Core Plugs

[InfinityJon]

Right, when I had the block sorted, my engine man took all my core plugs out as requested 

unfortunately, I forgot to photograph which way the plugs went into the engine. 
 

Any chance a kind soul would tell me if the the plugs go in dish first or dish out. 

I can’t find a diagram to show me.

if they are dish out, I get that flattening the dome seals the side flanges to the block but how does that work if they are dish in?

 

 

 

[Mike C]

Welsh plugs normally go  concave face in - so that when you punch them with a drift they expand outwards and seal. 

[Waldi]

Agree with Mike. That is the way they work.

Waldi

[Motorsport Mickey]

8 hours ago, Mike C said:

Welsh plugs normally go  concave face in - so that when you punch them with a drift they expand outwards and seal. 

To prevent protests from our members of Welsh extraction just to correct the spelling it's Welch with a c.

Welch plug[edit]

The Welch plug is a type of core plug that is made from a thin disc of metal. The Welch plug is dome-shaped and inserted into the casting hole with the convex side facing outwards.[5] When installed by striking the Welch plug with a hammer, the dome collapses slightly, expanding it laterally to seal the hole. This differs from other dish-shaped core plug designs, which form a seal when their tapered sides are pressed into the casting hole.[6]

The Welch plug was originally designed in the 1900s at the Welch Motor Car Company in the United States. Prior to the invention of the Welch plug, the core holes were sealed using pipe plugs. During the testing of a car, one of the pipe plugs backed out. In order to get back on the road, one of the Welch brothers installed a press-fit quarter or half dollar coin into the hole using a hammer. The design of the Welch plug was refined based on this principle of a press-fit metallic disc.[7

The core plugs more often used on modern designs are of the "cap" type which are shaped with almost parallel short sides, and are referred to as core plugs without a generic name. 

Mick Richards

Edited August 29, 2020 by Motorsport Mickey

[Mike C]

I never knew this-"The Welch plug was originally designed in the 1900s at the Welch Motor Car Company in the United States. Prior to the invention of the Welch plug, the core holes were sealed using pipe plugs. During the testing of a car, one of the pipe plugs backed out. In order to get back on the road, one of the Welch brothers installed a press-fit quarter or half dollar coin into the hole using a hammer. The design of the Welch plug was refined based on this principle of a press-fit metallic disc."

I always thought the Welsh invented them, probably back in the days of Richard Trevithick.

[InfinityJon]

So the cup type go in cup bottom first and the dish type are in dome out 

[BlueTR3A-5EKT]

35 minutes ago, InfinityJon said:

So the cup type go in cup bottom first and the dish type are in dome out 

TR6 will probably have the cup type core plugs.

If it looks like this it goes concave side out, as shewn.

 

 If it looks like this it goes domed face out which you then flatten to expand it into the recess.

 

Cheers

Peter W

 

[InfinityJon]

Thanks guys

[stuart]

1 hour ago, Mike C said:

 

I always thought the Welsh invented them, probably back in the days of Richard Trevithick.

He wasnt Welsh he was Cornish! https://en.wikipedia.org/wiki/Richard_Trevithick

Stuart.

[RogerH]

Ah!! a Cornish plug from Stuart.

 

Roger

[PodOne]

19 minutes ago, RogerH said:

Ah!! a Cornish plug from Stuart.

 

Roger

Can't see a pasty lasting long!

[stuart]

20 minutes ago, PodOne said:

Can't see a pasty lasting long!

Not usually!

Stuart.

 

[RogerH]

Cracking picture Grommet

 

Roger

[Motorsport Mickey]

The eyes...the eyes...look into the eyes...you have no control...lift up the food...give it to ME !

Mick Richards