8 replies to this topic

[spud]

Hi All,

I am in the process of looking for a mini. As I see it I have one main concern - when looking at the 1275 early nineties models, is there a big difference between the 'standard' 1275s and the Cooper 1275s? If so what are the differences?

I have learned that the standard ones are higher economy and lower power output but is there a big difference?
My other option is to get a 998 model and then drop in an engine of my choice
Cheers,

Spud.

[AlexM]

the 'standard' 1275's used a HIF38 carb and the coopers used a HIF44, i believe the inlet is diffrent too (i know the air boxes are different. The compression ratios are different as well with the coopers being 10:1 and the others being something like 9.4:1 The cam is milder on non coopers.

Its negligable really, buy the mini in the best possible condition you can find, if you are taking out the engine anyway then its not much issue. The only thing with 998's is that some didnt have rev counters.

[spud]

Thanks for that!

Are the valve sizes different too?

Could a standard head be skimmed to match the Cooper compression ratio?

Many years ago I had a 1275 engine in a mini (believed to be from an Austin 1300GT) which had 11 studs! But I can't remember for the life of me what was special about it. Can anyone refresh my memory?

TIA

Spud.

[AlexM]

11 stud heads were on the cooper S model is the 60's although many machine shops sell built engines with this modification.
I believe you are right about the head being different too, I'm sure skiiming the head could be done to match the compression ration but its not a huge factor in performance, and as modifying the engine beyond cooper spec would be a better idea.

[mini25]

so did coopers from the 90s not have the extra stud??

[Guess-Works.com]

no, the A+ 1275 engines were nothing like the original 1275 cooper ( 1300 GT or 1275 GT ) performance wise they are basically metro engines, with the 90's cooper getting something like the last MG metro engines. However, they do make a good basis to build a decent performance 1275 from.

Unleaded 1275's have smaller inlet valves than the unleaded. ( see the FAQ on heads )

[Retro_10s]

did the coopers have differenet rocker gear too??

[AlexM]

did the coopers have differenet rocker gear too??

I don't think so...

[minivanman]

maybe the JCG 90 bhp kit did have different rockers, they had a fair bit of fancy stuff.