beware the 1275 head conversion?

[chrisryder]

I fitted a 1275 head on my 1098 engine last February, and have just taken it off for the 2nd time. This time for good!

I'm going back to the 1098 head. Fun as the 1275 head was on the 1098, it's not really suitable for MY engine.

On a 1098 head, there are open waterways that don't correspond to anything on the block (just from casting I assume). In use, water sits on the top of the block and makes nice little rust patches. Whilst she still had the 1098 head, this happened on Bluey, rather badly. But is of no consequence with that standard head.

The 1275 head requires a 1275 gasket, and that gasket happens to sit just on the edge of the crater in the top of the block. So that's what's been giving me issues.

A shame, as I spent a fair bit of time and money on rebuilding that 1275 head, but I'll save it for when I build the 1275 for Monty.

I'm not saying there's a problem with all 1275 head conversions, there just was on mine. Something to be mindful of if doing the conversion yourself.

[John.n]

I would guess the corrosion is from a lack of antifreeze. thanks for the tip as I am currently changing to a 1275 head.
Regards,
John

[rayofleamington]

when doing this on one of my 1098's I had to use the 'wrong' headgasket due to this exact issue (i.e. the 1275 headgasket leaked water - very frustrating!)

I managed to find a 1098 gasket where the cylinder compression rings were just big enough to suit the head and that worked well. This was in the very early 90's when people still worked on engines more regular than now.. Therefore there were a multitude of gasket sets available.

[bmcecosse]

What was the problem?? Did water run out - or are you just bothered about the 'rust' marks??? This conversion is used extensively by the 998/1098 Mini lads with no problems reported - my own has been on my engine now for at least 6 years without the slightest loss of water (or any overheating). Did you use a 'copper' head gasket ? The increase in power is the best value for money performance improvement you can make on a 1098! I assume you had filed down the top edge of the water pump to let the head sit down on the block.............

[chesney]

http://morrisminorowners.co.uk/sutra875 ... ght=#87576
Bit more info BMC.

[bmcecosse]

Thanks Chesney - been away on hols with v poor internet, so only had time for v quick glances at the MMOC forum... So clearly the problem is a faulty block... Could be filled with braze I suppose, but yes - probably better to just find a good block.