Head Core Plug

[Rob Salinas]

Hello All,
The core plug under the cooling hose that exits the Therm housing is growing salt. I have a new plug, and have spoken to Ken. He said to pop the old one out, in the head is a ridge to keep the plug from pushing through. Was told to run a bead of JB Weld or such around the ridge, insert plug and tap domed top flat which expands the plug snug. Do not go beyond flat as when it starts going concave the edges pull in and will not seal. Then run another bead of JB in the grove between plug and head. Sounds pretty straight forward, has anybody else done this. Any tricks, or suggestions are greatly appreciated

Thanks,
Rob

[hanleyclifford]

Make sure you clean the seat carefully. When driving the plug be sure to get the drift dead center and don't hit it too hard. You will be able to feel the brass "give".

[Rob Salinas]

Thank You
Rob

[ndutton]

I'm just about to replace all the core plugs on a spare engine I'm rebuilding. In the past every core plug I've ever dealt with went into a smooth bore core hole (no ridge) and was a cup type plug with a skirt. I noticed on the A-4 there were two different types of core holes: the smooth type I'm accustomed to and the type with the ridge as you've seen and Ken mentioned. The plug for a ridged hole is a Welch plug, different than the cup style core plug. The Welch plug has no skirt and goes in domed side out.

Cup style core plugs . . . . .Welch plugs
. . . . .

In the case of my engine project (1977) I have Welch plugs in the block and head, cup style core plugs in the manifold.

edit:
and thank you for not calling them freeze plugs. There are serious but comical web pages that explain in detail how they are there to prevent freeze damage when nothing could be further from the truth. Gotta love the internet.

[67c&ccorv]

Welch - not "Welsh" plugs!

http://www.britishcarweek.org/welch_plug.html

[ndutton]

Originally Posted by 67c&ccorv

Welch - not "Welsh" plugs!

Uh.yeah . . . .???

[67c&ccorv]

Originally Posted by ndutton

Uh.yeah . . . .???

Norton Commando parts dealers would understand the confusion here...

[ndutton]

My confusion - and no problem here - was the post appeared to correct a wrong name when I was careful to get it right in the first place.

[67c&ccorv]

Originally Posted by ndutton

My confusion - and no problem here - was the post appeared to correct a wrong name when I was careful to get it right in the first place.

You should hear about the poor Norton parts dealer RGM in Cumbria, Wales;

"...they are not Welsh plugs - they are welch plugs - and I am am Welsh!"

http://www.rgmnorton.co.uk/