Just how fast can a bearing spin?
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From: College Station, Texas
Just how fast can a bearing spin? With the introduction of water in the engine (talking up to 6-8 quarts here), how long would it typically take an engine to spin bearings? 1000rpm? A couple of minutes? I have a buddy who lost a piston in a motor recently and upon tear down there was a nice hole in the bore. We assumed the rod had busted it after the piston came apart but upon further tear down, we found every bearing was spun. There was a combined 12 quarts of water/oil removed from the system. We are wondering if the block let water in first contaminating the bearings and then hydrolocking the motor or if the piston blew and knocked a hole in the block contaminating the bearings. Motor only had 4k miles and had outstanding oil pressure at all times with no knocking. Had clocked off 12.4 passes earlier that day.
383 Lt1 is the motor.
It was running KB pistons rated at a max of 34 degrees of timing on a car with a tune set at 39 total degrees of timing. We are sure this is why the piston let go but want a second opinion.
So, in short, how fast can bearings spin from water contamination?
383 Lt1 is the motor.
It was running KB pistons rated at a max of 34 degrees of timing on a car with a tune set at 39 total degrees of timing. We are sure this is why the piston let go but want a second opinion.
So, in short, how fast can bearings spin from water contamination?
i'm not kidding , but on a dodge ram i had , it developed a pinhole leak in the water pump housing and started to squirt water INTO the engine ,,, the thing is , i drove on a long road trip like that ( total of 600 miles ) adding about 5 gallons of water along the way (couldn't figure out then where the water was going ) ,,, long story short , took it to the shop to check, it turned out it milkshaked the oil - and i'm talking real bad ,,, so we fixed it ( didn't touch the bearings ) and the truck ran great for another 30k miles till i sold it ( with good oil pressure ) .
so ,, my opinion , its the detonation that killed it , but the water helped inthe process .
so ,, my opinion , its the detonation that killed it , but the water helped inthe process .
I have torn down an engine with a cylinder head gasket leak letting a good deal of water into the engine; when the car ran there was so much steam out the exhaust it looked like I was running seafoam! After a little idleing like that the car was parked until the rebuild.... I did try turning it over before the rebuild, and it just wouldn't catch. Upon teardown I found on of the pistons was hydro-locked. Cleaned it up, replaced the gasket and head, and it's still running today.
I have a friend who has put about 2k miles on a 3800 SC engine with a head gasket leak... car is still running. I tend to think head gasket leaks are less dangereous because the water gets flashed to steam and exhausted if it is leaking into the cylinder. However, if an oil / cooland passage cross, it might be a different story.
I rebuilt an engine that had an oiling problem; con-rod froze on the crank and just went to pieces... Piston stayed whole being moved down by the valves and up by the part of the con-rod still attached to it. I was driving the car when it blew, and it was obvious.
Bottom line - if the main bearing ever goes metal to metal it will spin before you can turn off the engine, like maybe a couple hundred rpm. If something disrupts normal oil flow; a "bubble" of water, or an air bubble, or just a failure of the oiling system, the amount of time till failure is directly proportional to how long the residual film of oil on the bearing can last. Better buy good oil.
I have a friend who has put about 2k miles on a 3800 SC engine with a head gasket leak... car is still running. I tend to think head gasket leaks are less dangereous because the water gets flashed to steam and exhausted if it is leaking into the cylinder. However, if an oil / cooland passage cross, it might be a different story.
I rebuilt an engine that had an oiling problem; con-rod froze on the crank and just went to pieces... Piston stayed whole being moved down by the valves and up by the part of the con-rod still attached to it. I was driving the car when it blew, and it was obvious.
Bottom line - if the main bearing ever goes metal to metal it will spin before you can turn off the engine, like maybe a couple hundred rpm. If something disrupts normal oil flow; a "bubble" of water, or an air bubble, or just a failure of the oiling system, the amount of time till failure is directly proportional to how long the residual film of oil on the bearing can last. Better buy good oil.
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