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Thrust Bearing Failure

Belle66

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Hi Guys, I had my engine rebuilt after a thrust bearing failure, thinking the cause was an incorrect flexplate. And now it has happened again after a few thousand miles. The only significant change I made prior to both failures was changing the shift point from stock to 5800 rpm.

Besides converter ballooning and blocked trans cooler lines what should i look for to male sure I don't do this again?

Thanks,
Joel
 
Did you properly seat the thrust bearing during installation? How much end play after assembly? 440'
 
without the convertor bolted up, there should be a specified space between the flex plate
and the convertor. I think it's 1/4". You need to look it up to be sure. Sorry about your
grief!
 
I have heard of a failure in the transmission that puts too much pressure in the converter and forces it against the thrust bearing.
 
Two Thrust Bearing failures should be investigated carefully, especially in an automatic.
OEM or aftermarket Stroker Crankshaft ?

3 more Questions:
1.) How much Crankshaft "end play" was #3 Main Brg set with.... or was the Engine assembled with ?
2.) What was the Vertical Clearance on the #3 Main Main Bearing.... as this is proportional to the amount of Oil 'leakage'(lubrication) to the Thrust face of the Bearing
and,
3.) How much taper is present on the #3 Bearing Bore in the Block
 
without the convertor bolted up, there should be a specified space between the flex plate
and the convertor. I think it's 1/4". You need to look it up to be sure. Sorry about your
grief!
Yep flexplate to converter has proper fit.
 
Two Thrust Bearing failures should be investigated carefully, especially in an automatic.
OEM or aftermarket Stroker Crankshaft ?

3 more Questions:
1.) How much Crankshaft "end play" was #3 Main Brg set with.... or was the Engine assembled with ?
2.) What was the Vertical Clearance on the #3 Main Main Bearing.... as this is proportional to the amount of Oil 'leakage'(lubrication) to the Thrust face of the Bearing
and,
3.) How much taper is present on the #3 Bearing Bore in the Block
1) .007" endplay
2) per spec...don't know exact number
3) was line bored
 
Is this a 440? Not trying to come off as insulting your intelligence but are you certain the proper bearing is being used?...There are different ones for different year blocks.
If you're sure the engine/machining/assembly side was done correctly, and the crank and bearing caps/bores check out okay that leaves a converter/transmission issue.

Before rebuilding and risking a 3rd failure I'd probably be biting the bullet and pulling the trans for a good going-through.
 
Is this a 440? Not trying to come off as insulting your intelligence but are you certain the proper bearing is being used?...There are different ones for different year blocks.
If you're sure the engine/machining/assembly side was done correctly, and the crank and bearing caps/bores check out okay that leaves a converter/transmission issue.

Before rebuilding and risking a 3rd failure I'd probably be biting the bullet and pulling the trans for a good going-through.
It's a mildly stroked 318 Poly. Gonna start pressure tests on the torqueflite soon.
 
Did the converter slide flush up into the crank? I've seen more than a few lately that bottom in the crank before the slide all the way forward. From stock to race regardless of brand. It all seems hit or miss. A street type converter won't balloon.
Doug
 
On 318 Poly Engines.... and common to most all early hemi 331/354/392 Engines

The #5 Main Main Bearing Vertical Oil Clearance is critical... and directly proportional.....
to:
the amount of Oil 'leakage'(lubrication) out to the Thrust face of the Bearing.

Forget specs
.0025" Vertical Bearing Oil Clrc on #5 is absolutely critical, with less than .0005" taper present in the #5 Main Bore.

Did the engine exhibit absolutely wonderful Oil Pressure at all times ?
If yes ?
then I would suggest some investigation of the #5 Main and Main Bearing Clearances in general may be warranted.

PS
with a 727 Chrysler, I have NOT heard of any Stator/Pump issues that can facilitate Convertor 'pressure' being exerted on a Crankshaft.... other than the as mentioned "clearance' that must be checked/present during installation between the Convertor Lugs and the Flexplate(full pump engagement)
 
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I would guess that the crank was damaged and overlooked thus taking out the thrust bearing again after the rebuild
 
Did the converter slide flush up into the crank? I've seen more than a few lately that bottom in the crank before the slide all the way forward. From stock to race regardless of brand. It all seems hit or miss. A street type converter won't balloon.
Doug
 
Good catch, the converter has a proper fit to the crankshaft...I checked many times before mating the engine and trans.
 
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