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cause for thrust bearing failure? 440

Posted By: aspenrt360

cause for thrust bearing failure? 440 - 06/04/13 11:55 AM

so we are getting the crank fixed right now the thrust bearing failed big time! i have never even heard this engine run but it seems to have been put together ok. i am having the block tanked to get all the oil passages cleaned out then new bearings throughout. we will give it a hone and a fresh set of rings while we are at it. it only had 4000 miles when it lost the thrust bearing. the converter looks fine but i am worried about the trans i don't know much about it and i am concerned it may have had something to do with the bearing issue.what could be some of the possible causes and what can i look for? thanks guy's
Posted By: Dragula

Re: cause for thrust bearing failure? 440 - 06/04/13 11:59 AM

Last time I saw one go that quick, it was a spacing problem between the convertor and the back of the crank. Turns out the convertor had extra thick flex plate pads on it for a mid plate set-up...Owner assembled it not thinking the difficulty he had was an issue.
Posted By: aspenrt360

Re: cause for thrust bearing failure? 440 - 06/04/13 12:03 PM

hmm the converter does have fairly thick pads on it i have not really looked at it to hard yet as i have been tearing down the engine and getting it to my machinist to have it speced out. so if the pads are to thick it does what? pushes the converter forward?
Posted By: Dragula

Re: cause for thrust bearing failure? 440 - 06/04/13 12:12 PM

Quote:

hmm the converter does have fairly thick pads on it i have not really looked at it to hard yet as i have been tearing down the engine and getting it to my machinist to have it speced out. so if the pads are to thick it does what? pushes the converter forward?





Not saying that is your cause, but if the pads are too thick, it pushes on eveything. It will push the back of the crank and you will loose one side of the thrust...Take a look and see what it looks like. Post a pic if you can.
Posted By: MR_P_BODY

Re: cause for thrust bearing failure? 440 - 06/04/13 02:17 PM

If you have good torque and the conv doesnt have balloning
plates the conv will grow and push on the pump and forward
on the crank... weak leak is the thrust bearing.. as
said if it didnt have some play to the flex plate it
will eat the bearing
Posted By: aspenrt360

Re: cause for thrust bearing failure? 440 - 06/04/13 05:58 PM

i am going to pull it tonight and try to find some part #'s or somthing to id it. he say's it is a B+M. that does not mean much if i don't know more about it!
Posted By: TheOtherDodge

Re: cause for thrust bearing failure? 440 - 06/04/13 06:09 PM

I killed my trust and could not determine why. Converter was fine, etc. My transmission guy who races sprint cars said he used to see alot of this and he puts in a oil grove on the trust side for additional oiling and it solved his problems. I did the same and have not had a problem since.
Posted By: Cab_Burge

Re: cause for thrust bearing failure? 440 - 06/04/13 06:32 PM

One way to check the preloading of the thrust bearing by the converter is to see if there is any play between the converter mounting lugs and the flexplate Mine usually have between .250 and .125 on torqueflytes. When you use a mid plate that removes the clearances nessitating redoing the converter to get some freeplay between the lugs and the flexpalte Take all four bolts loose and see if your converter will slide back and forth on the input shaft If it does and you have over 1/8 inch movement your probally good BTW, I have seen some that you need to put spacers(round washers) between the mounting lugs and the flexplate so you don't bend the fllexplate by tightening the bolts up when the mounting lugs don't mate (touch) evenly with the backside of the flexpaltes, in that case the converter hub was to long to allow the converter lugs to touch the flexplate like they should There is always a reason(and a cure) for component failure, figuring out the cause can be the hard part
Posted By: John_Kunkel

Re: cause for thrust bearing failure? 440 - 06/04/13 06:48 PM


In some rare cases the reaction shaft spins in the pump support and sends full line pressure to the converter instaed of a lower regulated pressure. This keeps a constant forward pressure of several hundred pounds on the crank.
Posted By: aspenrt360

Re: cause for thrust bearing failure? 440 - 06/04/13 08:06 PM

yep lot's of test fitting in my future! this guy is a good buddy and i would like to solve this problem for him. i hope i can figure it out. thanks for all the help guy's.
Posted By: dmking

Re: cause for thrust bearing failure? 440 - 06/05/13 03:16 AM

we bent a flex plate and took out the thrust.

i also seen a block that had the mains line honed
and the caps were not cut on a 90. loosen the cap
and good end play. torque it down and it gets tight.

that may be something to look at on the failure if
nothing else shown up.
Posted By: an8sec70cuda

Re: cause for thrust bearing failure? 440 - 06/05/13 01:24 PM

I've seen an externally balanced 440 w/ an internally balanced flexplate eat up thrust bearings. Changed the plate and no more problems.
Posted By: blue_stocker

Re: cause for thrust bearing failure? 440 - 06/07/13 05:53 PM

I had one 440 that had a constant thrust-destroying problem in my stocker when I was running it in a stick-shift class. I never did find what was causing that dilemma?!
Posted By: JohnRR

Re: cause for thrust bearing failure? 440 - 06/07/13 05:57 PM

Quote:



i also seen a block that had the mains line honed
and the caps were not cut on a 90. loosen the cap
and good end play. torque it down and it gets tight.






