PC-85-928S

Any good source of information about S4 cam removal?
Asking for friend who thinks he may have a weak or broken spring.

Speedtoys

Workshop manual?

Not hard, just time.

Mongo

http://dwaynesgarage.norcal928.org/

Look under the intake manifold service. Be careful - the bolts don't come out easily. My biggest piece of advice to you is when you start removing the bolts, if one feels weird, don't apply excessive force to it and ensure your hex key is properly seated in the bolt.