Mighty Mouse Lower Engine Build

In Part 1 of our article our GM Performance Parts (GMPP) 383 stroker block had arrived and we took it to Schmidt’s to give it the royal machining treatment. Now that all of the goods from Wiseco, Holley and Lunati have arrived, we are ready for the lower engine build.

If you haven’t built an engine before, don’t sweat it – it’s not really that difficult, but you will need a few special tools, many of which you can rent, and I strongly suggest that you get a good book about building engines. I have personally built about a dozen Chevy small block engines (and a few other Jeep and Ford engines too), but I still reference several books in my library.

We chose a fully balanced Lunati rotating assembly which included a Lunati Sledgehammer crankshaft, Lunati Voodoo cam, Lunati aluminum roller rockers and various other Lunati components (e.g. pushrods, polylocks, etc.). The Sledgehammer crankshafts are Nitride heat treated, sonic cleaned and forged from 4340 non-twist steel. This non-twist design produces a crankshaft with higher tensile strength which increases fatigue life. The Lunati Voodoo series of hydraulic roller camshafts deliver more area under the curve than any other series of hydraulic camshafts, which means better throttle response, quicker acceleration, more vacuum, and better efficiency – this translates into greater efficiency and maximum horsepower and torque output from your engine. We also received a set of Wiseco Pro Tru flat top forged pistons.

Engine Highlights: 

• GM Performance Parts 383 Stroker Block, 1-piece rear main seal, 4-bolt main – part # 88962516
• GM Performance Parts Serpentine Accessory Drive System w/out A/C – part # 12497697
• Lunati fully balanced rotating assembly
• Lunati “SledghammerSledgehammer” Forged steel stroker crank
• Lunati “Voodoo” cam, roller rockers, push rods, double-roller timing chain and lifter set
• Holley Stealth Ram multi-port fuel injection system – Part #: 91603211
• Holley aluminum 2.02 heads – Part #: 300-552-1
• Holley billet aluminum high-performance distributor
• Pro-Tru aluminum flat-top pistons
• High Performance engine bearings
• MSD Ignition 8.5 mm super-conductor plug wires

Part 2 – Lower Engine Build, Crankshaft Installation

We started the lower-engine build by cleaning the Lunati Sledgehammer crankshaft engine block journals with some chlorine-free brake parts cleaner and a lint-free rag. We then installed the main bearings into the block journals and caps, and then applied a thin coat of pre-assembly lube to the bearing surfaces. All bearings come as matched sets, so be sure to only install one set of bearings at a time, and keep them clean.

With crankshaft cleaned and all of the bearings installed in the journals and caps, my son went off to chase girls. I was still in need of an extra set of hands so I convinced the lil’ lady to put down the laundry basket, and help install the crank shaft into the engine. (Don’t tell her I said that… seriously).

Carefully, the crank was lowered into the engine block and set into place. The main-journal bearing caps were then put into place, and torqued to the appropriate pressure and in the correct sequence to seat the bearings. After a few spins of the crankshaft, we pulled the caps off again so that a small strip of PlastiGauge could be applied to each of the crankshaft main journals to ensure proper bearing clearance. Ours came well within specs, so we cleaned off the PlastiGauge and re-torqued the main caps.

Connecting Rods and Piston Installation

In our case, we needed to build the piston sets by attaching the connecting rods to the pistons. Our piston kit came with spiral locks that keep the wrist pin secured in place between the piston and the connecting rod. They’re a bit tricky to work with and a small, flat-blade screwdriver seemed to be the best bet.

The piston sets aren’t quite done yet though. You will need to set your piston compression rings into the bores of your engine block and take a gap measurement and ensure it is within specs. Ours were smack-dab in the middle of specification.

Prior to installing the pistons into the cylinder bore, we recommend giving it a good wipe down with automatic transmission fluid. Our sources tell us that this acts like an assembly lube for the pistons the first time you fire it up, thereby reducing initial piston / cylinder wall scrub-down.

Next, cover the connecting rod bolts with some soft plastic tubing (to prevent scratching the crankshaft and install a ring-compressor tool around the piston’s compression and oiling rings. Carefully slide the piston into the cylinder bore until it reaches the bottom of the ring compressor. Next, take a mallet with a rubber handle and tap the piston into the bore until the last set of rings clear the bore – remove the ring compressor tool. Ensure that the connecting rod bolts are clear of the crankshaft journal and then tap it home until the upper connecting rod bearing seats firmly against the crankshaft journal.

Install the Siamese piston as described above for the adjacent cylinder bore (the one directly across from it, not downstream). Once installed, be sure to take a gap measurement and ensure there is adequate clearance between the connecting rod caps. If you install a cap backwards (which is entirely possible), you will NOT have enough clearance and you will destroy your engine.

Cam Shaft and Lifter Installation

Once you are certain that your crank and pistons have been installed properly, it is time to install the camshaft. Start by placing all of your hydraulic lifters into a vat of engine oil. We distracted the little lady by pointing to a Tom Jones special on cable TV, and promptly stole one of her favorite Tupperware® bowls. Fill the bowl with engine oil and place each lifter into it, with the piston facing upward. Using a push rod, plunge the piston in each lifter several times to ensure oil fills the innards. Leave the lifters in the oil until you are ready to install them.

Moving onto the cam shaft… This is potentially the greasiest portion of the job. Coat the entire cam shaft quite liberally with assembly moly lube. Every new camshaft comes with a packet of this stuff, but we opted to buy a large tube high-quality moly assembly lube and use it copiously.

Once coated, you can either screw in a long bolt into the face of the camshaft, or screw in a camshaft installation handle tool. We chose the former. Carefully slide the camshaft into the engine block, sloooowly. Take your time and be sure not to bang the cam shaft against the bearing faces. Slide the camshaft all the way in until the camshaft face is flush with the face of the engine. Remove the bolt / camshaft installation handle tool.

With the camshaft fully seated in the engine, you can now drop each lifter into the respective lifter bore as seen in this picture. NOTE: Once a lifter has been run in an engine, it becomes matched to that specific lobe on the cam shaft – they are no longer interchangeable.

Next, there are a series of measurements that you can take on your engine, depending upon how particular you are with the build. For example, we took some piston TDC to engine block deck-face measurements.

Timing Chain Installation

Next, slide the crank timing gear onto the crankshaft as far as you can by hand and make absolutely sure it is not crooked or cocked at an angle. Once aligned, use a large socket (a 1 ¼” socket works well for a Chevy small block engine) to drive the crank timing gear fully onto the crankshaft until it bottoms-out.

During installation, you can use a degree wheel like we did to ensure accurate installation. It is not required, but is recommended by most engine builders.

With the crank and cam gears setup, reinstall the bolts using a good thread locking compound and secure with the bolt keeper tabs (if supplied – most are). Also, be sure to add plenty of assembly lube to the timing chain and gears. Don’t skimp. Lock the cam gear bolts into place by bending the locking plate tabs as seen in this picture.

Install your timing gear cover and seals. If you are using a chrome timing cover, we recommend scuffing the surface that the gasket and gasket sealer will be applied to. This will offer a better surface and prevent leaking. Using thread locking compound, install and torque the timing gear cover onto the engine.

Your lower end of the engine is now fully assembled.