Moparts
thrust bearing issues
Posted By: TheOtherDodge
thrust bearing issues - 07/13/11 05:53 PM
I think I wiped out my thrust bearing on the new motor already. I have measured .065 worth of movement and can visibly see it when I rev the motor and watch the crank trigger wheel in relation to the pickup.
I don't believe it is the converter, but talked to them anyways and they don't think it is either, mainly because Im only running 4.7 lbs of boost right now. It is a PTC unit.
What do you guys think? Oiling issue to the thrust bearing?
I have not taken it apart yet.
Posted By: goldmember
Re: thrust bearing issues - 07/13/11 06:12 PM
Is this the second time for this issue? How much clearance did you have when assembled? Possible alignment problem? Whats the converter to flexplate clearance?
Posted By: Cab_Burge
Re: thrust bearing issues - 07/13/11 06:18 PM
Their is only one thing that usually causes thrust bearings to die, that is pressure(forward or rearward thrust
)on the crankshaft
Posted By: goldmember
Re: thrust bearing issues - 07/13/11 06:25 PM
Quote:
Their is only one thing that usually causes thrust bearings to die, that is pressure(forward or rearward thrust )on the crankshaft
Naa,there are other causes as well. I do agree that is a possibility however.At least the crank being pushed forward(never seen a crank sucked back,but I haven't seen everything). Did this block have aftermarket main caps installed?
Posted By: TheOtherDodge
Re: thrust bearing issues - 07/13/11 06:37 PM
Yes, second time this has happend, but the first time, we changed converters and dont know if the thrust problem was there at that time.
The converter turns freely when not bolted to the flex plate.
The block does have aftermarket billet caps.
Posted By: Cab_Burge
Re: thrust bearing issues - 07/13/11 06:43 PM
Quote:
Quote:
Their is only one thing that usually causes thrust bearings to die, that is pressure(forward or rearward thrust )on the crankshaft
Naa,there are other causes as well. I do agree that is a possibility however.At least the crank being pushed forward(never seen a crank sucked back,but I haven't seen everything). Did this block have aftermarket main caps installed?
Belt driven superchargers can cause a lot of problems when thier not installed correctly, not saying his is but they can and have cause lots of problems on crankshafts 
Two different sets of main bearings with the same problem Time to find the cause All problems on cars are fixable, some are harder to diagnose than others
Posted By: goldmember
Re: thrust bearing issues - 07/13/11 06:46 PM
The converter turns freely is not the info needed. What is the distance between the converter mounting pad and the flexplate? What did the thrust bearings look like that were removed from the engine on the first go round? I'd be concerned with the main cap installation if it were mine.
Posted By: 526ciduster
Re: thrust bearing issues - 07/13/11 06:55 PM
Make sure the converter is not hitting the crank bolts. You can have flexplate clearance and the converter will hit the bolts.
Posted By: goldmember
Re: thrust bearing issues - 07/13/11 06:56 PM
Quote:
Quote:
Quote:
Their is only one thing that usually causes thrust bearings to die, that is pressure(forward or rearward thrust )on the crankshaft
Naa,there are other causes as well. I do agree that is a possibility however.At least the crank being pushed forward(never seen a crank sucked back,but I haven't seen everything). Did this block have aftermarket main caps installed?
Belt driven superchargers can cause a lot of problems when thier not installed correctly, not saying his is but they can and have cause lots of problems on crankshafts Two different sets of main bearings with the same problem Time to find the cause All problems on cars are fixable, some are harder to diagnose than others
Yep,I left out "the belt driven supercharger" as he doesn't have one. You are right that this problem needs to be found cause it would sure stink to do this over again.I had a mild 360 come through last year that was built by a local guy. The thrust bearing was trashed in less than 100 street miles,I could not believe what I found,but it was improper assembly that caused the problem.
Posted By: goldmember
Re: thrust bearing issues - 07/13/11 06:59 PM
Quote:
Make sure the converter is not hitting the crank bolts. You can have flexplate clearance and the converter will hit the bolts.
Posted By: MR_P_BODY
Re: thrust bearing issues - 07/13/11 07:33 PM
Quote:
Yes, second time this has happend, but the first time, we changed converters and dont know if the thrust problem was there at that time.
The converter turns freely when not bolted to the flex plate.
The block does have aftermarket billet caps.
