Main thrust bearing wear ????

[38turbo]

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.

yeah that would work to
i use my pocket screwdriver a lot you just have to be very careful not to hit the crank jorrnal once you get the bearing moving i put my screwdriver in the bearing tang area and work the bearing the rest of the way around
rods are easy
just make sure you pay attention to all the old and new bearings make sure they are the right size and also plasti gauge all of the bearings to make sure you have proper running clearance
#2 main has the thrust bearing
and the rear main lower bearing is different from the rest of the lower ones

 

[turbolou]

Reply

Convertor is most likely suspect. My last experience like this was a wonderful precision convertor that only had .040 air gap between flywheel & convertor. Should be 100 min. Also when a builder goes through a trans the line pressure is jacked up & all the more possibility of hydraulicking the convertor forward. If the engine was rebuilt & the crank not been re treated after being turned thats another problem. From the pictures the bearings looked wiped from lack of good oiling or possibly a poor grade of oil or trash contamination.. Another poss. is main caps moveing around under severe load or detonation. Are there any chatter marks on the main cap to indicate this.Try takeing a small three cornerd file & put a slight groove from the oil feed hole to the thurst side of the upper bearing to give it more oil. As stated if crank thrust surface is damaged in the least the bearings wont last.

 

[38turbo]

sorry its the upper rear main thats different not the lower

 

[fc227]

Thank you

sorry its the upper rear main thats different not the lower

 

[Chuck Leeper]

How does 1 get a clearance w/p.gauge, w/ the crank sitting in the main caps??

 

[fc227]

I thought the end play was .003 to .011

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)?

 

[Tony Shoaff]

38Turbo, it looks like you have no business going any further! You need to take it to a builder familar with the Buick motor before you have a pile of scrap metal. Sorry just trying to save you the grief.

 

[m233roller]

If the thrust surface side on the crank is rough AT ALL !! he's wasting his time changing bearings.

 

[GSTOY]

pics of a toasted thrust bearing

If the thrust surface side on the crank is rough AT ALL !! he's wasting his time changing bearings.

If your thrust bearing or crank has ridges like this, I wouldn't bother installing new bearings, they won't last. When you took the pan off, were their metalic chips lying in the bottom? Mines layed up right now waiting to get it rebuilt...soon...very soon

Steve

 

[BREAKIN IT]

If it is truly all stock, and has sat a lot, check the snout on the converter where it fits in the end of the crankshaft. If any rust buildup is in there then the flexplate cant do its job and it can wipe out the thrust bearing. I have had this happen.

 

[38turbo]

How does 1 get a clearance w/p.gauge, w/ the crank sitting in the main caps??

i'm rolling in a new set of rod and main bearings in a completly stock engine.
i'm not building a race engine or blueprinting an engine the plasti gauge gives me an idea what my clearance is lets me know if a major problem exists. also i do one bearing at a time the accessory belt is still on the front of the engine putting upward pressure on the crank. the full weight of the crank is not sitting in one main cap. if i was really worried about it or building an engine that .0001 mattered i wouldn't be using plasti gauge in the first place would i ???????

 

[38turbo]

38Turbo, it looks like you have no business going any further! You need to take it to a builder familar with the Buick motor before you have a pile of scrap metal. Sorry just trying to save you the grief.

Why do i have no business going any further. I am more than able to change a crankshaft in an engine which in the worst case is what i will have to do here. the reason for this post was to inform myself and get info from others on the cause of this problem. because it would do me no good to take and have the engine repaired by somone else reinstall it and then have it happen again because the cause of the problem was never solved. and when monitored a thrust bearing issue is not going to leave me with a piece of scrap metal there is nothing wrong with the crank journals themselves if the endplay gets out of specs then i will do somthing about it .

 

[38turbo]

If it is truly all stock, and has sat a lot, check the snout on the converter where it fits in the end of the crankshaft. If any rust buildup is in there then the flexplate cant do its job and it can wipe out the thrust bearing. I have had this happen.

never thought about that but your correct if the convertor rusted in place flex plate wont flex will it. Thanks for a good idea!!! i will be checking this next!!

 

[fc227]

Been there , done that. More than once !

If your thrust bearing or crank has ridges like this, I wouldn't bother installing new bearings, they won't last. When you took the pan off, were their metalic chips lying in the bottom? Mines layed up right now waiting to get it rebuilt...soon...very soon

Steve

 

[Chuck Leeper]

I'd guess..

i'm rolling in a new set of rod and main bearings in a completly stock engine.
i'm not building a race engine or blueprinting an engine the plasti gauge gives me an idea what my clearance is lets me know if a major problem exists. also i do one bearing at a time the accessory belt is still on the front of the engine putting upward pressure on the crank. the full weight of the crank is not sitting in one main cap. if i was really worried about it or building an engine that .0001 mattered i wouldn't be using plasti gauge in the first place would i ???????

not.
Relying on belt tension to get a measurement is about as logical as putting bearings against a crank that looks like that...
Your engine.. I could care less what you do..

 

[Tony Shoaff]

Good Luck

not.
Relying on belt tension to get a measurement is about as logical as putting bearings against a crank that looks like that...
Your engine.. I could care less what you do..

With your new talent of building motors over night If you know what you are doing? Why ask us?

 

[Lee Thompson]

Ease up on the guy.

He came on here asking for a little advise, that's all. One of you guys may have a ? someday that he is the only one with the answer.

 

[Tony Shoaff]

Was just trying to help. I have been there and wasted alot of money and time trying to do it my-self. If it's right from the start! You should not have to worry about it anymore.

 

[m233roller]

I surely didn't post what I did to start any pi--ing match or to slam the guy. I just stated that if the thrust side of the crank is rough, he's wasting time putting bearings in it. It WILL !!! just eat up the new thrust bearing.

 

[turbolou]

Reply

He came on here asking for a little advise, that's all. One of you guys may have a ? someday that he is the only one with the answer.

The advice will continue till the attitude improves !