Re: small block stroker autopsy
[Re: MR_P_BODY]
#2761321
04/07/20 11:44 PM
04/07/20 11:44 PM
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Joined: Dec 2005
Posts: 11,497 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,497
Fulton County, PA
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Yes, WAY more with the right pistons. The side clearance has nothing to do with oil getting off of the bearing.
So it grabbed the bearing, turned it and piggy backed it and there's no heat? Crank hurt? Rod has to be junk, right?
If the results don't match the theory, change the theory.
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Re: small block stroker autopsy
[Re: mgoblue9798]
#2761385
04/08/20 08:59 AM
04/08/20 08:59 AM
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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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Really loose side clearance is harmless, unless it allows the rod's pin eye to use the inner face of the pin boss as a thrust surface.
Boffin Emeritus
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Re: small block stroker autopsy
[Re: polyspheric]
#2761450
04/08/20 11:47 AM
04/08/20 11:47 AM
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Joined: Oct 2007
Posts: 156 Southern California
BIG DRAG
member
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member
Joined: Oct 2007
Posts: 156
Southern California
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Excessive side clearance will cost hp from adding more windage in the crankcase, it will also lower oil psi due to the clearance being larger. The oil has to go somewhere. I wouldn't bandaid an issue with excessive rod side clearance. Now it's not huge hp being eaten up but it all adds up. I learned this from an accomplished stock/superstock engine builder a long time ago.
What is the clearance at now?
Last edited by BIG DRAG; 04/08/20 11:51 AM.
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Re: small block stroker autopsy
[Re: BIG DRAG]
#2761453
04/08/20 11:51 AM
04/08/20 11:51 AM
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Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
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master
Joined: Sep 2014
Posts: 4,457
Washington
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Excessive side clearance will cost hp from excessive windage in the crankcase, it will also lower oil psi due to the clearance being larger. The oil has to go somewhere. I wouldn't bandaid an issue with loose rod side clearance. This just isn’t true. Side clearance has zero affect on oil loss through the bearing. None.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: small block stroker autopsy
[Re: madscientist]
#2761458
04/08/20 11:56 AM
04/08/20 11:56 AM
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Joined: Oct 2007
Posts: 156 Southern California
BIG DRAG
member
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member
Joined: Oct 2007
Posts: 156
Southern California
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Excessive side clearance will cost hp from excessive windage in the crankcase, it will also lower oil psi due to the clearance being larger. The oil has to go somewhere. I wouldn't bandaid an issue with loose rod side clearance. This just isn’t true. Side clearance has zero affect on oil loss through the bearing. None. Then why is it that when bearing clearance is excessive that oil psi goes down? Clearance is like a controlled leak, more clearance more leakage. This has been my experience.
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Re: small block stroker autopsy
[Re: BIG DRAG]
#2761483
04/08/20 01:03 PM
04/08/20 01:03 PM
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Joined: Aug 2003
Posts: 43,097 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,097
Bend,OR USA
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Think about what you said about the bearing clearances being excessive and how the rod side clearances affect oil flow out of the bearings and crankshaft There many misunderstood myths spread about racing and motors, if the rods have .0025 bearing clearances and .012 side clearances will they let more oil out than with .0035 bearing clearances and .008 rod side clearances? How about having .0030 bearing clearances with .030+ rod side clearances like most stock Street Hemi motor came with from the factory I've built and race a bunch of BB stroker motors with BB Chevy type H and I beam rods that had over .0035 bearing clearances and well over .035 side clearances using 5W20Wt oil and had the oil pump bypass spring set so it allow the motor to have 70 lbs. pressure with hot oil at 7000 RPM, many motors like that with no bearing problems so far I have torn down a bunch of Mopar BB, SB and Hemi V8 that had way over .030 rod side clearances from the factory, only one early (October of 1965) production 1966 street Hemi motor had less than the factory recommended max .016 rod side clearances, it was between .012 to .015 on all of them
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: small block stroker autopsy
[Re: BIG DRAG]
#2761491
04/08/20 01:41 PM
04/08/20 01:41 PM
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Joined: May 2003
Posts: 6,559 Downtown Roebuck Ont
Twostick
Still wishing...
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Still wishing...
