6.1 cylinder head bolt tq specs

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Correct the 12s get the extra 90 degrees the 8s do not
Cylinder Head—Bolts
M-12 Bolts
Step 1 34N-M 25FT. —
Step 2 54N-M 40FT. —
Step 3 Turn 90°

M-8 Bolts —
Step 1 20N-M 15FT. —
Step 2 34N-M 25FT NO EXTRA TURN REQUIRED
 
From the Factory Service Manual:

Tighten the cylinder head bolts in three steps using the sequence provided :
• Step 1— Snug tighten M12 cylinder head bolts, in sequence, to 34 N·m (25 ft. lbs.) and M8 bolts to 20 N·m (15 ft. lbs.) torque.
• Step 2— Tighten M12 cylinder head bolts, in sequence, to 54 N·m (40 ft. lbs.) and verify M8 bolts to 20 N·m (15 ft. lbs.) torque..
• Step 3— Turn M12 cylinder head bolts, in sequence, 90 degrees and tighten M8 bolts to 34 N·m (25 ft. lbs.) torque.

So it appears that the M12 are the Torque to yield fasteners. The factory recommends against reusing the Torque to Yield though some have done so with satisfactory results. As alway your mileage may vary.

Regards,

Joe Dokes
 
Thx folks.

Hadnt planned on having to check p-v clearance but the tighter lsa has me seeking insurance
 
can you not use a bore scope to have a look first before removeing the head
 
jimjimjimmy said:
can you not use a bore scope to have a look first before removeing the head
Click to expand...

Im not sure..never used one.

Would a bore scope give me the clearance in 1/1000ths?

FWIW....... The reason for head removal is to remove the hyd lifter and use one modified to a "solid" lifter so we can measure the p-v accurately.
 
you cant measure with it but i gues you could tell if it were really close your way is much better i was just thinkin out loud
 
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