Morris Minor Owners Club

Hi All,
Need a bit of advice, I have a 12A 1456 cylinder head (which I beleive is for a 998cc?) and a 1098cc block - are they compatible?
Cheers
Lance[frame][/frame]

Hi Lance,

Wouldn't recommend it at all. The 1456 head is from a 948 cc engine and has a round port in the intake rather than the usual square port. The inlet valve is 1 1/16in as opposed to 1 5/32 (or 1 and two and a half sixteenths) and you need as big an inlet valve as possible. The smaller valve will reduce the power available quite considerably and for the price of a secondhand compatible head, it isn't worth it. Ideally, you need a 12G295 head from a mini cooper as this will increase your hp and torque quite considerably as the size of the inlet valve goes up another sixteenth over the standard 1098 inlet valve. All these sixteenths add up when you are running an engine which is measured in thousandths of an inch!! Have a look and see what's on e-bay.

The standard 1098 head is designated 12G202.

What sort of inlet manifold do you have? I'm not sure if the 202 and 295 are compatible with the 1456. Hopefully someone else will know.

Hope this helps.

Chris

The head will fit - and will actually give you a slight increase in the compression ratio - and if you are looking for best economy and not too bothered about some performance loss - use it! A 295 head is great - unfortunately usually close to £100 (or more!) these days - and often well worn and needing some considerable care and attention. If not already skimmed - it also needs a good 60 thou off to get the right comp ratio on a 1098 engine. Best head by far is the 940 head - from the 1275 engine. Much bigger valves and raised compression ratio too - without any skimming. If using that 940 head - you may need to sink the exhaust valves by 40 thou into the head - but often even this is not necessary. If going that route - come back to us for more detailed advice.

What sort of inlet manifold do you have? I'm not sure if the 202 and 295 are compatible with the 1456. Hopefully someone else will know

Yes they are. However using the standard manifold on a 295 head would not be getting the best out of it. A budget purchase option would be the Mini 1000 manifold which will allow the fitment of a 1.5" carb and will mate to the rest of the Minor exhaust system. If you are prepared to pay a bit more you could consider removing the inlet part of the casting and fit a alloy aftermarket inlet for a 1.5 carb (for example: http://www.ebay.co.uk/itm/Mini-Alloy-In ... 35b3f48d61). pay a bit more and you can combine this with a oversized exhaust system.
You pays your money...as they say.