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King main bearings ??

Posted By: '72CudaRacer

King main bearings ?? - 07/21/14 03:14 AM

I'm building a 500 ci RB engine and am trying to use King bearings. Wanted HP series, but -.010's are out of stock everywhere (probably from problems in middle east). I got King XP series instead. Had to turn the crank (-.010") and line hone the block. When I fit the bearings, the clearance is all over the place, with the thrust unacceptable (to me). The measurements are as follows;
Cyl# Block bore Crank Clearance
1******2.9431"*****2.7397"*****.0032"
2******2.9435"*****2.7397"*****.0031"
3******2.9435"*****2.7398"*****.0025"
4******2.9435"*****2.7399"*****.0035"
5******2.9432"*****2.7398"*****.0031"

I pulled the caps back off and rechecked for anything under the bearing shells, but everything looked good. The block bore is off by a total of .0004". The crank varys a total of .0002". I can move the bearing shells around and the measurement follows the shells. I can't move the #3. Anyone see this with King XP bearings before? I've used the HP's with no problem in the past.
Sorry this turned out so long, just need some input from those that have been there before and what did you do to fix it?
Thanks,
Brian
Posted By: poppaj

Re: King main bearings ?? - 07/21/14 03:35 AM

I have used them with no problems but prefer clevelite coated series. Stock main caps?
Posted By: '72CudaRacer

Re: King main bearings ?? - 07/21/14 03:42 AM

Quote:

Stock main caps?



Yes, with main studs.

Brian
Posted By: jamesc

Re: King main bearings ?? - 07/21/14 04:49 AM

i realize this is not an "answer" but i've done a fair bit of precision measuring over the years and when i see people talking 10ths i'm leery. i'm not questioning you directly but imho it takes a lot to accurately measure .0001" with accuracy and repeatability and i have a pretty nice selection of metrology tooling for a backyard hack

how exactly are you measuring these clearances?
Posted By: '72CudaRacer

Re: King main bearings ?? - 07/21/14 05:00 AM

Quote:

i realize this is not an "answer" but i've done a fair bit of precision measuring over the years and when i see people talking 10ths i'm leery. i'm not questioning you directly but imho it takes a lot to accurately measure .0001" with accuracy and repeatability and i have a pretty nice selection of metrology tooling for a backyard hack

how exactly are you measuring these clearances?

Micrometer and dial bore gauge. Very repeatable. (no plastigauge here )
Measure crank with mic, set dial bore gauge to the mic and measure the hole.
I can live with #1,2,4 & 5, but #3 is just too tight to suit me.
I agree that to measure .0001" is somewhat subjective when the tool measures .0005".

Brian
Posted By: supercomp

Re: King main bearings ?? - 07/21/14 04:12 PM

Quote:

Quote:

i realize this is not an "answer" but i've done a fair bit of precision measuring over the years and when i see people talking 10ths i'm leery. i'm not questioning you directly but imho it takes a lot to accurately measure .0001" with accuracy and repeatability and i have a pretty nice selection of metrology tooling for a backyard hack

how exactly are you measuring these clearances?

Micrometer and dial bore gauge. Very repeatable. (no plastigauge here )
Measure crank with mic, set dial bore gauge to the mic and measure the hole.
I can live with #1,2,4 & 5, but #3 is just too tight to suit me.
I agree that to measure .0001" is somewhat subjective when the tool measures .0005".

Brian



Should be .0001 dial indicator.
Posted By: rickseeman

Re: King main bearings ?? - 07/21/14 07:03 PM

.0025 doesn't seem too tight for me. Is it for you folks?
Posted By: JohnRR

Re: King main bearings ?? - 07/21/14 07:12 PM

Quote:

.0025 doesn't seem too tight for me. Is it for you folks?



Street car no problem. I had that on the 383 I did the cam break in on yesterday, 40psi hot at idle with Crower cam saver lifters, stock volume oil pump.
Posted By: '72CudaRacer

Re: King main bearings ?? - 07/21/14 11:38 PM

Quote:

Quote:

.0025 doesn't seem too tight for me. Is it for you folks?



Street car no problem. I had that on the 383 I did the cam break in on yesterday, 40psi hot at idle with Crower cam saver lifters, stock volume oil pump.



Not a street engine. Drag race only. Should go 6.30's 1/8.
Brian
Posted By: '72CudaRacer

Re: King main bearings ?? - 07/21/14 11:41 PM


Should be .0001 dial indicator.


Should be a Mega block too, but oh well, it's what I got.

Brian
Posted By: Mopar_Rich

Re: King main bearings ?? - 07/22/14 01:40 AM

What's the crank end play with #3 installed?
Posted By: jamesc

Re: King main bearings ?? - 07/22/14 12:00 PM

if you're using a .0005" indicator than i would really be cautious about the readings. you're using the bore gauge as a comparator which is a good thing but setting the gauge with a mic (you must when using the gauge as a comparator) is very touchy and that coupled with possible indicator and measuring error can lead you astray. if you're looking for tenths accuracy you really need an accurate (read not chinese) tenths reading indicator.

as for the .0025" if that is accurate it might be a little snug for a race engine. a little loose and you can be OK, too tight and if it rubs well who knows. lots of variables and i'm always concerned about tolerance stacking.

wish i could give a definitive answer but without hands on i'm only guessing.

i'm completely anal OCD about measuring stuff and am never satisfied

Attached picture 8216010-tools001(Large).jpg
Posted By: Cab_Burge

Re: King main bearings ?? - 07/22/14 07:41 PM

Brian, are those bearings coated? If so you may be reading the thickness of the coatings If coated maybe Scotchbrite is your freind That or order another set of those same bearings and see what you get I'm with you on #3 clearances That is to tight for a race motor, especially with RB main sizes
Posted By: Anonymous

Re: King main bearings ?? - 07/22/14 11:01 PM

Run It!!! Big Deal--Looks great
If you were doing a circle track engine that uses .002 and water thin oil then it really really matters but a drag engine --run that thing and for-get it
After it strains a time or two it will be perfect--
Way more issues with how tight the studs are in the block and HOW you pull a torque wrench than with those numbers.
Your build is going great and you just don't know it.
OR...you can buy a half dozen sets --mix /match until you get perfect numbers--It will run exactly the same--you will have spent more $$$$--have lots of useless leftover bearings that will never get used and you will still win or lose based on how you hit the tree and drive the top end
You are good--shut your eyes and keep rolling...
Posted By: rickseeman

Re: King main bearings ?? - 07/23/14 05:30 AM

I'm doing a 440/512 bracket motor for a guy. Roller cam maybe 700 hp. The mains are .0029 to .0035. I thought that was a little loose. What do you guys think?
Posted By: Cab_Burge

Re: King main bearings ?? - 07/23/14 06:01 AM

I like them loose, the old adage of .001 for each 1.00 inch of crankshaft diameter works very well on general daily driver rebuilds On a race motor I like to see at least .0032 or larger on my 2.750 diameter main bearings motors A little looser is way better than a tiny bit to tight, especially when revving the drag motors over 6000 RPM
Posted By: '72CudaRacer

Re: King main bearings ?? - 07/27/14 02:56 AM

Quote:

What's the crank end play with #3 installed?

.0045"
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