Hey people, just got back in town and feeling good. Sorry for any =
problems.
While at Verns house for a week, Vern happen to tell me about and show =
me, his broken engine.  After talking with Vern and looking at his =
broken engine and asking him some questions. I found out that he and =
maybe some others might not be aware=20
how to inspect an engine that had come apart, rods broken, spun bearing =
etc. How you can determine the cause most of the time through this =
knowledge I am about to give you.  You need to be able to find out what =
was the actual cause of the engine break down, not just the collateral =
damage from the cause.  We will use Verns, pretty much stock, recently =
rebuilt engine, as
the example since I personal just looked at it. ", Please, Dont put any =
more into it, than stated".
Your engine comes apart, (catastrophic failure) only after around 2000 =
miles from engine rebuild. First thing you realize is
the engine did not last no where close to its normal life expectancy. =
"Do not " for any reason allow a shop or any one else
to convince you that after you spent a lot of money for them to rebuild =
your engine that this is normal or just happens some time. They should =
rebuild your engine with no additional cost to you. If they dont back up =
their word or work then pass the word around to all others to hopefully =
prevent this travesty of malpractice and misfortune from happening to =
some one else, lets work together. =20
First thing to do is:
(1) Remove heads carefully and lay them aside.=20
(2) With engine upside down, remove lower case halve (oil pan side) from =
upper case halve (be careful not to alter any=20
thing keep bearings pieces in their exact place when case halves are =
separated).=20
(3) Inspect the upper case, with crank and gears installed etc. After =
inspection you notice that one connecting rod is bent or broken, and has =
spun its bearing. You first realize it is not normal for the bearing to =
have been separated from its intended
location unless it was subjected to an extreme amount of high =
pressure-friction due to one of the following  A. Wrong size
bearing was installed, "to tight".  B. Oil viscosity break down due to =
over-temperature or by means of chemically. C. Wrong=20
oil application. D. Loss of oil supply to bearings. E. Severely out of =
balance crank, flywheel, counter balancer etc. F. Continuous "violent" =
detonation.
All of these can cause high pressure-friction, contact on rotating =
parts, thus allowing the bearing to have=20
been spun or thrown out from its original location.
(4) Gain viewable access to the bent or broken rod(s) large end (end =
cap) still installed on crank journal. A.  Inspect to see=20
if the letter "E" (represents the way the rod end cap was installed to =
the rod during the final bore, honing process), stamp mark on both lower =
rod halves alight with one another, (reference owners manual, engine =
assembly section, page 3-61 step in my book.  B. Make sure the letter =
"E", stamped on the lower halves of the rods, align up (MUST BE LOCATED =
SAME SIDE). If the rod cap is on backwards then you have found your =
problem. Bearing gone. If the rods=20
and end caps are found to be on correctly, then you go on.=20
(5) Retrieve old plain bearing halves that were spun from the rod.  A. =
Using a 3X magnifying glass or equivalent look at the bearing surface. =
B. Inspect bearing contact surfaces, for the following. C. The bearing =
contact surface in the center part of the bearing is dark colored, (dark =
blue, black color look to it). D. The dark excessive wear area appears =
to be=20
shinny and smooth, not all galled up on surface, does not looks like a =
sander was taken to it. Result: This indicates to me that oil was being =
supply to the bearing at time of failure, but this does not mean that =
the oil supply was sufficient (manufacture specification). E. We now =
know the bearing was spun due to excessive high friction-pressure =
rotational contact. =20
(6)  This could be caused by one of the following  A. Oil viscosity =
break down, due to over temperatures  B. Chemically=20
C. Wrong oil application  D. Wrong size bearing, (to tight). E. =
Inefficient oil supply.
For this reason the oil cannot maintain proper oil film clearance =
between moving parts. Result: High friction-pressure-bearing=20
to bearing surface, metal to metal contact. Bearings gone. But where did =
the excessive pressure come from? Lets see=20
if we can find out.
(7) One possible reason might be from excessive cylinder detonation(s), =
resulting in extremely high cylinder pressure which surpasses the design =
capability of the oil and reduces the oil film strength-clearance =
causing high rotational contact pressure-friction on parts, metal to =
metal contact. Bearing gone.  A. Inspect bearing center contact surface =
only. B. The bearing=20
center contact surface is dark colored same as above, but has a =
difference. C. The bearing center surface is galled up, looks like you =
put a sander to it, balling up of bearing surface etc. D. This shows =
that oil wasn't being supplied to the bearing at=20
time of failure.=20
NOTE. Loss of oil supply to bearings during operation, will create a =
high contact, high pressure-friction between rotating surfaces, metal to =
metal contact. Bearing gone.  Possible cause: Oil pump failure, Low oil =
capacity, Broken oil lines etc.=20
(8) Now lets see if the If the wrong size bearing(s) were installed, (to =
tight) not in accordance with manufacture specification.=20
 A. Lets say you look at the other bearings that are still intact and =
you want to see if they were installed with the correct=20
clearance this might be your "best"evidence yet, proving the bearings =
were (to tight).   B. First When you inspect all=20
bearing contact surfaces, you notice that the outer edges of the bearing =
contact surfaces, are shinny and smooth=20
more than center bearing contact surface which is a dull normal color =
look. C. The bearing outer edges have worn much=20
more than the inside bearing contact surface, possibly past the bearing =
plating, showing copper, brass color.  This shows the bearing was to =
tight when installed. D. Bearing clearances being closer than =
recommended, and oil system working, the oil film strength will be =
greater in the center of the bearing contact surfaces, but gets weaker =
the farther it gets from center and passes=20
out the end of the bearing. Bearing gone. Normal looking bearings after =
normal engine wear should be in conformity across=20
the surface of the plain bearing and not being wore down past the =
bearing surface plating, gouged or galled up. Their are areas=20
we did not discuss due to time, but maybe at a latter we will.=20
Doug Nelson Technical editor.=20