Torque for Superformance cam drive nuts?

[greggbferrari]

Finally getting my 308gt4 back together. I'm using the hex drive nuts (available from Superformance in the UK) instead of new ring drive nuts.

If I'm reading it right, the WSM says 13 kg-m, which I believe is 94 ft-lbs. That seems a lot for the 5-6 fine continuous threads on those nuts before the nut is notched. I suppose the ntoches are to lock the nuts, but they don't appear to grip the threads.

Anyone used the Superformance hex cam drive nuts and torqued them to 94 ft lbs?

Thanks.

[PFSEX]

What is the size of the nut? bolt?

torque is udually proportional to size of the fastener.

90 ft-lbs would indicate a BIG fastenener - something on the line of a wheel nut-bolt.

90 ftlbs will snap a small fastener or pull the threads

[fastradio]

Originally Posted by greggbferrari

Finally getting my 308gt4 back together. I'm using the hex drive nuts (available from Superformance in the UK) instead of new ring drive nuts.

If I'm reading it right, the WSM says 13 kg-m, which I believe is 94 ft-lbs. That seems a lot for the 5-6 fine continuous threads on those nuts before the nut is notched. I suppose the ntoches are to lock the nuts, but they don't appear to grip the threads.

Anyone used the Superformance hex cam drive nuts and torqued them to 94 ft lbs?

Thanks.

A couple of things...
Torque to proportional to numerous factors. Two of which are thread pitch and diameter.
The thread pitch is 17x1.0mm, which will support a fairly high torque figure
The actual torque figure is 12 kg-m (87 lb-ft.)
The factory "jet" lock type nut is far superior to anything else for that critical application.
Once the bearing is seated and the nut tightened, the notches will 100% engage the threads. If not, there are much bigger problems to contend with.
Other than not having, or wanting to spend the money for the correct tool, why take a risk and use an unknown commodity in such a critical application. The factory nuts are dirt cheap and even an aftermarket tool is less than $100.

[Steve Magnusson]

13 and 12 kg-m are both correct (depending on which WSM you believe )

It's a fine thread pitch, but the diameter is huge, as David mentioned, so no worries IMO -- AFAIK, no one has ever reported stripping those threads on FChat...

[greggbferrari]

Gentlemen, thank you. Careful cleaning, a little blue loctite, 13 kg-m (94 ft-lbs) and no apparent problems.

It's kind of thrilling to see cams in the heads after six months. :-)

[fastradio]

Originally Posted by Steve Magnusson

It's a fine thread pitch, but the diameter is huge, as David mentioned, so no worries IMO -- AFAIK, no one has ever reported stripping those threads on FChat...

I do have a 17x1.0mm die if the need should ever arise...

Originally Posted by greggbferrari

Gentlemen, thank you. Careful cleaning, a little blue loctite, 13 kg-m (94 ft-lbs) and no apparent problems. It's kind of thrilling to see cams in the heads after six months. :-)

You're welcome and congrats on your progress!