THE SHOP

July '16

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6 PRECISION ENGINE JULY 2016 PRECISION ENGINE sure that the shouldered washers are fully seated. This ensures that all fasteners align with their holes. Do this before you start to torque anything. Maskin's cylinder head torqueing procedure is as follows: CYLINDER HEAD TORQUE Dart specifies torque values for head installation to its block as follows: FASTENER THREAD SIZE TORQUE VALUE (FT-LB) 7/16" ....................................................................................................... 75 3/8" ......................................................................................................... 35 8mm ......................................................................................................... 22 Per Maskin's advice, I followed a very specific torque procedure for the 7/16- inch nuts: 1. Torque 7/16-inch nuts to 40 foot- pounds, then 50 foot-pounds, then 75 foot-pounds (in proper sequence) 2. Wait 5 minutes. 3. Crack all nuts loose (to zero foot- pounds) 4. Torque all 7/16-inch nuts directly to 75 foot-pounds (in same sequence pattern) 5. Crack nuts loose again to zero 6. Final torque 7/16-inch nuts directly to 75 foot-pounds Note: After cracking all 7/16-inch nuts loose to zero, I then re-snugged all 7/16- inch studs to make sure they hadn't loos- ened in the block. Next, torque the outboard 3/8-inch nuts to 35 foot-pounds and the 8mm stud nuts at the "between lifter" locations and the inboard locations to 22 foot-pounds, always following the tightening sequence as follows: Cylinder Head Fastener Torque Sequence ORDER.............. FASTENER LOCATION & SIZE 1 ....................... Center, above cyl bore 7/16 2 ....................... Center, below cyl bore 7/16 3 ........ Second from left, above cyl bore 7/16 4 .......Second from right, below cyl bore 7/16 5 ...... Second from right, above cyl bore 7/16 6 ........ Second from left, below cyl bore 7/16 7 .......................Far left, below cyl bore 7/16 8 ..................... Far right, below cyl bore 7/16 9 .....................Far right, above cyl bore 7/16 10 .................... Far left, above cyl bore 7/16 11 ......Second from left, between lifters 8mm 12 .............. Second from right, outboard 3/8 13 ................ Second from left, outboard 3/8 14 .... Second from right, between lifters 8mm 15 .............................Far right, outboard 3/8 16 .................... Far left, between lifters 8mm 17 ...............................Far left, outboard 3/8 18 .................. Far right, between lifters 8mm 19 ................................Center, inboard 8mm 20 ...............Second from right, inboard 8mm 21 ................ Second from left, inboard 8mm 22 ............................. Far right, inboard 8mm 23 ...............................Far left, inboard 8mm Installing the four special shouldered washers and torqueing the 8mm nuts onto the "extra" four stud locations (where these LS NEXT PROJECT Cylinder head torque- ing followed Dart's specific sequence and step values using CMD #3 high-pressure lubricant on nut threads and under-nut surfaces. Dart per- formed a great deal of research with regard to head clamping, so we followed its specs to the letter.

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