Topic: stripped cam cover bolt hole

[oddballmotorsports]

so I have an issue,  I have a cam cover bolt that is stripped.  I plan on putting a heli-coil on it to fix it,  however the engine is in a rather tight spot in my build, and taking the cam holder off is going to be a pain in the butt.  doing the grease on the tap to catch most of the aluminum shavings will keep them from falling in while tapping, but anyone have any suggestions on catching the shavings from drilling the hole out while prepping for the tap?  also, is the cam the last stop on the oil delivery?  if I don't catch all the shavings will their next stop be the oil pan?  thanks folks!

[jaytee-nz]

i recently had the same issue (although maybe not your tight access problem). I put a rag over the exposed head and completely covered it. Around the hole that needed to be drilled I used masking tape attached to the rag so that I completely isolated the hole, just leaving it exposed enough to drill and tap. That way nothing could fall in to the head.
You just need to be careful when removing the tape and rag so that the shavings don't fall in.

[spotty]

do the above but also get someone to hold a running vacuum cleaner beside the work site while you drill/tap/unmask

[PeWe]

I have fixed vave cover threads by covering the head with plastic or a cloth, make a hole where the job has to be done and tape the opening around the thread you'll fix. Clean first with acetone so tape will stick.
Be careful when removing the plastic so burrs will not enter. A piece of an old cotton sheet work fine too since burrs will stick to it and follow when removing it.
Vacuum cleaner to suck out the burrs from the hole before put the thread insert/helicoil in  and when taking the cloth off.

[oddballmotorsports]

is the hole blind?  I thought it went all the way through to where the cam lives, and what I was worried about is the shavings falling from the bottom side of the hole inside the rocker box, am I wrong?  that would be nice if I was..  I haven't investigated it yet, just know the threads are stripped...

[PeWe]

Valve cover have some bolt holes not going thru.
Threads for cam holders are different, some of them must not be drilled to deep. 
Those threads for valve cover going thru will go outside, not in engine or where oil flows.

Do not use a drilling machine, manually with a thread tap holder and it will not go wrong.
1.) Correct drill for the thread insert/helicoil type  The thread that are broken are not tall, max 10mm. Too short bolt used might be a cause of ruined thread. Most of the M6 bolts have 10mm thread depth.
2.) thread tool

Engine side covers should be checked how deep the threads are when there is a risk that the bottom of the thread will pop-in.
3.)insert the coil or insert. Inserts like timesert work fine if glued with loctite. (I use 272 strong and hot)

[oddballmotorsports]

yup it went all the way through to where the cam lives,  so, what I did was make a little spoon that went inside rocker adjustment hole,  it was bent in such a way so it would have the scoop part directly below the hole being tapped.  with the exhaust valve all the way open there was enough room to sneak it in there.  I put a smearing of grease in the spoon to catch any metal shavings as well as the tap,  then taped off all the holes.  a bunch of metal shavings fell through, and the spoon did its job and caught them all, as well as the tang from the heli-coil which had to be removed.  ran a shop vac aftwards just to be safe, and interesting to note, it was strong enough to suck up pooled oil inside the engine now back up and running and no more leaky valve cover