Oil Pan: Buttoning Up the Bottom End
The final major item that must be installed down the bottom of the LS1 is the oil pan, which again is a structural part of the LS1 engine. The primary area of loading is at its very rear, where the clutch bellhousing will eventually be secured using two bolts toward the bottom of the pan (along with six others in the engine block above). Therefore, like with the front and rear engine covers, proper installation of the oil pan is a process that dictates the expenditure of time and care.
THE TOP END: CYLINDER HEAD AND VALVETRAIN INSTALLATION
So far as the valvetrain goes, the only item we've installed is the camshaft. Unlike earlier generations of small-blocks, the cylinder heads on the Gen III cover the lifter area; therefore the lifters must be installed before the cylinder heads. (If you think cam swaps are impossible without removing the heads, though, think again: we'll show you how GM's neat lifter guides allow this.) And since we're using head studs instead of bolts, we need to install them before the heads go on.
Valve Lifter Installation
After a thorough external cleaning wipe with mineral spirits (don't submerse them or you'll pull the lube out of the ball bearings), we first soak all 16 lifters in the oil we're going to use at startup (10W-40). While this process pre-oils the interior of the lifters, it also can throw off the adjustment of a hydraulic cam, so we'll have to "bleed them down" later--a simple process you'll see next time. Still, in this author's opinion, it's not a bad thing to get some oil in there for lubrication--even though most of it will be squeezed out prior to startup
Cylinder Head Installation: Setting the Stage
It's possible to re-use the stock cylinder heads on a stroked LS1; their combustion chamber size is compatible with many pistons on the market and, if need be, the heads can be milled to reduce their ccs and get the compression just right. However, even ported castings will only flow so much, leaving a substantial amount of power on the table--especially with the increased cubes of a stroker.
Therefore, we've selected a set of ET Performance 215cc cylinder heads. See the sidebar for a full discussion of the features of these heads and why we chose them. Before we bolt them on, though, we need to install our ARP head studs and lay our head gaskets in place.
Cylinder Head Installation: Checking Piston-to-Valve Clearance
One critically-important step in any engine build is piston-to-valve clearance checking. Imagine the following: at the very end of the exhaust stroke, the exhaust valve is still open and the intake valve is just starting to open. At this same time, the piston is in very close proximity to the cylinder head, creating the potential for the valves to physically contact the face of the piston. If this were to happen, the valves and/or pushrods would be bent and the engine could be severely damaged. The risk is even greater if accidentally high rpms were to be achieved and the valves began to "float" (i.e., the valvetrain being pushed beyond design limits resulting in the lifters beginning to lose contact with the cam lobes).
The exact proximity of the valves to the pistons depends on many factors, including the camshaft profile, cylinder head design, valve diameters, piston valve relief design, and even connecting rod length. A generally accepted value is that the valves should not come within 80 thousandths of an inch of the piston at any time; this distance allows extra breathing room for the possibility of valve float (come on, don't say you've never hit Second when trying to powershift Fourth; accidental engine over-rev can happen to you!)As this clearance must be checked with the head torqued in place and the camshaft actuating the valves, there's no way to get a feeler gauge inside the combustion chamber and measure the distance between the valves and piston. Therefore, we'll need to temporarily assemble the head and valvetrain to the engine and use a very high-tech device inside the engine while we rotate it over. That device, friends, is our childhood pal Play-Doh: a great building material, projectile sibling defense weapon, and--for the truly daring--tasty snack.
We'll quickly note that an alternate method exists to check this clearance, and it involves removing the intake and exhaust valvesprings, installing light-tension checker springs, and using a dial indicator to measure how far down the valves can be pushed (by hand) before they hit the piston. This, too, will be done while the engine is being spun over by hand, and is considered the most accurate method of determining piston-to-valve clearance. But since we didn't feel like taking apart our already-assembled heads, we went with Play-Doh. Also, though a set of aftermarket rockers will be ultimately used, we'll put the stockers on here along with ETP's optional rocker stands to demonstrate that the stock rockers can be reused with the ETP heads for those on a tight budget.
Turning the crank again, we continue until the gauge cycles all the way to full lift and then down to 0.050 again. The degree wheel read 358 degrees, or 2 degrees ATDC (after top dead center), again just what Lunati specified. The cam had been installed perfectly! At this point, I pat myself on the back for a job well done (photo not available). | 
SLP's PN 55001 Heavy-Duty Oil Pump is available separately for $179.95 or as part of the aforementioned timing chain/oil pump package. The pump features a ported inlet as well as a ported outlet, which help to reduce oil temperatures and thereby increase engine life. The pump is assembled to GM blueprint specs and features a corrosion-resistant coating. | 
Slide the SLP-supplied oil pump drive gear over the crank snout. The keyway we've previously installed into the crank snout prevents this gear from spinning on the crank (you can see this in the top right under my index finger). At this time, take one last look into the engine block oil gallery to make sure nothing is in there (above and right of index finger). Note: such a gallery is more commonly referred to as a galley, but GM's service manual uses the former term; hence our choice of nomenclature. |
The SLP pump slips on and the supplied bolts are torqued to 18 lb-ft. Again, you didn't see these bolts in the layout photo of the pump because they actually were included in the timing chain packaging. As this pump has built-in clearance for the thicker-than-stock SLP timing chain, you will only need to use the supplied spacers (again, in the timing chain packaging) if you're reusing the stock pump. | 
The engine is now flipped over on its stand, and at the bottom of the SLP pump we find a plug concealing the oil pump's pressure relief spring. We opted to remove this plug and install SLP's supplied higher-pressure red spring, which serves to increase oil pressure over factory spec by about 5 psi. This will help match the Lunati-designed greater bearing clearances on our rotating assembly (see our sidebar on this last time). Besides, more oil pressure will never hurt the engine; it just could cost a couple extra horses to drive the pump. We'll err on the side of safety for this street motor. | 
The stock oil pickup tube and crank oil deflector can now go on--almost. First on the list of minor modifications, the deflector wouldn't fit onto our thick ARP main studs, so three of its holes had to be egged out a touch. More significantly, would the deflector clear the longer stroke of the Lunati crank? Since the oil pump was now on, we couldn't turn the crank via Powerhouse's socket, so we put a used bolt in the crank snout and turned it with a 24mm wrench. We got a touch of interference, with a few of the rod bolt heads just glancing against the deflector as they passed by (shown). |