Welch Plug

[HowardSmall]

I have to change the welsh plugs on my 2A 2.25 litre 4 cylinder engine.

Does anyone have any tips, etc that may make the job a little less daunting for a non-mechanic?

Howard

[incisor]

don't forget the ones at the back

[Blknight.aus]

The easy ones on the side you punch round about 44 degrees with a 6 mm punch then grab the top of them with a pair of vice grips and yank it out .


If you punch through it try again in a different place.

Eventually you'll mangle it enough that it will come out.

To pit them in lightly sand the mounting face, coat the lip of the plug or the mount with stag or hylomar and the sit them in place before gently driving it in evenly.

If your pulling them because you have one on the side of the block leaking be ready to pull the engine so you can do the ones at the back.

[keith73]

I did the side welsh plugs on mine recently and found it easy with the mud guard off.

[Lotz-A-Landies]

Except that Land Rover engines have core plugs not welch plugs.

Welch plugs are a slightly domed disk that are pushed up against a shoulder and then flattened out to seal.

I know I'm being pedantic.

[HowardSmall]

That is an option we had considered, the alternative being removal of the exhaust manifold. Did you do just those rwo?


Howard

I did the side welsh plugs on mine recently and found it easy with the mud guard off.

[keith73]

That is an option we had considered, the alternative being removal of the exhaust manifold. Did you do just those rwo?


Howard

Yes i did as those were leaking,but I'm going to replace the exhaust system anyway so I might do the middle one at the same time.

[Lotz-A-Landies]

You find a lot of firewalls where a hole has been cut to access the core plug at the back of the block.

Sometimes it's a nicely cut round hole and one of the plugs from the side of the tunnel inserted but mostly its a butchered hole.

[gromit]

Except that Land Rover engines have core plugs not welsh plugs.

Welsh plugs are a slightly domed disk that are pushed up against a shoulder and then flattened out to seal.

I know I'm being pedantic.

Welsh plugs come from Wales.

Welch plugs are a particular design of core plug (Hubbard Spring invented it).
Often called 'expansion plugs' or 'freeze plugs'. When water in the block freezes they tend to get pushed out hence people think that they are there to stop the block cracking when the water freezes (or expands).
The holes are where the core is supported so the water jacket is in the correct position when the block is cast so I guess the correct general term is core plug.

MG Cooling Tech -A Core Plug is not a Freeze Plug

Just checked and the Welch Brothers came up with the design and Hubbard Springs made them for the life of the patent (if you believe eveything you read on Wikipedia......)
[ame="http://en.wikipedia.org/wiki/Core_plug"]Core plug - Wikipedia, the free encyclopedia[/ame]


Colin

[Jordan]

Sometimes Welch plugs rust out. I take this to be an example of sacrificial corrosion - better the plug than the block. Mild steel is more prone to rusting than cast iron. I'd avoid brass plugs for that reason.
With the type of plug that is cup shaped, rather than a slightly curved disc, a good way to install them is to tap them in at the centre rather than at the edges. That tends to momentarily decrease the outside diameter, and avoids tilting it.