|The MGA With An Attitude
REPLACING the REAR CORE PLUG In Situ - CO-105E
This tip comes from Gary Roberts in Australia. Notice the photo shows application to
an MGB engine with the tall rear plate obstructing access to rear of the cylinder head.
Gary wrote: "I managed to push out the back plug through the opening of the rear side plug. The space around the cylinder was only just enough to push a 4mm rod. It seemed to come out too easily. It was covered in red sealant, maybe Stag, that was soft. The brass plug didn't appear to have been in hard contact with the sides of the hole all the way round. A classic car workshop has advised me to use steel and not brass plugs. I assume steel is a similar metal to cast iron and has more 'spring' than brass so it may put more tension on the sealing surface. As for rust I use 50/50 coolant ratio so I don't expect a failure using steel in the foreseeable future.
I made a small scraper that rotates around the sealing surfaces. The surfaces seem clear of old sealant so let's hope it will be clean enough. I will run a very fine emery around the hole surfaces if I can get access. The classic car workshop has recommended hi temp two part epoxy to seal the plug.
I made the 'pusher device' that will push the rear plug in supported by the back plate. I made a simple scraper to clean the recess for the rear plug.
I also made a drift for the accessible plug that I can install with a hammer. Hubbard Spring Company recommend using a drift diameter close to the plug size.
I have Permatex Cold Weld epoxy to seal the plugs that is good for 150 deg C. I will not be leaving the 'pushing device' in situ as I will apply epoxy around the lip of the hole.