Burning oil!

[phil.elsdon]

I have a fully rebuild '67 4A, been back on the road for over a year, and I get a good cloud of white smoke after starting the car when leaving work to go home. Don't seem to get it first thing in the morning when getting out of garage. I have fitted an oil catch tank in the re-breather pipe between the rocker cover and the PCV valve, this does catch a fair amount of oil (more on motorway journeys). This has reduced the smoking but not fixed it.

Any ideas how I can stop/reduce the amount of oil being sucked into the inlet manifold?

Edited October 21, 2008 by phil.elsdon

[Dazzer]

My advice would be to ditch the lot and just let it go to atmosphere.

 

There's no reason to put this back into the inlet manifold.

 

She'll run much smoother without.

 

All the best

 

Dazzer

 

 

 

 

 

 

 

 

I have a fully rebuild '67 4A, been back on the road for over a year, and I get a good cloud of white smoke after starting the car when leaving work to go home. Don't seem to get it first thing in the morning when getting out of garage. I have fitted an oil catch tank in the re-breather pipe between the rocker cover and the PCV valve, this does catch a fair amount of oil (more on motorway journeys). This has reduced the smoking but not fixed it.

Any ideas how I can stop/reduce the amount of oil being sucked into the inlet manifold?

[BrianC]

Isn't 'white smoke' simply steam from condensed water in the exhaust system?

Oil burns blue, whilst black smoke indicates over-rich mixture.

In my experience, most cars (ancient and modern) produce steam from the exhaust on start-up (unless the car has been stored in a warm or heated garage), especially in cold/damp weather, but it disappears after a few miles. I don't think it's anything to worry about.

[ianc]

The car will return from work warm and therefore any condensation in the silencer & exhaust will have been blown away. It is likely that your garage is well-ventilated and therefore dry - it doesn't need to be warm, good ventilation is the secret. Overnight, conditions will be such that no condensation could occur inside the silencer & exhaust, so no cloud of steam on starting from cold in the morning.

At work, especially at this time of year, the air can be humid and cool, so some condensation can occur inside the exhaust system during the day. The temperature drops rapidly as the sun goes down and one can see droplets of water appearing on the lawn in late afternoon. When you leave work, and as soon as the engine starts, any condensate inside the exhaust will be blown out as a cloud of steam, and this can persist quite a while. In addition, the combustion process itself produces carbon dioxide, some carbon monoxide, and water vapour - this adds to the cloud of steam. On modern cars, with much larger exhausts, a considerable quantity of water can be seen to pour out of the exhaust pipe when the engine starts, together with clouds of steam.

 

I would agree with Brian - don't worry!

 

Ian Cornish

[phil.elsdon]

Hi, thanks for the responses so far, my first time using the forum, I think it's great and shall continue to use it!

 

The smoke only occurs at very first fire up and then is gone straight away, so I don't think it is water vapour. Also when I have removed the inlet manifold from the head you can see the oil in the manifold pipe.

The problem is the inlet vacuum sucking all the oil from the rocker cover, I have the rocker oil feed pipe fitted, so I do get a lot of oil splashing around under the cover. There is a baffle fitted inside the cover to try and stop oil from entering the breather pipe direct, but I think the oil just runs down passed and gets sucked in.

How big is the baffle on an aluminium rocker cover?

 

The other thing I was thinking of doing was to feed the breather pipe into the air filter, this would cause less suck from the rocker cover and hopefully not draw as much oil in, but would still burn the smelly gasses (I tried venting to the air and it got a bit smelly when stuck in traffic).

[88V8]

How big is the baffle on an aluminium rocker cover?

 

The other thing I was thinking of doing was to feed the breather pipe into the air filter, this would cause less suck from the rocker cover and hopefully not draw as much oil in, but would still burn the smelly gasses

The baffle in the 1970s SAH alloy cover on my 6 is virtually non-existent, about 2" long across the end of the suction flange. Neverthless it doesn't suck that much, however I don't have an auxiliary rocker feed. I recall that Stan on the TR6 forum mentioned he has ditched his aftermarket alloy cover because of just this over-sucking problem, and gone back to the standard and better baffled cover, and that is what I suggest you do. Or ditch the rocker feed.

 

If you take oil mist into the air filter, btw, it will clog quicktime.

I recently put an oil separator (as opposed to a catch tank) on my car in the hope of minimising pinking. The suction takeoff with the separator is from the plenum, as standard. Haven't done enough miles since to judge the effect.

http://www.goodparts.com/shop/index.php?categoryID=8

You could give it a try if you want to keep the alloy cover.

Even though it's marketed for the 6, it will work equally well on the 4. If you have a mechanical fuel pump you'll need to weld a boss (supplied) to the sump for the liquid oil return.

 

However, I agree with those who have suggested that what you are seeing out of your exhaust is water, not oil. Oil blue, water white.

 

Ivor

[Allan Westbury]

Having discussed the merits of the PC valve will a number of the reputable suppliers/workshops the common opinion is to ditch it. Apparently it tends to work at odd times often to the detriment of performance. I removed mine earlier this year & fitted a simple catch tank & over 2000 miles collected only water - no oil, despite blowing oil out of the dip stick hole due to a kn~cked felt seal.

I admit to not knowing what effect the rocker oil feed will have on the amount of sh~t blown out into the tank & am using the original baffled cover.

[stuart]

Ditch the rocker oil feed pipe as that will over supply oil to the top end to the detrement of the bottom end any way. The feed banjo has too big a hole in it and feeds too much oil.

Stuart.