LOOK at my thrust bearings and tell me whats wrong!

[wild_maxx]

long story short...the motor i had built by a shop pretty much failed on me 1200 miles after i got it running.... i sent it back to them to be inspected and find out what the problem was... they said everything is fine and the motor looked great...

So they send me the block and all the internals un-assembled.... and i inspected it myself....

NOW the thrust/main bearings dont look too pretty... they have 2 deep gouges in them and the copper is showing all around them..... not sure where they came from or how they were made... they are on both sides of the bearings on both halfs.... so by the pics... anyone know what could cause this problem? The rest of the main bearings looked decent... so idk wtf could cause this..

[LEMHEAD16]

Maybe they didn't "Set the thrust" before they torques the mains?

[wild_maxx]

what exactly is setting the thrust?

[deviousKA]

Hey Shawn, they look like that on both sides of the thrusts?

What sort of bearing, or any part number marking?

Looks like oversized thrusts to me, shatty deal. Did you have a warranty on that engine?

BTw, those gouge looking things are oil reliefs.

[wild_maxx]

the only #'s on the bearing is: STD 2748 L 07N001 9416

and yes it is like that on both sides with the copper showing and the gouges in there..... I don't know what type of bearings these are but when i had the engine built there were supposed to check the line bore..... i did the the crank polished but not ground.... so idk wtf is going on....

[deviousKA]

And by oversized thrust bearing I mean the thrusts themselves, seperate from the main bearing. Its actually 2 parts. So you could get a STD main bearing with an oversized thrust.

Either that, or it is a manufacturing issue. Nissan thrusts rarely ever wear beyond tolerance of an oem spec bearing, and considering your crankshaft was only polished on not ground, there would be no reason for the thrusts to be machined and improperly fit for a larger size.

You will have to bring your crank back to the machine shop and buy a new set of standard bearings, and the machinist must verify end play. Even with that amount of wear to the babet of the bearing the crank will probably still check out.

EDIT: What was this failure situation? Did it seize?

[wild_maxx]

well the failure part was compression... after 1200 miles i only had 100 psi of compression on all 4. it started out at 130 but just kept going down.

i pulled it apart and saw the pistsons has some pretty bad scratches on the skirts so i sent it back to be inspected... they said everything was fine... didnt even note the thrust bearing wear....

the engine did not seize up so no damage was done to the crank.

They sent me a set of total seal rings.... whats your opinion on them?
Modified by wild_maxx at 11:05 PM 4/7/2006

[deviousKA]

Damn.

forged pistons or cast?

I dont like total seals and dont use them, especially not with a forged piston.

[wild_maxx]

they are forged supertech pistons. 8:1 compression.

[180sx]

wierd , maybe ur crank needed to be .10 ground down. Also Didn't u notice that ur ring gaps were way untorable clerance before sendint it out? or was it a diferent motor.?Sounds like u need a new machine shop to deal with , one where they don't smoke as much coco

[wild_maxx]

here's a link to my original post about my ring gap.... the machine shop said my ring gap was fine....

http://www.ka-t.org/forums/vie...light=

[pregmantis]

hey devious, why dont you like total seal rings? They are kinda expensive(gapless), do you think they are a waste of money? and, what rings would you go with?