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Rod Journal Size #2482108
04/13/18 12:41 PM
04/13/18 12:41 PM
Joined: Jan 2005
Posts: 1,772
Keymar, MD
DusterKid Offline OP
top fuel
DusterKid  Offline OP
top fuel

Joined: Jan 2005
Posts: 1,772
Keymar, MD
Curious as to the benefits of going to the 2.20 rod journals vs the standard 2.375

My thoughts, feel free to correct me if I'm wrong.
Less block clearancing
Lighter rod?
less bearing surface = less friction (free's up some HP?), but since there's less bearing surface is that harder on the bearings?


Engine I will be looking to build is a race motor and I'm looking to make 625-650 HP.

Re: Rod Journal Size [Re: DusterKid] #2482141
04/13/18 01:30 PM
04/13/18 01:30 PM
Joined: Oct 2007
Posts: 4,206
New York
polyspheric Offline
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polyspheric  Offline
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Posts: 4,206
New York
Lower journal overlap means slightly weaker crank (still safe).
Smaller journal means slightly reduced local oil pressure, which is a function of circumference × engine speed (still safe).


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Re: Rod Journal Size [Re: DusterKid] #2482185
04/13/18 02:48 PM
04/13/18 02:48 PM
Joined: Sep 2014
Posts: 4,457
Washington
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madscientist Offline
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madscientist  Offline
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Posts: 4,457
Washington
Unless you are burning fuel, there is never a reason to use a 2.375 rod throw. 2.20 is plenty big. 2.100 is more than doable most of the time N/A.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: Rod Journal Size [Re: DusterKid] #2482187
04/13/18 02:49 PM
04/13/18 02:49 PM
Joined: Sep 2014
Posts: 4,457
Washington
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madscientist Offline
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Washington
BTW, the smaller rod throw also reduces the weight of the rod, the rod bearing and the rod throw.


Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
Re: Rod Journal Size [Re: DusterKid] #2482261
04/13/18 06:50 PM
04/13/18 06:50 PM
Joined: Oct 2007
Posts: 4,206
New York
polyspheric Offline
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polyspheric  Offline
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Joined: Oct 2007
Posts: 4,206
New York
I agree, late SBC 2.100" is safe with any conventional stroke, but there are fewer rod choices by length than with BBC.
Caveat: if the grinding doesn't unmask an oil passage.


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