bearing journal
I know that the stock connecting rod journal diameter is 2.123"
on a crankshaft you have a crank journal (more commonly called a main journal) and a rod journal. the main journals of the crankshaft are where and how the crankshaft is held in the block. the rod journals are where your connecting rods are attached to.
bearing journal
small journal cranks can be ground to a minimum of 1.9585 (rod journals) big journal cranks 2.0685 ( rod journals)
The weight of the piston, rings, and connecting rod is concentrated out at the rod journal. As the crank spins, it throws that weight around. The counterweight is on the opposite side from the rod journal to offset this weight. This is why when you replace pistons or rods, the crank is rebalanced by adding or removing material from the counterweight.
That is another word for---The place on the crankshaft were the rod bearings are and were the crankshaft bearings are.
There are 5 main journals and 4 rod journals. Each rod journal holds 2 rods.
The main journal radius, rod journal radius or otherwise both are known as the fillet.
Just bought new rods with 2.10" journals
When rod bearing clearance is too tight the end result is what is called a spun bearing -- definitely a bad thing. Bearing clearance is the difference between the inside diameter of the bearing and the outside diameter of the crankshaft journal to which it is clamped. The bearing is supplied pressurized oil fed by the oil pump, it should never touch the crankshaft journal but should always float on a wedge of oil. If the clearance is too tight the bearing touches or drags on the crankshaft journal and the journal grabs the bearing and spins it inside the housing into which it is clamped -- which in the case of a rod bearing is the big end of the connecting rod. Once this happens it all pretty much self destructs as it chews up the big end of the connecting rod and the crankshaft journal as well.
New answer- A small journal has 1/2 in. Rod nutsA large journal has 9/16 in. Rod nutsA previous comment was "On The Engine There Is A Large Journal This Is The Crankshaft Journal That Is What They Must Be Talking About. Where The Rods Go Is Call The Small Journal. This Is The Only Way It Can Be. Hope This Helps"I will presume that this question is not about the difference between 'big end' and 'little end' of the connecting rods. Use of the word 'journal' indicates to me that the question is about big-end bearing size, not 'which end of the rod is which'.Technically, of course, the "journal" is the part of the crankshaft on which the bearing in the big end rides, but the measured difference between journal and bearing-bore spec would be little more than the thickness of an effective hydrodynamic lubricating film.Presumably this question concerns the GM 350 Chevy engine; look here for more specific information:http://en.wikipedia.org/wiki/Chevrolet_Small-Block_engine(Other related wiki pages related to specific GM small-block designs exist too). There is specific information on the different journal sizes -- ISTR specific mention is made, with dimensions, of at least one version of the engine that has different crank-journal specs depending on year.To answer the specific question, the 'definitive' way would be to remove one of the rod-bearing caps and push the rod up sufficiently to get a measurement on the crank throw. Measure the crank journal diameter at several points (to eliminate some of the effect of wear), then compare this to the tech information. I believe there are ways to tell from the engine serial number, but I do not know that information personally.Hope this helps properly...Small block engines (other than 350) before 1968 were small journal (2.00 rod journal). 1968 engines (other than 350) could be either large (2.100 rod journal) or small. After 1968 all small blocks had large rod journals with the 400 having larger mains than the others.