Should have about 3/8" movement fore and aft on the
converter(not bolted up)... if not it cant grow
with the heat and torque which can cause ballooning
in the conv to allow it to move rearward
Posted By: RodStRace
Re: thrust bearing issues - 07/13/11 07:44 PM
Which side of the thrust was chewed up last time?
Both, front or back?
Posted By: mopar400
Re: thrust bearing issues - 07/13/11 07:48 PM
I had the same thing happen on my 440 yrs ago on the rear thrust surface. Found the Clevite bearing was the issue. The thrust surface was too soft on the bearing. We found bearing material in the oil filter. From memory the bearing material was real soft and a silver color. It could be easily scraped away with your finger nail. We ordered another set of Clevites and the thrust surface was a copper color. Engine was ran with those bearings for 4 years without another issue. I've seen 2 sets w/ the soft material. This was around 2000. I can't remember part #'s anymore.
Posted By: TheOtherDodge
Re: thrust bearing issues - 07/13/11 08:24 PM
I guess I have some things to check.
As far as I remember, I had about 1/8" to 3/16" between the converter mounting pad and flex plate before bolting, but I dont remember exactly. I was enough for me to not be concerned at the time.
I have not taken the current thrust bearing out, but the previous one the entire rear portion was gone. Matter of fact, it took out the thrust on the crank!
Posted By: TheOtherDodge
Re: thrust bearing issues - 07/13/11 08:30 PM
"Make sure the converter is not hitting the crank bolts. You can have flexplate clearance and the converter will hit the bolts."
How would the converter hit the crank bolts unless it is really balooning..or am I missing something?
Posted By: TheOtherDodge
Re: thrust bearing issues - 07/13/11 08:30 PM
Goldmember you said "The thrust bearing was trashed in less than 100 street miles,I could not believe what I found,but it was improper assembly that caused the problem."
How was it improperly assembled?
Posted By: John_Kunkel
Re: thrust bearing issues - 07/13/11 08:48 PM
Even if the converter is hitting the crank bolts or if there is a flexplate pull-up problem, this is local to the rear flange and shouldn't cause forward thrust on the thrust main.
Posted By: MR_P_BODY
Re: thrust bearing issues - 07/13/11 08:58 PM
Quote:
Even if the converter is hitting the crank bolts or if there is a flexplate pull-up problem, this is local to the rear flange and shouldn't cause forward thrust on the thrust main.
Only if the conv has enough room to grow and not bottom
out in the pump drive... other wise it bottoms in the
pump drive and then pushes forward on the crank
Posted By: mac56
Re: thrust bearing issues - 07/13/11 10:02 PM
Quote:
"Make sure the converter is not hitting the crank bolts. You can have flexplate clearance and the converter will hit the bolts."
How would the converter hit the crank bolts unless it is really balooning..or am I missing something?
I had one converter that had an anti balloon plate welded around the snout and it would hit the bolts before it closed the gap for the flex plate bolts so even though it looked like a gap it really was up tight.
Posted By: MR_P_BODY
Re: thrust bearing issues - 07/13/11 10:31 PM
Quote:
Quote:
"Make sure the converter is not hitting the crank bolts. You can have flexplate clearance and the converter will hit the bolts."
How would the converter hit the crank bolts unless it is really balooning..or am I missing something?
I had one converter that had an anti balloon plate welded around the snout and it would hit the bolts before it closed the gap for the flex plate bolts so even though it looked like a gap it really was up tight.
Even if the flex plate had some bind it wouldnt push
forward... it has to bottom out in the pump drive
to push the crank forward
Posted By: Cab_Burge
Re: thrust bearing issues - 07/13/11 10:34 PM
If you have space between the converter bolt lugs and the flex plate and DON"T use spacers to fill that gap it will pull the converter forward up agianst the crankshaft
Probally causing your problem
The converter should not be held against the converter with any tension onto the flex plate
I have had to use harden head bolt washers bewtween the flexplate and the converter lugs to avoid prelaoding tension from the converter to the crankshaft, cheap imported cranksahfts
I'm guilty of using them
Posted By: rickraw
Re: thrust bearing issues - 07/13/11 10:35 PM
hey, i had the same issue a while ago with a 493. converter wasn't the problem. i wasn't using a cam button. i beleive the cam was was trying to come out of the block( i have heard higher spring pressures can force the cam to come out of the block). if the cam is out, the chain will pull the crank with it.
