4 replies to this topic

[R32Egor]

What are the standard valve sizes for 63ps HC SPI mini?

[Midas Mk1]

Haynes manual?

[R32Egor]

Yes got it🫣

[R32Egor]

Ok I have the 12A2E engine in the high compression cooper 63HP SPI mini 1996

I am getting different valve sizes from different sources

Haynes says 35mm inlet 29 outlet
Internet says 35mm inlet 29mm outlet

Mini sport says 33mm inlet 29mm outlet

I want to know to see if there is any point in purchasing a stage 3 head or just getting mine modified if the valve sizes I have are the same as a stage 3 head.

Obviously I can take the head off and measure but I would prefer not.

Thanks Jason

[bluedragon]

According to Keith Calver Identification by casting number

 

"Number Inlet dia. Exhaust dia. Nominal cc Standard fitment 

 

12G940* 1.312"/33.33 1.15"/29.2 21.4 Single point injection, also numbered 

12G940B cast into head at clutch end "

 

 

DLY

Edited by bluedragon, 20 March 2026 - 09:50 PM.