LazyEyeMcFly

truckdoug

iTrader: (25)

i just use the 3/8" milwaukee electric rattle gun

i do roll it over in 90* increments, a complete 2 revs on the crank

RB04Av

Only thing the TDC / rotate thing is for, is to make sure the valve spring pressure doesn't corrupt the torque measurement and leave the bolts loose. Not sure why those are called TTY; seems to me that around 20 - 25 ft-lbs is the normal-ish torque for that size as it is, can't see how 22 ft-lbs on a fine thread into aluminum is going to make em yield. Butt hay, what do I know...

Zmg00camaross

iTrader: (11)

I tighten them down by hand to compress the spring, then torque.works fine. If it is someone paying me and like a customer car I will roll the engine over and get it on tdc. Adjustable valvetrain of course it would be on tdc to set the valves.

vettenuts

iTrader: (4)

Rocker bolts are not TTY.

vettenuts

iTrader: (4)

Torque is a crappy measurement of the bolt preload (very inaccurate and highly dependent on friction). Adding valve spring force to this inaccuracy only makes it worse. GM procedure tightens the bolts at TDC cylinder #1 and then TDC cylinder #6, i.e., set at TDC firing stroke for cylinder #1 and tighten specific bolts then rotate one turn and tighten other bolts at TDC firing stroke of cylinder #6. Those bolts tightened at each position are those on the cam base circle.

One of the many ls1howto short cuts is to tighten all at the same time and then rotate and check. Doing this doesn't account for static vs. dynamic friction so the bolts will always show tight, even though the actual preload may be low. In other words, if you tighten a bolt to a given torque and stop, it will take more torque to get it rotating again after which the torque will drop. You will see this with a needle torque wrench, not a clicker.