Joined: May 2003
Posts: 6,559
Downtown Roebuck Ont
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Excessive side clearance will cost hp from excessive windage in the crankcase, it will also lower oil psi due to the clearance being larger. The oil has to go somewhere. I wouldn't bandaid an issue with loose rod side clearance. This just isn’t true. Side clearance has zero affect on oil loss through the bearing. None. Then why is it that when bearing clearance is excessive that oil psi goes down? Clearance is like a controlled leak, more clearance more leakage. This has been my experience. Bearing clearance will affect oil pressure, side clearance can't. Picture the bearing clearance as the garden hose on the side of your house. Say you're pumping 5 gallon per minute at 45 psi running it wide open watering the flowers. The flowers are your side clearance, zero effect on what comes out the end of the hose. Another way to look at it is ask yourself if attaching a 2" firehose to the end of your 5/8" garden hose will fill a bucket any faster. Kevin
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Re: small block stroker autopsy
[Re: BIG DRAG]
#2761496
04/08/20 01:54 PM
04/08/20 01:54 PM
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Joined: Oct 2007
Posts: 4,205 New York
polyspheric
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master
Joined: Oct 2007
Posts: 4,205
New York
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Quoting myself from my book ("Chevrolet Stovebolt Performance"*), the math using its 2.311" rod journal for this example: The only leak, or outlet path, for oil pressure in the rod’s journal to bearing clearance space is at the sides of the rod big ends. This annular clearance area is easily calculated. The journal OD is 2.311”; with a bearing clearance of .003” (generous, but possible), the leak area is the bearing ID area minus the journal OD area. Here, it’s 4.205 in2 ((2.311+.003)2 × Π ÷ 4) minus 4.195 in2 (2.3112 × Π ÷ 4). The leakage from each side of the rod is .0109 in2. The radial clearance between the rod and journal cheek is the surface area of a horizontal cylinder 2.314” OD times the width of the side clearance, or 2.314” × Π × W. For the side clearance to control the oil escape volume, the side clearance area must be less than the annular clearance; in this case, less than .0109”. If the side clearance area is equal to the known leak at .0109”, W is .0015”, or 1½ thousands. Therefore any value of W higher than .0015” (the rod is .003” narrower than the journal’s cheek-to-cheek width) has no effect on oil pressure or the volume released. Since the side clearance is always much larger than this, any more clearance is, of course, harmless. * http://victorylibrary.com/235BK.htm
Boffin Emeritus
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Re: small block stroker autopsy
[Re: polyspheric]
#2761499
04/08/20 02:00 PM
04/08/20 02:00 PM
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Joined: Dec 2005
Posts: 11,497 Fulton County, PA
CMcAllister
Mr. Helpful
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Mr. Helpful
Joined: Dec 2005
Posts: 11,497
Fulton County, PA
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Quoting myself from my book ("Chevrolet Stovebolt Performance"*), the math using its 2.311" rod journal for this example: The only leak, or outlet path, for oil pressure in the rod’s journal to bearing clearance space is at the sides of the rod big ends. This annular clearance area is easily calculated. The journal OD is 2.311”; with a bearing clearance of .003” (generous, but possible), the leak area is the bearing ID area minus the journal OD area. Here, it’s 4.205 in2 ((2.311+.003)2 × Π ÷ 4) minus 4.195 in2 (2.3112 × Π ÷ 4). The leakage from each side of the rod is .0109 in2. The radial clearance between the rod and journal cheek is the surface area of a horizontal cylinder 2.314” OD times the width of the side clearance, or 2.314” × Π × W. For the side clearance to control the oil escape volume, the side clearance area must be less than the annular clearance; in this case, less than .0109”. If the side clearance area is equal to the known leak at .0109”, W is .0015”, or 1½ thousands. Therefore any value of W higher than .0015” (the rod is .003” narrower than the journal’s cheek-to-cheek width) has no effect on oil pressure or the volume released. Since the side clearance is always much larger than this, any more clearance is, of course, harmless. * http://victorylibrary.com/235BK.htm Oil acts as a coolant. It needs to flow, not be trapped. Oil pressure is not what keeps the parts from contacting each other anyway. It's the hydrodynamic wedge. I'd still like to see pictures of the OP's parts. Never saw a rod bearing grabbed and piggybacked with out getting hot and destroying the rod.
If the results don't match the theory, change the theory.
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Re: small block stroker autopsy
[Re: CMcAllister]
#2761504
04/08/20 02:07 PM
04/08/20 02:07 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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I would expect a color change and spalling.
Boffin Emeritus
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Re: small block stroker autopsy
[Re: polyspheric]
#2761780
04/09/20 01:41 AM
04/09/20 01:41 AM
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Joined: Aug 2003
Posts: 43,097 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,097
Bend,OR USA
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I would expect a color change and spalling. The damage done depends on how long it was run with the bearings stacked one over or under the other one, if you run them long enough that way they will usually break a rod bolt and then the rod cap unwinds and breaks the rod and block Seen more than one BB Chevy have that happen at the drags in SO CA
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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