Mini cooper/Mg metro turbo heads

[youngun]

Which is the best option to fit to a standard moggy 998 A series and what other mods will be needed to ensure i dont lunch the engine, i.e. crank balancing, hardened valves etc etc
Does the metro turbo head fit?

thanks

[bigginger]

I *think* the 998 was a Mini engine. Mogs were/are 948 or 1098 - but there are plenty of people here with masses of things to do to them

[wanderinstar]

As already said, the 998 is a Mini engine. However most Mini tuning bits will fit a 948 or 1098 engine. The 998 Cooper head being the easiest to fit. Same size bores, so does not need block pocketting or valves sinking in head. However it will need about 080" taking of head, to keep compression acceptable.

[bmcecosse]

But most economic modification is to fit the 12g940 head from a standard 1275 engine - NOT the turbo head (these are quite valuable in their own right because of the sodium coolled exhaust valves). To fit this head you need to sink the exhaust valves into the head by 40 thou (easy 10 minute op for any machine shop), file a bit off the top edge of the water pump - and use a 1275 head gasket. Also either use the 1275 rockers - or re-arrange the rockers from the engine so they act directly on the now slightly re-positioned exhaust valves. This head (often ~ £10/20 on ebay) needs no skimming. A larger carburettor (HIF 38 SU and MG Metro inlet manifold) is needed to make use of the newfound breathing capability of the engine. Power should go up to ~ 60 bhp on a 1098 - say 55 on a 948.