Join Date: Jul 2016
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Ok so I followed the process and sequence perfectly ( by the FSM instructions), including the 1/4 turn at the end. Prior to 1/4 turn I marked each bolt with a line in the same direction to be sure they are all turned 90 at the end ( let's not get confused!).
It was apparent that the short bolts (exhaust side) end at a torque that is greater than the medium bolts, by feel at the end of that 1/4 turn rotation. A few of the short bolts torqued up quicker than the other short bolts and I went only 75-80 deg turn on those (used a square to accurately ge to 90).
Given the short bolts get torqued to 66ft-lbs same as the medium length bolts to 66ft-lbs, and then both get 1/4 turn, it makes sense that the short bolts go to a higher torque and correspondingly higher clamp force on the head. ( I believe the long bolts get torqued to 89 ft-lbs vs 66 (prior to 1/4 turn) to account for lower torque increase when for a 1/4 turn applied to a bolt with a longer stretch length (distance between the thread engagement at the block deck and the bolt head bearing surface) to achieve the same torque as a shorter bolt.
I AM concerned as I always thought head design is same torque on all fasteners so the clamp force is the same and gasket loading is even.
Can anyone shed light on this. IT JUST DOESN'T SEEM RIGHT but that is the Factory manual and is well documented.
I don't really feel good about this method or the result, but I don't know the mind of the engineers behind it and if other folks experience the same result ( and more importantly the effect on the head warpage or gasket failure).
1995 3500 2WD NV4500 105k Mods: stock plate full fwd + 0.060", AFC full fwd, stock gov springs +3 clicks, BD exh. brake, 60lb springs, EGT/Boost gages, rear axle air bags, 20psi boost (max) Towing: Alpenlite Avalon 36' ~14k, Reese 18K dual pivot hitch