M20 500cc Twin Cylinder Heads

[CR]

quote: To CR, checking the JSL list I find P/N.018890 Metering Jet Cylinder Head Oilways. Is this the correct part?

As far as I know JSL only sell the one metering plug and 018890 sounds like it.

Tap then in with a soft drift. I measured the holes before I fitted them and checked after. They'd closed a bit - but not enough to worry about. Sorry I can't remember detail of sizes, it was a while ago.

Compared to many marques (e.g Triumph - who take a dribble for the rockers via a T-piece in the return to the tank) the AMC twin rockers were never knowingly under-oiled. On the contrary.

I'd plug 'em and forget 'em. Just check once after re-assembly that the rockers are getting wet and don't worry. It can take quite a while for the oil to find its way up there after re-assembly, especially at tickover speed. Don't be scared to squirt them with oil and go for a good long run. It's only when the pressure comes up that all corners get good and wet.

I once ran a twin without rocker oiling for 900 miles (don't ask - it was in the days when I trusted others to reassemble my engines) and had absolutely NO damage.

Hope this helps.