Newly Built 455 Thrust Bearing Dilemma!!
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Joined: Sep 2017
Posts: 5,220
From: St. Paul Minnesota
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I will say that I would have to question the condition of the thrust surface of the crankshaft. I know your machinist said it was "fine" but is it really ? Hard to believe it did that much damage to the bearing and didn't hurt the crank some. I am not sure there really is a good way to absolutely check the thrust surface other than putting it in the crank grinder and running up on it with a freshly dressed wheel. Only other way might be to clean it all up and put it in the block with new bearings that have been coated with machinist die so you can see exactly where it is hitting.
Hopefully they will find something.
I will say that I would have to question the condition of the thrust surface of the crankshaft. I know your machinist said it was "fine" but is it really ? Hard to believe it did that much damage to the bearing and didn't hurt the crank some. I am not sure there really is a good way to absolutely check the thrust surface other than putting it in the crank grinder and running up on it with a freshly dressed wheel. Only other way might be to clean it all up and put it in the block with new bearings that have been coated with machinist die so you can see exactly where it is hitting.
Hopefully they will find something.
Checking the crankshaft thrust face can be checked several ways....in the block and out of the block.
In the block, remove the bearing cap and bearing. Push the crank rearward and set your indicator at "0". Rotate the crank manually while keeping gentle pressure on the crank rearward.
Out of the block,
Chuck the harmonic balance end in an engine lathe and make sure you have ZERO run out. Clean the centering chamfer in the crank and insert a lubricated "dead center" and lock down the tail stock You can now check out main bear journal run out and thrust face run out. Place th
...........
I will say that I would have to question the condition of the thrust surface of the crankshaft. I know your machinist said it was "fine" but is it really ? Hard to believe it did that much damage to the bearing and didn't hurt the crank some. I am not sure there really is a good way to absolutely check the thrust surface other than putting it in the crank grinder and running up on it with a freshly dressed wheel. Only other way might be to clean it all up and put it in the block with new bearings that have been coated with machinist die so you can see exactly where it is hitting.
Hopefully they will find something.
I will say that I would have to question the condition of the thrust surface of the crankshaft. I know your machinist said it was "fine" but is it really ? Hard to believe it did that much damage to the bearing and didn't hurt the crank some. I am not sure there really is a good way to absolutely check the thrust surface other than putting it in the crank grinder and running up on it with a freshly dressed wheel. Only other way might be to clean it all up and put it in the block with new bearings that have been coated with machinist die so you can see exactly where it is hitting.
Hopefully they will find something.
Checking the crankshaft thrust face can be checked several ways....in the block and out of the block.
In the block, remove the bearing cap and bearing. Push the crank rearward and set your indicator at "0". Rotate the crank manually while keeping gentle pressure on the crank rearward.
Out of the block,
1. Chuck the harmonic balance end in an engine lathe and make sure you have ZERO run out. Clean the centering champfer in the crank and insert a lubricated "dead center" and lock down the tail stock You can now check out main bearing journal run out and thrust face run out. Place the lathe in neutral or between gears in two fastest speeds. You can now manually rotate the crank.
2. You can also do the above using a "steady rest" with roller bearings on a main bearing journal.
3. Bench mounted dead centers, These have dead centers at both ends and slide apart or together on a keyway or dovetail.
You DON'T want to run up on it with a freshly dressed grinding wheel. You only need to check the thrust face run out on the crank. Once you "bump" it with grinding wheel, you have no idea if or how much run out you had.
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Registered User
Joined: Mar 2023
Posts: 75
From: South West Wyoming
Resolved may not be the correct word for what happened, but the thrust bearing wear seems to have stopped. Last Fall(2025), I had another conversation with my engineer builder about the thrust bearing wear. I suggested that I put some more miles on the car with the engine, while keeping a close eye on thrust clearance after each time out with it. He was 100% good with that. For whatever reason, the thrust clearance opened up to .011” and stayed at that clearance. I drove the car about 150 additional miles last fall and the clearance has since stayed the same. Did the thrust surface machine itself to achieve a surface area which is now in equilibrium with the thrust force from the transmission???? Unfortunately I have no idea if this is the case or not….
Fortunately I was enjoying the car before winter😎. Unfortunately the Precision of New Hampton torque converter is in the car, and it definitely needs either the Hughes or Coan converter. In the next month or so I plan on dropping the transmission ☹️ to reinstall the Coan torque converter. After that I will be keeping a VERY close eye on the thrust clearance to make sure it doesn’t start to open back up again.
The saga is not over, but hopefully it will soon be coming to an end…..
Fortunately I was enjoying the car before winter😎. Unfortunately the Precision of New Hampton torque converter is in the car, and it definitely needs either the Hughes or Coan converter. In the next month or so I plan on dropping the transmission ☹️ to reinstall the Coan torque converter. After that I will be keeping a VERY close eye on the thrust clearance to make sure it doesn’t start to open back up again.
The saga is not over, but hopefully it will soon be coming to an end…..
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