Engine Mechanical Specifications (RPO Code L37)

ENGINE MECHANICAL SPECIFICATIONS (L37)

Block
Crankshaft Main Bearing Bore Diameter 72.430-72.442 mm (2.8516-2.8521 in)
Crankshaft Main Bearing Bore Out-of-Round 0.010 mm (0.0004 in)
Crankshaft Main Rear Oil Seal
Bore 115.962-116.038 mm (4.5654-4.5684 in)
Runout 0.250 mm (0.0098 in)
Cylinder Bore Diameter @ 41 mm (1.610 in) Below Deck Face 92.992-93.008 mm (3.6611-3.6617 in)
Cylinder Bore Out-of-Round
Production 0.010 mm (0.0004 in)
Service 0.100 mm (0.0039 in)
Cylinder Bore Taper
Production 0.010 mm (0.0004 in)
Service 0.100 mm (0.0039 in)
Cylinder Head Deck Height 224.55 mm (8.8406 in)
Cylinder Head Deck Surface Flatness 0.100 mm (0.0039 in)

Cylinder Head
Camshaft Bearing Bore Diameter 27.013-27.033 mm (1.0635-1.0642 in)
Camshaft Bearing Bore Out-of-Round 0.010 mm (0.0004 in)
Combustion Chamber Depth - at Measurement Point 10.470-10.710 mm (0.4122-0.4217 in)
Cylinder Head Height - Deck to Camshaft Centerline Bore 136.00 mm (5.3543 in)
Surface Flatness - Block Deck 0.050 mm (0.0020 in)
Surface Flatness - Exhaust Manifold Deck 0.220 mm (0.0087 in)
Surface Flatness - Intake Manifold Deck 0.220 mm (0.0087 in)
Valve Guide Bore - Exhaust 5.969-5.989 mm (0.2350-0.2359 in)
Valve Guide Bore - Intake 5.969-5.989 mm (0.2350-0.2359 in)
Valve Guide Installed Height - Exhaust 14.300 mm (0.5630 in)
Valve Guide Installed Height - Intake 14.720 mm (0.5795 in)
Valve Lifter Bore Diameter 12.013-12.037 mm (0.4730-0.4739 in)

Valve System
Valves
Valve Face Angle 45 degrees
Valve Face Runout 0.038 mm (0.0015 in)
Valve Face Width
Exhaust 1.500 mm (0.0591 in)
Intake 1.000 mm (0.0394 in)
Valve Head Diameter
Exhaust 28.880-29.140 mm (1.1370-1.1472 in)
Intake 36.090-36.350 mm (1.4209-1.4311 in)
Valve Length
Exhaust 91.730-91.990 mm (3.6114-3.6217 in)
Intake 110.600-110.860 mm (4.3543-4.3646 in)
Valve Seat Angle 45.75 degrees
Valve Seat Relief Angle 20 degrees
Valve Seat Relief Width
Exhaust 0.160-0.360 mm (0.0063-0.0142 in)
Intake 0.110-0.310 mm (0.0043-0.0118 in)
Valve Seat Runout 0.050 mm (0.0020 in)
Valve Seat Undercut Angle
Exhaust 65 degrees
Intake 60 degrees
Valve Seat Width
Exhaust 1.300-1.700 mm (0.0512-0.0669 in)
Intake 0.420-0.820 mm (0.0165-0.0323 in)
Valve Stem Diameter 5.920-5.940 mm (0.2331-0.2339 in)
Valve Stem Out-of-Round 0.008 mm (0.0003 in)
Valve Stem Straightness 0.013 mm (0.0005 in)
Valve Stem-to-Guide Clearance
Exhaust
Production 0.050-0.100 mm (0.0020-0.0039 in)
Service 0.050-0.120 mm (0.0020-0.0047 in)
Intake
Production 0.028-0.068 mm (0.0011-0.0027 in)
Service 0.028-0.110 mm (0.0011-0.0043 in)
Valve Lifters
Valve Lifter Diameter 11.986-12.000 mm (0.4719-0.4724 in)
Valve Lifter-to-Bore Clearance 0.037-0.041 mm (0.0015-0.0016 in)
Rocker Arms
Valve Rocker Arm Ratio 1.68 to 1
Valve Rocker Arm Roller Diameter 17.740-17.800 mm (0.6984-0.7008 in)
Valve Springs
Valve Spring Coil Thickness 4.110 x 3.280 mm (0.1618 x 0.1291 in)
Valve Spring Diameter
Inside 17.750-18.250 mm (0.6988-0.7185 in)
Outside 26.23 mm (1.0327 in)
Valve Spring Free Length 40.790-43.690 mm (1.6059-1.7201 in)
Valve Spring Height
Closed 35.000 mm (1.3780 in)
Open 24.500 mm (0.9646 in)
Valve Spring Load
Closed 211.4-233.4 mm (47.5-52.4 lb)
Open 579.0-631.0 mm (130.2-141.9 lb)
Valve Spring Total Number of Coils 6.90-7.10

Cylinder Head Torque

Left Side

Important: DO NOT reuse the old M11 cylinder head bolts.

Step 1. Install new M11 cylinder head bolts in the cylinder head.
Step 2. Install the M6 cylinder head bolts at the front of the cylinder head.

Notice: Ensure the cylinder head bolts that are being used are the proper pitch or engine damage will occur. The thread pitch on the M11 cylinder head bolts and the engine block cylinder head bolt holes have been revised. In order to prevent engine damage it is important to identify which thread pitch is being used. Cylinder head bolts with a pitch of 1.5 mm have a thread length of about 48 mm (1.890 in) long. Cylinder head bolts with a pitch of 2.0 mm have a thread length of about 67 mm (2.638 in) long.

Step 3. Tighten the left cylinder head bolts in the sequence shown.
First Pass: Tighten the left cylinder head M11 cylinder head bolts to 30 N.m (22 lb ft)
Second Pass: Using the J 45059, tighten the left cylinder head M11 cylinder head bolts an additional 60 degrees
Third Pass: Repeat the sequence turning each bolt another 60 degrees
Final Pass: Repeat the sequence again turning each bolt a final 60 degrees, total 180 degrees
Step 4. Tighten the M6 bolts at the front of the cylinder head to 12 N.m (106 lb in)

Right Side

Tighten the intake manifold bolts in sequence (1-10) to 10 N.m (89 lb in)

Camshaft Bearing Cap Torque

Left Side

Install the camshaft bearing cap bolts in sequence.
Step 1. Alternately hand tighten the camshaft bearing cap bolts a few turns at a time until all caps are fully seated.
Step 2. Tighten the camshaft bearing cap bolts to 5 N.m (44 lb in).
Step 3. Tighten the camshaft bearing cap bolts an additional 30 degrees using the J 45059.

Exhaust Manifold Torque

Left Side (W/O RPO NC1 or NF7)
Tighten the exhaust manifold bolts to 25 N.m (18 lb ft)

Left Side (With RPO NC1 or NF7)
Tighten the exhaust manifold bolts to 25 N.m (18 lb ft)

Right Side (W/O RPO NC1 or NF7)
Tighten the exhaust manifold nuts to 25 N.m (18 lb ft)

Right Side (With RPO NC1 or NF7)
Tighten the exhaust manifold nuts to 25 N.m (18 lb ft)

Camshaft Gear/Sprocket Bolts
Tighten the camshaft sprocket bolts to 120 N.m (89 lb ft)