390
TECHNICAL SECTION
TORQUE SPECIFICATION CHART
These torque values are approximate and should not be accepted as accurate limits. Factors (surface finish, type of plating and lubrication)
in specific applications preclude the publication of accurate values for universal use. Manufacturers provide specific tightening instructions
which should be followed. DO NOT USE the values for gasketed joints or joints of soft metals.
To change inch Lb. to Ft. Lb. divide by 12; change Ft. Lb. to inch Lb. multiply by 12.
GRADES – Ft. Lbs.
BOLT SIZE SAE 2 (mild) SAE 5 SAE 8
1/4-20 6 11 12
1/4-28 7 13 15
5/16-18 13 21 25
5/16 -24 14 23 30
3/8-16 23 38 50
3/8-24 26 40 60
Torque Heads – 32-34 ft. lbs. max.
HEAD STUDS: GM originally referred to head studs as .003 & .006 oversize but this is confusing because it does not refer to the actual outside
dimensions of the threaded end. It was GM's simplified way of referring to the oversize threads (oversized width of the sides of the threads). When
replacing studs they should be installed with a torque wrench (see our blind ended nut C2001, page 13). They must torque to at least 10 Ft. Lbs.
BUT NOT OVER 30 Ft. Lbs. The lower studs should have a total length sticking out of the block of about 7-9/16" and the upper about 8-9/32". If the
standard size stud does not torque to OVER 10 Ft. Lbs. then you need to try a .003 & then a .006. If threads have actually pulled out of the block go
directly to a thread insert.
SPECIFIC TORQUE VALUES
Many bolts on a Corvair really need to be torqued. A good torque wrench is inexpensive – get one. We've listed some of the more common ones.
If you have a bolt not listed generally you can go by the Chart above.
GRADES – Ft. Lbs.
BOLT SIZE SAE 2 (mild) SAE 5 SAE 8
7/16-14 37 55 85
7/16-20 41 60 95
1/2-13 57 85 125
1/2-20 64 95 140
9/16-12 80 125 175
9/16-18 91 140 195
A/C or Smog Pulley to Balancer Pulley
25-35 Ft. Lbs.
Balancer Pulley to Crankshaft
40-50 Ft. Lbs.
Bellhousing to Block 20-30 Ft. Lbs.
Block Bolts (holds block together)
(see sequence) 50-55 Ft. Lbs.
Block Cover 7-13 Ft. Lbs.
Clamp – Exhaust Manifold
22-27 Ft. Lbs.
Connecting Rod 20-26 Ft. Lbs.
Cover – Block 7-13 Ft. Lbs.
Crankshaft Pulley 40-50 Ft. Lbs.
Cylinder Head Temp Switch
5-10 Ft. Lbs.
Differential Cover 40-60 In. Lbs.
5 Ft. Lbs.
Differential Yoke Bolt to Diff.
40-50 Ft. Lbs.
Engine Mount (Rear) to Frame
1961-64 14-22 Ft. Lbs.
1965-69 20-25 Ft. Lbs.
Engine Mount (Rear) Lower Nut
1961-64 50-60 Ft. Lbs.
1965-69 40-50 Ft. Lbs.
Exhaust Manifold Clamp
22-27 Ft. Lbs.
Flex Plate (PG) to Crank
30-40 Ft. Lbs.
Flywheel to Crank 40-50 Ft. Lbs.
Gen/Alternator Adaptor
7-13 Ft. Lbs.
Head Nuts (see sequence)
32-34 Ft. Lbs.
Head Studs to Block 15-30 Ft. Lbs.
Motor Mount Bracket to Block
25-35 Ft. Lbs.
Mount – See Trans.or Engine
Oil Cooler Adaptor to Block
7-13 Ft. Lbs.
Oil Cooler to Adaptor 8-12 Ft. Lbs.
Oil Filter 15-20 Ft. Lbs.
Oil Filter/Gen. Adaptor 7-13 Ft. Lbs.
Oil Pan – Stock 60-84 In. Lbs.
7 Ft. Lbs.
Aluminum 8-10 Ft. Lbs.
Oil Pan Drain Plug 30-35 Ft. Lbs.
Oil Pressure Spring Regulator Plug
10-20 Ft. Lbs.
Oil Pressure Switch 45-65 In. Lbs.
(4-5 Ft. Lbs.)
Oil Pump Cover 60-80 In.Lbs.
(5-7 Ft. Lbs.)
Oil Suction Screen Clamp
30-50 In. Lbs.
(3-4 Ft. Lbs.)
PG Pan Bolts 60-84 In. Lbs.
(6-7 Ft. Lbs.)
Pressure Plate to Flywheel
15-20 Ft. Lbs.
Pulley (A/C or Smog) to Bal ancer Pulley
25-35 Ft. Lbs.
Pulley to Crankshaft 40-50 Ft. Lbs.
Rear Engine Housing to Block
7-13 Ft. Lbs.
Rear Motor Mount Bracket to Rear Block
25-35 Ft. Lbs.
Rear Wheel Bearing Nut
1965-69 100-130 Ft. Lbs.
Rocker Arm Nut (minimum torque to
"hold") 5-10 Ft. Lbs.
Rocker Arm Stud 32-34 Ft. Lbs.
Shrouds (1/4" Bolts)
60-80 In. Lbs. (5-7 Ft. Lbs.)
Shrouds (3/8" Bolts) 10-20 Ft. Lbs.
Skid Plate (under oil pump)
15-20 Ft. Lbs.
Spark Plug 15-20 Ft. Lbs.
Studs – Head to Block
15-30 Ft. Lbs.
Stud – Lower (rocker arm)
32-34 Ft. Lbs.
Suspension – Adj Bolts 65-69
Ft. & Rear "Cam Bolts"
Front 75-85 Ft. Lb.
Rear 85-95 Ft. Lb.
Suspension Bolts – Ft. Cross member
mounting
Cars 40-50 Ft. Lbs.
FC 90-100 Ft. Lbs.
Switch-Cyl Head Temp.
5-10 Ft. Lbs.
Thermister I'd say at 5 Lbs.
5-10 Ft. Lbs.
Trans. Covers – Stds. 60-65
All (40-60 In. Lbs.)
4-5 Ft. Lbs.
1966-69 8-12 Ft. Lbs.
Trans. Crossmember to Trans.
20-30 Ft. Lbs.
Trans. Mount Nut
60-70 Ft. Lbs.
Trans. Mount to Crossmember
20-30 Ft. Lbs.
Universal Joint
1/4" 12 Ft. Lbs.
5/16" 22 Ft. Lbs.
Valve Cover – Stock
(40-60 In. Lbs.) 4-5 Ft. Lbs.
Aluminum 8-9 Ft. Lbs.
Wheel Bearing Nut – 65-69
Rear 100-130 Ft. Lbs.
Is The Block # Enough? – No !
Corvair people are very "creative". With a little work almost "any" year block can "really" have any year parts in it. To be sure it is good, also check the head numbers,
piston numbers, and crank numbers.
PROBLEMS ????????????? WE WANT TO KNOW!
If you find any problem with any part or aspect of our service, please let us know. Call, write, fax or email.
With OVER 14,000 part numbers it is possible for "something" to go wrong or get by us. We want to make it right!