BC

I have taken apart the 86 block now, partially for a reseal and some new rings, but also because I screwed up a bolt hole on the passenger head. I drilled it out for a Heli-coil so I could just put the regular bolt back in, but now I have broken most of the (very expensive) inserts, and no new ones will go in now. The tool used to insert them is also screwed up - it won't hold the little kink.

Are there "Thicker" eli-coils to go back to the original bolt size but from a bigger hole or am I going to just have to drill it out again (don't know how close I am to coolant passage) and use a larger bolt with a larger heli-coil?

John Veninger

Have it TIG welded.

RyanPerrella

OT

Brendan,

How did your new rings fit the cylinders? Did you use OEM Goetz or Porsche rings? What did your gaps look like?

BC

You mean closed up the hole entirely and redrilled and tapped?

Mike Frye

Brendan,

I think those heli coil things only come in one insert size. I've never seen them with different internal and external sizes for adjustments like that.

It would be a mess, but can you use two of them? One that's the right size for your bolt and one that's big enough to fit the right one in it?

I think filling it using a welder and then redrilling it is the right way to do it.

Jim bailey - 928 International

Or check out Timesert they are vastly superior to Helicoils...use a larger pilot hole. If you weld on that surface it may need to be ground down so the housing matches the head. But timeserts kits are not cheap although they often save far more than they cost

John Veninger

Yes, since it sounds like the hole is going to be way to big for the next size.

BC

LHS has a keensert, which is said to be similar to a timesert, which is not currently available from what I have checked in San Diego so far. I have no way of knowing who to call for the welding of the heads. Its so wierd here in San Diego, whenever I go on these wold goos chases to find people who have tig welders, or do plasma welding this, or machining that, I always get blank stares from greasy idiots with john deer hats on. Seriously.

BC

A keensert at the LHS seems to have a 6mm bolt kit that has an OD of 10mm.

GlenL

Drill and tap to the next largest size bolt. Maybe an SAE size. Yes. I did suggest that. Someone will hate on you later for it, but it'll work.

Or take it to a machine shop and let them solve it. Actually that's my recommendation.

BC

If I have the heads rebuilt fully, I will have it welded and retapped. But if I only lightly clean up the heads, and lap the valves in a bit (this all depends how far the guides are out), I will timesert the hole.

BC

Thanks everyone for the suggestions. You pointed me in the right direction as always.

SharkSkin

I second the timesert recommendation. Helicoils are a good first attempt, because if it gets buggered up there's still enough meatl for a timesert to work.

svp928

I second Dave's thought. Check here for all kinds of fun $$Stuff...incl. inserts and install kits.

www.mscdirect.com

jon928se

Can you use a stud instead?

Have stud made that is original thread size one end and one size larger the other end.

I prefer Timecerts to Helicoil/Recoil but I've never had problems with *coil, I can only think this is attributable to using the correct size drill (which is always a bizarre size)