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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.
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.
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?
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.
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 !!
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