Prevent overtightening the K&N filter cover plate – which it’s easily done – can cause the filters to collapse. This is not an issue on new filter housings but when refitted many times the cover gets worn and that’s when overtightening and crushing the filters becomes an issue.
When the cover gets worn from overtightening the bolts – look inside the top cover and you will see the worn area around the bolt surrounds / spacer tubes. To compensate for this add a washer ……
BUT ….. trying to fit a washer as well as the spacer tubes with the original standard arrangement is about impossible.
With a simple mod of replacing the long bolts with stud bar and domed nuts then the whole job of removing and refitting the K&N filters – and adding an extra spacer washer – becomes a straight forward job.
See earlier post for the mod at ……. https://mgb.tips/2019/11/30/kn-filter-mounting-mod/