18 replies to this topic

[MrIan]

Brain picking time everyone. Many years ago I was given a mini off of a mate that ended up getting scrapped, however he assured me it was a cooper S 1275. It was an external hinge mini with discs and cooper reverse rims. Car was scrapped but I kept the engine. I had it rebored years n years ago when it was stripped and have at the moment lost the id tag (was removed when rebored but I will have it).

 

Engine had twin SUs (with the black filter box for both of them).

Block is casting number 12G1279

Head 11 stud twin springs casting 12G940

Crank casting number 12G1817

 

I don't think for one min it's a cooper engine, i'm thinking maybe Austin 1300GT

Anyone have any info to help?

[62S]

As you suspect, it is definitely not a Cooper S engine.

 

Not all 1300 engines with twin carbs were high compression units but if the block is drilled for the 10 studs and one bolt cylinder head it will be from an MG 1300/Riley 1300/1300 GT.

[MrIan]

Blimey I can now see why going by casting numbers isn't a foolproof way to establish anything for sure anyway. Just had a quick look on Ebay at A series 1275 heads and found someone selling a 12G940 head, so the same casting number as mine. Looks nothing like my cylinder head, it's smaller and thinner than mine in the thermostat area and it hasn't got the extra stud and bolt holes. Yet 12G940 is cast into the head as it is on mine. !!!!!

I know for a fact mine hasn't been modified.

So really 12G940 doesn't mean anything specific ?

It's all fun eh ?

[Spider]

Blimey I can now see why going by casting numbers isn't a foolproof way to establish anything for sure anyway. Just had a quick look on Ebay at A series 1275 heads and found someone selling a 12G940 head, so the same casting number as mine. Looks nothing like my cylinder head, it's smaller and thinner than mine in the thermostat area and it hasn't got the extra stud and bolt holes. Yet 12G940 is cast into the head as it is on mine. !!!!!

I know for a fact mine hasn't been modified.

So really 12G940 doesn't mean anything specific ?

It's all fun eh ?

 

 

There 7 different 12G940 Castings that I've come across so far, all for 1275 engines, but very distinctive differences in the castings.

[MrIan]

Cheers for the info

[nicklouse]

As you suspect, it is definitely not a Cooper S engine.
 
Not all 1300 engines with twin carbs were high compression units but if the block is drilled for the 10 studs and one bolt cylinder head it will be from an MG 1300/Riley 1300/1300 GT.

Sorry not true.
Anyone could have and do machine blocks to suit. And at this time it is not that easy to tell if the engine is as it left the factory.

[MrIan]

Just checked the con rods to find casting number 12G1298/9.

[62S]

You have got the crank and rods from a 199 engine which is a high compression 1275cc unit from before the 1300GT was launched. As mentioned above it was fitted to the MG 1300 and Riley 1300.

 

Now, not that it really matters either way because your crank and rods do go together but, as Mr Louse is keen to point out, he is not located in Yorkshire and these parts may not have left the factory at the same time in the same block as you have.

 

8G199 later became the Goldseal engine number prefix for a 1300GT unit but that engine had the more common 1505 crank.

[MrIan]

Thanks everyone for all the info, as I said on another thread I just hope I can get the engine back into a running unit with all these original parts, block will have to be honed or maybe even rebored and skimmed due to surface corrosion, the crank will need a regrind for the same reason (as long as it's not too deep), I've not as yet found a number on the camshaft and that too will need a good clean before it'd go anywhere near an engine again. This is the trouble when you strip an engine get it rebored and then leave it in bits (even though all parts were wrapped in paper then put in plastic bags) for around 30 years in an old garage. !!!!!

[carbon]

Blimey I can now see why going by casting numbers isn't a foolproof way to establish anything for sure anyway. Just had a quick look on Ebay at A series 1275 heads and found someone selling a 12G940 head, so the same casting number as mine. Looks nothing like my cylinder head, it's smaller and thinner than mine in the thermostat area and it hasn't got the extra stud and bolt holes. Yet 12G940 is cast into the head as it is on mine. !!!!!

I know for a fact mine hasn't been modified.

So really 12G940 doesn't mean anything specific ?

It's all fun eh ?

Have a look on the top face of your head, there should be a number 12G1805 stamped just next to thermostat housing

[MrIan]

Yes there is 12G1805 there.

[carbon]

That's good, you have the correct head for a 1300GT unit.

 

If you have the crank accessible have a look on the webs between cyls 3 and 4, you may see that the original casting number has been ground off and another number has been stamped on the crank.

[MrIan]

Yes correct again, from my post above it has12G1817

Stamped but original has been ground away.

[carbon]

Correct crank for a 1300GT unit, tuftrided.

 

If it's still on std/std don't regrind unless absolutely necessary.

[MrIan]

It'll have to be reground I recon due to surface rust as it's been in pieces for absolutely years n years. I hope it's not scrap.