Performance IHC 345 - Part 4 - Assembly

Installing 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

Copyright 2001 Tom Mandera