C15 Rocker Shaft/Jake Bolts

I've really only ever heard of Acert rocker bolts breaking.

 

The difference in the bolts and torque specs are whether you have 12 of the 12 point bolts or have 9)6 point bolts with 3)12 point bolts. You want the 9)6 point bolts and 3)12point bolts to hold the jakes and rocker shafts down. These are a torque and turn spec and actually hold everything in down in the head for less valve train movement of the rockers and shafts. Using all 12 point bolts allows the shafts to move much more and causes fretting of the stands in the head over time. This allows the bolts to loosen, which can lead to bolt breakage.

 

Does any one have the part number for the updated bolts and torque specs? Thanks in advance.

 

You have to use the 3 12 point bolts over. These 3 bolts must be used in the third hole from the front on each jake brake housing. Otherwise to install the heavier 6 point bolts in this position will starve the jakes for oil and keep them from functioning properly.

If you have the updated bolts the spec is to torque to 40 ft-lbs in the same sequence, then to turn them 90* in the same sequence as before. All bolts and the stud are tightened in this manner.

 

He is wrong

The 3 required 12 point bolts are 167-0867, but the 9 required 6 point bolts are 257-2122