Need advice. New (to me) 911 smokes.

[ericwitte]

A little break free penetrant on the muffler bolts for a day should help that. The 911 exhaust is very easy to remove. The heat exchangers take more care.


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[fallingat120mph]

Here is mine after two years in storage. It took about 20-30 minutes, at idle, and a half hour drive to finally burn everything off.

I knew I was going to rebuild the engine so really did just pull it out of storage and start her up - mostly just to see how the engine would react.

The only leaks it had were the "triangle of death", which I fixed with the engine in.

Good advice here, but just wanted you and others aware of how much smoke will pour out after these cars sit for months/years at a time - let alone being overfilled.

I am still driving the car, same engine, now some 6-7 years later. It leaks and has 1 broken headstud, but after sitting without a start for at least 18 months I have come to conclude these engines are pretty tough...Find your baseline and keep things simple...good advice here but I would start with an oil change and then a long drive, checking the level along the way. Remember always check the level with the car warm!


EDIT: I have had the luck of using some great shops - with that said, try to clean the engine the best you can, and find the leaks yourself. Neither of my shops would immediately jump to dropping the engine and full rebuilds.

Erik

[fallingat120mph]

Originally Posted by LuvNH

Hello all. Thanks in advance.

New owner of a 79 SC.

PO swapped the original engine for a 78 engine (determined by s/n near fan and vin). I have the original engine (again, I assume based on that s/n) which was likely used for parts.

I knew that it smoked when I got it, and had a local shop (Porsche savvy) look at it. They ran it, degreased, added oil and a dye pack ran it to check for leaks. I was told that it was difficult to pinpoint the location of leak bc it was coming from everywhere. Got a quote for $5400 to drop engine and fix the typical 3 locales on the top. That’s an expensive (and far from complete) guess, so I got the car back to explore more options.

During my own cleaning, there was oil behind the air filter which I have learned comes from overfilling the oil. Dipstick was dry. Engine was cold - I get it.

The engine starts right up, but absolutely belches smoke. Creates a smokescreen and smokes up the interior after a few minutes. Revving the engine causes oil to spit out of the exhaust pipe. I heard lots of dripping sounds after I turned off engine. Dipstick was wet after a few minutes, not fully. Although the engine ran only for a few minutes.

Engine sounds fine, and moved the car forward and back a bit. Clutch feels fine.

After two weeks of sitting, it has dripped from three places. Mostly from the exhaust pipe, and there is a small puddle sitting on the lip there now. Also from the right side flange where the muffler meets the heat exchanger. I’m surprised the puddles are not larger. On cardboard only a couple inches across at best.

One shop said they could look into it and do any necessary work up only up to the cylinders. They won’t take them off and go further. No real price quote here.

Another shop recommends a reseal, all the way to splitting the case. Said they would take it apart, inspect and measure everything and replace as necessary. Not sure how this differs from a rebuild. Quoted price was $30K-$40K.

Need some advice.

Originally Posted by brighton911

LuvNH, be sure to include an update, it's always nice to know the outcome of a problem.

+1 on posting the progress/outcome!


Erik

[LuvNH]

Minor update.

Pulled the muffler. Drained about a third of a quart of oil out, grey in color. I’ll need to hang it some more to get more out although it is pretty much gone.

I’ll need help finding p/n for the exhaust gaskets. I will call pelican when I have time. Summer is not the time for these types of projects!

Not the stock heat exchangers for a 78 engine. See pics below.

Drained the oil. I did NOT warm the car first. I let it drain for nearly 24 hours. I got 10 quarts out. Measured by eyeing the jugs (hehe), 2 gallon size containers and another half gallon. I also weighed them to verify.

I was hoping to get more out to prove the overfill theory. I did not undo any hoses yet. I did not see much evidence of leaks from there.

A little evidence on the oil cooler and the tank itself, as well as on the exchangers.

I’ll put 8 qts in and start her up soon and enjoy the smoke show for a while. 20 minutes? Not sure how long to let it run to verify whether the overfill theory is valid or it is a larger issue.

Thanks again for all the help.

[Winter]

Great post, thanks for keeping us all in the loop!

It doesn’t have to be overfilled by much to leak like crazy.

