Performance IHC 345 - Part 4 - AssemblyInstalling the pistons...
Now that the tedious cleaning, cleaning, cleaning
and checking checking is done..
After fitting the piston rings to the pistons in
Part 3, it was time to start installing the
pistons into the block!
I slipped protective sleeves over the ends of the
rod bolts, and then placed the piston in some
10w30 motor oil to prelube it. The two bearing
halves were also soaked in the oil.
I then fitted the piston ring compressor to the
piston. I found that if I just dropped the
piston into the cylinder bore, fitted the
compressor to the piston, and then lifted the
piston out slightly, I could easily get the ring
compressor around even the bottom oil control
ring.
The rubber coated handle of my favorite 3lbs
sledge hammer worked well for easing the pistons
into the bores. I double checked to be sure the
"UP" arrow was pointing towards the valley. I
would then slip the two bearings halves into
place and slide the connecting rod down until the
it was seated against the crankshaft journals. I
then torqued to spec.
Once the pistons had all been installed, I
proceeded to plastigage every connecting rod
bearing to verify they were within tolerance.
Each one spec'd to around .0025 inches. The
allowable spec was .001 to .004.
I then turned my attention to the finished
cylinder heads, sitting in the corner of the
garage wrapped in plastic. The valve springs had
been installed with 155lbs of seat pressure -
high enough to scare the machinist, but only a
little high for an IH. The factory springs call
for 125lbs of seat pressure, and the heavy IH
valves will float beyond 4,000rpm. The stiffer
LS6 valve springs keep things in line.
I cleaned the mating surface of the cylinder
heads, as well as the block's deck. After
cleaning the deck but before putting the heads
on, I used my dial-indicator to check my
piston-to-deck clearance. I used the indicator
on a piston to first find TDC, then I moved the
indicator from measuring to the deck, to
measuring to the TDC piston, and verified about
.018 piston-to-deck clearance.
I then placed the first new composite head gasket
onto the block, and hefted the heavy cylinder
head into place. The cylinder head bolts were
then tightened to the factory torque spec in the
proper sequence.
I installed both cylinder heads, and then the
timing cover and gasket. The timing gears were
first covered with assembly lubricant. A new
front oil seal was installed in the aluminum
timing cover. I then gently tapped the harmonic
balancer onto the crank just the slightest bit
with a 2x4, and then used the retaining bolt to
draw the balancer the rest of the way onto the
crankshaft. The water pump housing and a brand
new water pump were then installed, with a clean
rag inserted into the distributor shaft hole to
keep debris out.
I then moved to install the oil filter adapter,
the double-drain double-hump Scout II oil pan,
the valve covers, and installed the various oil
galley plugs. You can clearly see the factory
oil pressure sending unit (towards the rear of
the block) and the new Autometer oil pressure
sending unit just in front of it. I left one
plug open and temporarily installed a mechanical
oil pressure gauge. The rear main seal was
installed by using a roll of masking tape as an
appropriately sized "washer" for the inside
diameter of the seal to be sure the lip was
pointing inward and not "popping" out towards the
end of the crank. The side seals were installed
using a T-handled allen-wrench instead of the
factory specificed 1/8" welding rod.
I rebuilt the oil pump prior to installing it. I
used all new gears from Northern Auto. The
"crimp sleeve" was removed from the long shaft
with a grinder. I checked the gear backlash with
my dial indicator and verified it was within
tolerance, then took an educated guess on the
end-clearance of the gears to the pump body. I
used a single .003 shim and assembled the pump.
I placed my dial indicator on the end of the
pump's shaft and verified .003 end play as the
manual called for. Lucky guess. I then crimped
a new sleeve onto the shaft through the use of a
chisel and hammer. The pump was then installed
using the provided gasket to mate the pump output
to the block, and new O-rings on the pump pick-up
after cleaning it.
Installation of the "tappet cover" or valley pan
was a little difficult. Because I had machined
material from the heads and the deck, the tappet
cover was slightly too wide. I did get the cover
to install, but it required a little "squeezing"
during the process. I later discovered I should
have used additional sealant (in addition to the
cork gasket) at the rear of the tappet cover,
because the installed motor now leaks at that
location.
Also notice the use of masking tape to mask off
the fuel pump hole and the intake side of the
cylinder heads.
Here you can see some IH Red paint applied to the
motor, with a dose of white paint to the harmonic
balancer. I then placed thin strips of masking
tape where the timing mark on the balancer is
located, and then re-painted the balancer with IH
Red. This yielded a distinct white line on the
balancer, making timing adjustments that much
easier. Others have painted their engines red,
and then gone back over the lettering on the
timing cover and the mark on the balancer with
"White-Out".
First the hydraulic lifters were soaked in motor
oil and pre-lubed by operating the plungers while
inside the oil bath. I then dropped the new
lifters into their bores in the engine. The
rocker shafts and arms were cleaned and then
assembled. I then installed the rocker shaft
assemblies and pushrods to the cylinder heads. I
applied some Permatex Thread Sealing Compound to
the rocker shaft bolts (I later realized I had I
applied much more than was necessary - use it
sparingly), and torqued the assemblies to spec.
With the engine a nice shade of red after several
coats, I hooked up the mechanical oil pressure
gauge and tested the oil pressure. I used a
deepwell 15/16" socket on the crank to rotate the
engine by hand. A custom oil-pump priming tool
was made by John Landry on his personal mill and
lathe. A similar tool could be fashioned with
either an old distributor shaft, or perhaps a
large slotted blade screwdriver with the handle
removed. The tool was inserted into my drill,
and then slipped into the oil pump shaft.
I ran the drill and noted a mere 25psi on the oil
pressure gauge. This was cause for some concern,
but we later attributed it to a pinched plastic
line on the cheap mechanical oil pressure gauge.
I rotated the crank while running the drill and
verified oil was getting to both rocker shaft
assemblies.
A new PCV valve was installed with the help of a
11/16" deep well socket and a hammer. I've since
learned that the rubber grommet the PCV installs
into is available new, and should also be
replaced. Oops.
I then moved on to the installation of the frost
plugs. I used sealing compound on the plugs
prior to installation. The driver's side exhaust
manifold was installed along with the dipstick
tube. You can already see the oil filter that
was installed prior to priming the oil pump.
With the bulk of the engine assembled, there
wasn't much left to do to it. I painted the
motor mounts black, installed the water pipes
with new O-rings, installed new Autolite Platinum
85 (AP85) spark plugs with a new Napa plugwire
set. A rebuilt Holley Points distributor that
had been recurved with a Pertronix Ignitor
installed was provided by Gryphin Racing and
installed.
The rest had to wait until I'd removed the
existing motor. The existing engine would then
donate the other exhaust manifold, the intake
manifold and carb, the clutch assembly, air
conditioning compressor, alternator, and bracket,
and power steering setup, starter, coil, etc
-Tom
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