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MG Midget and Sprite Technical - Mystery hole

Hi,

Whilst waiting for the paint to dry on my engine I decided to clean out the blocked coolant drain hole which was all silted up with crud. I managed to clean it out up to hitting the end of the hole, but then I can't seem to work out how the hole connects to the main coolant chamber around the pistons.

Anyhow I decided to shine a light down within the coolant chamber to see if I could see the drain point.

I then discovered a hole on the inside of the chamber that is really close to where the pipe that connects the oil filter head to engine block. It is on the other side of the engine to where the drain tap is so don't think it can be connected, but it is the proximity to where you screw in the oil connecting pipe which has got me a little worried.

I doesn't seem to have broken through into the oil system thankfully otherwise I have just thrown away a lot of money reconditioning the engine.

But I wondered what people made of this hole. Could it be just left over from the casting?

Many thanks

James





James Paul

Been reading an old post and have now unblocked the drain hole. Just needed some more gentle taps with a long but narrow screwdriver with a slight upwards trajectory and I broke through.

but I’m still a little worried about the proximity of this hole to the oil channel as you can see from the first photo.

I have checked and there is no hole on the wall of the oil channel as shown in the second photo.

I guess there isn’t much I can do about it.




James Paul

I am confused by this James. On my engine the coolant drain point is on the other side of the engine.
Perhaps there is more than one drain point?
GuyW

Hi Guy,

Yes that’s correct and the same on mine. This is another hole which I think might be either left over from the casting or it is corrosion of the wall.
James Paul

Ah, sorry. I had to re-read your original message where you refer to "hole" but mean 2 different holes
I was confused!
GuyW

It'd be interesting to measure down from the top of the block to it and then check down the outside of the block, it's probably further away from the oil hole than you think---strange though all the same--
William Revit

Hi,

I think you’re right the hole is after the point where the oil channel narrows so should be enough good metal between them.

I am thinking of filling the hole with something like J-B Weld HighHeat Epoxy Putty. I should be able to get access via the water pump opening using a long piece of dowel and pushing small amounts of the putty into the hole to seal it and hopefully prevent further damage.

Anyone got any thoughts on that?
James Paul

James, could you drill and tap it, then fit a set screw?
Bill Bretherton

Think access will be difficult for that solution Bill
James Paul

Is this hole from the water jacket? To where?
Or is it at the bottom of the stud hole? If the latter maybe it's to relieve pressure as the stud is screwed in so the block doesn't crack?
GuyW

James, Unless you're getting leakage between the oil and cooling systems I would leave well alone. I'd be very wary about introducing epoxy putty or similar unless you can be absolutely sure that it has bonded properly with the metal. If it were to come loose you'd have a lump of putty washing around the cooling system just looking for somewhere awkward to cause a blockage.

C Mee

At some point when painting a bare block I’m sure I’ve come across a small brass plug, that kind of diameter. I’m not sure where (it could even have been in the head) but a small hole plugged with brass rings a bell.

Anyway, I’d be trying to tap it as bill suggests or hammer in a brass plug. The oil galleries are sealed with brass plugs so if they are ok for that then should be ok for water jacket.
John Payne

Hi,

Thank you all for your input.

I think sometimes writing these things out sort of helps you work out what is going on.

Using the torch I've worked out that the hole actually links two areas of the water chamber!

Not sure why it didn't occur to me. I just didn't try to shine the torch in one area whilst looking for light in the other section.

I'm now thinking this 'wall' between the chambers could be crud build up as there is an old piece of wire stuck / rusted in there, so wondering if someone has had a go at trying to unblock it all.

I'll try to do some more investigations. At least my main concern isn't anything to worry about anymore.

Thanks


James





James Paul

The wire may be a core support, IIRC they're mentioned in Vizard and stay trapped in the block cast iron.
David Billington

That’s good to know as I’m thinking this wall might be to help control the flow. Think I’ll leave it alone.
James Paul

Yeah, Fairly common to find wire in B series blocks left from the casting process, sometimes you can get it out ,other times the end of it has got itself cast into the block and it's permanent--
If you can't get it out, it doesn't cause an issue, just shut your eyes and move on----------
willy
William Revit

This thread was discussed between 03/01/2022 and 05/01/2022

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