Smoke

[MikeMcD]

I have a 1970 Spitfire that smokes. The car had set in garage for several years before I bought it. I have been told this is probably dry rotted valve seals. The smoke doesn't start until the engine gets hot. This seems more like leaky rings. Any thoughts?

 

[tomgt6]

I had a car that fogged the neighborhood, smoke out the tail pipe, smoke out the oil fill cover, smoke out the crank case vent tube, and when I took the engine apart it was all rings. I had broken rings and damaged pistons. It is hard to say but you may have stuck rings and you can try to loosen them by putting some marvels mystery oil in the cylinders and let it sit for a couple days.

Also what color smoke is it. Could it be antifreeze burning off?

Time for compression and leak down test.

 

[Andrew Mace]

Unless someone added them (possible, but not very common), Spitfires don't have valve stem seals. I'm with Tom; rings could be stuck, or they could be bad. See if you can free them via the MMO as Tom suggests, and then maybe give the engine a bit of time to 'bed in' again after that long rest. Possibly, things will work out; more likely, you're looking at some level of overhaul.

 

[MikeMcD]

I guess the smoke is white, maybe a little blue. Definitely not black.

 

[Roger]

White smoke suggests a head gasket leak, or water getting into the combustion somehow. Since this only happens when hot, it's not the normal condensate you get when starting an engine. I'd suggest a cooling system flush and pressure test, or even just watch the water with the cap off and see it you're getting little bubbles when it's hot.
Blue is oil burning off, but if there's only a little it could be guides or rings.

 

[Silverghost]

White = water? Internal condensation from sitting so long, turns to steam at temp (noting it was said only happens when hot) carries a little oil with it (thus the slight blue) ?