Topic: cam and cam tower torque specs???

[J.Webster Designs]

hey guys, i have the top end back together and i need to know the torque specs for a couple bolts.

1. Rocker arm pivot pin bolts ( i believe they are 7mm or 6mm)

2.the cam sprocket bolts.

Thanks in advance

[J.Webster Designs]

anyone?

[J.Webster Designs]

bueller? bueller? anyone? bueller?

[scondon]

  Not sure which bolt you are referring to in #1

   Cam sprocket bolts are 13-15.9 ft/lbs

[J.Webster Designs]

the bolt in #1 are the two bolts that thread into the pin that allows the rocker arms to pivot. there are 3 bolts on per set of rocker arms. one bolt is 10mm the others i believe are 7mm or 6mm

[NitroHunter]

Just looked at a K8-F3 shop manual, and it doesn't show anything on these 
Anybody know?

[MCRider]

Just looked at a K8-F3 shop manual, and it doesn't show anything on these 
Anybody know?

Looking at my 1969 to 1977 Clymers manual, there are 6 bolts per cam tower (Early models used a pair of a stud/w/nut and bolt on the bearing caps. Many engine builders pulled the studs and replaced with bolts). 2 each on each bearing cap and 2 that go down the centers of the rocker pin, named the "cam tower mounting bolts" in the manual. In any event all the hardware is 6mm. (10mm wrench size)

The bearing cap bolts torque spec is 6.5 to 9.4 ft/lbs (quite a range). The manual skips any torque spec on the cam tower mounting bolts. I would be comfortable using the high end of that same range. They are hardened bolts (black in color) if memory serves. I would tighten those center cam tower mounting bolts first, then the inside bearing caps, then the outside bearing caps. Since no guidance is given there, why not? 

[NitroHunter]

If you measue the thread pitch and bolt diameter (6mm?) you could look it up on a torque chart, probably use the gr. 5 specs. If you don't have a decent inch-pound torque wrench it's a moot point though...
Hand snug with a dab of blue loctite?

[scondon]

 The larger center bolt has the same torque specs as the bolts on the cam bearing caps, around 8ft/lbs as nitrohunter points out. These bolts thread into old aluminum threads in the head and strip out very easily if over torqued. If your torque wrench is not good at measuring low torque values then it is very easy to over do and strip the head. I've stopped using a torque wrench on these bolts and tighten by "feel" now, but I don't suggest this method for first or second timers.

    Those very small outer two bolts on each rocker shaft thread into the hardened rocker shaft and are very hard to bugger up. Measure the size and get the correct torque value from the table in the manual if you want, but "tight" is an OK spec for these, in my opinion. These bolts were added to the late model SOHC's and are intended to stop the rocker shaft from spinning. Earlier models did not have these and the shaft spun as it wanted to, so even if you forgot to put these small bolts back in you are not in a bad way(I think  ).

[NitroHunter]

After observing the rocker wear on the shafts in a bunch of old motors I had mine Molybdenum disulfide (MoS2) coated along with some other stuff, and removed those bolts (like scondon said) as well. My thought was to let them move around. The wear pattern isn't localised and I've personally experienced no problems, but maybe some of the road race guys have other observations they could share.

[J.Webster Designs]

thank you all.

[scondon]

After observing the rocker wear on the shafts in a bunch of old motors I had mine Molybdenum disulfide (MoS2) coated along with some other stuff, and removed those bolts (like scondon said) as well. My thought was to let them move around. The wear pattern isn't localised and I've personally experienced no problems, but maybe some of the road race guys have other observations they could share.

   Our own "HondaMan" covered this in depth and claimed there may be even a "smidge" of horsepower to be gained from reverting to,or keeping with, the older shaft mounting method. He also pointed out the wear pattern, just to say that you are in good company with this line of thinking. Of course it's probably one of those things that only racers lose sleep over

[NitroHunter]

I was 'sleepless in Seattle'.
I snore now.

[scondon]