Camshaft housing nuts

[gijams]

I took out curved washers with standard nut and have replaced them with steel locking nuts. The torque down value is effected by the resistance of the lock nut but the curved washer also effects the torque valve. So I have put them in, is this unwise?

[MatthewBrum]

Why did you decide to not use the original nuts and washers. They should be ok to re-use. Just make sure you have the right tools to torque them properly. I would be concerned with the extra resistance of the steel locking nut.

[304065]

Not recommended. Since we can't measure stretch conveniently for the nuts that hold the cam tower to the heads, we use torque. The torque setting is an approximation of the torque value that the nuts reach when proper preload of the studs is achieved. Anything that deviates from the surface condition used by the engineers at Porsche, rust, grease, or the presence of a distorted thread or nylon locking feature will cause the torque achieved to differ.

The practical result is that your torque wrench will click WAY before the stud is stretched to the correct preload just because it's harder to overcome the friction of the distorted thread. As a result, you will have the equivalent of a WAY lower torque setting, not what you want.

Get yourself some DIN 934 M8 nuts and steel wave washers, these are inexpensive, or just use the ones on the engine originally, they aren't prone to corrosion generally because they sit inside the valve cover!

[gijams]

I will charge them out.