cylinder head compatibility?

[beanpole]

Which Mini head do I ask for at the scrapyard to ensure a straight swop for my 1098 Minor (F reg) ?

Steve

[picky]

the 12G295 head from the mini cooper is a straight swap and gives a good power increase. If you find one it is unlikey to be suitable for unleaded fuel though. a later 12G940 head from an MG Metro 1275 will be unleaded, but you may have problems with the valves hitting the block.

[wanderinstar]

I have a 295 head minus inlet valves and also the rarer 206 head which is complete. This was fitted to the early MG 1100. See Parts for Sale.

[beanpole]

I suspect the Mini 1275 will be like rocking horse S**t to find, so will a standard mini 1000 head fit ?

St4eve

[rayofleamington]

The 12G940 head isn't that hard to find, although not as common as other heads.
The 12G295 is a very very rare find in a scrapyard (close to impossible unless it is a mini breaker!)

[bmcecosse]

Standard Mini 998 head will fit - but it has smaller inlet valves so will lose a bit of power. The head for your 1098 is the 12g202 - very common lots of them about - slightly bigger inlets than the 948 head (and the Mini head !). The 206 or 295 head is the one to go for - however unless it has been skimmed already it will need about 80 thou taken off to raise the compression ratio - this will be slightly higher than standard which is worth a bit more power and economy. The skimming won't cost a fortune and will make sure the head is nice and flat. I think wanderinstar has heads for sale at the moment. If you go for the 1275 Mini head (12g940) it is the best head around - however the exhaust valves will hit the block (some say they get away with this - I don't like 'getting away' with things. So you can either grind little pockets in the block under the valves OR sink the exhaust valves into the head by 80 thou - which is not perfect for airflow but much easier than pockets. You also must use a 1275 head gasket and re-arrange the rocker gear so the exhaust rockers act directly on the valves. Rover cheated horribly on this with the later sintered rockers - these are so wide they still hit the valves, but well off centre ! Send me you email addy and I will send you pics of the head like this i have just done. A good advantage of the 940 head is that it does NOT need skimming on a 1098 engine. So for easy fitting - 206 or 295 - they are virtually identical - only difference i know is lack of location ring grooves on the inlet ports on the 206 head.

[rayofleamington]

some say they get away with this - I don't like 'getting away' with things.

The don't 'say' they state it as fact - If the seats are well sunk already (as is sometimes the case if the valves have been ground a couple of times) then the valves clear the block. Hhowever the head needs to be checked, you shouldn't just stick it on! If the valves/seats are in nominal condition then you will need to either sink the seats or pocket the block.

[bmcecosse]

I have to be careful what I say in case someone comes back and blames me for their ruined engine ! (I get enough hassle on here already). I made the measurements and the exhausts really do need to be sunk quite a bit for there to be clearance . Even then - I think it is still only a very few thou that are stopping the valves banging the block - could be just a thick head gasket giving the clearance ! So my firm advice is that it WILL NOT FIT without modification to the block or the ex valve seats. I decided 80 thou sinking would give me good clearance - and still hold my compression ratio at a worthwhile figure without skimming the head. BTW - a 206 or 295 is NOT a straight fit on a 1098 engine - the combustion chambers are bigger and so the compression ratio will be down. So these heads DO need skimming before they are worth fitting.

[beanpole]

This may seem daft, but how do I tell which head I am looking at ie 12G940, 12G295, 12G206 etc. ?

Steve

[bigginger]

It's cast into (onto) the head, just under the rockers.

[bmcecosse]

Casting number on the top surface - under the rocker cover. Seriously - get in touch with Wanderinstar and grab his 206 head from - they are hard to find in good order these days. Check if it has already been skimmed - heads were all 2.75" thick when new - and if not get it your local machine shop and have 80 thou off the face. De-burr the edges, grind in the valves - and you will have a useful improvement in performance.