Spark plug thread inserts

Not a question per se, but a rant......

I got a hold of an automotive machinist last week regarding the
installation of a spark plug insert for my dad's old Civic head. I
currently have a bargain basement Helicoil setup but the insert seemed
too large of diameter to install it in the extremely small area between
the four valves in the combustion chamber.

I called said machinist sight unseen because my regular shop was on an
extended Labor Day vacation. I told him the situation and that my
Helicoil seemed too large -- can he fit a spark plug insert into this
thing? I mean, from experience, can he tell me if it's just a waste of
time to drive the 25 miles, or is there a good chance it can be done?
The answer was, yes! it can be done and I will do it!

While arranging for pickup on the phone this morning, I asked if the
job went OK, and got the proverbial thumbs up. My dad picked up the
head since he wasn't busy, so I didn't see it until he got to my shop.
Wow! There's a standard Helicoil wire type repair in there! So I call
him and ask why he didn't ask permission first before installing a
substandard repair. I wouldn't have minded if he said "after examining
your cylinder head, your options are either a standard Helicoil or
nothing because there's not enough room for the proper repair in this
head".

Furthermore, he said he's been doing this for 15 years with no
problems. Perhaps he's magical or maybe I'm worrying about nothing.
But the combustion heat and pressure that will be exerted on *both*
sides of that insert will certainly be much greater than in a standard
Helicoil thread repair application. I can just envision the remaining
aluminum as it erodes away until the new insert and plug are ejected
through the car's hood.

Toyota MDT in MO

I've been doing alum. cyl. head repair for 24+ years and see Heli-Coils as
a fine way to go. The stuff I work on is strictly high performance and
Heli-Coils hold up fine in these heads, so a Honda head would should work
out fine too......

"Comboverfish" > wrote in message
oups.com...
> Not a question per se, but a rant......
>
> I got a hold of an automotive machinist last week regarding the
> installation of a spark plug insert for my dad's old Civic head. I
> currently have a bargain basement Helicoil setup but the insert seemed
> too large of diameter to install it in the extremely small area between
> the four valves in the combustion chamber.
>
> I called said machinist sight unseen because my regular shop was on an
> extended Labor Day vacation. I told him the situation and that my
> Helicoil seemed too large -- can he fit a spark plug insert into this
> thing? I mean, from experience, can he tell me if it's just a waste of
> time to drive the 25 miles, or is there a good chance it can be done?
> The answer was, yes! it can be done and I will do it!
>
> While arranging for pickup on the phone this morning, I asked if the
> job went OK, and got the proverbial thumbs up. My dad picked up the
> head since he wasn't busy, so I didn't see it until he got to my shop.
> Wow! There's a standard Helicoil wire type repair in there! So I call
> him and ask why he didn't ask permission first before installing a
> substandard repair. I wouldn't have minded if he said "after examining
> your cylinder head, your options are either a standard Helicoil or
> nothing because there's not enough room for the proper repair in this
> head".
>
> Furthermore, he said he's been doing this for 15 years with no
> problems. Perhaps he's magical or maybe I'm worrying about nothing.
> But the combustion heat and pressure that will be exerted on *both*
> sides of that insert will certainly be much greater than in a standard
> Helicoil thread repair application. I can just envision the remaining
> aluminum as it erodes away until the new insert and plug are ejected
> through the car's hood.
>
> Toyota MDT in MO
>

Al wrote:
> I've been doing alum. cyl. head repair for 24+ years and see Heli-Coils as
> a fine way to go. The stuff I work on is strictly high performance and
> Heli-Coils hold up fine in these heads, so a Honda head would should work
> out fine too......

That's reassuring, but I have heard of Helicoils pulling out and
blowing out from guys I talk to. I wouldn't think of using one
normally (with plugs) and am fairly certain that Helicoil recommends
againt it. Thanks for the reply.

