Classic cars forum & vehicle restoration.

Miken · Joined: 24 Dec 2012 Posts: 544

Ive recently got my 1927 Cowley back on the road after an engine rebuild where just about everything that can wear has been replaced.
I've been using it for the 10 mile trip to work and it goes very nicely.
However it does a strange thing when I first set off from home.
I live at the top of a very steep hill.
When I start up in the morning I drive about 400 metres down to the bottom of the hill where I wait to enter the roundabout and join the main road.
As I pull away it starts to emit a lot of thick grey oily smoke as I go round the roundabout then clears after about 50-70 meters.
After that its fine and doesn't do it again.
The oil level on the dipstick has hardly fallen in the 500 mile since the last oil change so im not worried (its just a bit embarrassing when there is a lot of traffic about).
Any ideas why it does this?
Im thinking that all the oil in the very long sump sloshes to the front of the engine as I go downhill and then gets splashed up the front cylinder .

Peter_L · Posted: Fri Aug 11, 2017 2:04 pm Post subject:

Does it do it when you get back from work and immediately drive back down the hill ?

I don't know the hill, but have you tried it, by stopping on the hill, both directions, and then moving off.

Miken · Joined: 24 Dec 2012 Posts: 544

mikeC · Posted: Fri Aug 11, 2017 5:49 pm Post subject:

Blowing smoke out after a descent is usually a sign of worn valve guides - the suction on a closed throttle pulls oil through the guides and then it's burned off when you accelerate at the bottom of the hill. But that doesn't explain it only occurring with a cold engine; keep an eye on it an see whether it occurs under other downhill circumstances, but it may settle down as you build up a bit of carbon in the combustion chambers ...
_________________
in the garage: 1938 Talbot Ten Airline
Recently departed: 1953 Lancia Appia, 1931 Austin Seven, 1967 Singer Chamois, 1914 Saxon, 1930 Morris Cowley, 1936 BSA Scout, 1958 Lancia Appia coupe, 1922 Star 11.9 ... the list goes on!

Peter_L · Posted: Sat Aug 12, 2017 12:53 am Post subject:

When you leave your house can you turn in the opposite direction, avoid the hill, and let it run a bit before navigating the said incline.

There is another option, move house... Laughing

alastairq · Joined: 14 Oct 2016 Posts: 1954 Location: East Yorkshire

Looks like a 'cold metal' issue?

Try starting from cold, then leaving it to idle until the 'gauge' registers? Then try the same journey, see what happens?

Might be a case of 'marginal' dimensions on the valve stems, or guides?

Possibly because the car is old, it needs that 'first fag-of-the-day'....and a good cough, before being ready to face the world? Smile