Smiffy wrote:
drmini in aust wrote:
Early S heads 12A185, AEG163 often used to crack between the valves because there is SOLID metal there between the exhaust and intake ports. Heat can't transfer into the water easily, so head expands there and cracks.
They fixed this problem- the 12G940 heads bring the water jacket down closer to the valve seats.
But the !2G295 is really an antique head- they came out in 1963 or so. And they are similar to the early S head in so many ways. I doubt 940 style improvements were ever done.
Yes, I have seen one cracked there.

Early 'S' heads used to crack between the valves because there was hardly any metal there. Afraid you just clutching at straws now to try and prove yourself right here, if it was easier to post pictures I'd sow you what it actually looks like in this area, because it is obvious you haven't actually seen one by that last statement

The 295 has more in common with the 940 casting than anything else, but witha good 4-5mm between the valves.
Mate, I am talking about the water jacket in between the valves, I know there is more solid metal there in the chamber between valves on a 295, but cooling in there is a problem as it IS solid.
Anyhow by the time racers have finished fitting big valves (eg 1275) in a 295 there is less metal there than you say.
BTW I've seen early S heads cut up, 202s, a 295, and a 940....
<edit> hey, I'm not saying the 295s all crack there like early S ones tend to, only that they have been known to crack in the heat of competition..
But if ya got `em, run `em...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.
