[AT] 39 Farmall A coming along.....

[Steve W.]

>> I was wondering if plastigauge would be needed to double-check stuff when 
>> it
>> goes back together.  I gotta get a copy of Spencer's engine overhaul
>> book.......
>>
>> You are correct, this is sort of a side project.  I have about 5 students
>> that are really eating it up.  Before it is over I intend for all 24
>> students to have played some role in it.  Basically when they are finished
>> with what I am actually grading them on, (basic electricity--they have a
>> test on the unit Friday) they can work on the tractor.  They are all 
>> fairly
>> proficient with hands-on type stuff so it works well to keep them busy.
>>
>> A lot of people don't realize it but career-technical education (formerly
>> vocational) classes in NC public schools have an end of course test just
>> like the "academic" subjects.  We have to make sure the students get the
>> core curriculum (in other words, what they will be tested on) first.  I 
>> will
>> keep my opinions on how the system is run, at least in NC, to myself.
>>
>> Al

Well it depends. I would say that you might contact an engine shop and
have one of their guys come over with micrometers and demonstrate how to
use those to measure the bearings and calculate the clearance. Then use
the plasti-gauge for the rest. This way they learn two ways to do the
job. and knowing how to read a mic is a basic skill they should have if
they plan on doing more engine work.

There are a few tricks to plasti-gauge.
One CLEAN EVERYTHING very well. ANY dirt/oil/crud will throw the
readings off.
Then set in the bearings. Seat them and set in the bare crank. Next
GENTLY lay a piece of the proper stick on each journal. (PG comes in
different sizes for different clearances, pick the proper one)
Now install ALL the bearings and caps on the mains.
Torque them to the proper level.

DO NOT ROTATE OR EVEN MOVE THE CRANK!!!

Pull them back off STRAIGHT UP! Now measure the sticks crush in three
places across the bearing. Ideal would be proper clearance all the way
across. Taper isn't good. You want the low side of the numbers IE: They
allow .001-.003 .0015 would be REALLY nice.

Wish I was in the area I'd loan you all the tools to play with.

You do know that if you lack a special tool most Autozones and Advance
Auto stores have tool loans.

-- 
Steve W.