03-12-2020, 02:35 PM
(03-12-2020, 10:59 AM)Chris KC Wrote: For what it's worth another way is to drill & tap oversize, Loctite in a threaded plug (metal of your choice, but I would suggest aluminium) and start again with a fresh hole. A helicoil is undoubtedly easier; though the plug method may present the opportunity not to drill quite through into the sump (ref discussion on oil leaks).
This is a sound method for fixing holes where a previous mechanic has drilled them oversize (sump bolts out to 5/16 BSW for example) as you can tailor the plug to fit whatever outer size you want, metric, UNC, BSP, anything really.
I looked into this many years ago and usually, when I have to do this in aluminium, I use Brass for the plug, as the thermal co-efficient of expansion is not wildly dissimilar to Ali.
It has to be said that inserting a helicoil (of whatever brand) is much quicker though and it's worth the expenditure on the kit.