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Bearing clearance
https://www.slantsix.org/forum/viewtopic.php?t=25340		 Page 1 of 1
Author:  61valiant [ Fri Oct 12, 2007 12:57 pm ]
Post subject:  Bearing clearance
Can someone tell me what the rod and main bearing clearance range is for a stock 225. Its in a 65 valiant if it matters. Thanks Blake
Author:  Doc [ Fri Oct 12, 2007 1:37 pm ]
Post subject: 
Rods = .0005 to .0015
Mains = .002 to .003
DD
Author:  61valiant [ Sat Oct 13, 2007 8:51 am ]
Post subject: 
Thanks. Blake
Author:  rftroy [ Sat Dec 15, 2012 6:19 pm ]
Post subject: 
Quote:
Rods = .0005 to .0015
Mains = .002 to .003
DD
I am assembling my Slant and have measured the main bearing clearance at between .0025" and .0031".
I am using a micrometer on the crank and a dial bore gauge to measure the bearings, both Mitutoyo.
The crank is well within spec on journal diameter, OOR, and taper.

The bearings are Sealed Power p/n 4092.
I was unhappy when I made the measurements; the factory service manual specs the main bearing clearance at .0010 +/- .0005" in 1969, .0005" to .002" in 1976, and maximum clearance before reconditioning of .0025".
.002" to .003" is the clearance given in the DC manual for racing clearances.

So, should I run these in a stock 225 without worrying about it?

Robert

edit: I have now found a few posts throwing doubt on the quality of Federal Mogul parts. Is there a better manufacturer of Slant Six engine bearings?
RT
Author:  CNC-Dude [ Sat Dec 15, 2012 10:01 pm ]
Post subject: 
Where were your housing bores and crank journals as far as their specs. You will always have bearing clearance toward the high side whenever your housing bores are at the high side of their specs and the crank is at the low side of their specs. The only way you can adjust the bearing clearances to a better spec at this point is to adjust the housing bores to a tighter dimension.
Author:  rftroy [ Sun Dec 16, 2012 5:28 pm ]
Post subject: 
Crank is .010" under; #1 main crank journal measures 2.7400" with 0.0000" OOR.
The #1 main bore is 2.9433 +/- 0.0001", the +/- is due to the machining marks in the block making the surface uneven.
I haven't been able to find the spec for the main bore dimension.
The bearing in this bore measures 0.0031" clearance.

I put bearings into two rods. Also, Clevite, i.e. Mahle, bearings.
One measured 0.0022" clearance, the other 0.0021".
The rod with 0.0021" clearance has a rod bore diameter of 2.3130" in the line of the beam, with 0.0003 OOR. I did find one reference on this site that the nominal rod diameter is 2.3130"
The crank journal for that rod has a diameter of 2.1768" and OOR of 0.0002". That means that this journal is 0.0002" below the nominal diameter.

This is not a problem with the machined parts of the engine. This is a problem with the Sealed Power, Federal Mogul bearings.

So the questions are:
1. Do they make the bearings with large clearances to reduce their risk exposure due to machinists who do sloppy work?
2. Is there a company that makes superior bearings?

Robert
Author:  CNC-Dude [ Sun Dec 16, 2012 6:52 pm ]
Post subject: 
They make race bearings for some popular applications to take up the extra clearance, but they are much more expensive than the street bearings, and they are only for std. journal sizes. In your situation, it is going to be easier to close up the housing bores a half and call it good.
Author:  Rug_Trucker [ Sun Dec 16, 2012 6:53 pm ]
Post subject: 
Try some fresh Plastigauge.
Author:  CNC-Dude [ Sun Dec 16, 2012 6:58 pm ]
Post subject: 
He's using dial bore gages and mic's.
Author:  Rug_Trucker [ Mon Dec 17, 2012 3:50 am ]
Post subject: 
Quote:
He's using dial bore gages and mic's.
I know.
Author:  robertob [ Mon Dec 17, 2012 6:29 am ]
Post subject: 
I've heard good things about King bearings. You could always order up a set and compare thickness to the Clevite stuff.
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