And here is a pic to prove it:

[LuvNH]

So, I drained the oil, got 10+ quarts out (total). Removed and hung the muffler as was recommended. Got a 1/3+ quarts out of that. Changed the filter. Cleaned a bit underneath. Got new metal washers for tank and plug. Torqued to 31 ftlbs.

Re-hung the muffler. Still need the pn for the heat exchanger/muffler gaskets. I have a lead on that, and will get there (Daansk performance exhaust). I reused the old ones in the interim. Added 8 qts oil. Pushed it outside and ran it. Took a minute to start, but when it did, same story. Same steady plume of smoke. Ran for about 10 min. I turned it off when I noticed a glow in the bottom the heat exchanger. See pic. Between the welds you can flame inside the exchanger. I assume it is residual oil burning off, and wanted to stop before anything got worse.

Because exhaust is designed to handle heat, I imagine that it can handle that, but need more informed opinions on this.

I only noticed a few drips thus far. The worst offender is the driver side muffler/exhaust gasket. Still have some oil trickling out of the muffler pipe, although I didn’t get the spattering like I did last time put time.

Thoughts?]

[Duc Hunter]

Wow, flame in the heat exchanger. Thats a new one for me to see. Great job on keeping us updated.

On a side note, I am curious what people say is a good oil level on the dipstick. On a stock car I know we can go by capacity alone, at least until it burns off some oil and we need to top it up. On my Rat Rod though "factory fill capacity" irrelevant because of the longer oil lines, much bigger oil cooler, etc. In my case thats because I have a 1975 2.7 oil tank thats supporting a 964 3.6 thats in my 1975 911S.

I have always run my air-cooled cars anywhere between the "1 quart low" line on the dip stick, up to halfway between that line and the max fill line, checked when the engine is hot and idling on a level surface. A long time ago I was told that above that and you risk blowing oil into the intake from the oil breather at higher RPM, etc. Anyone have any thoughts on where our cars should be filled based on teh dipstick to not be over full?

[Lyle O]

Keeping fill to just below mid-line on stick is the way to go. As mentioned ad-nauseum, check after the engine is fully warm and on level surface; VERY IMPORTANT! Running 10 minutes is barely enough time to adequately warm the engine (especially if you are not driving it).

Agreed as Chris said, haven't seen a photo of flame in HE before. To be honest, I would remove the HEs and clean them well INSIDE, and hang them out to dry, too. There is clearly a lot of oil in the system that needs to go, and it is too much for it to be "burned off". Use a lot of Kroil or other rust-cutter on the 12 exhaust mounting studs and try to remove. It's a little tricky to get a socket through the access holes, but you need a long extension with wobble connection and you can do it.

[dg567]

After you have the 8 quarts in it - I would take it out and give it a good thrashing to get it nice and hot. Thats the only way the exhaust will get hot enough to burn all the oil inside.

[dannobee]

Retarded ignition timing will make the exhaust glow at idle. Check it before you catch something on fire.

[Winter]

Originally Posted by Duc Hunter

Wow, flame in the heat exchanger. Thats a new one for me to see. Great job on keeping us updated.

I have always run my air-cooled cars anywhere between the "1 quart low" line on the dip stick, up to halfway between that line and the max fill line, checked when the engine is hot and idling on a level surface. A long time ago I was told that above that and you risk blowing oil into the intake from the oil breather at higher RPM, etc. Anyone have any thoughts on where our cars should be filled based on teh dipstick to not be over full?

+1 on the updates

In terms of the indicator marks on my dipstick, I do one mark below “middle”, that seems to be what works best for my car: ‘76 with Carerra oil cooler.

To the OP, it definitely seems as though you’re going to have to clean HEs out as well as clean as much of the engine as possible to really determine what is going on.

In my old - now sold - ‘75 targa with a 2.2 carb’d transplanted engine, I had to address multiple oil leaks, bad enough that they had put a lot of oil into the HEs.

Don’t worry, you’ll get there.

[EC900]

Nice stainless backdated HE’s one would wonder why a PO would have put them on a worn engine unless it was slightly better than the original, which is why we feel your smoke problem is related to overfill and not rings and guides.

