Thread: Picked up my Son's engine yesterday.

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Originally Posted by pat mccarthy

sorry not stepping on any ones toes.. but take it any way you will the bearing are dull out of the box and that finsh is the best to keep hands off

I don't think there's any stepping of toes here Pat! I asked a question 'cause I hadn't heard of this practice. I studied automotive in a trade school, we were taught to protect at all costs the surface of the mains / rods and their bearings. So I was shocked to see someone say they took a scotchbrite pad to a bearing!

Thanks to you and Dave for replying and providing an answer!

Originally Posted by 34_40

I don't think there's any stepping of toes here Pat! I asked a question 'cause I hadn't heard of this practice. I studied automotive in a trade school, we were taught to protect at all costs the surface of the mains / rods and their bearings. So I was shocked to see someone say they took a scotchbrite pad to a bearing!

Thanks to you and Dave for replying and providing an answer!

ok well post 59 is why it was done at one time the flash coating i call it. on the old MIch 77 would be falling off in the bearing box . but there so many bearings now to use and not all made the same some the finsh is machined other are not some are trimetal. bimetal many make up.s of babbitt

Originally Posted by pat mccarthy

ok well post 59 is why it was done at one time the flash coating i call it. on the old MIch 77 would be falling off in the bearing box . but there so many bearings now to use and not all made the same some the finsh is machined other are not some are trimetal. bimetal many make up.s of babbitt

Thanks Again for the answer Pat! 8-)

Originally Posted by pat mccarthy

sorry not stepping on any ones toes.. but take it any way you will the bearing are dull out of the box and that finsh is the best to keep hands off

They are babbitt dull (tin/lead/antimony, etc) but are very smooth. The way it was explained to me by an old time engine builder is that they were too smooth - like a non-honed cylinder wall and that they needed some texture to maintain an oil film. I don't buy that explanation and have never done it. The bearings are manufactured to maintain a certain oil film thickness at a certain crank to bearing clearance and with a certain oil feed wedge. While it doesn't hurt to Scotch-Brite, there is no really good reason to do it.

For a short while I worked in a bearing manufacturing area at GE for a while where we actually cast and machined bearings from a couple inches in diameter to over 24 inches. These bearings were finished on a lathe to a particular finish - and that finish was not really smooth. Many years later, I don't recall what that finish was (125 maybe) and these bearings mostly went into constant speed motors and turbines with minimum speeds of 3000 rpm up to over 6000, usually with 25psig oil pressure and operating continuously for years between inspections. As far as assembly in the field - most service engineers used ordinary STPQuarts of that stuff!!

Do it or not, caution plus a good cleaning afterwards is the best way if Scotch-Brite is used.

My turn------
You guys are misreading the bearing clearance specs--it is no .005-.021 but .0005-.0021----------------
And if you do have .006 you are way out of tolerance!!!!!!

AAnd as far as toe stomping-------I guess I would be called an old or old time engine builder---we never scotchbrighted bearings back THEN---because scotchbrite hadn't been invented yet---however we did sand bearings with 400 wet or dry paper because we would then have a consistant pattern in the bearing surface so we could tell how much/where/how the bearing/crank journal oil supply was working---The surface of the bearing show never touch the crank as it should ride on the oil film and thats where oil wt., flow, clearance,pressure all come into play.

And for those back THEN who didn't like Valvoline because it foamed and others didn't---if your oil foams its the oil system causing it, not the oil and an oil that foams will have more surface tension than non filming oils so it will protect bearing/crank , along with other parts better.

These days with the non foaming syn lt weight oils the bearing clearances get more crital , especially with alum engines, however that old OLDSMOBILE could probably run on the old grease from the local drive in resturant

Well, I only scotchbrited them after I took my belt sander to them first. JUST KIDDING !!!!!!! Actually, all I did was spray them with WD40 and LIGHTLY, wipe the surface with a scotchbrite........VERY lightly. The reason I did that was I went on line and read a lot of engine building tech articles and that is what they said to do. I didn't take anything off or scratch the dullness, but I'm glad you guys mentioned that these new type bearings are meant to leave alone. We won't do that to the rod bearings. Thanks.

Jerry, yep, you are right about the .0005 thing, I never was good with decimals and am never sure how many zeros go in there. It was actually .0006. After we got the mains torqued the crank spun nice and free, and we could also see all the welding the balancing shop did to get it right. They said the crank was really out. All the shop did was polish the crank as it never needed turned, and we went back with the same std size bearings that we had in it originally. We always had 50 psi oil pressure, at least that part of the build was ok.

Thanks again for the tips, guys.

Don

Not understanding what you mean Gary ???

Originally Posted by roadster32

Not understanding what you mean Gary ???

When Don tore down the engine to find a ring issue,I asked him during the assembly if he was watching the last piston put in as he turned the crank over if he was watching the oil pattern on that last bore.A ring that got caught,or twisted while putting in that piston would leave a line in the oiled bore of that bore.Yepper-not a literary giant here.

IC2 i know what bearing s he has i sold them to him i use over 4 makes of bearings at the shop some machined finsh .some use indium .silicon bi metal.tri metal, alum .i not going to write a book here but i do more bearings in the year then i care to think about and not all in moms and pops car but stuff getting the snot kick out of it and 300+ shot of Nos so hi Hp engines not like 500HP but way past that . not as old as Jerry but not a kid

Are there realy people older than Jerry

why would you go online for that B.S engine building crap don???? when i could of filled you up here . yep i knew what you meant ..0006 i think if you had .006 your plastigage would of rolled out and landed on the floor or go to blue plastigage or run down to the 7/11 and pick up some bubble gum and used that for gage stock but then i understand not trusting what one guy post s on here

Originally Posted by cffisher

Are there realy people older than Jerry

well he is as old as my mom not to old . i have to say that because i am getting old .some times i have a hell of a time keeping up with mom when she on a mission

Sooooooooooooo,if Jerry is older than me,that means it adds days for me???.Hummm.Naw never mind.

Pat, I figured I bothered you guys enough with questions, so I read a few articles in magazines and went on line to fill in some gaps. Ok, while we are talking, we have never degreed a cam, I have a dial indicator and need to get the wheel. What tips do you guys have there.

What confuses me is, when you find out the sprocket is out a few degrees, or whatever, what do you do, drill the mounting holes bigger and put in offset bushings>

Don

Written better than I could:

How to Degree A Camshaft: Engine Builder