Toyota MDT in MO

Comboverfish wrote:

> Al wrote:
>
>>I've been doing alum. cyl. head repair for 24+ years and see Heli-Coils as
>>a fine way to go. The stuff I work on is strictly high performance and
>>Heli-Coils hold up fine in these heads, so a Honda head would should work
>>out fine too......
>
>
> That's reassuring, but I have heard of Helicoils pulling out and
> blowing out from guys I talk to. I wouldn't think of using one
> normally (with plugs) and am fairly certain that Helicoil recommends
> againt it. Thanks for the reply.
>
> Toyota MDT in MO
>
Ask if he used an oversized helicoil:
http://www.casa.gov.au/airworth/aac/PART-6/6-058.HTM

"Comboverfish" > wrote in message
oups.com...
>
> Al wrote:
> > I've been doing alum. cyl. head repair for 24+ years and see Heli-Coils
as
> > a fine way to go. The stuff I work on is strictly high performance and
> > Heli-Coils hold up fine in these heads, so a Honda head would should
work
> > out fine too......
>
> That's reassuring, but I have heard of Helicoils pulling out and
> blowing out from guys I talk to. I wouldn't think of using one
> normally (with plugs) and am fairly certain that Helicoil recommends
> againt it. Thanks for the reply.
>
> Toyota MDT in MO

Be reassured again. I have been using them for 40 years with great success.
I have also seen a number of botched installations that did blow out. And as
your machinist said, it's the only insert that will fit. I don't know why he
characterized it as other than a first rate repair.
Heli-coils are used commonly on aircraft engines and can also be found in
Porsche engines.
Why would you not use one? And where in the world did you get the idea
Heli-coil recommends against? The fact is they sell kits specifically for
spark plug thread repairs.

On 7 Sep 2005 15:01:56 -0700, "Comboverfish" >
wrote:

>
>Al wrote:
>> I've been doing alum. cyl. head repair for 24+ years and see Heli-Coils as
>> a fine way to go. The stuff I work on is strictly high performance and
>> Heli-Coils hold up fine in these heads, so a Honda head would should work
>> out fine too......
>
>That's reassuring, but I have heard of Helicoils pulling out and
>blowing out from guys I talk to. I wouldn't think of using one
>normally (with plugs) and am fairly certain that Helicoil recommends
>againt it. Thanks for the reply.
>
>Toyota MDT in MO

Actually, they make a kit for spark plug threads. I've used them on
outboard motors. Never had the occasion with cars.

Chas Hurst wrote:

> Why would you not use one? And where in the world did you get the idea
> Heli-coil recommends against? The fact is they sell kits specifically for
> spark plug thread repairs.

Yes they do. I HAVE one of these very kits. The machinist installed a
STANDARD Helicoil, the kind that is made of 2mm thick stainless wire.
A real spark plug repair insert is solid, eliminating most of the
compression blowby and erosion faults inherent in a standard Helicoil.
In fact, the solid insert is to be installed with high temp sealer
around it as a precautionary measure.

As previously stated, I felt uncomfortable trying to install my
Helicoil brand plug insert due to the space limitations. The machinist
said he could put one in over the phone, and he has more experience
(good or bad) than I do, so I brought it to him. If he had told me
that he was just going to thread a simple Helicoil in it even though I
had asked for a plug insert specifically, I would have tried another
shop.

Toyota MDT in MO

NickySantoro wrote:

> Actually, they make a kit for spark plug threads. I've used them on
> outboard motors. Never had the occasion with cars.

Yup, but the machinist installed a regular wire type Helicoil when I
specifically asked for (any brand) of spark plug insert made soley for
that purpose.

Toyota MDT in MO

Comboverfish wrote:
> Al wrote:
>
>>I've been doing alum. cyl. head repair for 24+ years and see Heli-Coils as
>>a fine way to go. The stuff I work on is strictly high performance and
>>Heli-Coils hold up fine in these heads, so a Honda head would should work
>>out fine too......
>
>
> That's reassuring, but I have heard of Helicoils pulling out and
> blowing out from guys I talk to. I wouldn't think of using one
> normally (with plugs) and am fairly certain that Helicoil recommends
> againt it. Thanks for the reply.
>
> Toyota MDT in MO
>

just to make you feel better next time you have to have one of these
repaired...

http://timesert.com/html/sparkplug.html

I believe they actually require less "meat" than a Helicoil.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel

Nate Nagel wrote:

> just to make you feel better next time you have to have one of these
> repaired...
>
> http://timesert.com/html/sparkplug.html
>
> I believe they actually require less "meat" than a Helicoil.
>
> nate

Thanks for that tip. I've heard good things about Timecert, esp. in
respect to the Ford V8s and V10 that throw plugs like a roman candle.
Lisle has another system; when I asked the machinist he said that Lisle
has a .020" larger outer diameter than the Helicoil brand but he
mentioned nothing of Timecert.

Toyota MDT in MO