Xflow misfire when hot

[MarcNS]

Went to Bourne today for the car show and whilst trying to find somewhere to park the engine went over 80 degrees and started misfiring over 3000 rpm, it did this until I parked up.

(With the Holbay cam it normally stutters below 3000 rpm then goes!)

It ran home to Stamford with no problems but never got to the same temp.

Any thoughts as to what to look at first?

 

[virden]

An air lock causing a hot spot in the head?     My X/F is very sensitive to airflow, on the move the temp stays around 80c, as soon as I stop even just waiting for the traffic lights, the temp will climb.  I have fitted a manual over ride to the fan switch which helps.

[Andrew Gilbert]

when mines hot it can do this but after a few minutes it seems to clear, I believe its something to do with my carbs being a little too tight to the manifold allowing it all to froth a little, now since loosened. Although I too have a misfire problem that only happens when on track.

1st few laps all's fine but come the 3rd or 4th it develops a mis then it misfires badly for about 30 secs but then clears when cooled, go out again and the same scenario. So now have replaced the dist cap and rotor plus leads coil and now will be doing the fuel pump, the only other thing I can think of is as pointed to in the latest low flying, the alternator wiring. So thats next. On normal driving all is well? 

[MarcNS]

I have a new coil on order as a spare and a boot full of spanners so will see how it goes to and at Throckmorton.