This guide covers the assembly of the Mitsubishi 6G72 DOHC V6 engine (naturally aspirated or twin-turbo). This engine was used in the 1991-1999 Mitsubishi 3000GT/GTO and 1991-1996 Dodge Stealth.
Note: The 6G72 SOHC variant is significantly different in construction despite having the same engine code and is not covered by this guide.
The factory procedure and specifications will be used to assemble the cylinder block, crankshaft, connecting rods, pistons, cylinder heads, valvetrain, and camshafts into what is known as a "long block". If you are using aftermarket or upgraded internal components, please consult your local machine shop or engine builder for the correct assembly specifications for those components.
Clean and inspect all parts, removing paint, rust, gunk, and grit. This is very important for internal components.
Reusing worn or damaged parts may result engine failure. Your local machine shop or engine builder can usually recondition worn parts rather than replace them.
Assemble the engine in a clean and dust free work area. Place oiled parts on a lint-free rag to avoid picking up debris from the work surface.
Use a tap to clean out threads before assembling parts.
Loosen the main bolts and carefully remove the girdle.
Measure the width of the Plastigauge to determine the bearing clearance of each journal.
Main bearing clearance should be 0.0008-0.0020 in (0.020-0.050 mm).
Do not continue if bearing clearances are out of spec. Double check that the main bearings, crankshaft, and girdle are installed correctly and that the crankshaft isn't excessively worn.
Spin the crankshaft one complete rotation. It should spin smoothly throughout.
Attach a dial indicator to the nose of the crankshaft to measure end play.
Use a large flathead screwdriver to carefully move the crankshaft side to side. Zero the indicator at one extreme, then take a measurement at the other extreme.
Crankshaft end play should be 0.0020-0.0098 in (0.050-0.250 mm).
Do not continue if the end play is out of spec. Double check that the thrust washers are installed correctly and of the correct thickness.
GREAT info!! My first complete build and I'm NERVOUS!! Still trying to figure out where certain items go. From my complete gasket kit I can't seem to find info on where the small copper crush washers go and the small O Rings. Would appreciate your info. THANKS!!