Posted By: supercomp
Re: thrust bearing issues - 07/13/11 10:48 PM
Make sure main cap thrust surface is not thicker then the block.
Posted By: TheOtherDodge
Re: thrust bearing issues - 07/13/11 10:51 PM
I don't have any spacers now. The converter is bolted directly to the flex plate.
Unlike big blocks, small blocks have a cam plate to keep the cam from walking forward.
supercomp: explain?
Posted By: ZIPPY
Re: thrust bearing issues - 07/14/11 04:07 PM
Was it mocked up without the crank, but with the bearings to make sure the thrust surface(s) line up squarely (comparing upper to lower)?
Was the main cap just torqued down, or was the thrust bearing seated first? (referring to forcing the crank forward in the block during torque down)
Either of these can cause an oiling issue. If the bearing shell thrust surfaces are not square with each other, the oil film gets scraped off the thrust surface....
Just throwing a 'maybe' out there
Posted By: TheOtherDodge
Re: thrust bearing issues - 07/14/11 04:11 PM
Zippy, I did not mock up the bearings to check alignment. I did set thrust after final torque, which I thought was the way you are supposed to do it.
Posted By: ZIPPY
Re: thrust bearing issues - 07/14/11 05:19 PM
Quote:
Zippy, I did not mock up the bearings to check alignment. I did set thrust after final torque, which I thought was the way you are supposed to do it.
I was taught to set thrust/force the crank forward more during torquedown, rather than after.
I can't claim that's perfect info...but that's what the instructors taught me in '88 or whatever it was. It may be flawed somehow for all I know.
Ex: if final torque is 90, then go about 30, set thrust. Do the other caps to the same torque. Verify end play/thrust. Then 60, set thrust again, do the other caps, check the gauge. Then 90, same routine.
Could be converter, but prob. not with that low of boost? 
Posted By: Cab_Burge
Re: thrust bearing issues - 07/14/11 05:47 PM
Quote:
Zippy, I did not mock up the bearings to check alignment. I did set thrust after final torque, which I thought was the way you are supposed to do it.
How can you set the thrust after all of the main bolts are torque to spec? I torque #1,2,4, and 5 to the final torque specs, it varys with motors. I torque #3 to 20 to 30 Ft lbs and then check the end play, thrust measurement. If within spec I tighten # 3 to final torque specs. and check it again, if it is not within, to little, I use a dead blow hammer and tap (whack it hard 
) the crank back and forth to settle the bearings shells in the caps and center them on the main caps, I then check it again 
If it is okay then I tighten it down and recheck when tight, if not within specs. it is time to figure out why
Posted By: TheOtherDodge
Re: thrust bearing issues - 07/14/11 06:09 PM
"How can you set the thrust after all of the main bolts are torque to spec? "
Why can't you? The crank better not be that tight where you can't set the thrust!
Posted By: goldmember
Re: thrust bearing issues - 07/14/11 06:20 PM
Quote:
"How can you set the thrust after all of the main bolts are torque to spec? "
Why can't you? The crank better not be that tight where you can't set the thrust!
You have to set the cap correctly and I don't see how you'd do that with the cap torqued tight to the register. The cap should have enough clearance between the bolt/studs to allow the cap to be aligned with the block,making the bearing aligment correct.
Posted By: Cab_Burge
Re: thrust bearing issues - 07/14/11 06:23 PM
Quote:
Quote:
"How can you set the thrust after all of the main bolts are torque to spec? "
Why can't you? The crank better not be that tight where you can't set the thrust!
You have to set the cap correctly and I don't see how you'd do that with the cap torqued tight to the register. The cap should have enough clearance between the bolt/studs to allow the cap to be aligned with the block,making the bearing aligment correct.
Posted By: B3422W5
Re: thrust bearing issues - 07/14/11 06:57 PM
I had thrust bearing issues with my old 422 smallblock motor.
The new owner of the car had the motor freshened, and the 727 freshened as well.
The guy who is going through the trans told him he thought the problem with the thrust bearing was because of the line pressure the trans was using( 160), as the transbrake valve body was a Griner and as far as i know is supposed to be set there( the trans i had built by JPT, a long standing expert in performance automatics) i kinda doubt that this guy is correct about the 160 pressure being to high and being the cause.
