Mopar thrust bearing failure

devo340 · 09-09-2017, 05:25 PM

I keep killing the thrust bearing in my 360 Stocker after 10 passes.
Last time, had the thrust repaired on the crank, freshen the convertor, changed to another 904 trans, did away with the quik disconnects on the trans cooling lines.
After the thrust repair, I had .002 endplay.
The time before, had .010 endplay.
All the bearing look great.
Anyone else have this problem?

Lee Valentine · 09-09-2017, 05:32 PM

.002 is too tight it will cause a failure.

jims5600 · 09-09-2017, 06:05 PM

I agree with Lee,that is rather snug. Out of curiosity,what is your stall
speed? I have seen a real high rpm stall causing early thrust brg.
problems but I would think a stocker wouldn't hit all that hard.
All your end play etc is within specs I assume.
Good luck devo

jmcarter · 09-09-2017, 06:36 PM

Quote:

Originally Posted by jims5600

I agree with Lee,that is rather snug. Out of curiosity,what is your stall
speed? I have seen a real high rpm stall causing early thrust brg.
problems but I would think a stocker wouldn't hit all that hard.
All your end play etc is within specs I assume.
Good luck devo

And along the same lines, sure the converter isn't ballooning? Might want to ask whoever freshened it about that. Had a "other brand" that caused me some problems before changing to ATI

devo340 · 09-09-2017, 07:03 PM

I though .002 might be too tight, I checked the service manual & it had .002-.010 for range.
It is a ATI convertor, sent it back to them. Asked about it ballooning, no concerns found. It was freshened up at that time also.
It is footbraked to 3K to leave.
Another racer was having the same problem with a 340 Stocker.
He recommended me to a guy at Pro Trans.
They have a piece called the "destructor" that goes into the convertor charge hole.
I haven't disassembled the engine from this last failure to inspect the bearing yet. Just cut the oil filter open, found bearing material & the crank has excess movement.
I checked the crank during the last race, it didn't kill it until the last two passes. Also lost a tenth at the same time.

Greenlight · 09-09-2017, 08:29 PM

0.002" is way too tight for a race engine.

0.007" is more typical for a race engine. I lot of flexing occurs under the high stresses in a race engine.

Also, please check the end play with JUST the upper bearing in place, then again with JUST the lower bearing in place to confirm the alignment of the upper to lower bearing halves.

You know the saying, "If you have too much bearing clearance you are the only one who knows. If you don't have enough bearing clearance, EVERYBODY knows."

It's best that you are the only one who knows.

BillK · 09-10-2017, 06:01 PM

Devo,

Is this a new engine or has it run before without hurting the thrust bearing ?

The reason I ask is I had a problem with a thrust bearing in a 350 Chevy years ago. The block had been align honed and when they cut the cap they cut it crooked and it was tilting the thrust bearing just slightly. Took me a while to figure it out.

Did something change in your combination right before your thrust problem started ?

Just thinking out loud

devo340 · 09-10-2017, 09:12 PM

Quote:

Originally Posted by BillK

Devo,

Is this a new engine or has it run before without hurting the thrust bearing ?

The reason I ask is I had a problem with a thrust bearing in a 350 Chevy years ago. The block had been align honed and when they cut the cap they cut it crooked and it was tilting the thrust bearing just slightly. Took me a while to figure it out.

Did something change in your combination right before your thrust problem started ?

Just thinking out loud

Not a new engine. Ran the car in 2016 with no concerns. Had a trans leak, pulled it & had it looked at to be freshen. Trans guy couldn't find anything wrong. resealed it. Took it to our first race this season, lost #6 rod bearing. Had the crank ground, replaced 2 rods, new rings & intake valves. Just freshen the engine. Wasn't as fast it should have been, slowed way down after the 2nd race back. found the thrust had severe wear allowing the crank counter weight rub the main web in the block. Had the crank repaired, all the bearings looked really good. replaced bearings & oil pump. lasted for two more races, started slowing again. cut the filter apart, found bearing material. also excess movement in the crank. haven't pulled the engine yet.I still had the last oil filter from 2016. it was perfect inside. May be coincidence, started having problems after the trans was checked out.

