Brain fade - half shelling a .010 bearing for more clearance

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Re: Brain fade - half shelling a .010 bearing for more clearance

Post by gmrocket » Thu Jun 07, 2018 4:17 am

Getting to the point of being moved to advanced engine tech

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Re: Brain fade - half shelling a .010 bearing for more clearance

Post by MotionMachine » Thu Jun 07, 2018 8:14 am

There are some automotive applications where oversize o.d. bearings are available. I've line bored a couple of BBC's for .010" over mains. The strangest o.s. I've seen is a .015" over for the Kent Ford 1.6 that's used in many things, Formula Ford being one of them. King now makes a .002" and a .005" for Subaru's.

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Re: Brain fade - half shelling a .010 bearing for more clearance

Post by Krooser » Thu Jun 07, 2018 10:05 pm

Who's on first.
Last place in the B-main is better than anyplace in the grandstands...

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Re: Brain fade - half shelling a .010 bearing for more clearance

Post by groberts101 » Thu Jun 07, 2018 11:02 pm

Krooser wrote:
Thu Jun 07, 2018 10:05 pm
Who's on first.
Abbot!.. err, wait.. or was it Costello? :lol:

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Re: Brain fade - half shelling a .010 bearing for more clearance

Post by Krooser » Fri Jun 08, 2018 12:28 pm

Actually posts like this get you thinking which is good...
Last place in the B-main is better than anyplace in the grandstands...

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Re: Brain fade - half shelling a .010 bearing for more clearance

Post by engineguyBill » Fri Jun 08, 2018 1:25 pm

Think of it this way - when a crankshaft journal is ground undersize, a corresponding "undersize" bearing is needed. Therefore a journal that is ground .010" undersize will need -10 (-.010') bearing set which has thicker shells than a STD bearing set does. SO -.009" bearing has thinner shells than a -.010" and -.011 bearing has thicker shells that the -.010". Therefore, a -.009 bearing will result in additional clearance over the -.010" bearing and the -.011" bearing will have less clearance than the -.010" bearing.
When mix/matching bearing shell sizes, the bearing manufacturers recommend that the thicker shell be placed in the cap side of the main bearing and in the rod body of connecting rods. However, I have done it both ways and have not seen any difference/problems.
Last edited by engineguyBill on Fri Jun 08, 2018 1:26 pm, edited 1 time in total.
Bill

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Re: Brain fade - half shelling a .010 bearing for more clearance

Post by In-Tech » Fri Jun 08, 2018 1:32 pm

engineguyBill wrote:
Fri Jun 08, 2018 1:25 pm
Think of it this way - when a crankshaft journal is ground undersize, a corresponding "undersize" bearing is needed. Therefore a journal that is ground .010" undersize will need -10 (-.010') bearing set which has thicker shells than a STD bearing set does. SO -.009" bearing has thinner shells than a -.010" and -.011 bearing has thicker shells that the -.010". Therefore, a -.009 bearing will result in additional clearance over the -.010" bearing and the -.011" bearing will have less clearance than the -.010" bearing.
When mix/matching bearing shell sizes, the bearing manufacturers recommend that the thicker shell be placed in the cap side of the main bearing and in the rod body of connecting rods. However, I have done it both ways and have not seen any difference/problems.
Lol, if I read you right Bill, you contradicted yourself.
Time to get the ball mic out.
Heat is energy, energy is horsepower...but you gotta control the heat.
-Carl

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Re: Brain fade - half shelling a .010 bearing for more clearance

Post by groberts101 » Fri Jun 08, 2018 3:54 pm

In-Tech wrote:
Fri Jun 08, 2018 1:32 pm
engineguyBill wrote:
Fri Jun 08, 2018 1:25 pm
Think of it this way - when a crankshaft journal is ground undersize, a corresponding "undersize" bearing is needed. Therefore a journal that is ground .010" undersize will need -10 (-.010') bearing set which has thicker shells than a STD bearing set does. SO -.009" bearing has thinner shells than a -.010" and -.011 bearing has thicker shells that the -.010". Therefore, a -.009 bearing will result in additional clearance over the -.010" bearing and the -.011" bearing will have less clearance than the -.010" bearing.
When mix/matching bearing shell sizes, the bearing manufacturers recommend that the thicker shell be placed in the cap side of the main bearing and in the rod body of connecting rods. However, I have done it both ways and have not seen any difference/problems.
Lol, if I read you right Bill, you contradicted yourself.
Time to get the ball mic out.
haha.. reread it again.. he has it right. And even I understood it.. which means he succeeded in dumbing it down enough to get the point across to most knuckle headed nut jockeys. errr.. wait.. that didn't sound right. :oops:

Like I said in the above when I replied too quickly.. I just went through this with my too loosely clearanced SBF mains. I bought the crank off ebay after it was freshened so ended up doing things ass backwards from a building/clearancing standpoint. Bought coated -.011" mains and all was good again.

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Re: Brain fade - half shelling a .010 bearing for more clearance

Post by In-Tech » Fri Jun 08, 2018 4:38 pm

SO -.009" bearing has thinner shells than a -.010" and -.011 bearing has thicker shells that the -.010". Therefore, a -.009 bearing will result in additional clearance over the -.010" bearing and the -.011" bearing will have less clearance than the -.010" bearing.
:lol: Hahahaha, I did have to reread it.

Std journal bearing is 2.100" O.D crank (forget built in clearance for this convo)
-.009 journal bearing is for 2.091" O.D. crank, thicker by .009" per pair of shells vs Std. More clearance
-.010 journal bearing is for 2.090" O.D. crank, thicker by .010" per pair of shells vs Std
-.011 journal bearing is for 2.089" O.D. crank, thicker by .011" per pair of shells vs Std. Less clearance

Krooser was right, this was a good memory lesson.

Sorry Bill, I know you know your stuff. :oops:
Heat is energy, energy is horsepower...but you gotta control the heat.
-Carl

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