Mopar thrust bearing failure

[devo340]

Originally Posted by Ed Wright

You can slide the converter back from the flex plate when unbolted, right?

Yes

[devo340]

Thanks for the response guys.
Got a lot of things to check out in the off season.
At least my kid won some cash in the Bracket car last night to pay for repairs on the Stocker. LOL

[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

[devo340]

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]

do you have another transmission you can test with?

[ss3011]

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 .

[devo340]

Originally Posted by David Lee

do you have another transmission you can test with?

Yes, used my spare transmission.

[Coleydog]

Could it be a balance issue after fixing the crank? I'll be running a 340 for the first time and I'm all ears on these small engines.

[Hacksaw]

Originally Posted by Coleydog

Could it be a balance issue after fixing the crank? I'll be running a 340 for the first time and I'm all ears on these small engines.

Unlikely a balancing issue. A 340 is internally balanced and has different journal sizes than a 360.

[James L Miller]

Originally Posted by Hacksaw

Unlikely a balancing issue. A 340 is internally balanced and has different journal sizes than a 360.

Except for the 1973 cast crank 340. It has a special balancer on the front, but probably could be internally balanced with lighter rods and pistons (that part should be easy with the stock 340 slugs). All the rod journals are the same size, the 360 has larger main journals than the other SB Mopars.