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 :p

[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 (http://mgaguru.com/mgtech/cooling/cool_105.htm)

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......)
Core plug - Wikipedia, the free encyclopedia


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.

[Lotz-A-Landies]

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.Thats what brass core plugs are for.

My understanding of core plugs is not for sacrificial purposes or any other reasons like freezing protection, its because you need something to hold the casting sand in position when the block is cast and then get it out before machining and assembly. Yes you can use the lost wax method but it still needs to be held in position during the casting.

[Jordan]

Yes, the main reason for core plugs is understood. But they can rust if made from steel - I've seen it. At first annoyed at having to replace it, I consoled myself that it's better that way.
Brass plugs should last forever, but I think using anti-corrosion additive in the coolant would be safer.
Or, is that too conservative? A block or head could last a long time before rust was an issue - maybe?

[Lotz-A-Landies]

I always try to use brass plugs if I can get them in the correct size.

It was really embarrassing, we were doing a display at the Kapooka Army Base for their open day when a welch plug (yes it was a welch plug) in a 1943 International Harvester M5A1 half-track blew out from rust when it was giving rides to kids.

It is really difficult to find welch plugs these days.

[Dinty]

Just google Graham Matthews auto parts in Sth Oz, this damn new bull??><< SYPD stuff is US but anyway they will have what you want, only catch is you can't just buy one, min order I think is 10, anyway cheers Dennis:D

[gromit]

Can you get brass Welch plugs (the dished type) ?
Because of the way they're retained would brass work and hold tight ?

A quick search throws up Autobarn, Supercheap etc. list the Cup type core plugs (under Welsh plugs, freeze plugs etc.), I'm sure if you asked they would have access to the dished type.



Colin

[Lotz-A-Landies]

Can you get brass Welch plugs (the dished type) ?
Because of the way they're retained would brass work and hold tight ?

A quick search throws up Autobarn, Supercheap etc. list the Cup type core plugs (under Welsh plugs, freeze plugs etc.), I'm sure if you asked they would have access to the dished type.

ColinIt was an odd imperial size, the big problem is the person organising the parts for the work had actually purchased dished core plugs for an application where a welch plug was required. Not the thing to do when you're in the bush miles away from an auto parts store on a Saturday afternoon.

[russellrovers]

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. :(hi diana can you let me know re tub jim

[chazza]

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.


Good advice; however; if a decent corrosion inhibitor is used in the cooling system, analytical corrosion can be eliminated.

I use Castrol Corrosion Inhibitor, or Castrol Anti-boil anti-freeze in my cars.

When I pulled the Disco's engine apart after 250 000km, there was absolutely no corrosion anywhere inside the cooling system, even though there was copper and brass on the radiator and steel and aluminium on the block,

Cheers Charlie

[gromit]

Good advice; however; if a decent corrosion inhibitor is used in the cooling system, analytical corrosion can be eliminated.

I use Castrol Corrosion Inhibitor, or Castrol Anti-boil anti-freeze in my cars.

When I pulled the Disco's engine apart after 250 000km, there was absolutely no corrosion anywhere inside the cooling system, even though there was copper and brass on the radiator and steel and aluminium on the block,

Cheers Charlie

Same here, also using Castrol anti-boil anti-freeze at the correct ratio in the Defender, and Series I. The other vehicles have just a corrosion inhibitor added until they get back on the road.
The Castrol corrosion inhibitor has been discontinued but I've found other brands.

I've started record cards for each vehicle so I know when things like coolant was last changed. As long as you change within the timescale they quote the corrosion inhibitor will be doing it's job.

The problem starts when you buy a vehicle with unknown history, has it been left standing for years half full of water causing internal corrosion ??


Colin