white smoke when starting ?

[1dazpay]

anyone know why there is white smoke flowing out of the exhaust and it will go away in about 5 seconds and only when cold. i have a webber 32/36 on a l20b i have a good idea that its gas and have adjusted the carb to death and still white smoke.

[dat521gatherer]

probably just condinsation.

[vgwagon]

That's normal, when exhaust cools condensation occurs and moisture builds up in the exhaust system, when you start the car up you burn that moisture off .

[1dazpay]

wish it was but not a lot of condinsation in phoenix az. smoke is a little thick and and the engine has a rough idle until it clears up.

[Bugeye]

white smoke is water or condinsation

blue/grey somke is oil

[Fineline]

Valve stem seals?

[datzenmike]

I find with valve seals that leak down on shut off cause a definite blue puff on start up.

 

Over rich/flooding makes black smoke.

 

Sounds like steam.

 

Check that the intake/exhaust manifold bolts are tight. The two coolant holes in the head to the intake runners could be leaking into the intake over night. The fact it runs rough when smoking, tells me there is something in the cylinder causing this.

[1dazpay]

that sounds possible thanks i will give it a look.

[hogboy52]

Too much oil in the crankcase will be picked up by the counter weights and thrown on the cylinders. Smoke goes away as oil is sent to the top of the engine.

[charlie6178]

what brand of head gasket? if it's a fel pro.... that's your problem right there.

[veryboard]

condensation just like seeing you breath.As long as your white smoke goes away don`t worry about it.If it doesn`t go away it could be head gasket.If you don`t have to top up you rad all the time than your probably ok.

Edited November 1, 2008 by veryboard

[datzenmike]

I don't have a problem with Fel Pro h/g. For most applications, if you clean both surfaces and bolts and holes, torque them down right they work fine.

[datsunfish]

wish it was but not a lot of condinsation in phoenix az. smoke is a little thick and and the engine has a rough idle until it clears up.

 

I dont think the scientific act of condensation is only limited to wet areas. But I am no scientist.:D Rough idle initially could be the need for a full tune up and carb cleaning or rebuild.

[hogboy52]

My own '77 620 will "puff" a cloud when the oil level gets over the "H" mark after several hours of sitting. I've had it happen with other cars as well and it would stop if I kept the level under the "H".

[rat tail dragger]

well the problems is you need to install chrome valve springs and it will go away

[ppeters914]

well the problems is you need to install chrome valve springs and it will go away

 

...and a Ratsun sticker. Don't forget the Ratsun sticker. :D

[datzenmike]

?

[rat tail dragger]

the ratsun sticker helps filter the smoke threw the chrome valve springs

[ppeters914]

C'mon, Mike, don't play dumb. We know you know all the old-timer secret handshake mechanical tricks. :D

[DanielC]

Some white smoke is normal. Go back and smell it, if it has a sweet smell, could be a coolant leak.

Get a radiator pressure tester. and see if the cooling system holds pressure.

[racerx]

white smoke is normal for a few minutes when warming it up, specially if cold. Just in case do a compression check...

[koback68]

I dont know if your datsun is an auto or stick if its an auto you have a vacuum line that goes from engine to tranny the end at the tranny plugs into a vacuum madulater if that goes bad it can suck tranny fluid up the vacuum line and will smoke white just an idea

[banzai510(hainz)]

I seen that on a volvo P1800

white smoke and no brake fluid!!!!!!!!!!

 

Power brake diaphrame was bad.

[DRIVEN]

I'm with DanielC. Go smell it. If it's sweet, you are burning coolant. The rough-run that clears up when the smoke goes away makes me suspect head gasket. You could pull your plugs and see if any one or two look different from the others. Coolant in the cylinders works great for cleaning carbon build-up.:D

[620man]

I'm with DanielC. Go smell it. If it's sweet, you are burning coolant. The rough-run that clears up when the smoke goes away makes me suspect head gasket. You could pull your plugs and see if any one or two look different from the others. Coolant in the cylinders works great for cleaning carbon build-up.:D

 

I had a 78 620 that did that and it turned out to be the head gasket.