Scat crank thrust bearing killed again

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345man2

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Wondering how many people have had thrust bearing problems It’s a 416 with scat crank. P t c convert 904 it killed one a couple years ago same setup replaced crank sent converter off checked line pressures thought it was fixed prob didn’t have fifty miles on motor and thrust out again has any one had this prob or any answers that’s a lot of money for fifty miles
 
Is your driveshaft bottoming the tailshaft? What is the application? Drag, dirt, street?
 
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What kind of thrust clearance do you have upon assembly?
 
Sounds like you don't have the converter in all the way. If you have .004 thrust it should live. Unless you are using tar for oil.
 
Driveshaft isn’t bottoming 5 to 6 thousands end play at assembly and converter was seated on flex plate with bolts tight with a little over 1/8 flex plate converter clearance
 
What are the operating pressures of the transmission? Who built the tranny? What was the endplay on the input shaft? What cooler are you using? Did you make sure the cooler lines are clear?
 
Pressure in cooler lines were good worked with a and a checking them b and m super cooler lines are new just replaced them can’t remember end play but going to check it again when pull it apart dodge dealer tranny guy built trans
 
345man2 said:
Pressure in cooler lines were good worked with a and a checking them b and m super cooler lines are new just replaced them can’t remember end play but going to check it again when pull it apart dodge dealer tranny guy built trans
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See question in post #3.
 
345man2 said:
Wondering how many people have had thrust bearing problems It’s a 416 with scat crank. P t c convert 904 it killed one a couple years ago same setup replaced crank sent converter off checked line pressures thought it was fixed prob didn’t have fifty miles on motor and thrust out again has any one had this prob or any answers that’s a lot of money for fifty miles
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You might try the Search Threads & Posts section. Use "Stroker Thrust Bearings" as your search subject.
 
You really have to watch some of these aftermarket cranks. One bit me in the butt and wiped a thrust because the convertor hub was to tight in the crank hub. Make sure it floats in there EASILY.
 
What clearance between converter hub and crank do you run pittsburgh
 
345man2 said:
What clearance between converter hub and crank do you run pittsburgh
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I won't run less than .008 and I'm comfortable at .010 thrust


I read this wrong so I hit edit. I have never measured convertor to hub clearance as I go by feel. I've had zero on one after market crank or close to it and another was to tight to my liking. I just used a flapper wheel on a die grinder to give me more clearance.
 
That was my next question... How did it fit the hub? And last, assuming you have not dialed the transmission case because most don't - but it might be a good idea if the block was align honed.
 
moper said:
That was my next question... How did it fit the hub? And last, assuming you have not dialed the transmission case because most don't - but it might be a good idea if the block was align honed.
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"...the flex plate gets its name because it will flex forward and backward as the engine rpm increases. this is due to fluid pressure inside the converter as well. as any front to back movement of the snout by flexing the torque converter is able to float in the crank hub..." bottoming of converter is also addressed...
 
Thanks for that. Everything must be fine then and the crank just is terrible.
 
moper said:
Thanks for that. Everything must be fine then and the crank just is terrible.
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doubt the crank had anything to do with it unless it was machined tight. If you had .005 then its not the crank. As mentioned, check the snout to crank fit.
 
Block was line honed the converter to crank fit was snug but not tight going to check more when I pull it apart I was running a t ci flexplate and and 9.5 p t c convertor
 
OP, did you take the pan off to find this after 50 miles? Or is there some other external symptom that is showing this?
 
Was under the hood cracking throttle and saw balancer moving
 
345man2 said:
Was under the hood cracking throttle and saw balancer moving
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When the engine is fresh it takes very little load to kill the thrust. Almost none. I lost a threat because I was in the army and let the builder assemble the short block so I could finish the rest up on leave. He didn't tell me he swapped out dampers and timing covers (1982 so I no longer remember why he did it) and the damper barely touched the timing cover and ate the thrust.

Of course, the prick said I couldn't adjust a clutch and that's what ate it. When I got back home and took it apart, I showed him the marks on the timing cover and the fact that the thrust was gone on the DAMPER side and not the flywheel side. He was fired.

You need to double check all that stuff around the converter. That's why I asked if you had the converter all the way into the pump and I should have mentioned as PBR did to check the fit of the hub to the crank. I've seen OE cranks that were undersized and the finish was horrible. Had to stick the in the lathe and fix it. Most aftermarket cranks should be better than that, but poo poo occurs.
 
good points all
check finish on crank and that thrust is parallel- I've seen them like files and warped- ground too fast
I drill through the thrust with a 1/16 then through the block into the main feed around .040 then put a cup around the thrust hole
I also use the bearing scraper and relieve the parting lines from the oil groove back
I've had trouble with stick shifts also
Anyone use Gil Younger s trick of cutting through the flexplate holes on the following side
Gil's theory was that the flex plates were too stiff
RIP friend
 
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