14 replies to this topic

[RossKnight]

I had my 1293 in for about two weeks, and all seemed fine, had a few people who drove behind me saying it smelled a bit, but they're used to modern cars and I knew the car was running rich. I then removed the engine as I wanted to redo the timing cover gasket, clean it up and paint the engine, fit the new ally rad etc etc, so it was out for about a week whilst I did all that.

 

I put it in again last week, and since then I've been getting white smoke out of the exhaust, seems to be randomly, not under load, and not specifically when there's no load, I mean it's happened just as i've braked and gone around a sharp corner with barely any throttle. Now apart from the obvious embarrassment of looking like del boys 3 wheeler smoking down the road, I'm obviously worried too haha.

 

Now the only thing that's changed since the engine went back in, was that I switched the breather hose to the timing case side, and put the filter on the transfer case side instead, as previously it was the other way around.

 

I believe it could be brake servo related? After all it was moved out the way when I swapped the engine so it may have disturbed something? I've just taken the banjo bolt off the manifold, and there is fluid around the threads and down the pipe, I also noticed slight smoke was coming out of the manifold hole. I checked the brake reservoir and it doesn't seem drastically low, but I guess it wouldn't take much to make a lot of smoke?

[Ethel]

Sounds probable, easily checked by disconnecting the hose and going for a drive. Taking care that your brakes won't be as good, of course.

[RossKnight]

Just finding something to block the manifold hole up with now. Don't fancy using duct tape as it may end up in the engine haha.

[Icey]

Sorry - I'm not seeing the connection between exhaust smoke and brake servo. You changed breather connections and then you blame the brake servo, could you explain that a little more?

 

There is next to no chance of anything is entering the intake from the servo, it's a sealed vessel. If there is fluid in the intake manifold you need to be looking else where. I'd be stunned if brake fluid ever got through to the intake via the servo - I can't even picture the route it would take.

 

It sounds more like you're getting a lot of oil through the breathers, especially if the inside of the manifold is wet (assuming with oil). If that's true then you'll looking and worn components - either rings or valve seals.

Edited by Icey, 09 July 2015 - 12:08 PM.

[RossKnight]

Hmm, despite the fluid on the vacuum hose etc making me think that I'd found the cause, after a short drive around the village with no servo, smoke still seemed to come out, but under load.

 

Next step I guess will be vent the breather to the atmosphere to see if that changes anything.

Edited by RossKnight, 09 July 2015 - 12:07 PM.

[RossKnight]

This post from dklawson explains it better than I can.

If the rubber diaphragm inside the servo fails, brake fluid can be sucked out of the reservoir and eventually be burned in the engine. If you have noticed any white acrid smoke in your car's exhaust recently, this would confirm the diaphragm has failed.

 

 

Sorry - I'm not seeing the connection between exhaust smoke and brake servo. You changed breather connections and then you blame the brake servo, could you explain that a little more?

 

There is next to no chance of anything is entering the intake from the servo, it's a sealed vessel. If there is fluid in the intake manifold you need to be looking else where. I'd be stunned if brake fluid ever got through to the intake via the servo - I can't even picture the route it would take.

 

It sounds more like you're getting a lot of oil through the breathers, especially if the inside of the manifold is wet (assuming with oil). If that's true then you'll looking and worn components - either rings or valve seals.

 

[Icey]

Well that's a new one! Thanks! I can't say I'd put the diagnosis high on my list though, it can't be a common failure scenario.

[RossKnight]

More common than you'd think, especially on old yanks with servo assisted transmissions etc.

I'm planning on mounting the go pro to the rear window looking down so I can see exactly when there is smoke as its not too safe driving whilst looking out the back window.

[Steve220]

I've never seen that happen. Ever. You'd know if the diaphragm split, you'd basically have to stand on the brakes to get it to slow down and the seals in the master cylinder would have had to perish and then get passed the O rings.

Is it large clouds or white smoke?

[RossKnight]

I've never seen that happen. Ever. You'd know if the diaphragm split, you'd basically have to stand on the brakes to get it to slow down and the seals in the master cylinder would have had to perish and then get passed the O rings.

Is it large clouds or white smoke?

I've previously read about it in this forum and others quite a lot, there's a fair few topics just on this forum alone of the very problem.

I'll try and get a video tomorrow so everyone can see better.

[dklawson]

It doesn't have to be a split.  Any number of minor leak paths can develop and let brake fluid get sucked into the intake manifold.  It's easy enough to tell.  Smell the smoke coming out of the tail pipe.  White and acrid = brake fluid.  White/blue and oily = engine oil. Black and sooty = mixture problems or leaky float valves.  White and sweet = antifreeze.

 

If you cannot smell the smoke, take the car for a run.  When stopped, disconnect the servo hose at the manifold.  Examine the swab for liquid.  If any is present, smell the swab and then touch it to the tip of your tongue.  If it is brake fluid it will have a strange bitter taste.  Motor oil and gasoline have a very different "burning" and "oily" taste that you will just know.

[surfblue63]

Well that's a new one! Thanks! I can't say I'd put the diagnosis high on my list though, it can't be a common failure scenario.

I had the white smoke scenario with my innocent Cooper. The servo diaphragm had a small hole in it. A new servo and non-return valve cured it. 

[surfblue63]

By the way, you haven't done something daft like put too much oil in the engine.

 

PS When you go for your test drive make sure you go down a hill with the car in 3rd gear with your foot off the accelerator. When you put your foot down on the accelerator see if you get a load of smoke out the back. If you do then it is most likely that the valve seals or guides are at fault. 

Edited by surfblue63, 09 July 2015 - 04:21 PM.

[RossKnight]

By the way, you haven't done something daft like put too much oil in the engine.

 

PS When you go for your test drive make sure you go down a hill with the car in 3rd gear with your foot off the accelerator. When you put your foot down on the accelerator see if you get a load of smoke out the back. If you do then it is most likely that the valve seals or guides are at fault. 

 

I'd filled it up above max initially when I put the engine back in, I drove up the road to check all was well and left it running whilst I bled the cooling system, then checked the oil level and realised it was overfilled a bit so I drained some back out to be safe.

 

Yeah, that sounds like a good test, hopefully if it is white/blue smoke and not actually white smoke like I first thought, than it'll be just head related and not piston rings.

[Spider]

I have one of my Minis that had the Oil Separator on the Timing Cover, without fail, on LH Corners, white smoke! Oil was being drawn up via that separator.

 

Block it off, just use a bolt or nearly anything and go for a short spin, you'll soon work out if that's the trouble.

 

I fixed mine by going over the the separator on the transfer housing.

 

Another thing to look at is the Carb(s) if using an SU. Over-fill the Dashpot and it will do this, mainly on acceleration, but they tend not to do it for too long as there's not a lot of Oil in them.