Hi - new member here, and apologies for jumping in with an immediate question.
I’ve just re-shimmed my tappets on an XJ6 4.2 engine, and have reinstalled the camshafts to which the sprockets are secured with 4 bolts with locking tabs.
My question is what is the specified make up torque for the bolts?
I have searched this forum and elsewhere to no avail. When I removed them I found that they had been assembled with loctite as well as having the locking tabs. I haven’t reassembled with loctite, and will rely on the correct torque and the locking tabs.
Whenever I have questions about non-specified torque values (which unfortunately is most fasteners on the car), I just consult a standard toque value chart and assume they’re comparable to modern grade 5. Exceptions would be things like banjo bolts which are drilled lengthwise and worse going into aluminum.
Assuming they are the same as the 2-bolt cams and 3/8-24 UNF (fine) that would be 26 foot pounds for a Grade 5 equivalent.
Is there any strength marking on the heads?
My XJ12 factory Service Manual has several pages of torque values for many bolts on the car. I wonder if the XJ6 manual would have the same thing?
Don’t assume that the threads in the cam flanges themselves will support upgrading the bolts. Use the original bolts if you have them. I could be wrong, but I don’t recall seeing locking plates on cambolts? I believe that the originals should be drilled for safety wire.
Looks like an update, wire on early cars, locking tab plates on later.
The arrows mean “up to these 7G 7L numbers” and “after these 7G 7L numbers”. 7G is the 2.8 Liter and 7L is the 4.2 Liter.
