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Re: Oiling Mods Big Block [Re: Flo] #2128697
08/09/16 02:07 PM
08/09/16 02:07 PM
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BowtieKillr Offline
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Hey flo I read somewhere to use .125 restrictors to the cam bearings. That is what I installed on a 512 im beginning to build. Is .125 too much. Should I change to .080 . This is a street strip car.

Re: Oiling Mods Big Block [Re: BowtieKillr] #2129261
08/10/16 07:12 AM
08/10/16 07:12 AM
Joined: Sep 2005
Posts: 401
Berlin, Germany
Flo Offline OP
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Flo  Offline OP
mopar

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Posts: 401
Berlin, Germany
Originally Posted By BowtieKillr
Hey flo I read somewhere to use .125 restrictors to the cam bearings. That is what I installed on a 512 im beginning to build. Is .125 too much. Should I change to .080 . This is a street strip car.


I cannot tell you if .125" is "too much". Stock there is no restriction at all and it works. The question is, how much more oil compared to stock do you want to direct to the mains and rods.

From all I found .080" should be enough to keep the cam bearings alive. I did NOT test it yet though! IF this is enough also heavily depends on the clearance of your cam bearings. If everything is really nice and tight there, much smaller should work. the otehr way around: if your bearings are really nice and tight you also do Not need a restritor ;-)

For reference:
Current Daimler 4 banger Diesel has ONE .080" (2mm) restriction for the WHOLE 16valve cylinder head:
That means: 10 cam bearings, 16 x hydraulic lifters and spray nozzles for cam followers.

Yes, there are 60years of manufacturing technology inbetween that motor and our B-Blocks, but just to give an idea.


1967 Fury III 4door HT tiny 318, late model roller block, bored and stroked to 344
Re: Oiling Mods Big Block [Re: Flo] #2129262
08/10/16 07:23 AM
08/10/16 07:23 AM
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BowtieKillr Offline
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Ok Thanks, this cam is tight in the bearings so I guess Ill keep the .125. Thats a lot smaller than the factory orifice

Re: Oiling Mods Big Block [Re: Flo] #2129339
08/10/16 11:51 AM
08/10/16 11:51 AM
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Posts: 2,666
Stuttgart, Arkansas
rickseeman Offline
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rickseeman  Offline
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Stuttgart, Arkansas
A new hemi block uses a .040 orifice to lube the 8 rocker arms.


2011 Drag Pak Challenger
Re: Oiling Mods Big Block [Re: rickseeman] #2129497
08/10/16 02:35 PM
08/10/16 02:35 PM
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Posts: 43,252
Bend,OR USA
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Cab_Burge Offline
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Originally Posted By rickseeman
A new hemi block uses a .040 orifice to lube the 8 rocker arms.
The three new world cast iron blocks, wedge and Hemi, I've check had .039 restrictors in thier full time oiling passages to the rocker shafts work shruggyI now use .039 restrictors on all my motors with Indy heads with external oiling on true needle bearing roller rockers up Maybe a little bigger restrictor on bushed or non roller rockers like ductile iron or extruded aluminum with roller tips work

Last edited by Cab_Burge; 08/10/16 02:38 PM.

Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Oiling Mods Big Block [Re: Flo] #2129546
08/10/16 03:21 PM
08/10/16 03:21 PM
Joined: Oct 2007
Posts: 4,209
New York
polyspheric Offline
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I've seen good and bad math trying to proportion oil flow among many functions by relative restrictor size, but there is a limiting factor discovered eventually by anyone who does this.
A piece of grit will find a .030" restriction, and stay there. Even .035" is safer.


Boffin Emeritus
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