Worn crank main cap bearings?

[Iain]

This is the centre crank main cap on my XE, the goldy colour seems to fade out to silver towards the middle:

http://iainel.co.uk/images/forums/Misc/rps20141013_183708.jpg

And where it's silver on the crank facing surface it looks to have 'worn through' into a goldy colour. That bit on the right area isn't a reflection, it's gold in appearance on the bearing

http://iainel.co.uk/images/forums/Misc/rps20141013_183733_649.jpg

http://iainel.co.uk/images/forums/Misc/rps20141013_193526_964.jpg

Many of the other cap bearings show signs of 'wear' on the very middle. Not checked the tops yet only the bottoms.

Thoughts? Pull the crank and remeasure and new bearings? I know it's difficult to see with pics and I only had my phone on me...

[millworm]

Gold bits are where oils has maintained a gap between moving parts witch is good bit silver is where there has been metal to metal contact, either through worn bearings or poor oil preassure

[millworm]

Would defo put new bearings in, I replace tem every time I take them off, don't like reusing them

[Iain]

The silver part in the main area of the bearing has some signs off gold showing through, as if it's worn through the silver to expose the gold?

[comptoncj]

How many miles have those shells done? And have you used it for track days etc? Have you got an oil pressure gauge?

[Iain]

15k.

Yes lots.

Yes I have and the main reason the engines out is to uprate the oil pump as I've had pressure issues. However never thought the pressure dropped enough to cause damage.

[millworm]

The silver part in the main area of the bearing has some signs off gold showing through, as if it's worn through the silver to expose the gold?

Could possibly have been where it's worn though the coating it witch case it's shagged

[comptoncj]

It doesn't take much to start wearing the shells, slight oil starvation a few times will show up, that said 15k of track driving and they don't look that bad. My last xe had oil pressure issues down to a cheap pump, are you going down the let pump route?

[Iain]

Zlet yeah. I'll be replacing them while I'm there then as they all have slight marks like the pics :)

[comptoncj]

Always good practice to replace them and check clearances etc.

[Andy]

refit them and check clearance using plasti gauge

[mowgli]

http://iainel.co.uk/images/forums/Misc/rps20141013_183733_649.jpg

i'm more interested in the 2 worn bits on the side of the bearing.

i'm assuming you are getting a lot of crank thrust movement & they are worn cos of the conrods catching them.

i'm not sure if you can get oversized thrust faces on gm crank bearings or not.

[Iain]

There appeared to be some movement in the crank. That's the middle thrust bearing Mowgli so rods don't come into it.

When I get new bearings will the thrust be right out the box or do I need to fine tune it? I think when I built it I sanded them slightly to get a certain amount of sideways movement...?

[mowgli]

sorry, i'm having an alzheimers moment, something is still catching though, which is always a worry, considering the journal should be round & the thrust face should be smooth & flat.

new shells should have the correct thrust face tolerances on them, but it is still wise to get the feeler gauges out.

have you had the crank measured to see if it needs a grind?

[Iain]

Crank isn't out yet just pulled a few caps off so far. I'll get it out for measuring in the next few days