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

[MotionMachine]

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.

[Krooser]

Who's on first.

[groberts101]

Who's on first.

Abbot!.. err, wait.. or was it Costello?

[Krooser]

Actually posts like this get you thinking which is good...

[engineguyBill]

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.

[In-Tech]

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.

[groberts101]

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.

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.

[In-Tech]

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.

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.