plug in cc

[40plyguy]

 Wondering what the plug located in the head in the combustion chamber of #6 cyl is for?

[Silverdome]

To find top dead center and/or stroke length.

[Hubler13f]

I pulled that plug the other day to find TDC and found it to be filled with carbon build up or something, I carefully replaced it trying not to dislodge whatever is blocking it, I didn't see anything out of the ordinary while the head was off, but mine is definitely blocked.

[Don Coatney]

If the head is off it is the best time to clean out the hole. Use a gun cleaning wire brush.

[jeffsunzeri]

6 minutes ago, Hubler13f said:

I pulled that plug the other day to find TDC and found it to be filled with carbon build up or something, I carefully replaced it trying not to dislodge whatever is blocking it, I didn't see anything out of the ordinary while the head was off, but mine is definitely blocked.

Entirely common. It won't hurt a thing to drill through the carbon to allow a welding rod to insert.

[Hubler13f]

7 minutes ago, jeffsunzeri said:

Entirely common. It won't hurt a thing to drill through the carbon to allow a welding rod to insert.

Thanks good to know, I just didn't want to knock it loose after I got everything back together and have it get lodged or block a valve open. I'm sure if it's carbon it wouldn't last long, just made me nervous.

[plyroadking]

It also doubles as an explosion whistle port.....

[medium_jon]

It also doubles as an explosion whistle port.....

@plyroadking: that is right Special 

[Don Coatney]

The wolf whistles I have seen run om manifold vacuum not cylinder pressure.

[plyroadking]

1 hour ago, Don Coatney said:

The wolf whistles I have seen run om manifold vacuum not cylinder pressure.

You're correct, I've got a wolf whistle too, on the a vacuum port. Explosion whistles run off of compression.