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Whats this Head
https://www.ausmini.com/forums/viewtopic.php?f=2&t=80557		 Page 1 of 2
Author:  MiniBill [ Sun Mar 03, 2013 8:28 pm ]
Post subject:  Whats this Head
Hi ausminians:
I'm wondering whats this head off and will it fit my 1098 and whats your opinions on it.

Cheers Bill

Here's a few pics

Image

Image

Image
Author:  SuperCooper [ Sun Mar 03, 2013 8:38 pm ]
Post subject: 
Off a 1275. Has 11 head studs as per S ,or has been drilled . Standard they have 9 studs.

Could go on an 1100 with some valve pockets cut into block.
Author:  SuperCooper [ Sun Mar 03, 2013 8:38 pm ]
Post subject: 
Off a 1275. Has 11 head studs as per S ,or has been drilled . Standard they have 9 studs.

Could go on an 1100 with some valve pockets cut into block.
Author:  SuperCooper [ Sun Mar 03, 2013 8:38 pm ]
Post subject: 
Off a 1275. Has 11 head studs as per S ,or has been drilled . Standard they have 9 studs.

Could go on an 1100 with some valve pockets cut into block.
Author:  mini13 [ Sun Mar 03, 2013 9:49 pm ]
Post subject: 
cold be a late S head or 1300gt Head,

looks like it has the 1.4" inlet valves,

get some sand paper and clean up the flat bit by the thermostat, S's and 1300 had Id stamping there.

failing that look for signs of porting.
Author:  drmini in aust [ Sun Mar 03, 2013 9:57 pm ]
Post subject: 
If it's an S head it should have 12G1805 stamped in 1/8 letters near the thermostat.
If it has 12G938 or nothing stamped there, it was probably a stock 1275 head (Oz models Morris 1100S, Morris 1300 auto, or MG Midget) and has been drilled out.
As SuperCooper said they can work good on a 1098, but you need to cut valve pockets in the block with big lift cams or rockers.
If cam is stock or a tame grind, and the valves are recessed into the seats a bit, you can usually get away without this.
Author:  MiniBill [ Sun Mar 03, 2013 11:02 pm ]
Post subject: 
SuperCooper wrote:
Off a 1275. Has 11 head studs as per S ,or has been drilled . Standard they have 9 studs.

Could go on an 1100 with some valve pockets cut into block.


drmini in aust wrote:
If it's an S head it should have 12G1805 stamped in 1/8 letters near the thermostat.
If it has 12G938 or nothing stamped there, it was probably a stock 1275 head (Oz models Morris 1100S, Morris 1300 auto, or MG Midget) and has been drilled out.
As SuperCooper said they can work good on a 1098, but you need to cut valve pockets in the block with big lift cams or rockers.
If cam is stock or a tame grind, and the valves are recessed into the seats a bit, you can usually get away without this.


Thanks guys for the info but i'm still confused .........
Call me confused :-) , now i was going to get the 1098 head decked " that came with the car " would i be better off using the 12g940 decked instead or the original that came with it ? and would i have to do a stage kit " extractors , carbs , manifold etc to make better use of it ? ...... bear in mind this is for a daily driver" would it be better" Money Wise " to deck my 1098 or 12g940 which will need bigger carbies , exhaust etc
Author:  mini_mad_matt [ Mon Mar 04, 2013 1:02 am ]
Post subject: 
Just use the 1098 head.

The 12g940 head will not fit straight onto an 1098 without doing some modifications to the block. Fitting a 12g940 onto a small bore is more of an extreme performance modification.
Author:  MiniBill [ Mon Mar 04, 2013 11:13 am ]
Post subject: 
mini_mad_matt wrote:
Just use the 1098 head.

The 12g940 head will not fit straight onto an 1098 without doing some modifications to the block. Fitting a 12g940 onto a small bore is more of an extreme performance modification.


Thanks matt , will stick with the stock one till/if i decide to give the mini a perfomance upgrade.

Thanks for all the replies guys its greatly appreciated.

Cheers Bill
Author:  TK [ Mon Mar 04, 2013 11:55 am ]
Post subject: 
The 940 head will fit on your 1098 block without mods if you use a standard cam and the head/block haven't been skimmed. You will notice a big difference using the 940 over a stock 202.
EDIT; that's if the 940 ia an 1100S type.
Author:  XC9000 [ Mon Mar 04, 2013 12:33 pm ]
Post subject:  12G940
The valves appear larger than 1100s and Mk2 Cooper S.

