Mini. What is the reason for smoke coming out of the oil filler hole

elvis221, Oct 31, 10:25pm
What is the reason for smoke coming out of the oil filler hole.
morrisman1, Oct 31, 10:32pm
blocked crankcase ventilation and the blowby from the rings has to come out the oil filler!
elvis221, Oct 31, 10:50pm
Where is this located ! will it unblock it self, if not how do we fix it.
smac, Oct 31, 10:56pm
elvis221, presumably this is the same engine that you'd already figured out has stuffed rings!

Blow-by is the term used to describe the cylinder pressure blowing past the rings, into the crankcase, pressurizing it. With pressure down there, it has to go somewhere; if you don't have adaquate crankcase ventilation elsewhere then yes it can cause smoke/vapour/oil to blow out the filler hole.

However, given that this is an engine that hasn't run for years, it could also just be the running temperature boiling off the water that has condensed in the system over time.

I still recommend you get somebody familiar with the A series to have a look first hand, as there's a whole bunch of things that could be going on. I don't mean paying squillions - simply look up your local club and drop them a line. There'll be bearded friendly guys just begging to come have a play.
elvis221, Oct 31, 11:18pm
Cheers smac It is a project car me and my son are working on , the engine is now running. He tookit for a small run around our turn around, simply because of no brakes. It is just that the smoke or vapour is blowing out the oil filler. Is it easy fixed !Can we clear it with a after market product!
smac, Nov 1, 2:40am
If it's rings, no, it's not an easy fix. If it's just water vapour, then it should be gone after one good heat cycle. If it's blocked (or non-existent) breathers, that's fixable. As I said in your previous thread, get a manual and start reading, or get somebody there in person.

However given the compression results you were giving, and the fact you never really explained (or perhaps never understood) what you did to fix it last time, rings looks probable.
supernova2, Nov 1, 7:25am
Please don't be discouraged but if you dont know the answers to the questions you have been asking it going to turn into a very expensive "project" for you and your son.Whilst a mini is a very basic motor its not the easiest to wrok on if you have to pull it to bits because of the way the motor is attached to the gearbox.I agree with the others - join the appropriate car club - Morris, Austin, BMC whatever you can find locally.There will be plenty of free advice and assistance from there.
lovemore_mbigi, Nov 1, 1:33pm
If the rings are completely munted, you'll get a steam train funnel type puff of smoke in time with piston stroke - very distinctive.

If its just oil vapor/smoke/mist coming out when the engine's hot, that's perfectly normal - within limits.Using a light GTX 20-50 oil will tend to accentuate this whilst switching to a heavier Penrite grade will reduce it dramatically.

Note that Minis are designed to run with the oil cap in place and will run poorly with it removed.Check the dipstick oil seal for integrity too.
elvis221, Nov 2, 2:20am
Would an oil flush solve the blow-by problemIf it's blocked (or non-existent) breathers, how is it fixable.
smac, Jan 22, 9:12pm
No. I think you said this is an old 998! If so you probably only have a pipe coming off the tappet cover at the rear of the block. If it's just a pipe, they don't block. If it has a cannister attached these can (and do) block up. There may also be another cannister attached to the timing cover (depending on age of engine). Both of these can be removed and the old clogged up steel wool/mesh taken out.but then you're into replacing gaskets etc and quite frankly unless you're just after something to do it's not worth doing that alone.

You've previously said you have one cylinder waaaay down on pressure. If your rings are poked no amount of breathers will solve this.