Non-standard apark plug thread insert size

[Devin]

These used heads I got had one spark plug hole drilled out (right side, of course), and as I found out, tapped to what looks like M17 x 1.25. The spark plug that came with it appears to have 1.25 thread but measures at around 16.8 mm.



Whereas my M16 inserts measure a hair under 16mm. I'm having a **** of a time finding a thread insert with M14 x 1.25 inner thread and M17 x 1.25 outer thread.

I thought maybe this was two inserts but it looks like one.



Any assistance would be appreciated. I'm very close to getting this engine back together!

 

[Devin]

The more I look at that picture the more I think this is two sleeves, of increasing size.

 

[Irish Pride]

Might have to have the hole welded and retapped.

Why are you going with this head? Why not another one and not deal with this issue?

-Chad

 

[Devin]

This is my replacement head!

 

[Irish Pride]

This is my replacement head!

Again, why go with this one and not another? I have spare heads if you need one. Just pay the shipping and it's yours.

-Chad

 

[luigisho]

Again, why go with this one and not another? I have spare heads if you need one. Just pay the shipping and it's yours.

-Chad

Take this offer and don't look back.

 

[Texas Marauder]

Take this offer and don't look back.

Agreed. Why deal with a patched up head?

 

[luigisho]

Just curious. Were you made aware of this janky part of the head before getting it?

 

[Devin]

Negative. Plugs were still in the head when I got it from Mike.

 

[Devin]

I have my original head that was leaking oil like a sieve. I originally got these other heads to avoid downtime on the car and that has failed spectacularly. I have new valve stem seals. Would it make sense to replace those on my original right head if I'm going to have to dissassemble one anyway?

 

[PaulTAutoX]

These used heads I got had one spark plug hole drilled out (right side, of course), and as I found out, tapped to what looks like M17 x 1.25. The spark plug that came with it appears to have 1.25 thread but measures at around 16.8 mm.

View attachment 98112

Whereas my M16 inserts measure a hair under 16mm. I'm having a **** of a time finding a thread insert with M14 x 1.25 inner thread and M17 x 1.25 outer thread.

I thought maybe this was two inserts but it looks like one.

View attachment 98113

Any assistance would be appreciated. I'm very close to getting this engine back together!

Not saying it is what I'm sorta seeing here, but have seen where a male thread stripped out the aluminum threads on the female side and it looked like a thread insert was still on the male thread.