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

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..

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.

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

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

Yeah ,I corrected it Uncle Charlie...

? .0008 at the parting line ???

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

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

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

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...

Randy ,thanks for coming here and offering your advice!!! We appreciate you my friend.Please feel welcome and hang around Take care, Dan-O

Randy ..

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

I'm learning slowly lol!!

Thanks Aaron..

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 !! .. 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..

Halfing is a common practice .

Lem Evans wrote:Halfing is a common practice .

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

500 plus WOW good job guys
Rick

Either way seems to work fine .

Bearing Tips And Tricks
1. Always check your micrometer with a standard before measuring.

2. Always use the same micrometer for the journals and to set the inside mic diameter.

3. Torque the rods and mains to spec before measuring a bearing inside diameter.

4. Changing rod bolts or moving from bolts to studs in the main caps will affect bearing clearance.

5. Temperature will affect the accuracy of the micrometer and the size of journal diameters both inside and out.

6. If you have one tight and one loose rod-bearing combination, try switching the bearings between the two. We've seen this work several times when the clearances are just a little bit off.

7. Never mix different bearing families when customizing bearing clearance. If you are using Federal-Mogul coated bearings, don't mix in a half shell uncoated race bearing.

"Never mix different bearing families when customizing bearing clearance. If you are using Federal-Mogul coated bearings, don't mix in a half shell uncoated race bearing"

It's been done with good results .

x2 ... all the time

1/2 Federal Mogul - 1/2 Clevite

1/2 ACL - 1/2 Federal Mogul

1/2 King - 1/2 Clevite

1/2 aluminum - 1/2 tri-metal

1/2 bi-metal - 1/2 babbit

1/2 coated - 1/2 Alecular

And any mixture of all of the above.
Don't vary the halves by any more tha 1/2 thousandth of inch between them.

EDIT: Get those oil clearances where you want them to be...

Those bearings aint that smart.....the lower ACL doesn't the upper is a FM .

so the different materials that the bearings are coated with have no effect ............ on the life of the whole deal ...... dont flame me on this one guys just learning

The way I see it...if one was coated that'd be a good thing . Coatings are not manditory [spell] but a nice thing in a high end engine....so why would it be bad to put one half of one in a rod/main ?

Where did the opinion you posted come from ...a mag. or the net ?

magazine

Typical mag. deal . But the good thing about it was that 'we' got to talk about it and get the fact of the matter out there .

WOW! this is great info....

Thanks to all..

Aaron

When mixing rod bearings, it is usually good to keep all the top halves one type and the bottom halves the other type but, I have seen them all over the place in a pinch.

Years ago ... a guy who was a "consultant" where I worked ALWAYS used a different top half than bottom for a thrust main bearing. He said that both bearing shell materials would impart their best qualities for containing crank thrust.
He was a pretty famous person who had a garage in Daytona Beach.