt worse than the number 2 main. A quick pressing back and forth on the rod assembly should give a hint to the condition of the bearings there, but definitely look also.

How do I know this? I had it happen on a 340 many years back. When I asked the machinist why this happened, he explained that he had talked to Mr. Carrillo about this and his thoughts were that the slight lack of oil caused a scouring effect on the bearing surface. The babbit is basically sucked off the face of the bearing by the viscous shear of the oil. Sufficient oil is present to keep the bearing from going into total destruction. This is what I learned in 1984. Since then, I have tried very hard to keep enough oil in the system.

Does your pan have baffles? How much extra capacity do you have? Race engines can store as much as two or three quarts of oil in the upper end of the engine during a race. I have filled right side valve covers completely full in the past.

[Reg]

Yes there was lots of babbit in the oil pan. i was able to run with an extra 3 litres of oil, I had a total of 8 liters, or maybe 7.5. I am going to put that oil line from the right valve cover back down to the pan. that is actually the only reason I pulled the engine. anyway I have sort of baffles in my pan. I cut off the bottom of a truck pan and put it over my car pan. I cut only the bottom out of the car pan and extended the pickup down to the bottom. I tried to watch my oil pressure and only once noticed a bit of a drop. I am guessing that was when most of the damage was done. I still had quite high pressure, I think it never went below 40lbs. who can watch all the time? there is a bit of scoring on the crank, I don't have the cash to do it all again. I am thinking of running lighter oil, i had 10w40. new bearing don't cost all that much, the two rod bearing I looked at, no.1 and 2 I could see wear but no bronze color like that main. I will look at some more tomorrow and hopefully this one I opened is the worst.