Re: Bearing clearance on mains with BM aluminum block
[Re: mopar dave]
#3093654
11/12/22 09:42 AM
11/12/22 09:42 AM
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Joined: Feb 2008
Posts: 711 Central TEXAS!!!!
sr4440
super stock
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super stock
Joined: Feb 2008
Posts: 711
Central TEXAS!!!!
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I think i may start this 572 Hemi project over the winter getting into it over the holidays. I have the BM aluminum block with steel caps. What bearing clearances are needed on the main bearings? I will be using Callies steel rods, so i assume .030 on the rod bearings is fine? I like my engines a little loose, but I think .030 is way too much. Lol I am pretty sure you meant .003 which i would be fine with. Joe
Last edited by sr4440; 11/12/22 09:43 AM.
Without Data, you’re just another guy with an opinion.
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Re: Bearing clearance on mains with BM aluminum block
[Re: mopar dave]
#3093698
11/12/22 12:57 PM
11/12/22 12:57 PM
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Joined: Oct 2007
Posts: 4,205 New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,205
New York
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The rods and crank are both steel, aluminum has nothing to do with it. .003" is too loose for the rods, .0025"
Boffin Emeritus
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Re: Bearing clearance on mains with BM aluminum block
[Re: polyspheric]
#3093702
11/12/22 01:09 PM
11/12/22 01:09 PM
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Joined: Jan 2004
Posts: 4,540 Motor City
6PKRTSE
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master
Joined: Jan 2004
Posts: 4,540
Motor City
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I have .0022-.0025 on my rods and .003 on my mains on my Hemi.
1963 Belvedere 440 Max Wedge Tribute 1970 Charger R/T S.E. 440 Six Pack 1970 Challenger R/T, 528 Hemi 1970 Charger 500 S.E. 440 4 BBL 1970 Plymouth Road Runner 383 1974 Chrysler New Yorker 440 1996 2500 RAM 488 V-10 4X4 2004 3500 Dually Cummins 4x4 2012 Challenger R/T Classic.
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Re: Bearing clearance on mains with BM aluminum block
[Re: mopar dave]
#3093716
11/12/22 02:12 PM
11/12/22 02:12 PM
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Joined: Aug 2003
Posts: 43,007 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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>003+ on the rods and .004+ on the main bearing in iron block with steel rods work well for me, I'm in the middle of assembling a new KB aluminum wedge block that has .0040+ on the mains and around .0027 + on the rods, I would feel a lot better with .003+ clearance on the Scat steel H beam rods. This motor has a set of CNC ported B1 heads with a sheet metal tunnel ram with two Mark Sullens E85 prep Dominator carbs, I'm going to try NOS on it starting with two kits, 150 on the small kit first and then, maybe, another 300 HP on the second kit if it will (the chassis) take it I've never used any power adders so this will be the first time My thinking on any HP or and race motors bearing clearances it is way better to have way to much bearing clearances than a TINY bit too little
Last edited by Cab_Burge; 11/12/22 02:14 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Bearing clearance on mains with BM aluminum block
[Re: mopar dave]
#3093816
11/12/22 09:44 PM
11/12/22 09:44 PM
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Joined: Aug 2003
Posts: 43,007 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,007
Bend,OR USA
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Last edited by Cab_Burge; 11/12/22 09:45 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Bearing clearance on mains with BM aluminum block
[Re: mopar dave]
#3094066
11/14/22 03:42 AM
11/14/22 03:42 AM
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Joined: Jul 2005
Posts: 707 California
BigDaddy440
super stock
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super stock
Joined: Jul 2005
Posts: 707
California
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Do aluminum block engines require additional main and rod oil clearances? If so, can someone explain why?
I've built a lot of (iron block) engines throughout the years and typically shoot for .002-.0025" on my Mains and .0015-.002" on my Rods. Obviously application and rod journal sizes matter here. I'm talking hot street engines, not full race.
On a race engine I wouldn't be afraid to run .003-.0035" on the Mains and .002-.0025" on the Rods, but I don't see a need for more oil clearance than that.
Last edited by BigDaddy440; 11/14/22 03:43 AM.
1969 A12 Roadrunner 1970 Plymouth Cuda 1968 Dodge Dart
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Re: Bearing clearance on mains with BM aluminum block
[Re: BigDaddy440]
#3094071
11/14/22 08:28 AM
11/14/22 08:28 AM
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Joined: May 2005
Posts: 1,944 Apollo, PA.
B1MAXX
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top fuel
Joined: May 2005
Posts: 1,944
Apollo, PA.
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Do aluminum block engines require additional main and rod oil clearances? If so, can someone explain why? . No
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Re: Bearing clearance on mains with BM aluminum block
[Re: mopar dave]
#3094089
11/14/22 09:39 AM
11/14/22 09:39 AM
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Joined: Jan 2003
Posts: 13,319 Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 13,319
Marion, South Carolina [><]
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Mine has .0035" on the mains and about .0027" on the rods (steel), if I recall correctly. Don't have my folder here where I keep everything written down. Mine is a KB block FWIW. Been running it that way since 2006.
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 on mains with BM aluminum block
[Re: challenger451ci]
#3094139
11/14/22 01:43 PM
11/14/22 01:43 PM
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Joined: Jan 2003
Posts: 19,304 Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,304
Las Vegas
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FWIW I would shoot for .0030" ish for main clearance. Will depend on the final application, mainly street, street/strip, strip/street or just a race car. Rods depends again on material being used. And by all means restrict that oil going up top. I have my stuff down to .029" restrictors and there is still PLENTY of oil up top. And yes you will loose oil pressure when its warm. Just like an iron block will how much is a guess at best as they all seem yo vary and I have used nothing but aluminum blocks pretty much for the last 12 years.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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