Vented or unvented fuel filler cap?

[justin131]

Hi,

I'm a recent owner of a UK registered 1964 3.8 etype FHC on 38,000 miles (not wholly substantiated). I wondered if I should be using a vented or un-vented fuel cap. Looking through the service history of the car, there has been a petrol smell issue for many years.

There was also a strong fume smell which I resolved by connecting the engine breather pipe to the carb back plate!! I'm getting a lot of smoke from the engine breather but no blue smoke from the exhaust. What's the likely cause of this - I'm guessing valve guides??

Many thanks,

Justin.

[iRS]

Hi Justin,
I'm pretty sure the tank should be vented. I've had a look at my fuel cap and I can see a vent hole.
As for the crankcase, then I would suspect rings - though I think these engines normally wear guides sooner than rings. Also its not uncommon for them to have a slightly smokey exhaust, so atc least yours is good there. I would suggest a leak down test.
Hope this helps.

[justin131]

That's great - thanks.