Morris Minor Owners Club

Should core (welsh) plugs be fitted concave in or concave out?

I've only ever done them on Ford (kent) engines and fitted them concave in by tapping gently around the edges with a mallet and brass drift.

My Morris engines have them fitted concave in. One of them has what looks like sealant putty all around it. Looks like time to change!

If they're cup welch plugs, then they're fitted with the "concave" side facing in (fit them using a socket of the appropiate size).

On the sidevalve, they're dome welch plugs & are fitted concave out.

It's common to use a thin sealant around the outside, just to be sure.

Fot Minor 1000, I might be wrong but it totally seemed like they were designed to have the concave part on the inside - then you whack the middle of the domed part with a big hammer to spread it and make a tight seal.

[I used sealer on the last one I did as the block surface was a real mess - the previous core plug had been pushed nearly all the way out by frost and it had been left like that for many years ]

It's been a while since I looked at a 1000 block so maybe Ray is right.
On a "normal" engine, the top part in this picture faces inwards:

hmm - the ones I got last year for a 1000 engine (fit both the 1098 and 948) were just a domed disk - without a lip on the edge (i.e it was a dish type plug, not a cup one). It was the same type as the originals therefore not like the one in Scott's picture.

The last one went in using a socket on the edge and a few light taps, followed by a few big whacks in the middle to make it spread.

If your engine needs a cup type, then assembly is likely to be different!

The dish ones must go in with the dish sticking out so you can spread it by walloping it flat . The cup type go in so the bottom of the cup is furthest in the block. like Scott says.

I confirm Ian's post - Cup type - A+ block - inwards. Early type with dome out - then bash it not quite flat!