Hi all,
Didn't want to hijack the cam caps stripped threads, er... thread, so here we are.
We've acquired a set of cases in which the M6 bolt for electrical ground is broken off just below the surface. Don't know the history.
Our plan is:
Repeated application of MMF* for a few weeks prior to using a heat gun and drilling the broken bolt with a left-hand flute drill, to prep for using an extractor. We might luck out & see the broken bolt spin out while drilling. If not, application of the extractor along with more MMF* and heat is next.
If the extractor is unsuccessful, the next step is to use progressively larger left-flute drill bits. If necessary, we may have to drill the threads out of the cases.
The ground bolt does not carry any real load aside from just the torque needed to secure the ground ring terminals.
We're unfamiliar with the selection & use of thread repair schemes in aluminum. What say the forum on the advantages/disadvantages of Time-sert vs Heliciol? Which to use on this particular application and why?
Thanks all.
Good Ridin'
slmjim & Z1BEBE
" MMF = Magical Mystery Fluid. A 50/50 mix of acetone and ATF. From an article published in Machinist Workshop Magazine circa. 2007.
"Recently “Machinist Workshop Magazine” did a test on penetrating oils. Using nuts and
bolts that they ‘scientifically rusted’ to a uniform degree by soaking in salt water, they then
tested the break-out torque required to loosen the nuts. They treated the nuts with a variety
of penetrants and measured the torque required to loosen them.
This is what they came up with:
Nothing: 516 lbs
WD-40: 238 lbs;
PB Blaster: 214 lbs;
Liquid Wrench: 127 lbs,
Kano Kroil: 106 lbs
(ATF)/Acetone mix (50/50): 50 lbs.
This last “shop brew” of 50% automatic transmission fluid and 50% acetone appears to beat
out the commercially prepared products costing far more."