main bearing, is this normal wear?

grendi_250ci

Well-known member
Supporter 2021
my 250cid engine has been completly rebuilt (viewtopic.php?f=48&t=63391) and upgraded in 2010.
now less then 1000 miles later i had to replace the rear mail seal.
when i took down the oil pan and removed some of the bearings, i noticed some wear on them.
what do you guys think, is this normal wear ~1000 miles after a rebuilt or did the guy that grinded my crankshaft mess up?
pictures:
http://img38.imageshack.us/img38/7149/bearing2.jpg
http://img36.imageshack.us/img36/4578/bearing26.jpg
http://img252.imageshack.us/img252/8067/bearing5.jpg
 
That one bearing (first pic) is probably the only one that would be of concern to me, that is a large wear patch. But before you can start assigning any blame, it could be poor oiling, a poor fitting bearing, or as you first asked a bad machining job on the crank.

However none of that wear looks terrible/bad enough that it is cause for alarm. If it were mine, and as long as there are no circumferential scratches (all the way around) and no ridges in the crank journal, I would go buy a new set of bearings (the bearing size is on stamped on the backside of your current bearings) and plastiguage them. If the tolerances come out good, clean up the plastigauge and assemble the motor with the new bearings. If the tolerances are a little loose you may need to go with .001 or .002 tighter on the bearings before reassembly.

I hear some people have fancy dials and measuring devices to measure the crank bearing surface and the inner diameter of the bearings. I have never been privvy to such tools so I always use the plastigauge method.

-ron
 
CoupeBoy":3dtlemdr said:
I would go buy a new set of bearings (the bearing size is on stamped on the backside of your current bearings) and plastiguage them. If the tolerances come out good, clean up the plastigauge and assemble the motor with the new bearings. If the tolerances are a little loose you may need to go with .001 or .002 tighter on the bearings before reassembly.

that's pretty much what i was planing to do.
i'll also change the oil to penrite classic 20w60 and then i'll proably check again how it looks after the next 1000-1500 miles.
 
Yeah, could have been a lot of things. Even if it sat for a long time prior to be started.

I wouldn't go 20w60. Having oil too thick can easily cause worst problems on the bearings.
 
the ford car shop manual lists 20w40 for temperature above 32°F (page 19-03-08)
that's why i choose that oil.
the penriteoil website recommends 25w70 :shock: (but theses guys are from australia and it's not getting that hot here :mrgreen: )
 
8) i agree with the others, those bearings are in pretty good shape overall. i assume the first bearing is the front one, and if it is then the wear pattern in it is normal as that bearing has the highest unsupported load, and the lowest oil pressure available to it.
 
CobraSix":lj0ny3pl said:
Yeah, could have been a lot of things. Even if it sat for a long time prior to be started.

I wouldn't go 20w60. Having oil too thick can easily cause worst problems on the bearings.

Yeah - 20w oil unless you are in a pretty hot climate seems really excessive, and if nothing else will certainly hurt your fuel economy. A good 10w-40 or 15w-40 should be more than adequate. Just be sure you get something with a reasonably high zinc content. Most 10w-30 oils these days don't have the anti-wear additives older engines need, but most Xw-40 oils do since they're generally intended for higher-mileage engines where the anti-wear is important.
 
rbohm":3k7etp5t said:
i assume the first bearing is the front one, and if it is then the wear pattern in it is normal as that bearing has the highest unsupported load, and the lowest oil pressure available to it.

no, the picture shows bearing 2, 5 and 2-6 (left to right).
bearing 1 and 7 are currently keeping the crankshaft in place

@thesameguy
if you live in europe, it's hard to get oils with decent zppd levels.
the oil i'm planing to use has 1610ppm zinc and 1440 ppm phosphorus and is recommended for 1950-1970s era petrol and diesel engines, where SAE 30 or old style SAE 20W-50 or 20W oils were originally recommended.
that's pretty much what ford recommended in 1969.
but if my oil pressure is higher then normal, i'm going to look for a 15w40 with high zppd levels
 
:unsure: What about the crankshaft journals? Can you post a picture of them? If you are going to the trouble of pulling it down and replacing the bearings I would also have the crank micro polished to make sure it's finish is right. :nod:
 
grendi_250ci":3cw3qk31 said:
@thesameguy
if you live in europe, it's hard to get oils with decent zppd levels.

Check out Motul Syngergie+ 10w-40. You should have access to it. I have been running Synergie+ in my '62 with good results. If you're feeling spendy, 300V is even better.
 
69.5Mav":3p2o2cw8 said:
I have seen realy toasted engines come out with better looking mains. You might consider getting bearings with a copper coat under the cad coating. I believe it's called a tri-metal process. You are down to the steel on yours.

The crankshaft was grinded, micropolished and hardend during the rebuild and it looks like new by eye.

The bearings in the pictures are made by federal mogul and as far as i know, they do have a cooper layer, as you can see on the sides of bearing number 5.
Currently, only the top layer has some wearmarkes but they don't go down to the cooper or steel layer.
 
Are you using a good oil filter? Filters without an anti-drain back valve should not be used on many Ford engines were the filter mounts like on these sixes (laying on the side). Those bearings are not that bad but dose look as though you maybe having dry starts. :nod:
 
bubba22349":2d4lwd4v said:
Are you using a good oil filter? Filters without an anti-drain back valve should not be used on many Ford engines were the filter mounts like on are sixes (laying on the side). Those bearings are not that bad but dose looks as though you maybe having dry starts. :nod:

the old filter was from motorcraft, not sure what type.
the new one will be a royal purple 30-8A and that one has an anti drainback and a bypass valve
 
Those bearings look fine to me. No where near the copper that is under that layer that you see.
I'd just keep using the oil and filter you are currently using.
 
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