Mysterious Engine Failure - Ideas, please

[Graham Barker]

My 1937 Ruby on a recent run: the engine coughed and misfired to a standstill after about 8 miles.  Checked carburettor jets at roadside and found them clear. Restarted motor which was still hot but it coughed and misfired to a standstill after about a minute.  So got tow truck home.
Drained petrol tank - a little rust powder came out. Blew back through fuel line and it was clear.  Dismantled fuel pump and interior was clean - I had overhauled it with new diaphragm 12 months ago. Incidentally there is a cartridge type fuel filter between the fuel pump and the carburettor. Checked this and found that it blows through quite freely. Manual prime with fuel pump worked well.  Engine started fine so went driving, but it coughed and misfired to a standstill after about 2 miles.  Tow truck home.
Replaced ignition contacts engine ran for a few seconds then coughed and misfired to standstill.
Replaced coil, condenser, distributor cap and spark plugs with successive tries at starting the engine.  By the end of this process the engine will not run at all - only a misfire or two.
Battery has been checked and found healthy and had it fully charged during these latest tests.
Any ideas on what to do next?

---

On further reflection, I realise that I fitted the new contact points before the engine troubles began.  I set the gap to 12 thou and it is still at least 10 thou.  The old points were set to 25 thou.  The distributor spindle has a little play.  Would it be possible that setting the gap to 12 thou has brought on the trouble considering some spindle wear?
Any comments gratefully received.
Graham

[David Stepney]

It is worth setting the points to a wider gap to see if the problem goes away, but, from the symptoms described in your other thread, I would have a look at the fuel supply as well.
I had a worn distributor bush on my car when I first had it, and this gave rise to an intermittent misfire, especially when pulling hard, but it didn't give rise to an involuntary stop on the road.

I bought a rebuilt distributor off Ebay and that cured the misfire. I subsequently had my original distributor rebuilt by the same person who sold it to me and keep that as a spare.

It is probably worth getting your distributor overhauled as a worn spindle bush can give rise to all sorts of mysterious poor running.