David Lee · 09-10-2017, 09:37 PM

do you have another transmission you can test with?

ss3011 · 09-10-2017, 11:38 PM

Are both the dowel pins that align the bellhousing still in the block . Sounds like something didn't go back together the same after the trans repair .

09-09-2017, 05:25 PM	#1
devo340 Junior Member Join Date: Apr 2016 Location: Sapulpa, OK Posts: 84 Likes: 93 Liked 165 Times in 27 Posts	Mopar thrust bearing failure I keep killing the thrust bearing in my 360 Stocker after 10 passes. Last time, had the thrust repaired on the crank, freshen the convertor, changed to another 904 trans, did away with the quik disconnects on the trans cooling lines. After the thrust repair, I had .002 endplay. The time before, had .010 endplay. All the bearing look great. Anyone else have this problem?

09-09-2017, 05:32 PM	#2
Lee Valentine Senior Member Join Date: May 2004 Location: Brookfield, CT Posts: 708 Likes: 13 Liked 322 Times in 68 Posts	Re: Mopar thrust bearing failure .002 is too tight it will cause a failure. __________________ Lee Valentine 1661 STK

09-09-2017, 06:05 PM	#3
jims5600 Member Join Date: Oct 2011 Posts: 125 Likes: 47 Liked 21 Times in 9 Posts	Re: Mopar thrust bearing failure I agree with Lee,that is rather snug. Out of curiosity,what is your stall speed? I have seen a real high rpm stall causing early thrust brg. problems but I would think a stocker wouldn't hit all that hard. All your end play etc is within specs I assume. Good luck devo

09-09-2017, 07:03 PM	#5
devo340 Junior Member Join Date: Apr 2016 Location: Sapulpa, OK Posts: 84 Likes: 93 Liked 165 Times in 27 Posts	Re: Mopar thrust bearing failure I though .002 might be too tight, I checked the service manual & it had .002-.010 for range. It is a ATI convertor, sent it back to them. Asked about it ballooning, no concerns found. It was freshened up at that time also. It is footbraked to 3K to leave. Another racer was having the same problem with a 340 Stocker. He recommended me to a guy at Pro Trans. They have a piece called the "destructor" that goes into the convertor charge hole. I haven't disassembled the engine from this last failure to inspect the bearing yet. Just cut the oil filter open, found bearing material & the crank has excess movement. I checked the crank during the last race, it didn't kill it until the last two passes. Also lost a tenth at the same time.

09-10-2017, 06:01 PM	#7
BillK Member Join Date: Nov 2005 Location: Waldorf Md Posts: 222 Likes: 10 Liked 26 Times in 15 Posts	Re: Mopar thrust bearing failure Devo, Is this a new engine or has it run before without hurting the thrust bearing ? The reason I ask is I had a problem with a thrust bearing in a 350 Chevy years ago. The block had been align honed and when they cut the cap they cut it crooked and it was tilting the thrust bearing just slightly. Took me a while to figure it out. Did something change in your combination right before your thrust problem started ? Just thinking out loud __________________ Bill Koustenis

09-09-2017, 08:29 PM	#6
Greenlight Member Join Date: Dec 2004 Posts: 208 Likes: 9 Liked 70 Times in 18 Posts	Re: Mopar thrust bearing failure 0.002" is way too tight for a race engine. 0.007" is more typical for a race engine. I lot of flexing occurs under the high stresses in a race engine. Also, please check the end play with JUST the upper bearing in place, then again with JUST the lower bearing in place to confirm the alignment of the upper to lower bearing halves. You know the saying, "If you have too much bearing clearance you are the only one who knows. If you don't have enough bearing clearance, EVERYBODY knows." It's best that you are the only one who knows.

09-10-2017, 09:37 PM	#9
David Lee VIP Member Join Date: Oct 2007 Posts: 1,097 Likes: 405 Liked 250 Times in 101 Posts	Re: Mopar thrust bearing failure do you have another transmission you can test with?

09-10-2017, 11:38 PM	#10
ss3011 Senior Member Join Date: Feb 2002 Location: Southeast Michigan Posts: 885 Likes: 63 Liked 221 Times in 102 Posts	Re: Mopar thrust bearing failure Are both the dowel pins that align the bellhousing still in the block . Sounds like something didn't go back together the same after the trans repair .