Ken wrote

Many thanks for that. Is it feasable to install the bearings = and torque down the case to arrive at clearances by subtracting the = crank journal size from the bearing I.D.?

Ken

that's what I do but you need a good = bore gauge. I use a sunnen bore gauge it reads out in .0005ths increments. It takes = allot of rechecking and practice to get it right . measuring the bearings in the = case gives you a size of the bearing with the crush factor. the bearing ID. = does shrink when the case is torqued. I also look to makes sure the = case half's still touch with a flash light when I install the bearings = to check the crank to bearing clearance. As I said in the first post = preparation is key to getting a good reading of the actual dimensions. I use a wire = brush from the paint store to get the sealing surfaces clean. the brush lasts just = long enough to get the job done then I trash it. I also file the case at the = sealing surface to debure it.

we are talking about WBX engines = here But I think I should say that the above procedure is also mandatory on = all type 2-4 blocks. most type 2-4 blocks wont pass this flash light test

Bob,
You told us the difference = in size, blue vs. red bearing, and that
the differences are miniscule.
Question:
Are the red and blue dot larger or are they = smaller than the
standard (no dot) main bearing?
And which is larger = of the 2 color coded, the blue or red dot?
Thanks for any info.
Harald

I spent some time this AM with my = bore gauge and a few sets of 2.1 main bearings. I was quickly reminded that the tri = metal thin walled 2.1 main bearings are not round until they are = installed and torque into a case (sorry I don't have time for that Today but soon). So with that in mind I found that the bearings where = all over the place. next I looked at the boxes and as you pointed out some = read .001 RED and some say .004 BLue This is hundreds of a millimeter. Some of the boxes I opened had color = codes some did not. I think that the difference is so small that most folks could = not measure the difference. So it sounds like you want to what I would = call noodle around (I define noodling as spending way to much time fine tuning = something that might not matter) sounds like you want find out if the = crank main bearing needs to have a tighter fit for longer life or increased oil pressure? And is it important to custom fit the = larger bearings to a warn crank? The 2.1 cranks for the most = part don't show allot of wear even at 150 K. As long as the clearance are within = the spec the then you are good to go. I have even used a set of USED mains = in my 84 Camper 2.1 big valve engine because the measurements = where within spec. NO PROBLEM I would say there = are more important factors that would determine the oil pressure or life of an = engine. Some of those things would be setting the fuel injection up correctly = to prevent fuel dilution or creating a lean condition, making sure that the big end of the con rods are round, rod = bearing clearance, oil changes, load and the performance of the cooling = system over the life of the engine.