Smoke from rocker cover breather?

[VW]

Whats that a symptom of then?

Its not real bad, but its there none the less.

[Brigsy]

Worn rings probably, do a compression test.

[VW]

Yeah, i guessed that was the main culpret, i already new the rings were a little worn.

Hows that work then? Combustion smoke getting past the rings into the block?

[VW]

I already planned to rebuild the head at some point.

How can i tell if ill get away with a hone and a set of rings rather than a full rebore?

[whitbytom]

I wouldn't worry about it, sounds like oil vapour to me? It's normal for any engine to produce a bit of oil vapour out of the rocker cover when hot

[VW]

It smokes a bit from the zorst when hard accelerating up hills too, thats what made me think the rings were going a little anyway.

After driving up hills i get a bit of thin smoke wafting out from the bonnet sides. Not alot but some.

I'd rather sort it now while i have the money than let it get bad enough to need a rebore rather than a hone and new rings.

If it already sounds bad enough to need a rebore anyway then ill ignore it for now

It doesnt stink of buring oil though.

Engine doesnt seem to breath particuarly great, could it be a breathing issue?

As i say, i planned on rebuilding the head anyway. While its off ill check the bores/rings but how can i tell if it needs hone/rings or rebore?

Is it possible it could be a valve stem seal/worn guide problem?


Bloody 6 cylinder engine so this may cost a bit

[VW]

Oh, it still pulls well and seems to have plenty of torque.

[jrevillug]

All engines will chuck a bit of oil mist out of the breather, especially at idle.

However, it should reduce significantly when you rev the engine. If it doesn't then the rings are worn. That fits withthe smoke on hard acceleration that you've described.

To find out if the engine need a rebore you should really measure the bores. However, a rough guide is to see whether there is a big wear lip at the top of the bores. If you can feel it with your fingertip then you will need a rebore. If you can just about catch it with your fingernail then it's marginal - reboring will give a much longer life, but rings might work for a while.

[Brigsy]

Like i said comp test it before assuming the worst. If its putting blue smoke out the exhaust it'll most likely be worn rings. Is it using plenty of oil?

as for rebore/rehone, that can only really be answered when the engine is in bits.

[VW]

Cool.

Ill do a bit more testing and see if the smoke goes when reved.

Ill go ahead with the top end rebuild and have a good look at the bores when the head is off.

[whitbytom]

If the bores are worn it will cause the crankcase to pressurise, and blow air/oil vapour out of the breathers. I'm not familiar with the engine you're on about, but I'd check all the oil breathers on the engine for blockages too. On an old Golf engine I had, when you took the oil filler cap off while the engine was running it would chuff out oil vapour like a steam train!
You could have worn stem seals, but if it's smoking on hard acceleration it's more likely to be the bores, just sounds like a generally tired engine

[VW]

Yeah, ill comp test first.

Not sure about oil usage, not had it long. Ill keep an eye on it.

It doesnt smoke alot, you can only tell at night when someones headlights are behind you.

That and the misting from the breather.

The breather smoke doesnt smell burnt though.

As i say, ill do some testing and see what i can find out.

Anyone know if i can get the pistons/rods out a zephyr straight 6 without pulling the engine out?

[CR500Dom]

What car is it ?
I`d check the breathers are clear first.....

If they are blocked then it forces oil past the valve stem seals and rings

Do the simple cheap stuff first

VW 8v are notorious for it.... bought a couple now that have smoked really badly

10 minutes work with the rocker cover, some petrol and matches normally solves the problem nicely ;D

[jrevillug]

Re: The compression test. If it's low put a bit of oil down each cylinder - just enough to cover the top of the piston.

Don't forget to hold the throttle wide open when testing - probably grandmother/eggs situation, but I've heard of people reporting a low compression reading when not doing that, taking the engine to bits only to find that it's fine.

If the compression reading goes up then the rings/bores are worn. As said, you can't tell how bad the bores are 'till you get the head off.

James

[Deleted]

just going to add that some of the much older engines (presuming this is onthe zephyr) onyl had a simple breather system, my minx merely had a pipe out the side of the tappet chest cover and vents on the oil filler cap so some top end smoke was inevitable...

compression test will reveal any nasties, to confirm its rings and not top end squidge of oil down the bores will seal bad rings and give better readings than a non wet test, could even be a simple case of headgasket letting oil into bores or gases out into engine...

like you say when you do the top end you;ll see whats amiss

[VW]

Thanks folks, yes, its the zephyr I'm talking about.

I think the breather system is just a breathable cap on the rocker cover. It cant be blocked as thast where the smoke comes from ;D

Ill comp test it first, then rebuild the head.

[Seth]

As rottie said, there's probably also a pipe somewhere on the side of the engine so would be worht looking for that. Would have to be really neglected for that to get sludged up though.

[Deleted]

hi seth, my minx suffered cause some fun driving had thrown a load of mud up the end of the pipe as it simply pointed directly down..

this in turn made the engine actually build pressure inside the cases and leak oil onto the manifolds and thus in turn smoke from under the bonnet

[mikemai47]

Feb 18, 2009 18:13:21 GMT VW said:

Thanks folks, yes, its the zephyr I'm talking about.

I think the breather system is just a breathable cap on the rocker cover. It cant be blocked as thast where the smoke comes from ;D

Ill comp test it first, then rebuild the head.

I had many Ford 6s years ago, Smoke from cap and exhaust on acceleration was always rings I'm afraid, used to fit rings with a ridge dodger top ring, don't know if you can still get such things now though, Love your car by the way, good buy

[VW]

If there ridged ill rebore, only way really.

Not had a chance to look under it at all yet but i asked on the NSRA and ive been told you cant get the sump off with the engine in.

If the engines coming out anyway i might rebore while its out.

Ill make the decision when the head comes off.

Thanks.