I had a similar problem after a linebore only it locked the crank solid when the #3 was torqued down.
Posted By: pittsburghracer

Re: cause for thrust bearing failure? 440 - 06/07/13 06:07 PM

I think a lot of these issues are caused by engine builders not SETTING ( or seating ) the thrust bearing properly during an engine build and correcting if needed the thrust bearing clearances. With more and more engines going together with NEW after market cranks and bearings made who knows where this area needs SPECIAL attention.
Posted By: JohnRR

Re: cause for thrust bearing failure? 440 - 06/07/13 06:20 PM

Quote:

I had one 440 that had a constant thrust-destroying problem in my stocker when I was running it in a stick-shift class. I never did find what was causing that dilemma?!




Could it have been the constant pushing of the clutch pedal ?

I'm adding a oil channel in the #3 bearing on my latest builds , going in stick cars, to help put more oil between the crank and the bearing.
Posted By: torkrules

Re: cause for thrust bearing failure? 440 - 06/07/13 07:02 PM

Quote:

so we are getting the crank fixed right now the thrust bearing failed big time! i have never even heard this engine run but it seems to have been put together ok. i am having the block tanked to get all the oil passages cleaned out then new bearings throughout. we will give it a hone and a fresh set of rings while we are at it. it only had 4000 miles when it lost the thrust bearing. the converter looks fine but i am worried about the trans i don't know much about it and i am concerned it may have had something to do with the bearing issue.what could be some of the possible causes and what can i look for? thanks guy's




Typical candidates are:

Rough on the thrust face of the crank. When the crank is machined it leaves "star burst" lines radiating outward. Very difficult to polish

Ballooning torque converter from excessive pressure in the converter

Lack of play between flex plate and converter

Excessive clutch pressure (4 speeds). The heavier the clutch, the more pressure needs to be exerted to release it. This force pushes the crank forward against the rear thrust surface. I try not to start my car with my foot on the clutch because there is 0 oil pressure. I also try to shift to neutral and have my foot off the clutch at stop lights.
Posted By: BIGSPEED

Re: cause for thrust bearing failure? 440 - 06/10/13 06:22 AM

99 and 1/2 percent of thrust bearing failures are related to the convertor,trans,trans cooler ,flexplate etc.NOT THE ENGINE BUILDER,HAVE YOU EVER SEEN A THRUST WEAR OUT ON THE FRONT SIDE?43 years in the engine building business never seen one thrust failure on the front side!Bill C.
Posted By: JohnRR

Re: cause for thrust bearing failure? 440 - 06/10/13 02:18 PM

Quote:

99 and 1/2 percent of thrust bearing failures are related to the convertor,trans,trans cooler ,flexplate etc.NOT THE ENGINE BUILDER,HAVE YOU EVER SEEN A THRUST WEAR OUT ON THE FRONT SIDE?43 years in the engine building business never seen one thrust failure on the front side!Bill C.




I don't think he was talking about the PROFESSIONAL engine builder
Posted By: Performance Only

Re: cause for thrust bearing failure? 440 - 06/10/13 03:11 PM

Quote:

I think a lot of these issues are caused by engine builders not SETTING ( or seating ) the thrust bearing properly during an engine build and correcting if needed the thrust bearing clearances. With more and more engines going together with NEW after market cranks and bearings made who knows where this area needs SPECIAL attention.




I have to agree with this. generally speaking, It's not the experienced guys having these issues unless it's due to factors outside of the engine, but from what we see here, that's seldom the case.
Main caps cut crooked during a line hone/bore is a very common cause as is not setting the clearance properly during assembly and verifying it, especially when changing over to studded mains.
Posted By: pittsburghracer

Re: cause for thrust bearing failure? 440 - 06/10/13 03:11 PM

Quote:

Quote:

99 and 1/2 percent of thrust bearing failures are related to the convertor,trans,trans cooler ,flexplate etc.NOT THE ENGINE BUILDER,HAVE YOU EVER SEEN A THRUST WEAR OUT ON THE FRONT SIDE?43 years in the engine building business never seen one thrust failure on the front side!Bill C.




I don't think he was talking about the PROFESSIONAL engine builder




BINGO. Thanks for picking up on that.
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