[rotorwrench]

The 600 series green Loctites are for cylindrical object locking and have a guide on the back of the package that tells you what they were made to do. It would be wise to use one that is appropriate for the job in holding capability and temperature capability. Otherwise it should be over-sized for correct fit. The temperature capability is likely the least controllable factor in working with cylinder components. Exhaust valves transfer heat to the cylinder block though the guide so they can get very hot at times.

The old two piece guides were not very well suited for use in engines. Ford used them clear up into the early V8 era due to the mushroom tip valve stems. On the model A, a poor fitting two piece guide used in it's history could have damaged the guide bore.