86 Merc 115 inline 6 has a groove in #6

[redjmp]

I have a deep groove running most of the way down my #6 cylinder.
Is is very big and maybe 3/16" wide and looks like it was machined in.

Is this normal and if so what is it for?
Compression was fine in that hole ~125psi

 

[redjmp]

Here is a pic. The groove is deep on one side and tapers on the other.

 

[Faztbullet]

Picture didnt come thru, if at the 6 o"clock position sounds like wrist pin dropped...

 

[racerone]

It is not normal.-----It was not machined , so something is wrong in there.

 

[redjmp]

Horror of horrors! No c clip found on that side of the pin!
Omg! Still gave good compression numbers....?
So I suppose this means a re-sleeve.
If I can find someone who does that in my neck of the woods.... If its even possible?
What's a shop charge for something like that?

This thing has run well for 100's of hours and I'm tempted to just put it back together as is and see...