Date: Tue, 9 Oct 2001 07:51:43 -0400
Reply-To: Robert Donalds <bostneng@FCL-US.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Robert Donalds <bostneng@FCL-US.NET>
Subject: Re: B. Bobs 2.1 main bearings, one more question
Content-Type: multipart/alternative;
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
Harold wrote
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
Harold
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.
Bob Donalds MN.
Master Noodler
as always all rights reserved
http://www.bostonengine.com
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