Was 12G940 the type used on Mk1s :?:

I recall that the Mk2 inlet valves (unsure about exhaust) were reduced in diameter - possibly to avoid craking between the two valves.

But the simple answer as already stated and you have decided is do not use this head on the 1098cc, unless you are going all out and decking the block and you are prepared to cut the valve clearances for a higher lift cam. if you are going that way I guarantee you wont be using a standard low lifting cam.

Also see this recent thread: http://www.ausmini.com/forums/viewtopic ... highlight=
Author:  Bubbacluby [ Mon Mar 04, 2013 12:43 pm ]
Post subject:  Re: 12G940
XC9000 wrote:
The valves appear larger than 1100s and Mk2 Cooper S.

Was 12G940 the type used on Mk1s :?:

I recall that the Mk2 inlet valves (unsure about exhaust) were reduced in diameter - possibly to avoid craking between the two valves.


Worked 12G2940 was mk2 Cooper S and clubman GT. 12G940 was also on morris1100S and 1300's (non worked though)

Mk 1 was AEG-163 and one of the valves (coulda been both cant remember) were bigger and it was common to crack between the valves.
Author:  drmini in aust [ Mon Mar 04, 2013 2:58 pm ]
Post subject:  Re: 12G940
Bubbacluby wrote:
XC9000 wrote:
The valves appear larger than 1100s and Mk2 Cooper S.

Was 12G940 the type used on Mk1s :?:

I recall that the Mk2 inlet valves (unsure about exhaust) were reduced in diameter - possibly to avoid craking between the two valves.


Worked 12G2940 was mk2 Cooper S and clubman GT. 12G940 was also on morris1100S and 1300's (non worked though)

Mk 1 was AEG-163 and one of the valves (coulda been both cant remember) were bigger and it was common to crack between the valves.

Yes the inlet valves on Mk1 and Mk2 S are the same size, but they reduced the exhaust diameter by 1/16" (to 1.156") for the 940 heads including S.
Note the later valves are all ~2mm longer than Mk1S ones.
Author:  XC9000 [ Mon Mar 04, 2013 7:34 pm ]
Post subject:  Re: 12G940
drmini in aust wrote:
Bubbacluby wrote:
XC9000 wrote:
The valves appear larger than 1100s and Mk2 Cooper S.


Yes the inlet valves on Mk1 and Mk2 S are the same size, but they reduced the exhaust diameter by 1/16" (to 1.156") for the 940 heads including S.
Note the later valves are all ~2mm longer than Mk1S ones.


Thanks Doc. Ever so reliable. :)

After our discussion a week or so ago (you may not remember with so many posts since then!); you were saying you can get more from a 202 than a 940. Well yesterday I bought a shaped 202, the vendor claimed it was a Waggot head. It has X2 valve springs; good even shaped chambers, well ported but I cannot remove both exhaust and inlet from No.1 chamber. others released ok. I managed to pursuade the offending valves to move about 8mm with a pursuader and a block of timber. i gave up and left them soaking in the hope that they will get easier but i doubt it somehow.

I cannot recall procedure for replacing the valve guides. Is that a common job for a workshop? Do they make them or are they a Repco etc?)

The valves can be 1/16" bigger. What is your thoughts on S/S inserts and getting bigger valves please - oh GREAT DOCTOR :?: (praise be to the Dr)

PS: If you are coming on the MITG Run Sunday I'll put the head in the boot for discussion over it...
Author:  drmini in aust [ Mon Mar 04, 2013 7:59 pm ]
Post subject: 
Yes you can get more torque (on a smallbore) from a radically modded 202 or 295 than a 940. Because, the ports are smaller and gas speeds are higher. Works great for smallbore motors.
But, this costs you time & $$$ for the porting and new parts (big valves, etc etc).
OTOH, a stock 940 (1100S) head with an hour or 2 spent deburring the insides will give better HP than a stock 295 at minimal cost.
As others have said I agree with notching the top of the block, if you are after HP. You won't get big HP with stock cams.
Torque with a 940 head on a smallbore may be less at lower speeds, however my 1220 motor was doing low 16s at Castlereagh dragway back in the late `60s. And the head was an 1100S with stock valves, double springs and a bit of basic porting.
Mind you the 544 cam and twin HS4s helped...

Sorry I won't be coming down next weekend, as I'm off to Brissy for Matt Read's 50th knees-up. :P
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