Heli coil ?

Helicoil is very easy to use. Drill it using the proper drill, tap it out and insert the helicoil.

I am not sure about using it for headbolts but it is commonly used for manifold bolts.

You might want to pick up a used block to use instead of the original.

"Ernie Leimkuhler" wrote Helicoil is very easy to use.(clip) ^^^^^^^^^^^^^ I don't know what this particular block is made of, but it is probably either cast iron or aluminum. A Helicoil in either of these materials can be expected to be stronger than the original. The insert is made of stainless steel. Since the interface between the insert and the block will have a larger diameter than the original, there will be more gripping area.

Another option if there is enough metal present around the hole would be to drill and tap the next size head bolt you can get.

Have it professionally Helicoiled. It's easy enough to do, but you need a magic tool that's expensive. For a small one-off job, it's cheaper to have it done for you by the guy who already has it. A machine shop that grinds heads can almost certainly do it for you.

I've never heard of an overheating head pulling the thread out of a head bolt hole. I'd suspect previous gorilla-damage - maybe a past owner just tried to stop a leak by over-tightening things ?

The original owner may have Gorillia -ed the head bolts. They are 11 mm and they have a 1.5 tp. Thats an odd ball the bolts are 6 to

Many headbolts seal coolant from the valve area. Heli-coils, being a wire spiral, will allow leakage that can only be stopped by the use sealants, and no gasket manufaturer recommends using sealants on their headgaskets. If the headbolts go into a blind hole, (they have a solid bottom that does not enter the water jacket), then a heli-coil will do. I prefer to use a solid insert, such as a "time-sert" in these cases. Contact a local VW shop, and he may have some "case-savers" that fit and can be installed with normal metric taps, for a lot cheaper than a "time-sert' kit. Either will hold more strain than a Heli-coil.

Now there's a risky idea. The great advantage of Helicoils is that they're narrow, barely larger outside than the original tapped hole. Solid inserts are always a few mm bigger, and in a modern head than might be space you just don't have to spare.

I've never heard of an engine where coolant is deliberately sealed by a head bolt. Maybe Yank lumps do this, but the nearest I can think of is the infernal Jaguar straight six (a nightmare to remove the head from, if corroded).

Check it out

Nice. Of the solid inserts, that's certainly the slimmest I've seen.

I was told by a machine shop, when I told them that my plastic tool for installing the heli-coils stripped out, that one could be made from a regular bolt with a notch similar to the original tool into the end. Worked like a champ. Still had to use their tap, though, which isn't cheap. I do three or so engines a year so I have a few different size sets on hand. There are a number of engines with "wet" head studs that have the block end open to coolant. Don't recall which ones, but the manuals are pretty specific about sealing up the threads. If someone didn't seal up the threads, they might also be equally ignorant enough to think that more torque is better. On VW air-cooled motors, if you torque the head studs beyond the light

"P4_Squisher" wrote in message news: snipped-for-privacy@comcast.com... | The original owner may have Gorillia -ed the head bolts. | They are 11 mm and they have a 1.5 tp. Thats an odd ball the bolts are 6 to | 7 inches long and the machine shop didnt have the tap for it. I suggested he | take it to a bigger engine machine shop. | | "Andy Dingley" wrote in message | news: snipped-for-privacy@4ax.com... | > On Fri, 15 Oct 2004 19:25:16 -0700, "P4_Squisher" | > wrote: | >

| >>Does anyone have advice on this kind of repair, using the Heli Coil | >>method. | >

| > Have it professionally Helicoiled. It's easy enough to do, but you | > need a magic tool that's expensive. For a small one-off job, it's | > cheaper to have it done for you by the guy who already has it. A | > machine shop that grinds heads can almost certainly do it for you. | >

| > I've never heard of an overheating head pulling the thread out of a | > head bolt hole. I'd suspect previous gorilla-damage - maybe a past | > owner just tried to stop a leak by over-tightening things ? | >

| > -- | > Smert' spamionam | |

I'm thinking the same thing. The machine shops could not up size the fastener because of the close proximity to the water jacket. Then locating the Helicoil kit was an insurmountable task. He sold the engine and car for parts, and washed his hands of it. Thank you for your ideas.