Why I don't miss building motors sometimes.

[wsuwrhr]

If you are getting your measurement by "doing the math", install the bearings, torque the bolts, and use a mic and dial bore gauge to find out the true clearance. It will be different than measureing shell thickness, etc.....
Well that is how it started out.
I already did that.
.0005 up and down. Not near enough.
I know it CAN be different, but it can never be more clearance, right? Doing the math is the maximum the clearance can ever be.
I have never had this problem in the past so I am trying to sort it out before I kick a rod out. Not good.
Brian

[lucky]

hey What torque wrench are you using ?- get a bigger bar

[wsuwrhr]

hey What torque wrench are you using ?- get a bigger bar
Haha, looks like if I use that method I don't need to tighten them as much.
I bought a nice Snap-On torque wrench a couple months ago.
Brian

[steelcomp]

Federal Mogul competition brg P/N 8-7135CH-1 (+.001)
If the crank, bearings, and rods are standard, that's a pretty typical OEM clearance (.0015-.0002) You might want the rods honed to the max of the tolerance, maybe pick up a few tenths. The fed mogul brgs usually run about .0005 big, so the +.001 shoud get you another thou an-a-haf.

[gn7]

Federal Mogul competition brg P/N 8-7135CH-1 (+.001)
If the crank, bearings, and rods are standard, that's a pretty typical OEM clearance (.0015-.0002)
didn't you mean (.0015-.002) and yeah, I have seen numbers like that more than once and they worked fine, if your not spinin a ton, can't recommend 50 wieght oil though

[steelcomp]

didn't you mean (.0015-.002) and yeah, I have seen numbers like that more than once and they worked fine, if your not spinin a ton, can't recommend 50 wieght oil thoughYeah, of course I meant .002. I'd never recommend 50 wt anyway.

[wsuwrhr]

I bought the +.001 bearings. We will see where that gets me I guess.
Brian

[TIMINATOR]

All these xperts! The rods and mains will allways read larger across the parting line than top to bottom! This is because performance bearings are "delta wall", they are thinner at the parting line than at the middle. So if there is any mismatch due to improper, or lack of machining, the thinner edge of the bearing wouldn't tend to scrape the oil film from the crank. Measure the clearance perpendicular to the parting line(90 deg).Clevite and FM have catalogues, this info plus much more, is in there. It is our experience that aftermarket cranks run larger than factory units, this makes the clearances tighter. We use and stock HX bearings(.001 extra clearance), and also can polish a crank to add to the clearance, this is normal activity for engine builders.We set up a 10ths indicating dial bore gauge to the crank journal size to directly read the clearances. Not to be a smart-a**, but this is one reason you should let someone qualified check and assemble your engine. Also never hone the rods or main bores to adjust clearances, the fact that the bore is smaller than the bearing shell is what allows heat transfer from the bearing, and it is also what keeps the bearing from spinning in the bore, its called crush. We allways machine everything to the tighter end of the tolerance limit to enhance the crush. Buy the correct bearings, or remachine the crank. TIMINATOR

[YeLLowBoaT]

I've always measured all of the barring surfaces(in place and torqued), then had the crank ground to give the proper clearance for those numbers, not what it says in the book... but I'm not a engine builder...

[wsuwrhr]

Did you even read my post?
Just curious.
Not to be a smart ass...but reading your post seems like you replied in the wrong thread.
All these xperts! The rods and mains will allways read larger across the parting line than top to bottom! This is because performance bearings are "delta wall", they are thinner at the parting line than at the middle. So if there is any mismatch due to improper, or lack of machining, the thinner edge of the bearing wouldn't tend to scrape the oil film from the crank. Measure the clearance perpendicular to the parting line(90 deg).Clevite and FM have catalogues, this info plus much more, is in there. It is our experience that aftermarket cranks run larger than factory units, this makes the clearances tighter. We use and stock HX bearings(.001 extra clearance), and also can polish a crank to add to the clearance, this is normal activity for engine builders.We set up a 10ths indicating dial bore gauge to the crank journal size to directly read the clearances. Not to be a smart-a**, but this is one reason you should let someone qualified check and assemble your engine. Also never hone the rods or main bores to adjust clearances, the fact that the bore is smaller than the bearing shell is what allows heat transfer from the bearing, and it is also what keeps the bearing from spinning in the bore, its called crush. We allways machine everything to the tighter end of the tolerance limit to enhance the crush. Buy the correct bearings, or remachine the crank. TIMINATOR