Pontiac G8 Forum banner

1 - 20 of 27 Posts

·
Registered
Joined
·
29 Posts
Discussion Starter #1
Good morning G8 community. I seem to be experiencing repeat thrust bearing failures. Below is a little history on up to current.

Started with an LS3 swap built by a shop in Florida, as well as circle D convertor, tuned by shop in south Florida. The engine lived for about 6400 miles before the thrust was completely wiped. (yes I was finding unreal amount of metal in my oil but was told by builder its fine keep changing the oil it'll clear up) At this point everything was toast, the counter weights on the crank were just starting to rub the main bearing webbing on the block. Engine build 2.0, new iron block bored and stroked to 408, TSP forged crank, Diamond pistons, Carillo rods, everything brand new in this engine, everything. New circle d 258mm triple disc billet front as well. Got it fired up, carried to get tuned and now have about 350 miles on it. Drained the oil and its almost like de ja vu, same metal I had with the other engine WTF. Yes some is absolutely break in, fully understood especially with a stroker. BUT I measured my crank end play and its already grown .002" since assembly.

So my question is, what in the transmission would be causing this? its the only logical explanation that 2 engines are experiencing the same symptoms. It does have an aftermarket cooler, with the factory cooler bypassed and the lines look to be 6AN.

Thanks in advance for any tips, advice and suggestions. I can post the first trans tune if anyone would like to see if there's something in there that may have damaged the trans or created excessive pressures.
 

·
Registered
Joined
·
4,139 Posts
Sounds like the wrong flex plate was used. The torque converter was pushing on the flex plate that put pressure on the crank that wore out the thrust bearing
 

·
Registered
Joined
·
2,175 Posts
When the trans was bolted to the engine, what was the converter to flexplate gap (pullout)?
  • After bell housing bolts are tight, check free movement of converter. It should have 1/16 to 1/8″ (ON GM ONLY) of clearance between pads on converter and flex plate. If you have more than 1/16 to 1/8″, install equal thickness washers to reduce clearance to 1/16 to 1/8″ (ON GM ONLY). If not enough clearance, remove transmission and check to see if converter is seated in front pump properly.
 

·
Registered
Joined
·
4,139 Posts
Or the converter neck , the notches that engage the pump are not deep enough and it holds the converter too close to the engine. Can’t think of anything else that would put pressure on the crank. Was it the front or the back edge of the thrust bearing that wore out?
 

·
Registered
Joined
·
29 Posts
Discussion Starter #5
thanks for the replies, the flywheel I assume and hope is original to the car. I didn’t do the first engine swap. The second engine I did do myself and carried the flywheel over. I’ll have to check that out. The TQ converter did have 1/8” of pull back. The rear of the thrust was worn. I can’t imagine 2 TQ converters machined incorrectly but anything is possible at this point.
 

·
Registered
Joined
·
29 Posts
Discussion Starter #7
Here are a few, the front of the thrust has zero wear, rear is wiped out, journal is wiped as well as the thrust surface on the crank. Look at the trash in the oil pan😕
182929
182930
182931
182932

182933
 

·
Registered
Joined
·
4,139 Posts
Is there a part number stamped in the flex plate? A good place to start.
 

·
Registered
Joined
·
29 Posts
Discussion Starter #10
Found a slightly better one from the first failed engine when it was removed. Cant see the part number on the tag.
182935
 

·
Registered
Joined
·
29 Posts
Discussion Starter #11
So my flex plate does not look factory, it looks like a pioneer 82235CG. Not sure why it’s not factory and where my flex plate went. Any suggestions? Should I pull it and put something else in?
 

·
Registered
Joined
·
4,139 Posts

·
Registered
Joined
·
2,175 Posts
TCI399757. Be aware that
any of the $100 plates, regardless of branding are chinesium. When you search, you will find they fail when pushed.
 

·
Registered
Joined
·
29 Posts
Discussion Starter #14
Does the flywheel I have look correct? Is it factory G8GT?
That TCI piece looks nice, Probly the direction I’ll go if this plate needs replaced. Should have done it to begin with honestly.
 

·
Registered
Joined
·
2,175 Posts
OEM on left, tci on right
 

Attachments

·
Registered
Joined
·
29 Posts
Discussion Starter #16
Thanks for the picture, so mine does look correct. On your factory flywheel which side says engine side? Maybe I can use that to compare to the picture of my fywheel installed.

Thanks for helping me with this.
 

·
Registered
Joined
·
2,175 Posts
That image was from last year, don't have the flex in front of me. Based in the bolt witness mark and convertor witness, yours look mounted correct.
 

·
Registered
Joined
·
2,175 Posts
Unless there is something on the motor front pulling is forward. Aftermarket dampener? Since you have the pullout correct, not familiar enough with the transmission front workings to suggest something pushing.
 
1 - 20 of 27 Posts
Top