Main thrust bearing wear ????

[38turbo]

Had oil pan off for rear main seal decided to roll in a new set of rod and main bearings. bearings were a little worn not bad some stuff embeded in them from what our wonderful filtration systems let through. until i got to the main thrust bearing the thrust side of bearing towards rear of engine was worn considerably and has grooves in it the crank was also worn a little and starting to groove. however the thrust side of bearing facing front of engine not hardly worn at all.. anyone else run into this? have included pics engine is bone stock first time oil pan has ever been removed 41k miles 86 gn

what can cause this?? somthing in trans/convertor forcing crank forward or misaligned pulleys pulling crank forward?

had another 86 gn with 60k miles i put bearings in it to and don't remember the thrust bearing being worn like that

the crank does have end play in it now without the engine running there is nothing forcing crank forward i will bring my dial indicator home from work and get the exact end play reading with new bearings tonight

top pic thrust toward front of engine
second pic worn side of thrust bearing towards rear
i know pics arent that great time to invest in better camera

 

[Chuck Leeper]

"to the main thrust bearing the thrust side of bearing towards rear of engine was worn considerably and has grooves in it the crank was also worn a little and starting to groove. however the thrust side of bearing facing front of engine not hardly worn at all.. anyone else run into this?"

As you said, the converter is pushing forward.. thus the increased wear on the back side.. Considered normal, until the wear exceeds the tolerances.

 

[wickedtt]

Had oil pan off for rear main seal decided to roll in a new set of rod and main bearings. bearings were a little worn not bad some stuff embeded in them from what our wonderful filtration systems let through. until i got to the main thrust bearing the thrust side of bearing towards rear of engine was worn considerably and has grooves in it the crank was also worn a little and starting to groove. however the thrust side of bearing facing front of engine not hardly worn at all.. anyone else run into this? have included pics engine is bone stock first time oil pan has ever been removed 41k miles 86 gn

what can cause this?? somthing in trans/convertor forcing crank forward or misaligned pulleys pulling crank forward?

had another 86 gn with 60k miles i put bearings in it to and don't remember the thrust bearing being worn like that

the crank does have end play in it now without the engine running there is nothing forcing crank forward i will bring my dial indicator home from work and get the exact end play reading with new bearings tonight

top pic thrust toward front of engine
second pic worn side of thrust bearing towards rear
i know pics arent that great time to invest in better camera

What torque converter was behind this motor?

 

[38turbo]

stock tc will do endplay measurements in morning
just seemed pretty bad to me
wanted to know if theres anything i can do to stop the wear the crank was already getting grooves in it wouldn't be suprised if its out of spec when i take measurements in morning
if i remember correctly endplay spec is around .004 to .008
pretty sure its more than that even with new bearings

 

[38turbo]

havent had car but about 4 months and it looks like it was well taken care off all stock 41k miles doesn't appear to have been raced or abused
just suprised to see that much wear in 41k

 

[Tony Shoaff]

Stock converter highly doubtful causing wear. After market very possible. Run hard, boost levels to high, oiling issue, lots of different things can cause thrust bearing wear. They look good from here I can show you what worn looks like from my old engine builder not mating the main billet caps properly to the block.

 

[38turbo]

if it was the case of just the bearing being worn wouldn't worry about it to much i just didn't like what it was doing to the crank. don't think it has to do with the cap mating to the block beacuse the upper thrust bearing was worn the same as the lower and evenly

 

[Tony Shoaff]

Could just be boost levels with stock crank? Call Dan @ DLS your in Indiana. He will explain what to ck at least?

 

[38turbo]

OK just went out and measure endplay with new bearings its at .008 which is right at the high end of the spec i believe. wonder if the crank will just wear away faster now (maybe hardness gone)?

 

[38turbo]

no one else has ran into this ????

 

[bison]

If the PR valve in the pump was modified it could be a problem with any converter. Id verify cooler pressures before pushing it when you get it together. 008 is ok if the thrust surface is good. Crank will need to be welded and re-ground on the thrust if not.

 

[38turbo]

not a trans guy what pressure should i expect
don't believe trans has ever been out of car doesn't look like it to me

 

[38turbo]

It's still in spec at the high end but in spec. think it will be ok to put it back together for now maybe get hv oil pump and watch it closely not a big deal to pull inspection cover and check endplay every now and then. if it starts getting worse then i'll have to bite the bullet and pull the engine. just didn't want to have to do this car is so clean and 100% stock afraid if i pull the engine my mind will start to wander

 

[bison]

not a trans guy what pressure should i expect
don't believe trans has ever been out of car doesn't look like it to me

under 50 psi

 

[38turbo]

so i'm looking for under 50 psi in cooler i'm going to install the gauge with a t fitting in the cooler lines this the way i should do it???

 

[Lee Thompson]

Imo

Since no one directed an answer toward you question. If the crank thrust surface is ROUGH, I'm afraid that roughness will do the same thing to a new bearing. Can you polish the crank--by polishing I mean only remove the HIGH ridges. I could send you a new thrust bearing and install it to see what endplay you have then. It will be very important to get the # 2 cap back in alignment so one edge of the new bearing don't protude more than the other.
Where is Chesterton? I am driving from Anderson to South Bend Sat. GM mixed and matched upper and lower main bearing to get the tight clearance needed for good oil pressure. Look at the back of the mains for #s and letters. I have a book somewhere explaining what the letters mean. I'm talking .0001. Best of luck.

 

[fc227]

How do you install the bearings with the engine in the car ? How do you push the mains out?

 

[38turbo]

i did use a piece of crocus cloth if thats how you spell it and smooth down the high spots in the area of the crank that was worn didn't help much but took sharp edges off. don't think the thrust bearing will have a affect on oil pressure the journal isn't worn and i plasti gauged all the rods and mains every thing right in the middle of specs. i put the oil pan back on yesterday so i'm gonna keep an eye on the end play if it starts getting worse i'll pull the engine and get a new crank or have this one repaired. would really like to find the cause of the problem. oh and chesterton is in nw indiana between portage and valpo

 

[38turbo]

How do you install the bearings with the engine in the car ? How do you push the mains out?

it's really not that hard i have a stiff piece of plastic thats flexable i use to get them started then i use a little pocket screwdriver CAREFULLY if they are really tough most of the time they come out really easily
on hard ones sometimes it helps to rotate the crank while pushing on the bearing
i'm a diesel mechanic and this is very common practice for us most engine overhauls are done in frame (you don't pull the engine unless damage to crank or block)

 

[fc227]

Kinda like a piece of semi ridged plastic tubing used in-home wells? The reason why I ask, Is because I am thinking of doing the same thing over the winter.

it's really not that hard i have a stiff piece of plastic thats flexable i use to get them started then i use a little pocket screwdriver CAREFULLY if they are really tough most of the time they come out really easily
on hard ones sometimes it helps to rotate the crank while pushing on the bearing
i'm a diesel mechanic and this is very common practice for us most engine overhauls are done in frame (you don't pull the engine unless damage to crank or block)