Welch Bros apparently came up with the Welch plug (funny that). The Welch car company was purchased by General Motors (1909)
Core plug - Wikipedia, the free encyclopedia
The Welch plug is a type of core plug used to plug the holes used in the casting process to hold the sand core for the waterways in place. Early days they were threaded plugs but threading the block and making a threaded plug is expensive so a 'lower cost' solution was needed.
They use foam cores now, these melt to nothing so core holes are not needed (saving more in the manufacturing process).
You'll sometimes see them called freeze plugs because people think they are there so that if the water in the block freezes they push out. This can happen but isn't the reason they are there.
[ame="http://www.youtube.com/watch?v=yXVLbzI3xTE"]How It's Made Engine Blocks - YouTube[/ame]
Colin
'56 Series 1 with homemade welder
'65 Series IIa Dormobile
'70 SIIa GS
'76 SIII 88" (Isuzu C240)
'81 SIII FFR
'95 Defender Tanami
Motorcycles :-
Vincent Rapide, Panther M100, Norton BIG4, Electra & Navigator, Matchless G80C, Suzuki SV650
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