Hi,

I seem to be getting water in my oil, both under the rocker cover and in the sump.

I did the usual things, a compression test was fine and with the plugs out, there is no obvious water getting into the bores.

My friend came around and we pressure tested the cooling system and it wouldn't hold pressure. We took the head off and there wasn't anything too obvious as far as leaks go.



We did notice that a couple of the little brass plugs in the photo above were standing a little proud (maybe .5 - 1mm) and when I gently touched them, they pushed back into place.

Do these plugs actually hold water behind them (and potentially the cause of the water leak) or are they just covering access holes, in which case there could be a crack in the head?

I'll take the head to a head service place and get them to pressure test it but was just looking for ideas.

Thanks,
Simon

Yes those plugs are core plugs, they cover the water jacket. The holes were put there to get the sand out, after casting.
Tap a hole in them, pull them out, turn up some new brass ones a few thou oversize, and drive them back in.
Just like we do with oil gallery plugs.

However that IS an early S head (not a 12G940), these are renowned for cracking between the valves. Get it crack tested...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks for that Doc.

I was hoping that that might be something to do with it.

If that's all it is then that's gotta a lot easier to fix than a crack.

I'll sort that out then get it pressure tested I guess.

Unfortunately, as you point out, it is an AEG163 and I've already had to have it welded up before.

Cheers,
Simon

I prefer fitting cast iron plugs to the brass ones. They don't move and they don't leak. Cast Iron ones don't give trouble, where as the Brass one sometimes do.

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Can plugs be bought off the shelf? Or have they got to be turned up like Doc said?

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

I think brass ones are available and maybe the cast iron ones too, but I turn them up. They are usually a 'stock bar size' anyway, but the finish and size of 'stock bar' is not always desirable for for plugs that you want a seal on.

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I repair the brass ones in the face of 940 heads (when sunk in) by tapping the hole to 3/8BSP then screwing in a brass plug with Loctite 262. Finally I deck the head and the plugs too.
Keith Calver uses this method in the UK.

You may be able to do the same, depending on the hole size.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I'll take it up to the local head place and have a chat to them about it. I don't have the skills to repair it myself.

Thanks very much for your advice.

On the topic of water, i've noticed water comming out of the exhaust of both my minis and alot of other cars both old and modern aswell. Is this a concern in the minis? I assume aircon is a contributor in the new cars? Does water out the exhaust of the mini mean water is somewhere in the engine it should not be?

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Dog Food! Most kids like it more than Broccoli.

For every 1L of fuel burned you create 1.25L of water, as water vapour.
This condenses in the exhaust system during cooldown, that's why you see water dripping out on modern cars on cold startup, followed by mists of steam as it all warms up.
This is normal.
On my Valiants way back in the 70s there was a 3mm? hole drilled standard in the muffler at the lowest point, to let it drain out.... there is probably a law against this now (well there is for everything else it seems).

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.