I have a 1971 142S. On deceleration, for instance, letting off the gas at 60mph in 4th gear, intermittent large white clouds of smoke can be seen coming out of the tailpipe. I see them in my rearview mirror. You can also smell them (I am not sure how this is possible since they are behind the car.) I cannot positively identify the smell as gas, oil, water, or whatever.

This happens while the car is warm (i am not sure if it happens while cold). It happens consistently. It is not necessary to heavily downshift to get it to happen. No smoke appears even under heavy acceleration. The engine sounds great and seems to have plenty of power. I have had this problem with the original exhaust manifold, and with brand new IPD headers. I have a weber downdraft carburetor.

What could the smoke be caused by? I have not adjusted the valves, could that be it? I have adjusted the timing and dwell perfectly with a timing light and dwell meter.

Any ideas?

Asa -

In thinking out your situation, two points:

1) Deceleration, if the engine is braking and not in neutral, brings high manifold vacuum. See what happens to smoke if it begins and you immediately put trans in neutral. Does smoke quit?

2) White smoke it, as I learned long ago, is steam - if it's pure white.

Can you re-create the situation in the driveway? Partner revs engine and lets off gas, you in back check exhaust. Make a scoop with your hand and bring a "handful" to your nose. Is is wet smoke? Boiled anti-freeze smell?

Let us know. It's a real poser.

Regards,

Bob

:>)

Normally on deceleration the engine is sucking something, Oil past the valve stems as per the previous post. Are you losing brake fluid, it may just be sucking leaking fluid out of the servo????

Regards

the idea of pete fluitman is also a very good one it did not cross my mind just now

Thanks pete

I think you and the other fellow are right about the valve seals. The brake fluid idea is very novel! I am not missing any fluid though.

The oil is very annoying and stinky. Can I replace those valve seals?although the clouds keep cars behind me about 500 feet :)

As Walter said, yes you can do it with the head in place. Another way of keping the valve in place is to stuff rope in the cylinder. Basically you set the engine so the piston is at the top ofthe stroke in whatever cylinder you are working on, both valves closed. Turn the engine slightly contra to its normal rotation and put rope into the cylinder through the sparkplug hole, then turn the piston back to TDC. I had a 145 E that had this oil blowing problem, though it was clear the smoke was oil which is what made be think of brake fluid. In the end the only thing that cured it was replacing the worn out valve guides. For which the head definitely needs to come off.

Regards

only save way to replace seals is taking off the cilinderhead however it is possible without doing so but there is a danger of losing the valve and not getting it in place again put airpressure on a sparkplughole with a special adapter then remove valvespring DO NOT LET AIRPRESSURE OFF take off valveseal mountspring etc

be carefull doing this and only one at the time in the same cilinder

I must say it's easyer said than done

greetings and good luck

walter

netherlands

the smoke you see is probaly a bit off unburned oil no reason to be worried

those are only the valvestickseals.

When you would see it when accelerating only than it is pointing to clinder and pistondamage

this defenitely is here NOT the case this engine is the same I had a few years ago in my 122s it ran 1,300000km's without problems only once the cilinderhead had to be modified to lpg and the last 300000km's it did the same as your car doe now.

So just keep it driving

Walter