Fellow vanagon types and so forth mores=
With all the talk =
about main
bearings color codes I think I can clear the air on this subject. It=
has
been suggested that the difference in size of the blue verses red is .004=
ths.
The measurements I have taken show that the difference is .00025 ths.
that turns out to be a 1/4 of .001ths. Why they would bother =
to
make two different bearings sets with so small a clearance =
change
baffles me. The clearance for the main bearings is important and =
hard to
measure I have spent thousands to be able to do this accurately=
every time. Plastagauge is nice but not the cure for knowing the
clearances of the main and rod bearings and it has let me down =
to
many times.
I have never found =
the case
measurements or the bearing clearances listed for the1.9 or 2.=
1
engines and I am not going to offer them today. what I will say=
is
that I have found the need to align bore most 1.9 blocks. the reason=
is
they loose the crush on the bearing over time In layman's terms the=
hole
is to big.
As for the 2.1 block some are fine and
some need to be align bored and there is only one way to tell. That =
one
way is with a top of the line bore gauge and a couple of hours
to get the block clean at the mating surface and bolted together. I =
can
say that if the middle bearing web is out of round then it needs to be =
align
bored the other thing you need to know is that the crush is greater on =
the 2.1
main bearings because they are a thinner walled tri metal design
bearings.
The clearance =
for the
main bearings to the crank on the # 3 and # 4 bearings is=
.002 to 004 ths. as taken from the type 2 Bentley book yes its =
a
different engine but the basic requirements of main bearing =
clearances
are the same and the journals dimensions are also the same.
the # 2 splitshell bearing is not the same in the =
WBX 2.1
engines as the type 4 or the 1.9 engines. the type 2 book says the =
min
clearance is .0012 ths to .0035 ths. As for the WBX 2.1 I would not =
want
any less than 0015 ths on this split bearing to be safe. The # 1 =
bearing
next to the flywheel calls for .0019 to .004 ths I have found most
cases with bearings installed to measure close to the high limit of =
new
spec. the wear limit is .0074 ths. WOW
As for the rod =
bearings I like
my rods to have .0015 ths between the rod bearing and the crank
journals the type 2 book lists .0008ths to .0027 ths as the new spec=
this
is for both the 1.6 and the 2.0 air cooled engines.
I have =
recommended not
reusing the 2.1 rods over without having the bolts changed and resizing =
the
big ends of the rods
I just finished and =
test drove
my 84 westy to the transporterfest in brookline MA.
with a stage 3 2.1 big valve =
engine
I'm really pleased with the =
increase in
power. I had some concerned about the injection system but the exhaust =
gas
tests showed everything is a go. I did have to back off the main spring =
for
the air door in the air flow meter to get the mixture set right. The =
mixture
adjustment was much more sensitive than any I have seen I think=
the
big valves are the reason. The flow bench showed a 20% increase in =
air
flow threw the heads at all valve lifts we
tested.
Because of the past shortage of WBX main=
bearings
I used a set of used main bearings in this engine with no problems the
clearances where right where I wanted them and no oil light at =
hot
idle
my new web page with lots of updates and=
head
flow chart specs for the big valve engines is almost ready and I will =
keep you
all posted
as always all right reserved =
DIV>
hope this helps
Bob Donalds
Boston Engine Exchange