Hi folks, it’s Pop here. Janet did an excellent job explaining basically the what’s and why’s of rebuilding her little 200ci six banger. More air, more fuel, bigger spark, bigger explosion and more power. Carl’s Machine Shop was fantastic, and now we have to assemble the parts. This indeed trips my trigger and I will explain the procedure much to the boredom of some of you. But, perhaps we can convert a few into budding “gearheads”.
We’ll begin with the bare engine block which was cleaned up, magna fluxed (a process to detect cracks…it passed), over bored 60 thousands of an inch (this is the maximum and was necessary because of scoring in cylinder #4, the result of a broken ring), and new freeze plugs installed.
The crankshaft went in first with .010” over bearing inserts. This requires clearance checks using plastigauge. Plastigauge is thin plastic thread which when compressed, spreads out and its width is then measured to determine clearance. The top bearing shells are placed in the block, then the crankshaft, then strips of plastigauge across the bearing journals, then the bottom bearings and caps. The bearing caps are then torqued to specs. The caps are then removed and the width of the plastigauge measured. I won’t further torture you with the measurements acceptable throughout the assembly procedure except to say, “everything checked out”. (Janet: “Except to say we had to do math…math sucks.”) The crank is then removed and turned over 180 degrees and the process repeated, assuring a straight bore and shaft. Everything checking in specs, the bearing surfaces are lubricated, assembled and torqued to specs. One final step, the crankshaft is then moved forward and backward to check end play.
The camshaft (which opens and closes the valves) was original and installed by Carl’s with new bearings, as this requires special tools. (Janet: “Some of the only tools Pop apparently does NOT have in his garage. It’s just a matter of time.”)
Next, the pistons with new rings (which snap into piston grooves, hold compression and control oil on the cylinder walls), three rings per piston. Before the rings are installed in the piston grooves they must be placed in the proper cylinder bore and the gap between the ends measured. Too close a gap and the ring will break when it expands with heat, spelling disaster. (Janet: “Apparently I got my dramatic nature from my father.”)
Each piston is fitted to numbered connecting rods then placed in the proper cylinder and attached to the crankshaft, plastigauged, lubed and torqued to specs. With the installation of a new oil pump, the “bottom end” is now complete.
New timing chain (which goes on gears at the front end of the crankshaft and camshaft) is installed and the front cover and oil pan installed. We’re now ready for our new and improved cylinder head.
One final and most important measurement is needed, valve clearance. We now have oversized valves and increased openings with our new 1.6 to 1 rocker arms. Heaven forbid the valves hit the pistons at top dead center! That would again lead to disaster. (Janet: “Need I say more?”)
With #1 piston at the top dead center, we fill the space between the block surface and the piston with clay (in our case, Playdough). We also filled #6, then install the head gasket and head. The head bolts are torqued, the valve train assembled and adjusted and the engine turned over 720 degrees or two revolutions of the crankshaft (one revolution of the camshaft). With fingers crossed, we disassemble the valve train, remove the head and measure the distance from the bottom of the valve indentations to the piston surface. Yes! We have clearance!
The top end is now reassembled and the oil pump driven by an electric drill (the bottom of the distributor shaft will do this). Checking for oil flow from the rocker arms aaaaaaaand – success!
Finally, valve cover on and new Ford blue paint job.
During Janet’s next visit we’ll install our Autolite two barrel carburetor with automatic choke onto the beautiful adaptor plate on the intake manifold. Add our new 50,000 volt ignition and big exhaust headers and we’re ready to kick some ass.
(Janet: “Pop and I have very different ways of showing overwhelming excitement.”)