Brand New 600hp short block. Thrust bearing failure 1k miles in

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  1. #1

    Default Brand New 600hp short block. Thrust bearing failure 1k miles in

    All, Someone directed me to modular Fords in another post. Appreciate any direction/help.

    Post is kinda long, I wanted to try and not leave anything out.

    In Short I have a suspected rear thrust bearing failure at only 1k miles in on a brand new engine, I had no issues with the same trans/TC on stock boosted motors, the only difference here is:

    new motor - 4.6 2v. built for 600hp
    new flex plate (americanmuscle_com/sr-flexplate-6bolt.html)
    Rebuilt TC new for new engine(but worked fine for 4 years prior in 2 different stock motors). Im still going to send it back to them for inspection.

    I know we are all guessing for the most part, but maybe also basing the guessing off of previous experiences or knowledge.

    Thanks in advance to anyone that reads this and/or responds ha.

    Long Story

    Im being told its my torque converter(custom edge racing 3200 high stall) or trans (4r70W rebuilt level4 from Darrin at BCA a god father of these transmissions). Ive ran this transmission and torque converter in 2 stock engines for over 5 years, never heard of a thrust bearing in my life or had any similar failure. I had the torque converter rebuilt new for the new engine/build.

    The one engine took 150k miles of hard beating from me personally (250k total on the engine total), running hot, over heating, rich/lean tunes. Ran 2.5 years of that boosted. I eventually blew a rod or lifer. I always had mild emailed tunes from one of the best tuners for these cars. I got a used engine (supposedly with 30k Miles). I then went and got an actual dyno tune (a bit more aggressive then my emailed tunes). That engine lasted almost a year of beating on it and over heating.. but I blew the head gasket (and after tear down, I had a cracked lifer bore).

    I wanted to do everything right this time, so I paid a proper race engine builder shop to build out the short block for 600HP, upgrade some things in the heads, cometic head gaskets. ARP everywhere possible etc.. any time there was a question or concern I upgraded/bought it. I had it installed from the same shop, to avoid any issue there.

    After 200 miles, I got the first oil change (new filter too). I then put another 800~ miles going back and forth to the engine builders and other shops, resolving exhaust leaks (after market CATs didn't mesh well with the OEM studs on the exhaust manifolds). The car was also always running hotish on freeway runs when it never did this before. Eventually get everything going, dyno tune scheduled and.........

    I hear what I think is another exhaust leak, but it ends up being a tapping from the flex plate on the metal gasket in-between the trans and engine. The engine builders are telling me to take it to a trans shop, so I take it there, they confirm it is coming from the flex plate but is too busy to put it on the lift and says he wouldn't worry too much about it, but to see if I can get it looked at by another shop.

    The car is also starting to crank slow, I checked a random spark plug, and it looked fine. I think maybe the starter is slow and hitting the flex plate or sliding out, so I had the starter replaced.. sound was still there. we slightly bent the metal gasket between the engine/trans and the noise went away. I was relieved and thought the problem was solved...

    20 minute test drive, all good, 20 minute ride back and things start to go bad, Im losing power, loud tapping/knocking and for the first time ever the car registers misfires in cylinder 4 and 8 (just 116 misfires and it wasn't growing) but still there. The car also was running coolant temp HOT (even though it was a 60 degree night, with highway speeds).

    I instantly pulled over, turned the car off, towed it home, then back to the engine builders. Its been sitting there waiting for them to take apart. They did say the oil was very dark/black. Which Im not sure how the trans/TC would cause that at all.

    Ive reached out to multiple engine/trans experts who all don't believe it was the trans( the trans has its own internal thrust washer and the pump is mounted to the trans cast internally), highly doubtful its the TC balloning (from its size and anti-ballon plate and 4 years of no issues). Engine builders are sure its trans/TC. What should I be looking for? oil starvation maybe? what else would be damaged internally that definitely would of not been from a Torque Converter? Im thinking what ever caused the thrust bearing failure is the same reason the car was running hot on freeway runs (even on cold nights with no aggressive driving at all).

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  3. #2


    Thrust bearing failures in automatic trans cars are usually the torque converter being pushed forward on the trans input shaft and in turn pushing the crank up against #5 thrust. The fix is the transmission builder turning down the pressure forcing the converter forward.

    Engine builders that do not want to be bothered will take your car and set it aside allowing it to sit until you raise a big enough stink they decide to work on it. When they do they will tell you whatever they found was your fault and it will cost you $XX to repair it. These types of shops usually promote how impressive they are, in order to get your business. You will not usually realize how unimpressive they are until something goes bump in the dark and they announce it is your problem.

    Bad driving manners are almost always the tune. I would revisit the tuner and ask for help there.

    Thrust bearing issues are not associated with over heating. Bad tunes and cooling system problems are associated with overheating.

    All other issues not withstanding, a dead thrust bearing means the engine must come out and be rebuilt.

    Last edited by eschaider; 11-21-2019 at 03:29 AM. Reason: Spelling and Grammar

  4. #3


    Test post.

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  6. #4


    Not sure what happened here, I wrote a big reply, it said something about being pending moderation, been waiting days. Tried to post in another thread and it let me so i tried here again.

    Ed, super appreciative of your time and reply. Every post i read on here, your the man with the knowledge. Dead on about the engine shop.

    Ive talked with my transmission builder([email protected]) in great detail about the problem, he doesn't believe its the trans at all, unless some cooler line was pinched (but i was not having any transmissions issues, trans temps were great) and I ran this tranmission for almost 5 years in 2 motors, 2.5 years of that boosted without any thrust bearing issues... with the same torque converter. Same as my torque converter builder Andre (edge racing) doesnt believe it was any type of balloning with my setup, size of converter and anti-balloning plate.

    Though I will have the TC inspected as well as the trans.

    The car had some type of heating/oiling issue from the start I believe. I know your saying cooling is tune/cooling system but everything was brand new cooling wise, it was a cold cold night. Any highway driving (I have 4.10s also) even on a cold night the temps would just rise and rise, Ive been driving these engines for 10+ years in all conditions and never had one over heat at night let alone with 70mph cold air blowing across it. 7+ tuners, 2+ engines, probably close to 50+ total tunes if not more across the years... running rich/lean/blown head gasket.... etc..

    It seems to be something with oiling was off from the start then just keep getting worse and worse as the engine shop was having me take it to 4+ other shops, anywhere but them). I started to tear down, hoping to have the engine pulled this week. Anything special I should be recording in part of that process? I was going to record the unscrewing of the TC, see if the TC slights forward at all? Not sure here, ill just try to document and document... If the TC is stuck/warped in..checking for trans dowel pins, marks on the TC hub

    Cylinder 1-4 Borescope video:
    Cylinder 5-8 Borescope video:

    Spark plug at 1k miles on the engine, just before its last drive later that night.

    Spark plug at 1015-1030~ miles after a test drive later that night.

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