KING MAIN BEARING CLEARANCE'S AT PARTING LINE..?

boss9coupe on August 20th 2009, 9:22 am

Guys

the local machine shop measured my crank tunnel with the bearings in and arp studs 200000 series torqued to 100lbs with moly .. they said i have 2.5 thou top to bottom and 8/tenths more across the parting line.. or were the bearings butt up.. is this much difference in clearance normal for this style bearing..? what do you guys think..?
sorry not real hip with engine lingo..hope you understand..

frpp A460 block line honed by (another machine shop)
king main bearing std size box p/n MB5242-HP
back of bearings M5242 STD PRO SERIES KL

Thanks Aaron..

56Tbird on August 20th 2009, 9:29 am

The rule of thumb is .001 per inch of journal size. It'll live where your at. You'll see all your wear on top and bottom not at the mating spots on the sides.

c.evans on August 20th 2009, 9:29 am

Aaron,

Yes, that's normal. You only measure for proper bearing clearance "on the vertical", meaning from 12:00 high to 6:00 bottom. The greater bearing clearance from 3:00 to 9:00 is built into the bearing by design.

Hope this helps,

Charlie Evans

c.evans on August 20th 2009, 9:31 am

56Tbird wrote:The rule of thumb is .003 per inch of journal size. It'll live where your at. You'll see all your wear on top and bottom not at the mating spots on the sides.

Dan,

Check your math. I think you meant .001" per inch.

Charlie

56Tbird on August 20th 2009, 9:32 am

Yeah ,I corrected it Uncle Charlie... affraid

chuck stevens on August 20th 2009, 8:36 pm

? .0008 at the parting line ???

Lem Evans on August 20th 2009, 8:44 pm

chuck stevens wrote:? .0008 at the parting line ???

Think it was .0008" more at the p. line .

boss9coupe on August 21st 2009, 6:37 am

sorry guys..

yep .0008" more at the parting line or as the machine shop explained it to me 8/tenths of 1 thou" more at the parting line..

Thanks for your help

Aaron

rmcomprandy on August 21st 2009, 9:15 am

If your machine shop had a question about it ... I would find a different machine shop. One who is aware of what is actually happening out here in the real world.
That is what is called bearing "eccentricity" and more or less of that eccentricity is built into evey brand and style of bearing shell throuout the world.
.0008" is really not very much...

56Tbird on August 21st 2009, 9:32 am

Randy ,thanks for coming here and offering your advice!!! We appreciate you my friend.Please feel welcome and hang around Very Happy

Take care, Dan-O

boss9coupe on August 21st 2009, 10:59 am

Randy ..

Yes you are correct...and i will...you seem to be able to read between the lines.. Shocked

I'm learning slowly lol!!

Thanks Aaron..

boss9coupe on August 22nd 2009, 11:54 am

just reading in carcraft magazine online tech section..

about customising bearing clearance..they are saying you can increase or decrease the clearance...by using a half shell undersize +0.001 or -0.001 oversize with a half std bearing shell from the same series bearing and manufacturer !! Shocked

.. is this correct ??

and if so could i get closer to were (i think ?) i should be by mixing them?

these are my clearance's now .0029" on the rods.. scat h beams and king std size hp bearings.. I'd like to be closer to .0025" if needed

.0025" on the mains king std size hp bearings.. I'd like to be closer to .0027" to .003" if needed

and also if this is do-able were would you put the oversize bearing in the rod half or the cap?
and the mains the undersize bearing in the block half or the main cap?

is this MIXING a "no go" in your opinion..??

I will be running a Kaase oil pump and oz brand (penrite) 20/60 weigh mineral oil.. maybe will go lighter..
any education appreciated..

thanks Aaron..

Lem Evans on August 22nd 2009, 12:28 pm

Halfing is a common practice .

ndmus88gteng on August 22nd 2009, 1:29 pm

Lem Evans wrote:Halfing is a common practice .

very good info. could someone explain the proper method . top1/2 bottom 1/2 ect. study

500 plus WOW good job guys
Rick

Lem Evans on August 22nd 2009, 2:26 pm

Either way seems to work fine .

KING MAIN BEARING CLEARANCE'S AT PARTING LINE..?