Is there a definitive guide to cylinder head numbers?

[The vast minority]

Simple question,
Where will I find a guide on casting numbers for 1098 and 1275 heads?

Amongst other stuff, I've got a Peter May big valve cooper S in the box, that has extra holes emerging close to the rocker cover presumably for extra studs to pass through. I'm keen to ID the base head.

Also, any guide to engine numbers greatly appreciated.

Im new to A series engines but won't be for long ;)

Thanks
Al

[les]

12a185 mk1 S. Aeg163 mk1 & mk2 S. Later replacement for S ----12g940.

[bmcecosse]

Let's see pictures of the S head !

[The vast minority]

Thanks both
I'll take a pic on the morrow and post it here.
Cheers
Al

[philthehill]

http://mgaguru.com/mgtech/engine/be100.htm

http://www.calverst.com/articles/ch-cyl ... _%20no.htm

The Vizard book on 'Tuning The 'A' Series' has similar information regarding the identification of 'A' Series heads.

As regards the 11th hole just behind the thermostat housing - the bolt (not a stud) should only be torqued to 25lb/ft as the top of the block is quite thin in that area and if over torqued can break out of the top of the block.
Note: 1. The bolt may have been converted to stud but still only torque to the reduced specification/torque as the same risk still applies.
Note: 2. Not all 11 stud heads are Cooper 'S'. The 10th and 11th holes can be easily drilled through any 940 head as there are internal cast pillars that allows the drilling of the extra holes.
My own 940 head has had the two extra holes drilled and the front bolt converted to a stud.
Phil

[The vast minority]

Many thanks all
Here are pics, it's defo a 1275 cooper s, it's a 12G940 stamped up 2g1805 with a big S

Double springs,
The real deal.

Can't post pics, system failure
Al

[les]

The aeg163 head was inclined to crack, and when I had this problem I searched high and low to get a replacement, even getting the bmc dealer to look further afield but unsuccessfully. The only head then available was part number 12 g 1805, being casting 940, whIch I had to settle for but I did have many more years without any problems? Think I've still got the receipt! Unfortunately not the S.

[jagnut66]

Hi,
Hopefully this question isn't going totally off topic:
Is there any way of finding the engine number when the plate, usually rivetted to the top of the engine, just in front of no. 1 spark plug, is missing? Is it stamped anywhere else for example?
My main, numbered engine, has been out awaiting repair for a while and my spare engine is now fitted, or will be refitted once I finish fettling a replacement gearbox but this has lost it's ID plate (before I bought it) and I was wondering whether there might be a way of finding its number.
If not can I get it issued with a replacement number from the DVLA??
Or am I just inviting trouble involving them, now that the 'human' element of local offices have been removed??
Many thanks,
Mike.

[MrIan]

Many thanks all
Here are pics, it's defo a 1275 cooper s, it's a 12G940 stamped up 2g1805 with a big S

Double springs,
The real deal.

Can't post pics, system failure
Al

Well my cylinder head has the 11 studs/bolt, large valves with twin springs very large area near the thermostat, is casting 12G940 and stamped 12G1805S which I've found it is from an Austin 1300GT. I too thought it was an S but apparently not.

[les]

Hi,
Hopefully this question isn't going totally off topic:
Is there any way of finding the engine number when the plate, usually rivetted to the top of the engine, just in front of no. 1 spark plug, is missing? Is it stamped anywhere else for example?
My main, numbered engine, has been out awaiting repair for a while and my spare engine is now fitted, or will be refitted once I finish fettling a replacement gearbox but this has lost it's ID plate (before I bought it) and I was wondering whether there might be a way of finding its number.
If not can I get it issued with a replacement number from the DVLA??
Or am I just inviting trouble involving them, now that the 'human' element of local offices have been removed??
Many thanks,
Mike.

I don't think you will find the number, and dvla might get hold of the wrong end of the stick if you involve them. Why don't you use the number from the numbered engine you have, if you eventually put that one back, then reinstate its number. You can only use one engine at a time! There are numerous engines that have lost their id over the years, it doesn't appear to be an issue any more.

[philthehill]

The 12G1805S 11 stud head was used on other transverse engine 1300cc engines including the Riley 1300 as pictured below.

http://www.bing.com/images/search?q=bmc ... ay&first=1

At first glance it appears to be a Cooper 11 stud 'S' head but looks can be deceptive.

[The vast minority]

Many thanks all
Here are pics, it's defo a 1275 cooper s, it's a 12G940 stamped up 2g1805 with a big S

Double springs,
The real deal.

Can't post pics, system failure
Al

Well my cylinder head has the 11 studs/bolt, large valves with twin springs very large area near the thermostat, is casting 12G940 and stamped 12G1805S which I've found it is from an Austin 1300GT. I too thought it was an S but apparently not.

According to this, it is from the Austin 1300 and the cooper S[frame][/frame]

[les]

MrIan, I think you will find the head you mention was fitted to the mk3 S also. By the time that mark was introduced the S was a shadow of its former self!

[philthehill]

http://www.ebay.co.uk/itm/Mini-COOPER-S ... 23568283e1

Put up the link as there is a photo of the 12G1805 stamp.

[The vast minority]

http://www.ebay.co.uk/itm/Mini-COOPER-S ... 23568283e1

Put up the link as there is a photo of the 12G1805 stamp.

Blimey, that's fit for scrap

[bmcecosse]

The 940 version of the S head doesn't have the larger exhaust valve of the 'real' S heads. In fact - it's no different to any other 'large inlet valve' 940 head - except for the 11 holes. Strange that the Turbo head was NOT drilled with the extra holes - not deemed necessary, even though this is the highest power A series from the factory. However, if this is a modified head - it's always possible the valve guides have been repositioned to allow fitment of ever larger valves. An accurate measure of the valve head diameters will tell all.

[jagnut66]

I don't think you will find the number, and dvla might get hold of the wrong end of the stick if you involve them. Why don't you use the number from the numbered engine you have, if you eventually put that one back, then reinstate its number. You can only use one engine at a time! There are numerous engines that have lost their id over the years, it doesn't appear to be an issue any more.

Thanks Les.

[The vast minority]

The 940 version of the S head doesn't have the larger exhaust valve of the 'real' S heads. In fact - it's no different to any other 'large inlet valve' 940 head - except for the 11 holes. Strange that the Turbo head was NOT drilled with the extra holes - not deemed necessary, even though this is the highest power A series from the factory. However, if this is a modified head - it's always possible the valve guides have been repositioned to allow fitment of ever larger valves. An accurate measure of the valve head diameters will tell all.

Thanks Roy
It's purported to be a Peter May race head, in the box with the build number.
That's the key here I think.if it's what has been claimed, it's not a standard head.
One day I Shall measure the valves, today I've got to unload 3 engines and put them in stock.

[philthehill]

I understand the original question to be about identifying the base head quote "I'm keen to ID the base head" unquote which is what this thread has tried to do.
That the head has been modified is irrelevant to that question.

[The vast minority]

I understand the original question to be about identifying the base head quote "I'm keen to ID the base head" unquote which is what this thread has tried to do.
That the head has been modified is irrelevant to that question.

One cannot argue with your logic sir, your absolutely right.