Morris Minor Owners Club

While in the engine noticed this small round hole behind the dipstick.It had a small round piece of metal in it originally that fell out.It seemed to be in the hole as a cover.I don't think there is leakage from there but wondering what it is.It is on a marina 1275 engine.

The item in question is a core/welch plug.
It is not standard and it has been modified with possibly an additional plug to cure a coolant leak.
I would change the core/welch plug soonest.
Take care when fitting a new core/welch plug as there is no back stop to the core plug so in theory the plug could be knocked right through into the water jacket and then it is near impossible to get the plug out.
As your engine block has the ribbing it is a Ital 'A' Plus 1275cc engine which is stronger than the Marina block

Looks like there is a leak there. I can see fluid in your picture

Stephen

Thank you are they changeable from outside the engine if so how please.Arexthey screwed in etc.

Usually a hole punched into the the plug, with a sharp spike, allows one to ‘hook’ the plug out. The plug is an interference fit, so it’s tapped in carefully flush with the block face, use a core plug sealant.
As mentioned don’t let the old or new one fall into the block. In your case you may be able to enter a engineers tap, of appropriate size, into that hole and perhaps pull the core plug out, although it might be too tight.

Classiccars wrote: ↑Mon Sep 25, 2023 12:03 pm Thank you are they changeable from outside the engine if so how please.
Arexthey screwed in etc.

Yes.
No, there are removed and fitted with brute force. See this youtube video for fitting: https://youtu.be/4aejqRkgGaE
Removing is punching a screwdriver or similar through the middle and levering it out.

I've never seen one with an extra bit in the middle.....

You can buy them from ESM: https://www.morrisminorspares.com/search/core-plug

philthehill wrote: ↑Mon Sep 25, 2023 10:29 am

I'm assuming the Plugs are the same size on the A Plus Engine, but I'm sure Phil can confirm that

Those ESM core/welch plugs are the wrong ones. They are for the small block 'A' Series plus some Cooper 'S''s.
These are the ones you need:-
http://www.minispares.com/product/Class ... o%20search
As I said above you do need to be careful when hammering the core/welch plug fitted to 'A' Plus engines. With this type of plug it is better to drill a 3/8" hole and then lever out the plug.
Use a vacuum cleaner nozzle when drilling to catch any swarf/crud.
Good luck.

philthehill wrote: ↑Mon Sep 25, 2023 3:22 pm Those ESM core/welch plugs are the wrong ones. They are for the small block 'A' Series plus some Cooper 'S''s.
These are the ones you need:-
http://www.minispares.com/product/Class ... o%20search
As I said above you do need to be careful when hammering the core/welch plug fitted to 'A' Plus engines. With this type of plug it is better to drill a 3/8" hole and then lever out the plug.
Use a vacuum cleaner nozzle when drilling to catch any swarf/crud.
Good luck.

Thanks for the A Plus correction Phil.

I didn't realise the A Plus used the Cup Style. Now I've looked closely at the photo, I can see that's what they are....

Great info as usual gents thank you.

Could someone have fitted one the universal expanding type plugs and the centre has come off?

I will havecalook thanks.

Did you find out what type of core plug was fitted?

Phil sent a picture thanks

So what was the centre boss with hole as that's not a standard core plug as Phils link.

Could the insert in the core plug be for an aftermarket water temperature sensor?
Just a thought

Paul