Rod Bearing Question

[Tim Rogers]

Josh Foster wrote:
>  The rod bearing "grades" as found on the crank at
> #1 read "2-1-1-0".  I've read Geo's article in SCC about his DET swap and
> I've read Mike K's article on Sentra.net.  Both state "When buying
bearings,
> I have also observed that if an engine has any kind of mileage on it, the
> next tighter bearing size can be used other than the number that is
stamped
> on each journal of the block and crank."

> Does this mean to go ahead and expect to run "2-2-2-1"?  Or just order a
> couple spares like "2-2-2-1-1-0" then I would pretty much cover most all
> expected combinations?  I would rather have them on hand since my local
> dealer isn't the greatest, so I'll be going through Greg V.

> I guess the original "2" just better be in good shape since I believe it
is
> the "tightest" - FSM is outside, but I think that is correct.

I have been slowly rebuilding the motor in my roadgoing NX2K and followed
the same advice that Josh quoted.  I reinstalled the rods with the "one
grade tighter" method and rotated the crank after each rod went in to feel
the resistance to turning that was added by each rod.  Each one added a
marginal amount of drag except for the #2 unit, which upped the resistance
by what felt like a factor of 4 over the other ones.  So, I went to my local
parts store and bought some plastiguage (at $1.50 for enough to build an
entire engine, you can't go wrong.)
I tested each bearing and they were all within the standard clearance of
0.0008" to 0.0018" except for #2, which did test out to be too tight.  So, I
had to order the stock grade for that journal and it plastiguaged out just
fine and had the same resistance upon rotation that the other rods had as
well.
The FSM is *very unclear* as to what clearances the three grades of 1, 2 & 3
represent (page EM-55,)  but it was my experience that the Lower the number
was, the Tighter the clearance was.
If anyone has some clarification on this, I'd like to hear it, please.
When ordering your bearings, be aware that like oysters, Nissan doles out
the bearings on the half-shell.  In other words, you need to order 2
bearings for every journal.  I had a rookie parts counter clerk my first
time in and ended up having to go back a second time to get the other half
of my bearings.

Tim Rogers
'93 NX2K- Sapphire Blue, CAT Back, JWT S4's & ECU, Tokico/Eibach, JUN
Flywheel, P/R CAI, 15X7 Borbet Type H's.
'91 NX2K- White, SCCA ITA racecar-to-be
'91 NX2K- Black, parts car