while the motor was out for a combination of things, i decided to pull a few of the rod and main caps to see what was going on under there and i really wish i hadnt! first off, the thing always had awesome oil pressure: almost 80 on cold startup, 55-60 cruising and 15-20 at idle. i know the copper is bad, and that makes me very very sad... does this situation warrant having the crank ground or polished and whatever else done to the rods?? i am on a rediculous budget and need the truck pretty bad, what would happen with just replacing the bearings? thanks

 

The top picture is it burnt or just a little bit of oil dripping down?

As for replacing bearing you need to mic your crank first you might luck out and your crank is fine but burning through the bearing to me says that the bearings were replaced before and not properly installed or the main cap wasn't cleaned up. It would behoove you to check your cam bearings too.

If it were me I would fully tear the motor down replace your bearing and maybe get the crank polished depending on the damage. As much as it would cost to have it ground you might as well buy a replacement newer stronger cranks are getting very affordable now.

 

If you are on a budget check out www.partsdinosaur.com he will hook you up for a very good price I have bought all my stock parts from him.

 

yes just oil dripping down, this is terrible news, i should have left it alone and I'd be blissfully ignorant...

 

I'd just swap out the bearings if the engine is still in the truck. You've got bearing wear, but who knows...maybe it was revved a bit high when still cold? The journals look OK.

The one bearing shows similiar to a couple of mine where it must be taper on the journal, or the block needs alignhoning, or something or other.

Most high mileage engines are down to copper, yet they get torn down due to worn cyl bores and rings. You oil pressure seems fine.

I might even only change the bottom halves. I would guess the top haqlves arn't showing any copper.

Plus....that surface coating is super thin. Doesn't take much wear to show copper.

But if your engine is out, it isn't a lot of work to strip the block and have everyting checked over. It's sort of up to you, and not a cast in stone thing.

 

thank you argess, that makes me feel a little better! could dirty oil be a culprit to some of the wear? when i cleaned out the oil pan there was plenty of carbon or trash in there, also a ton of it caked/baked onto the bottom of the intake.

 

Yes....I was probably wrong before when I said about revving a cold engine.....that can spin a bearing. But carbon is definately a cause of wear.

On your bearing where the wear is even, it is likely carbon or dirt. On the one where the copper is just along once edge, that may be an alignment issue.

Now it just so happens I recently rebuilt my engine for reasons not related to the crank or rods. I did install new bearings and only after everything was back together did I notice some copper on the old ones. Like yours, but a bit worse on the tapered pattern one.

I will be pulling the oil pan off over the winter and if the wear is back with the new bearings, I'll just replace the bottom half of the first 4 and leave #5 alone as it's a pain to change under the car.

I'm not about to get block work and crank work done unless I have no choice. As long as the oil pressure is fine and the engine works fine....and in your case, your oil pressure sounds great.

What I try to keep in mind is that there is a right way, a wrong way, and an acceptable way to fix things. It's figuring out where that acceptable line is that is a judgement call.

ps: I had the copper showing a bit on #3 and #5. All the others looked fine. I think it is carbon, but due to variations in tolerances, some journal/beaaring clearances may be tighter in some spots than others. Whatever the reason, it happens, and I think a lot more than most people realize. As you said, now you know, it bothers you. If you hadn't of looked.......

PPS: Holy Crap ! I just looked at your pics again.....arn' they #3 and #5 as well? The more I look at your pics, the more I think mine are worn the same. Perhaps that wear pattern is very, very common.

 

good info, sadly, i think my wife feels like i passed the acceptable point long ago! i swear this truck has it out for me....

 

Here's the pics of my #3 and #5....all the others were fine. I'm not worried about it.

 

i only pulled #3 main and random rob caps, whatever was facing up really to check.

 

those look good to me just old age however if yo u are worried about it coming back King AM bearings are around 5x thicker in bearing material compared to standards.

 

OK, pulled everything out today and i'm kinda worried now. the rod bearings appear to be .030 oversize and the mains .020 over. im getting this by some tiny numbers on the back of the bearing under a part number i think. they are FM bearings and with the exception of a few, all are showing copper. how much can the crank be ground?

 

Mine are currently at 40/40.

Are you sure you need the crank ground?

Bearings are designed to let debris become embedded in them, thereby saving the crank.

I sort of think my problem may have something to do with my oil filter being a metal screen unit and only filtering to 40 microns.

Regular paper filters usually filter at 20 microns or better. A problem can occur when the engine is revved too much when it is cold as the filter internal bypass opens and unfiltered oil goes through the engine. Although the oil in the sump has been cleaned during the last time the enigne waas run, the bottom of the filter can be holding some crap and it may come loose and flow through the engine when the internal bypass opens in the filter.

 

Measure your crank you will find if it is oversize or undersize and most bearings have odd sized versions too.

 

I would check the crank at least with the figer nail test and see if you feel any resistance or if your nail wants to hang on anything.. and I dont know about using a half a bearing ? maybe for a farm truck to get by with.. But i at least micro polish the crank and use bearing in sets.. But thats just me..

The remark above this post...Check crank to see if its over sized ? Never seen one grow before ? Well yes I have..it was welded up on the throws to be ground to a stroker crank..So there is a such thing , just not in this case..LOL..

Anyway if itsd a beater truck ?? Carry on !!