Date: Thu, 25 Oct 2001 14:44:33 -0400
Reply-To: Kenneth D Lewis <kdlewis@JUNO.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Kenneth D Lewis <kdlewis@JUNO.COM>
Subject: Re: B. Bobs 2.1 main bearings, one more question
Content-Type: multipart/alternative;
Bob;
OK. I measured the bearing ID( in the case) and the crank's OD.
Subtraction should give me the clearance. What is tolerance here? How
about differences in orthaganol ID measuments i.e. out-of-round?
Anybody know of some good WEB sites with this info?
TIA
Ken Lewis
86 Crewcab,60 356
http://Neksiwel.20m.com/
On Tue, 9 Oct 2001 07:51:43 -0400 Robert Donalds <bostneng@FCL-US.NET>
writes:
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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