Re: Bearing clearance
[Re: dvw]
#2978448
10/26/21 01:00 AM
10/26/21 01:00 AM
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Joined: Sep 2017
Posts: 340 Red Deer, Alberta
Greenwood
OP
enthusiast
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OP
enthusiast
Joined: Sep 2017
Posts: 340
Red Deer, Alberta
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Your numbers don't subtract correctly. Is this a typo? If not then the math shows .0045" and .005" bearing clearance. That's quite a bit. Even if you used .011" under bearings it would be .0035" and .004". Though that loose wouldn't scare me the question is if the crank has been cut .031" under, why is there so much clearance ? I'd check the big ends of the rods for size. Doug I probably should have typed that differently. Yes, .0045-.005" total bearing clearance, or .0025" per side. Does that make more sense?
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Re: Bearing clearance
[Re: Greenwood]
#2979257
10/28/21 02:43 PM
10/28/21 02:43 PM
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Joined: Jun 2006
Posts: 5,161 CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,161
CT
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I'm not an expert, but since you haven't gotten too many replies I'll chime in. That sounds pretty loose for rods to me, I'd think your oil pressure would end up pretty low even with an HV pump and 20W50 oil.
Are you sure you have a standard .030 under bearing in there? As mentioned perhaps the rods need resizing. I'd shoot for more like .0025-.0030.
Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street
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Re: Bearing clearance
[Re: GTX MATT]
#2979266
10/28/21 03:02 PM
10/28/21 03:02 PM
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Joined: Jan 2003
Posts: 13,354 Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 13,354
Marion, South Carolina [><]
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I'm not an expert, but since you haven't gotten too many replies I'll chime in. That sounds pretty loose for rods to me, I'd think your oil pressure would end up pretty low even with an HV pump and 20W50 oil.
Are you sure you have a standard .030 under bearing in there? As mentioned perhaps the rods need resizing. I'd shoot for more like .0025-.0030.
That's awful loose.
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: Bearing clearance
[Re: an8sec70cuda]
#2979267
10/28/21 03:13 PM
10/28/21 03:13 PM
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Joined: Jan 2003
Posts: 9,985 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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master
Joined: Jan 2003
Posts: 9,985
Frostbitefalls MN (Rocky&Bullw...
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I'm not an expert, but since you haven't gotten too many replies I'll chime in. That sounds pretty loose for rods to me, I'd think your oil pressure would end up pretty low even with an HV pump and 20W50 oil.
Are you sure you have a standard .030 under bearing in there? As mentioned perhaps the rods need resizing. I'd shoot for more like .0025-.0030.
That's awful loose. Double check everything. Then shoot for the .001 per inch of bearing journal plus .0005 which should put you at .002375 to .002875, or .0024 to .0029. If you are in that range, that will be fine. Just be sure and have full torque on the rod bolts when you check them.
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: Bearing clearance
[Re: an8sec70cuda]
#2979269
10/28/21 03:15 PM
10/28/21 03:15 PM
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Joined: Aug 2003
Posts: 43,123 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,123
Bend,OR USA
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I'm not an expert, but since you haven't gotten too many replies I'll chime in. That sounds pretty loose for rods to me, I'd think your oil pressure would end up pretty low even with an HV pump and 20W50 oil.
Are you sure you have a standard .030 under bearing in there? As mentioned perhaps the rods need resizing. I'd shoot for more like .0025-.0030.
That's awful loose. I would use .0030 total max You need to remember Mopar design the stock rod bearings to be wider at the rod bearing parting lines than they are up and down in the center of the bearings in the rods, that provides a wedge of oil in those wedges to continually coat the bearings on every revolution the motors makes I use a lot of BB stroker cranks that have the BB Chevy 2.200 rod journals on them and I shoot for between .0025 and .0033 oil clearances in the center of those bearings, I like and use the narrow full groove main bearings and like between .003 to .0040 bearing clearances on them
Last edited by Cab_Burge; 10/29/21 01:24 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Bearing clearance
[Re: Greenwood]
#2979572
10/29/21 12:28 PM
10/29/21 12:28 PM
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Joined: Dec 2006
Posts: 2,105 Byron, NY
W.I.N. Racing
top fuel
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top fuel
Joined: Dec 2006
Posts: 2,105
Byron, NY
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Looks like I'd better do some more checking. I only snugged the bolts, then measured at a 45 deg. angle from perpendicular. Thanks guys! Check them with the bolts torqued...
'01 P1500, Blown/Inj BAE,/Veney ,Bruno/CS2,Dana 60 '01 Dodge 3500 S Cummins Auto, Fresh air kit, 4" Exhaust, '05 Dodge Magnum R/T - Too Much to list '60 Willys CJ5 '01 International LPX - Project,DT466, Allison '64 Plymouth Valiant, Inj 528 Hemi, 2spd
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Re: Bearing clearance
[Re: Greenwood]
#2979594
10/29/21 01:15 PM
10/29/21 01:15 PM
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Joined: Mar 2006
Posts: 9,824 MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,824
MI, usa
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Looks like I'd better do some more checking. I only snugged the bolts, then measured at a 45 deg. angle from perpendicular. Thanks guys! That would certainly add to the inner diameter measurement. When you torque the rods clamp them across the parting line. A couple pieces of aluminum in a vice will work. Doug
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Re: Bearing clearance
[Re: Greenwood]
#2981575
11/04/21 09:23 AM
11/04/21 09:23 AM
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Joined: Jun 2006
Posts: 5,161 CT
GTX MATT
master
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master
Joined: Jun 2006
Posts: 5,161
CT
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Perfect, make sure you check them all! Good luck!
Now I need to pin those needles, got to feel that heat Hear my motor screamin while I'm tearin up the street
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