Stripped distributor adjustment bolt
 

While adjusting the timing on my 84 4runner, I noticed that the the distributor bolt would not tighten enough to hold the dizzy position. I backed out the bolt all the way and found what I believe to be the remnants of an old Helicoil on the bolt. I found that LCE and other sell the specific bolt with blue loctite on the end and two washers. Thinking I was screwed and I would have to be tapping out the head for a new bolt, I decided to try the bolt without this helicoil “spring” that it came out with and I did get it to tighten enough to hold the distributor in place to get me home. Question: Can I tap and install a helicoil without removing the head or has anyone else had this happen. I am so ready to do an engine swap.

If I remember that is a blind hole so drilling and installing a thread replacement should not be a problem.

** I have not had enough Coffee so I might be wrong !!

It's not a blind hole, it goes through to the innards of the engine. That's why thread sealant is needed. You don't need to remove the head to safely tap for a helicoil, just the valve cover. Set a shop vac up right inside the hole to catch any chips from tapping the hole.

If what you had in there was a "thread repair" and it came out your bolt would certainly just spin, pretty much the point of being able to slide it in without turning it..

What was on the bolt were very likely the stripped threads..

You need to get eyes on the hole, good light, maybe a depth guage, to verify if it is a blind hole and fixable in place.