He told the new car owner the pressure should be about 60
Anyhow, i am unsure what the resolution is or will be.
Posted By: TheOtherDodge
Re: thrust bearing issues - 07/14/11 07:35 PM
Ok, then I did that wrong, but that is how I have always set it. I guess I got lucky before. I just spoke to the machine shop and they confirmed but said that most likely that did not cause the problem, but is a consideration.
Im going to see if I can drop the pan with the motor in the truck (maybe have to lift it a bit) and look at it and see if I can just replace the thrust bearing.
Also the machine shope echoed the possiblity of line pressure being too high...
Posted By: rickraw
Re: thrust bearing issues - 07/15/11 03:16 AM
line pressure is not the cause. if u lower it, u could smoke the trans. i'm running a 904- 180# 1st, 160# 2nd & 3rd. no thrust problems. stay safe, seeya.
Posted By: ETASPEN
Re: thrust bearing issues - 07/15/11 04:01 AM
I'm gonna go out on a limb here, as this is rare...BUT, before you freshened the engine, did you wipe the trans or converter? If so, the crankshaft could be "broke", cracked, whatever you want to call it. The impact from the converter, front pump on trans can break a crank. I know folks whom have seen the same symptoms after a trans failure. PM supercomp...he been there, done that.
Posted By: John_Kunkel
Re: thrust bearing issues - 07/15/11 10:08 PM
Transmission line pressure doesn't put pressure directly on the crank but converter pressure does....under normal circumstances the converter pressure is much lower than line pressure.
But, in rare cases, the transmission reaction shaft can spin in its support and shut off the outflow of line pressure from the converter, when this happens the converter pressure regulator valve doesn't function and converter pressure is the same as line pressure.
Posted By: 526ciduster
Re: thrust bearing issues - 07/15/11 10:25 PM
When you get it apart look at the back of the converter and see if it has hit the crank bolts. I had two motors do this and it killed the thrust in both. One turbo car and one procharged car. We had a na car hit too but caught it before the thrust was damaged.
this may not be your problem but is worth checking into.
Posted By: oldtimer5151
Re: thrust bearing issues - 07/16/11 01:15 AM
Cab had the right idea about oil problem. The thrust bearing problem is either a bent crank or improper alignment of the main caps. A crank may feel free when you spin it in a new build. Put a lot of pressure on the thrust and any mis-alignment will break up the pressure film of the oil-result-bearing material all over pan. Any race engine must be align honed by good machine shop.
Posted By: J_BODY
Re: thrust bearing issues - 07/16/11 01:26 AM
Did this on my 498. wiped out the bearing and grooved the crank. Had the crank repaired, put in new thrust bearings, got a NEW torque converter, and never had the prob again.
Posted By: TheOtherDodge
Re: thrust bearing issues - 07/23/11 07:03 PM
As a follow up, I just have the line pressure checked and it was fine at about 140 lbs.
Posted By: mopar400
Re: thrust bearing issues - 07/24/11 08:30 PM
Posted By: Twostick
Re: thrust bearing issues - 07/25/11 03:12 AM
Did you say there was a gap between the converter and the flexplate that you can't lose by pushing the converter forward? Not a good sign IMHO.
I saw this on a fresh Hemi in the shop where my engine was being built. The engine had a bunch of dyno time to dial in the EFI and was fine when delivered to the customer. As it turned out when the install was done the snout on the converter was interfering with the the register in the crank. This caused a gap between the converter and the flexplate which the guy who installed the engine thought was no big deal and just "sucked 'er in" with the bolts. It wiped out the thrust in short order. Luckily that's all it did. Long story short new converter happy new thrust bearing.
Seeing as this is X2 and likely not your first rodeo I predict it will be something obscure like this. Like has been posted, not a lot of ways to cause this and short of rookie type mistakes it'll have to be something outside the box.
Kevin
Posted By: TheOtherDodge
Re: thrust bearing issues - 07/25/11 01:59 PM
Kevin, IRRC, there was some space, maybe 1/8th of an inch between the mounting pad and flex plate..not enough or too little to throw up a caution flag when I was installing.
I also did not notice any crank to converter hub interference, but I did not specifically look for that. Like I said before, I didn't notice anything unusual about the converter install.
When I pull the motor in a few weeks (buying a new house this weekend and won't have time to mess with truck for a while) I will post what I find.
