Welch Plugs

[MK1_Oz]

[gen mk 1rs2000]

i did mine , but geez its a risky operation ( i tap threads
on a daily basis at work )
BUT tapping cast iron particularly with such a small fine thread so
very close to an edge , is frought with danger
personaly i have never seen a problem with welsh plugs
but have heard some possibly tall stories

[Gary P.]

I believe it is done because on High HP engines the blocks have a tendency to twist slightly and welsh plugs have been known to "walk" out. I have never personally heard of anyone experiencing this but Danny doesn't usually do things without reason.
As Steve said, be very careful though. On my original block I had a crack develop in the external wall of the block radiating out from one of the locating bolts, resulting in a coolant leak.

[ozstang65]

302 Boss blocks (and others) had screw in plugs. I don't know if they were in smaller than standard holes or just tapped into the standard holes. It may be possible to tap the standard holes??

[MK1_Oz]

thanks. i have only tapped 1 hole and never in cast iron. might give it a miss. High temp silicone maybe to help the plugs stay in place??

[ozstang65]

Stag or 8 hour Araldite are some adhesives that I have heard of being used.

[gen mk 1rs2000]