rt61

Can anyone suggest a diagnosis for massive white smoke. After driving my '82 911SC (221K original miles) for 30 miles at 50-70mph, I exited to a residential area and was at a stop light. Just starting in 1st gear - I heard a large clanking noise that went away and then the car started belching out huge clouds of smoke. It seemed white and not blueish.

I drove about 1/2 mile and then stopped the car. I started it again and saw that the oil level was good; the oil pressure was good; the temperature was two bars below red. I did not hear any rattling, but the car is still blowing smoke - though not as heavily. When I try to start, it seems to rattle in 1st gear.

I get the car towed home and up on jacks. When I start the car in neutral - the smoke blows pretty heavy, but no grinding. I listen to the valve covers with a stick and don't hear any rattling on the top or bottom.

I open up the covers and checked the rocker arms on each cylinder and they seem OK. I'm going to try a compression test tomorrow.

What else should I look for?

Rick

old man neri

What does the smoke smell like? Are there any liquid deposits in your tail pipe? Is it cold out?

You didn't accidentally fill it with diesel or something did you?

KeithC2Turto

I am not an expert but might check the intake and see if it is sucking in oil form the tank breather.

jakeflyer

Zimmermann is out of town for the holiday and Steve may be off also. It may be wise NOT to run the engine until you get some expert advice so that you do not cause more damage than you already have. If you look at the plugs, the plug or plugs that is the source of the burn that produces the smoke may be black and oil coated. You may be able to spot the bad cyl. that way. Could be a broken ring, cracked piston, or a valve guide that came loose. My bet is the guide.

smshirk

good advice

Steve Weiner-Rennsport Systems

Rick,

The VERY first thing I would do beyond what you have already done is perform a leak-down test to check for piston/ring problems.

Don't start it up anymore.

rt61

OK - just getting around to reading your posts after spending all day working on the car. Here are my responses to the questions:
1) The ambient temperature when driving the car was 75-85 degrees with moderate humidity in Orange County, CA.
2) I'm pretty certain I did not fill the car with diesel, as Costco did not have diesel at the pump I used.
3) The smoke smells oily. Yes, there is oily condensation in the tail pipe.
4) Since I had all the covers off, I decided to do a valve adjustment, and also change out the spark plugs prior to the compression test.
5) The NGK BP8EGV plugs were originally installed Nov 2005, 7500 miles ago. I intentionally used a 0.064" gap vice .028".
All of the plugs were oil fouled and wet. I replaced the plugs with Champion Copper Plus RN9YC with .030" gap.
6) I recheckedall of the rockers on the lower valves and they look intact.
7) I closed up the valve covers and put back in about 8 qts of oil.
8) I got the following compression test results (cranking at least 3 separate times for about 2 sec each).
With the engine cold (ambient 75 degrees) vice the recommended 100-110 degrees
#1 121 psi (in Mar '03 at 205K miles whereas I'm not 221K, I got 128 psi)
#2 120 psi (Mar '03 - 133 psi)
#3 112 psi (Mar '03 - 110 psi)
#4 127 psi (Mar '03 - 134 psi)
#5 116 psi (Mar '03 - 127 psi)
#6 130 psi (Mar '03 - 130 psi)

I started the car in neutral (didn't read your posts yet), and heard no grinding or rough running. The car continues to bellow white smoke.

Unfortunately, I don't have a leakage gauge and don't have enough time to spend doing an engine drop (for the 1st time), and then fixing the ring, piston, or valve guide. Maybe I'll invest in one (they are $82.50 on eBay).

Do you still believe it to be one of the 3 conditions - broken ring, cracked piston, or a valve guide that came loose?

Rick
p.s. - thanks for advice over your holiday weekend.

old man neri

I am by no means an expert at this but if compression is fine then it is probably not a broken ring or cracked piston. Perhaps a valve guide. With the valves closed you would still get good compression but the guide would leak when the valve is open. Of course it could also be a bunch of other stuff that I don't even knwo about.

When you did your valve adjustment, did you notice any slop in any of the valve stems? Could you wiggle any of them?

TT Oversteer

I find it interesting that all of your plugs are oil fouled. A mechanical problem in one cylinder wouldn't cause this and the compression test results are not stellar but dont indicate a failed cylinder either. I wonder if you sucked something into your intake causing the initial noise and now you are ingesting oil through your breather. Try taking your air box apart and see if there's any oil entering the intake.

old man neri

Excellent suggestion by TT. Didn't think of that myself.

rt61

Here is some additional information and respones to the most recent replies:
1) The Carrera chain tensioners have NOT been installed.
2) I looked in the airbox (I did install the pop-off valve). I found a small pool of oil in the airbox. The air filter (installed in 2004 at 213K miles) was still in good shape.
3) I didn't get around to checking the valve stems.
4) Two days prior to the incident, I added 1 qt of 10W30 oil, as the dipstick (when the car was cold and not yet running) showed at least a quart low. I use the car as my daily driver and did not experience any problems on Thursday or Friday driving the 3 miles to/from work.

I pose the following questions:
1) If the oil was over-filled, what sort of mechanical problems would that cause?

2) If the chain tensioner failed while starting up from a stop in 1st gear - would that cause the timing chain to jump a sprocket and therefore create white smoke? However, I note that when I start the car, it doesn't seem to be running too roughly.

3) If I sucked something into the breather - wouldn't the air cleaner protect the system, or wouldn't I see something on the air filter? If I did suck something into the breather, how would I check or clear the problem?

I've got calls into Dutch Treat in Hawthorne, and John Dayton Enterprises in Signal Hill to see if either can make time to look at the problem.

GothingNC

Seems to me that you probably overfilled the oil since a quart was added with the engine cold/nont-running and there is some residue on the air box.

Air box should be bone dry.

I would use an extracter to siphin some oil out and then check the level with the dipstick running at operating temp.

John

old man neri

To check the oil you must have the car warm and idling on level surface for 30 seconds.

My guess is you over filled.

scottb

White smoke? New Pope?

TT Oversteer

I agree, it sounds like you overfilled your oil tank. The dipstick reading when the engine is cold and not running is not reliable. You must have the engine running, car on a level surface and oil at operating temp. Then the dipstick should read midway between the upper and lower mark. The oil in the airbox came from the breather tube and caused your white smoke. I'm concerned the "large clanking noise" you experienced may have come from hydraulic lock from a slug of oil in one or more of the combustion chambers. Short of a teardown and inspection of your connecting rods and bearings I'm not sure how you could tell if any serious damage was done. I'm hoping there is some other explanation that's less serious (I'm just thinking out loud here). I would clean out the airbox really well, change the plugs, take out at least a quart of oil and see how she runs. Good luck and let us know how it turns out.