Would you describe the smoke as:
White? Water vapor -- blown head gasket, cracked head or block
Bluish? Oil smoke -- bad rings, valve stem seals, valve guides
Black or sooty? Unburned gas -- rich mixture, choke on, timing
I'm actually not familiar with the symptoms of a burnt valve, but what you
are describing seems rather more drastic than that.
on 7/6/05 3:07 PM, R. Martin Rogovein at email@example.com wrote:
> I was driving the B today, noticed it was running a little rough, esp. at
> idle -
> nothing really out of the ordinary, I thought maybe I got a tank of bad fuel
> or something.
> Then, while waiting at a light the revs started to drop (it usually idles
> smoothly around 900) and it started to stutter.
> I gave it some gas to keep it alive, and was rewarded with a white
> smokescreen that would have done James Bond proud.
> From then on it kept running rough, smoking especially while accellerating,
> and seemed to be way down on power as well, and would ping if i tried to
> give it gas too quickly in any gear.
> Oil pressure was normal and stable (45 idle, 70 at speed), temp stayed right
> at N.
> Engine has burnt oil since I got it (a quart every few tanks of gas -
> probably rings), but I always am careful to keep it topped off (checked
> today before I headed out and it was fine).
> My guess, without opening anything up to see, is a burnt valve.
> Do the symptoms fit, or do you pros have a better idea?
> R Martin
> 70 roadster
> Tel Aviv
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the primer red one with chrome wires