Now that I am rested, here are the details of my engine failure.
Unfortunately, my hopes of a recoverable situation were thuroughly dashed. The
engine was balanced as evidenced from the markings of 1-4 L and R on each rod
and piston. I think that the rods were originally of an H beam design with a
ridge or bar around the entire beam and small end; my rods were H beam in shape
and clearly showed that the small ends and the beam had been ground, what leads
me to beleive that there was another ridge around them was that about 3/4 inch
of this bar was left on each side of the rods where the big ends tapered into
the beam. It was the #3 rod that broke, the small end was still in the piston,
and I know this to be the source of the failure because one peice of the H that
was left exposed by the failure was the same darkened color as the whole inside
of the block (almost black). So I know that the rod was cracked for a very
long time, if not from the factory. The engine had 1100 miles on it since the
rebuild from the PO. My feeling is that when they removed the extra ridge from
around the rod, in an effort to lighten them, the remaining rod was no longer
strong enough to hold the crack together. So the rod snapped at the top of its
stroke, because there was no indication of impact damage to the bottom of the
piston which was sitting at the top of the bore. About 1/3 of the skirt was
missing from the #3 piston, including half of the wrist pin bearing surface on
one side. Either the rod broke and the action caused the fracture of the
piston, or the piston broke, cocked in the bore and caused the rod to break. I
think it was the first one because there was no damage to the #3 sleeve. The
rod removed a chunk of the block, on the passenger side, under the engine mount
of about 25 square inches, gutted the pan on that side,crushed and tore the
motor mount (stock olds mount), and opened up the galley from pickup to oil
pump and broke open the water jacket; on the other side it punched straight
through the block about 5 times and punced straight through the pan about 8
times. The #3 rod swung through the #4 sleeve about two inches up, and cracked
and holed the piston on both sides, in line with the damage to the sleeve. It
also hit the cam; the cam broke between the #2 intake lobe and the 2nd
bearing, this first section consisting of the front of the cam and the first 4
lobes walked out, the timing chain started to eat the cam gear and all four
spokes of the cam gear cracked. The second bearing and the next two lobes (#3
cyl) broke and were forced up in the journal about 40 degrees, the #3 exh lobe
was the only one showing significant damage, was in line with the broken rod,
and was forced up tells me that this was the point of impact. The #3 rod was
curved about 30 deg presumably from this impact. The next two lobes, for #4
cyl, were in the pan, however the big end cap of the #4 rod showd significant
signs of damage from impacting this. It bent the bolt hole around one of the
rod bolts and I had to hammer the rod apart from this damage, the crank shows a
few small dings from the same impact, the remainder of the cam, from the 3rd
bearing back (4cyls worth) was intact. What I think happened was that the #3
rod hit the cam made the rear most break (at 3rd bearing) which left a bent cam
connected to the timing gear. The bent, spinning cam then impacted the #4 rod
cap causing the other fractures, forced the cam to angle up, cracked the
timing gear, and broke out the lifter guides for the #3 int and exh and the #4
exh. One of those pushrods was severely bent, but I found them all in the pan
so I don't know which one. The #4 exh rocker broke where the valve arm joins
the rockershaft bearing surface. I think that when all of this happened the #7
intake was open and the valve colided with the piston, because this was the
worst bent rod of all, I think this is what caused the back halft of the cam to
stop turning. I saw no visual indications that any of the pistons had collided
with any of the valves, everything looked decent and without telling scratches
or dents. One of the lifters from the #3/4 area was shattered and about 1/3 of
them were chipped around thier cam surface. Most of the valve train and block
parts were found in the oil pan, along with the remains of the coolant and the
oil. I also found some magnetic parts that were probably from the #3 rod,
since about 1/2 inch of it is unacounted for. The bearings from #3/4 big ends
look perfect as does the rest of the bottom end except #3 and #4's parts. That
leaves me in need of an entire engine as even the heads are suspect if enough
force made it up there to break a rocker arm. The valley pan gasket was
severly dented up around #3/4 but the intake showed no signs of being hit.
Basically I think my only useable parts are the flywheel, pulleys, front cover,
intake, exhaust, and valve covers. Oh well. AND THE MORAL OF THE STORY IS....
you really ought to magniflux old parts, especially if you are going to try and
lighten a stock part. It looks like the rod was cracked from new but it was
probably the loss of so much strengthening material that caused it to let go.
Unfortunately the motor was built about a dozen years ago, buy a guy that was
into these motors in Medina, OH. My dad traded him an old Oliver tractor for
the motor and trans, so no chance of reimbursement or anything there. Whew!!! I
think that about covers it.James Nazarian71 B tourer71 BGTV8 with ventilated
block and 4 piece cam85 Dodge Ram with bad gas mileage
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