Inspecting condition of big end/main bearings

[kemicalx]

G'day all,

I'm after some tips (and preferably pictures) of what and what not to look for when inspecting the bottom end bearings for signs of; a) regular wear, b) adverse wear and c) serious damage..

I've just started stripping down my 7M (have stopped until i pick up some plasigauge) and would like to know what i should be looking for. I'll post some pictures of what i've found so far later on.

Thanks a lot guys,
Ash.

[2jzhilux]

if you have stripped down the motor for the price the bearings are i would just replace them anyway
but you are looking for them to be smooth with no deep grooves or pitting on the bearings

[kemicalx]

thanks for the advice.. but they aren't very old at all, should there be any markings on them at all?

[Draven]

Ninja-edit. misread

[2jzhilux]

there will be slight markings but definately no grooves
maybe post a pic and we could tell you if they are stuffed

[BeRad]

replace them anyway can never be to careful

[kemicalx]

I will post pictures in a minute, but I was hoping this thread could be more than a "are my bearings fubar'd? thread" I’m hoping it could be more a future reference for all. I've only removed one big end bearing so far, and there are no deep grooves cut into it, there is a cross hatching pattern visible on the bearing, and there is slightly over 0.30mm movement of the con-rod along the crank journal which is just out of spec, if the con rod had been moving back and forward on the journal I’d expect to see a crosshatching pattern but the angle of the cross hatching is wider than ~0.30mm movement would create.

edit- btw these are ACL bearings and only around ~35k km's old

[2jzhilux]

ok then
future reference for all= when you remove your bearings especially after 35000kms replace them dont reuse them

but back to the point have you torqued them down and plastigauged them if so what were the results
the main thing your looking for is correct oil clearance
and i think if your thrust clearance between the crank-rods is slightly out of specs i dont believe it will cause any major problems with the bearings

[amichie]

When the ACL bearings were fitted was the crank reground??

[kemicalx]

unsure, it looks to be in pretty good condition though.

[tmca pimp]

if there are any scuffs or heatspots they're pretty much done for, before replacing you'll need to be aware if they are within specs. thanks...yeah, no worries

[slide86]

this is what they SHOULDNT look like



these came out of my 4agze. lack of oil change and low oil pressure were the cause. (previous owner)