Tracking down low vacuum on this 72 xke (I’ve owned since new, but it’s been in storage forever). Vacuum reads as if wrong valve timing; but can’t imagine the chain actually skipping notches. More likely intake leak(s).
So — my question: the aluminum intake-to-head gasket: is it reusable or 1-time use only? Moreover, are people substituting the fiber/paper gaskets used on later (injected) v12’s?
Those intake gaskets have been revised several times, first replacing the metal with fiber and later replacing the 12 pieces with 2. I haven’t really heard anything horrible about any of them. Note, though, that if you go with the later 2-piece gaskets on your pre-H.E. engine, you may need to cut them into 4 pieces and/or trim them up a bit to ease spark plug changes.
We have had cases of chains shearing the teeth off the idler sprocket, which screws up the ignition timing. I can’t recall problems with valve timing other than an actual broken chain or broken tensioner.
Remember to check for an obstructed exhaust system as a possible cause of low vacuum.
I bought the 12 piece Cometic gaskets that don’t require re-torque and are thicker. Very happy with them.