Main Bearing Clearance

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There's no such thing as an oversized bearing. PERIOD. That would mean you've ADDED material to a STANDARD crankshaft. How stupid does that sound? Undersize bearings are meant to fit an undersize crankpin. Stop bein ghey.

Undersize simply refers to the inside DIAMETER of the bearing being SMALLER than a standard bearing. Dumbasses.
 
StrokerScamp said:
There's no such thing as an oversized bearing. PERIOD. That would mean you've ADDED material to a STANDARD crankshaft. How stupid does that sound? Undersize bearings are meant to fit an undersize crankpin. Stop bein ghey.

Undersize simply refers to the inside DIAMETER of the bearing being SMALLER than a standard bearing. Dumbasses.
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who r u calling a dumbass?

oversize..
http://www.cnc-motorsports.com/engi...triarmor-coated-bearings-0-001-clearance.html

undersize .009...which covers a .010 under crank thats on the big side..
http://pitstopusa.com/i-5077618-clevite-h-series-rod-bearing-009-undersize-tm-77-sb-chevy-each.html

I remember being wise ***, except i was usually right..
 
That's an incremental bearing in .001". I was talking about regular undersizes such as .010, .020 and .030. THOSE sizes are not available in oversize.
 
1wild&crazyguy said:
the second link is for an 'on the big side' .010 under crank=.009....

Maybe try not to categorize all including ur buddy in the dumbass group
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Oh hush up. You know I dont think you're a dumbass. you knew what I meant the whole time. lol
 
66 Dartman said:
How do you get to that??? If it gauges out at .001 you have that all the way around!!!!:D
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This I agree with, but it would equal a .002" difference in the OD of the crank journal and the ID of the bearing. So is that how it works? Or do you need a difference of .004" to get a clearance of .002"?
 
1wild&crazyguy said:
heres some more

http://www.summitracing.com/parts/KGB-CR8008HP010X/


http://www.summitracing.com/parts/KGB-CR8008HP010X/
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Yeah but them are undersize. What I was sayin.....and you know it dammit....was that when you get a crank turned, the crankpin diameter decreases. So, as such, you need a bearing with a decreased or undersized inside diameter. Unless you're simply trying to get dead specific on clearances, you'll generally not need an "oversize" bearing. In other words, if the machinist does his job, the undersize bearings will be right.
 
Rodzilla said:
This I agree with, but it would equal a .002" difference in the OD of the crank journal and the ID of the bearing. So is that how it works? Or do you need a difference of .004" to get a clearance of .002"?
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I was replying to this post.
 
StrokerScamp said:
Yeah but them are undersize. What I was sayin.....and you know it dammit....was that when you get a crank turned, the crankpin diameter decreases. So, as such, you need a bearing with a decreased or undersized inside diameter. Unless you're simply trying to get dead specific on clearances, you'll generally not need an "oversize" bearing. In other words, if the machinist does his job, the undersize bearings will be right.
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If this, if that...:blah5:


its all relative....so it's an .001 oversize of a .010 undersize=.009, how exactly does this matter as to helping this duder when its already been stated by me, u and others to have the crank polished or get a .009, .019, or whatever the hell diameter bearing he needs.

I dont care anymore, this dispute is no longer about helping the guy...so im out.
 
SGBARRACUDA said:
The diff between the O.D. of the crank and I.D. of the bearing is your clearance.
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Is it? Cause is order to have the .002" difference between the two as you mention actually only gives .001" clearance all the way around(the measurement you get with plasti gauge). That's my confusion. I understand perfectly how these to different measurements can come up. But which way do people refer to. Say do instance I need .002" clearance on my mains, are people always talking about the measured difference between crank journal and bearing ID?
 
Rodzilla said:
This I agree with, but it would equal a .002" difference in the OD of the crank journal and the ID of the bearing. So is that how it works? Or do you need a difference of .004" to get a clearance of .002"?
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If your looking for .002 thats what the plastigage should read and that will give you the clearance you need you don't multiply the reading by2
 
Rodzilla, what is your intended purpose of this build? This question is key to you getting the clearance you need. .0015 is fine for street with the correct oil viscosity for your temperature (read this as NO 20W-50!!!). Are you driving in winter? Are you drag racing? What is your redline? What type of oiling system are you using?

These questions need to answered before I can give you some guidance.
 
Clearance guidlines are with the crank resting on the bottom bearing via plastigauge or by micing the crank OD and torqued bearing ID, they are the same. THINK about it...
 
If it turns 5000 revolutions per minute, how long does it take to turn 5000 times?
 
crackedback said:
If it turns 5000 revolutions per minute, how long does it take to turn 5000 times?
avatar1969_1.gif
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Dammit Crack, you've forced me to get HER out again!!

jeans.gif
 
ramcharger said:
Rodzilla, what is your intended purpose of this build? This question is key to you getting the clearance you need. .0015 is fine for street with the correct oil viscosity for your temperature (read this as NO 20W-50!!!). Are you driving in winter? Are you drag racing? What is your redline? What type of oiling system are you using?

These questions need to answered before I can give you some guidance.
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Its a street car, very little track time. 340 Stroked to 416. Shooting for 550-600HP 550 TQ. Will be Dyno'd. Eagle forged crank, recently balanced, polished and chamfered and apparently no one checked my clearances worth a crap. Glad I did my own plastigauge. This car will see 2000miles a year at most. Show quality resto, but still a driver for local cruising. I want to see .002" for clearance, I think that will be a good number to shoot for and for sure the .001" I have right now aint going to cut it. Redline will be 6800-7000. Oil will be a good quality 10-30 to start and later going to royal purple synthetic 10-30 as well. Oiling is via HV oilpump, oiling mods on sticky in this section done but I went with the bushed lifter bores.
 
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