Innie or outie?

MM sent me the Welch/Freeze Plugs I ordered from the diagram of my 1098. Today I got around to fitting them. The block has stepped holes that are clearly a stop for the plug. The plug had a flange that is about twice the depth of the stop in the hole. It would seem logical to me that the plug would be seated with the lip (edge) of the flange against the stop and in the sealant (an "outie"). I used a large impact socket (about the size of the plug and a shop hammer to install.

The result was a deformed plug that could not be salvaged. I then tried installing the next one with the cup in (an "innie") and experienced greater success. as I had ordered extra, I installed the rest with the cup in. Although driven in to the stop, the excess flange length protrudes above the edge of the block.

Have I just made a bad rookie mistake?

Right the second time. Cup dome out , flange to the outside, visible. Smacking the cup spreads the plug. The excess flange may me a manufacturing issue. One never can be sure these days.

Yep... innie. I might have thought the originals were that way (to just copy).

It has been years since I rebuilt my Mini's 1275. Even then the replacement plugs were too tall for the holes. However, I remember clearly that the factory plugs were domed end in with the straight side pointing out of the counterbores. Since I wanted to retain the original look I made a fixture for my lathe so I could cut the plug sides down to the correct height. Once that was resolved I applied a thin film of RTV to the counterbores and tapped the plugs in place using a large socket inserted inside the plug.

dklawson said:

It has been years since I rebuilt my Mini's 1275. Even then the replacement plugs were too tall for the holes. However, I remember clearly that the factory plugs were domed end in with the straight side pointing out of the counterbores. Since I wanted to retain the original look I made a fixture for my lathe so I could cut the plug sides down to the correct height. Once that was resolved I applied a thin film of RTV to the counterbores and tapped the plugs in place using a large socket inserted inside the plug.

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Thanks Doug. That makes it very clear, but not having a Bridgeport, I'll have to live with the longer flange. Thanks again.

JimLaney said:

Thanks Doug. That makes it very clear, but not having a Bridgeport, I'll have to live with the longer flange. Thanks again.

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Understood. However, too long, is too long. Even if you put the plugs in "open" side first, the domed end will stick out too far to look right. An alternative (without a lathe or mill) is to install the plugs closed end first and then carefully dress the plugs down close to flush using an angle grinder or cutoff wheel. Just avoid grinding the block!