6 replies to this topic

[Kaison]

Model: Rover Mini Sprite 1275
Year: 1992
Description of problem (please be as in depth as possible):
Well, the previous owner told me that the car has a metro head which he also said is the equivilent to a stage 2 head?
Just wanted to know how I can check that and also how I can identify what heads they are for future reference.



Any non-standard parts that might be involved with the problem? Apparently it's got a metro head.
It has a fletcher lcb and that's all you need to know

Edited by Kaison, 25 September 2010 - 11:54 AM.

[Asphalt]

If you take off the rocker cover, there's a number on the head. Probably 12G940, which is a 1275cc head.

The thing is: about any 1275cc head that's not of a Cooper S Mk1/Mk2 has this very same number. And there are quite a lot of differences between those heads! The most obvious difference is between A and A+ (1980 onwards) heads:

The top head is a A, the bottom one is a A+ head:



Metros all got A+ heads. And then there are two different A+ Metro heads: smal and big valve heads. Smal = 33mm inlet valves, big = 35mm inlet valves. To check this, youneed to take off the head and measure a valve.

The next important point is: there is no such thing as a 'Stage 2' head!!! What tuner A sells as 'Stage 2'is another guys 'Stage 7.5' and so on... There's NO fast rule of what a 'Stage 2' head is... It's a bit of a very useless information. So the seller might be right or not - since there's no fast rule... Tricky, hey?


Head Casting numbers:

2A628 - 26.162/25.4 - 24,5 - 848, 998, 948 Sprite
2A609 - n/a - n/a - Smalbore closed chamber
2A629 - 26.162/25.4 - 24,5 - 948, A35, A40 und 1098 Morris Minor (open chamber?)
12A1456 - 26.162/25.4 - 24,5 - 848, 998, 948 Sprite
12A1458 - 26.162/25.4 - 24,5 - späte 848, 998
CAM4810 - 26.162/25.4 - 25,5 - 998 A+ (unleaded from 1988 onwards)
12G202 - 29.464//25.4 - 26,1 - Cooper 997, 1100
12G206 - 30.988/25.4 - 28,3 - Cooper 998, MG1100
12G295 - 30.988/25.4 - 28,3 - Cooper 998, MG1100
12A185* - n/a - n/a - Smalbore, similar 12G206 (pos. Formula Junior)
AEA626 - n/a - n/a - Formula Junior & Formula 3, 'S' Type (large bore, open chamber), f. XPS engine
AEG305 - n/a - n/a - Formel 3, XPS engine
AEG136 - 35.56/30.988 - 21,4 - Cooper S MkI/MkII
12G940** - 33.274/29.464 - 21,4 - 1300, 1275GT, plus A+ incl. Turbo
12G940** - 35.56/29.464 - 21,4 - MG1300, 1300GT, Cooper S MkIII (MkIIIS stamped 12G1805) & MG Metro (A+)
12G939 - n/a - 21,4(?) - 1275cc w/ Emission Control System, Healey Sprite MkIV, MG Midget MkIII, Austin America
12G1316 - n/a - n/a - 1275cc w/ Emission Control System, 1275LS, 1275 Moke (Australia)
12G940 + Stamping 12G938 - 33.274/29.464 - 21,4 - Morris 1100S (1275cc!) and 1300 Automatic (Australia)
(LDF105800 - 33.274/29.464 - 21,4 - MPI) - not confirmed yet!

Edited by Asphalt, 25 September 2010 - 11:18 AM.

[Kaison]

Thank you - that's VERY helpful!

By your picture and detail, it's an A+ head small valve head - 33mm
I just can't read the casting number! I assume it's the "blob" on the far left of the head in the picture.

Any other way of reading this?

[Guess-Works.com]

The casting number is between 4 and 5 pushrod holes

[Kaison]

Okay - I'm a little worried. . . it's be ground off.
All I can see is 12**4* - That might not be correct but that's all I can make out. . .

Does this mean it's stolen or could it just be where it's been skimmed?

[Jordie]

12G940 = 1275 head

Theres no engine id numbers on the heads, so you wouldnt expect the number to be destroyed if its been stolen etc.

[ukcooper]