New main bearing scratches

[ytsejam82]

Hi! got these main bearings today.

Finally assembling the case i thought.... then i saw this, is this acceptable silverline main bearings? I can clearly feel them with my fingernail.

[Tcash]

[williamM]

Worked for Frost boats a while and when he was building motors in the early days, they used to build a form round the journals and pour molten white metal as the bearing. Next used bearing scrapers in a cross hatch pattern till the crank would sit proud in the bearing with the caps on. They then hooked the crank to a 30 hp electric motor and began spinning it while slowly tightening the main caps. the friction would melt the white metal as the tolerances closed . at just the right moment (expirence was essential) they would loosen everything up and allow to cool over night- Next morning the mess was cleaned up and a final fit using shim stock as early plastigauge, they had a set of new bearings.
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some days I get up and just sit and think. Some days I just sit.

opinion untempered by fact is ignorance.

Don't step in any!

[SGKent]

no files, no sandpaper. Babbitt is soft and will pick up any material left on it. Only acceptable tools are Babbitt knife/scraper or if you are really good a flat blade on a pocket knife. I'd return them. They were bounced on each other in the box or production. Once you start to mess with them the seller has no obligation to take them back. Some flipper will buy them. Only the high spots need be removed.

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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[skills@eurocarsplus]

talk to the seller...

if you own them, lots and lots of wd-40 and some 0000 steel wool and polish them up a hair.

don't think for a second that little scratches like that don't end up in them during break in anyway from all the ring swarf floating around. don't overthink it...
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[ytsejam82]

Yaay! they are sending me a new set of bearings

[ytsejam82]

So after getting 2 new shipments of bearings the first is still in best condition

Well i have now assembled the cam crank + gears and torqued the case to test and all is now rotating well (easy no binding) ( a bit resistance to start rotate but once start spinning i goes easy, i suppose it is the oilfilm?

But after splitting the case, i see this? Is this something to worry about? should i use fine sandpaper on it?

[williamM]

If the clearances are good (I like to run .001 on new mains) then run them- the break in will usually clean up any .0002 or more irregularities.

Skills- "don't over think it" X3
_________________
some days I get up and just sit and think. Some days I just sit.

opinion untempered by fact is ignorance.

Don't step in any!

[skills@eurocarsplus]

that would be a cause for concern. something's not right....looks like there are witness marks opposite of the reddish marks you have....but they look polished

not knowing what you did/oil/assy lube etc I would investigate.
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[SGKent]

no to the sandpaper. It embeds in the softer main bearing and will destroy the crank. Use some plasti-gauge from your flaps to see what the bearing clearances are at 4 or 6 different spots on each of the split shell bearings and rods. Do not rotate it while you are torqueing or unbolting to see what the clearance is.
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“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[williamM]

X2- its all about clearances- after break in it's an all new surface any way. your crank has eaten all those imperfections off and is now running on that bearing on it's own terms.
_________________
some days I get up and just sit and think. Some days I just sit.

opinion untempered by fact is ignorance.

Don't step in any!

[Tcash]

plastigauge

https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=plastigauge

[ytsejam82]

i torqued the case together with alot of oil on the bearings, and rotating it with a screwdriver.

Sadly i already sandpaper some other bearings with fine 1000 paper

[Abscate]

You'll be fine. If we could see micron size and get inside our engines I think most of us would die at the horrible things in our engine.
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.ssS!