GreasyB

Ok well I have a thrust bearing in my engine that went bad. Is it possible to just get the oil pan off some how and change the bearing out with the engine still in? And also how much would I have to raise the engine to get the oil pan off. Any help appreciated.

cnorton

If you don't fix this problem right, it will be back, worse the next time. If the thrust went bad and you don't find the cause, correct the problem, clean up the debris, and make sure that the crank thrust surface is not compromised, you not have heard the end of it. Do yourself a favor, pull the motor and do the job right.

Good luck,

c

GreasyB

Hmm. Sounds like I am screwed then. I dont have the space to pull the engine out. I'm doing good to change the oil in this amount of space.

shoebox

I'm wondering how you came up with the problem and how you know you have it.

Dave1980

I know we talked in the past about this cnorton, but never really discussed the symptoms of a thrust bearing going out. So what signs does and engine give you that the thrust is going out?

white97T/A

How ironic, we had a car come to the dealership where I work with a thrust bearing that had come out. It was not on an LT1 but the symptom was oil spraying out of the area where the thrust bearing and crankshaft seal are.

cnorton

I've only encountered thrust bearing failure a couple of times. Be aware that my experiences are based primarily on 40+ years of hands-on drag racing in Stock and Super Stock classes. I have never been a line mechanic nor a service writer, both professions that expose one to the volume of issues that create true expertise . The situations that I have dealt with are usually related to extreme applications and can be traced to mistakes or omissions (my own) during assembly. Just about everything in a motor failure can be traced to the assembler. Occasionally, a part fails but often even that can be attributed to an ill-advised decision or oversight that could have been avoided.

Once, many years ago I lost a thrust bearing due to, I suspect, inadequate clearance between the torque converter and the flexplate. The converter snout didn't seat cleanly in the back of the crankshaft during installation (at midnight, the night before the race) and that resulted in the flexplate being slightly stressed, putting a constant pressure on the thrust surface. That one was eaten up so badly that the end play in the crankshaft (as discovered during a pre-race tear-down at the 1980 NHRA World Finals) was detectable by movement of the dampener at the front of the motor. Later, I lost a thrust bearing after a couple of runs because I neglected to specifically ask the crank grinder to pay special attention to the thrust surface when the mains were turned. I don't think the thrust surface on the crank was true to the centerline of the crank. So much for getting a good deal on machine work. The runout resulted in a tight spot in the thrust clearance. Needless to say, I now spend as long as it takes during assembly to check the thrust clearance both before the crank goes into the block and with a dial indicator during assembly. Any time an assembly begins, I'm prepared to spend a couple of hours massaging parts by hand to get the clearance I want. Actually, it's an exception when everything goes together without some extra work.

Relative to my response to Greasy, every time I've encountered a thrust issue, there is enough metal in the filter and floating around in the system to compromise the life expectancy of the engine if it's not disassembled and cleaned thoroughly. He may or may not have a thrust issue. I took his diagnosis at face value. In my world, there are NO situations in which metal in the oil or in the filter can be corrected without taking the engine apart. It would seem logical that if an engine runs a few thousand miles (or as few as ten runs) without showing signs of metal in the oil and/or other symptoms of distress, it will be good for the long haul. It may or may not be fast but it isn't likely to eat itself unless other factors come into play.

GreasyB

I just figure that is the only bearing that would keep the crank from moving back and forth. I can move the crank enough by hand to make a clanking sound. But as far as oil pressure goes that seems good. And also I do not notive any clank noise at start up. Only thing that lead me to this was just when I was taking off the front hub I notice movement in the crank. No other symptoms. Oh my opti went out that is why I was tearing it apart to begin with. I talked to my engine builder. He was saying somthing about if when breaking in the engine I had the clutch in alot of the time it might have compromised some clearance or another? Have any of you heard of this?

mdacton

like Mr. Norton said you need to check your oil.

Take the filter off, get an oil filter cutter and check the filter media......If it has metal in it then the engine has to come apart.

If not it will not take very long to self destruct.

cnorton

Your engine builder is correct. Holding the clutch down during break-in could exert pressure against the thrust at a time when it is vulnerable. That would be similar to the situation I encountered when the converter was jammed against the flexplate.

Greasy, if you're working at the front of the motor and you can move the crankshaft forward-to-back more than .010" of an inch by pulling and pushing on the dampener, you have reason to believe that the thrust may be compromised. Keep looking for the basis of the problem.

Good luck,

c

96capricemgr

Eagle crank in that 355 by any chance??? I know they were shipping them with messed up thrust surfaces at one point and that a lot of people make the mistake of buying them.

GreasyB

Well either way, with your theory the engine needs taken apart.

GreasyB

I can move the crank more then that. But if this was the cause of the problem. Do you see any reason to take out the engine and rebuild it? Or would it work out if I were to replace the thrust bearing and go with it from there? I have very limited money and space right now. So I am trying to keep away from taking the engine out. But if that is what it really needs then it will have to wait. But if I dont absolutily have to then I wont.

cnorton

Before you pull the motor out, remove the filter and cut it open. Look for metallic debris in the folds of the filter element. Significant crank end play suggests that quite a bit of material has been eaten away from the thrust surface of the bearing. It's worth cutting the filter to verify the fact that metal is floating around in the motor. Also, if it is feasible, set up a dial indicator on a magnetic base with the needle on the front of the dampener. Move the crank back and forth and get a reading on how far it is moving. If you can check the filter and then get a rough measurement of the crank movement and let us know what the actual numbers are, we'll have a better idea of how serious the situation really is.

c

GreasyB

Nope. Stock crank.