12g940 casting water jacket holes
Turbo Mini Forums

We all know the issues of keeping a turbo engine in our mini’s cool, and we are all aware of the various mod’s about for improving engine cooling.

But! And this is a big but. Why are the eight water jacket holes at the back of a 12G940 head of a smaller bore size than those in a 998 head.

And why have all but three of the 14mm/ 9/16 diameter water jacket holes at the front of the head and between the combustion chambers been restricted or blanked off, where as on the 998 heads all these water jacket holes are open.

Number 4 cylinder is the most at risk from excessive heat build up plus the water take off point has been left un drilled to further exacerbate the problem. Like most I have opened this tapping and modified my water system to suit.

Can anyone see or offer a reason why these other holes should not be opened up.

I admit to not having looked at the corresponding blocks to see if the deck had been drilled so the water ways continued down into the engine core.

Edited by Mr Joshua on 16th May, 2009.

Own the day

these little mods are to force the water to go in the back of the block and then around the fourth cylinder . 998 being less touchy about the cooling these tricks haven't been used.

I presume its something to do with keeping the flow in various areas

I was looking at an 1100 engine the other day and the three big water jacket holes are different sizes which i thought was quite a good idea

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