You mentioned gray oil found in the muffler. When oil is gray - it’s old dirty oil too. This would indicate a substantial amount of water diluted it either in the oil tank or the muffler which will hold water vapor accumulations.
This is also another indication of short run times and/or any quick start ups like in the off season. The oil is not getting hot enough to burn off combustion moisture. So I advise to refrain from any winter garage start up/shut down, also always try to go driving rather than idling to reach 190° operating temperature with 20-30 mins being minimum.

Check the timing as mentioned for that muffler glow. The residual oil won’t combust but certainly an exhaust that hot will lead to more disastrous event. Get an infrared temp tool and spot check various areas and heads. Once the glowing exhaust is sorted, proper oil level then find time to drive a hour to burn off the remaining residual oil. It may take a few trips over a week or two but eventually subside.
The HE’s are a flat bottom sardine can frying pans any copious amount of lingering oil will cake up and cook each time which is why it was mentioned to try and clean them out. Less crud inside is less time they’ll smoke and when you turn your cabin heat on - guess where the burned oil smell goes.

The drip leaks at the muffler connection could be coming from chain cover gaskets or loose nuts that can be re-torques but use new crush washer where needed unless you’re going to replace gaskets altogether. BUT any dripping also tends to travel front to back and winding up at the muffler connection. So spray down with brake cleaner, wipe everything clean & dry, wrap some blue paper shop towels along a suspected route overnight and look for evidence of where the drip(s) originated from.

[LuvNH]

Ugh.

When I removed the muffler and saw how much oil was in there, I knew some had to be in the HEs. So I can see the point of removing and cleaning the them. Don’t need any flame there. Actually doing so is going to be a pain, however, for several reasons.

On the positive side, I ran the car longer this time and have not seen hardly any leaks. The one drip on the exhaust/muffler gasket is problematic admittedly, but 12 hours later, no new spots on the cardboard underneath. The cam covers have been and remain dry. The valve covers are dry, but maybe a little evidence on the oil cooler.

On a different note, I noticed my red light on my dash stayed lit too. Does that mean the alternator isn’t working? Or fuse, etc.?

[Duc Hunter]

OP I believe the gray oil is ONLY from the moisture that collected in the muffler. Once oil leaves the oiling system all bets are off on how its condition can info the health of the engine. So I would not give that a second thought until everything else has been cleaned up and checked.

[Showdown]

I’m curious to how rich the car is running… could that flame in the HE be unburnt fuel? Wild!


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[LuvNH]

Originally Posted by Showdown

I’m curious to how rich the car is running… could that flame in the HE be unburnt fuel? Wild!


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After I turned off the ignition, the flame burned for a few seconds and slowly died. Didn’t behave like fuel.

[EC900]

Wonder if that glow would be a caked up, burnt oil conglomerated ember at the bottom HE pan. Eventually something like that will dissipate to ash over time.

[LuvNH]

So, busy summer and doing things as time permits.

First, removed the muffler and the SSI HEs (pics).

After I removed the muffler the first time, I hung it and drained ~1/3 qt of oil out of it. I then re-installed it and ran it. More smoke and the flame in the rt side HE (pic earlier in thread). Abort, shut off, back to the garage.

The HEs had some gunk, but not a ton. I sprayed degreaser, let it sit, then dumped it several times. Came out clearer every time. I then cleaned out the degreaser with some rubbing alcohol, dumped it then let it sit in the sun, then sat them in front of the fan for a day or so. They are clean and dry now.

I picked up the muffler and was surprised how much oil came out this time. A cup or so, which i assume was blown from the HEs into the muffler. That is still hanging. I am hesitant to spray too much in there. The baffling may prevent me from purging the cleaners adequately.

I think the majority of the leaks come from cylinder #6, right by the oil cooler. I suspect that oil leaks from the cooler or the TOD above and leaks down that side and makes its way into the HE from the bottom of #6. The question is at what rate. This helps explain why the flames were in the rt side HE, not the left. The rt is the problem child.

I cleaned the cylinder surface and studs.

Starting to reinstall everything and have a couple questions. The PO used 12mm flange nuts, with 2 washers each, in the locations that would not used the barrel nut. I bought the copper 12mm nuts and proper 8mm hex barrel nuts. The new ones are not flange nuts, and I have seen installation with those alone, nut I am tempted to use 1 washer each.

In the locales that would normally utilize the barrel nut, he used 10mm nuts with 2 washers each. There may be an issue with the access holes for the barrel nuts not lining up with the exhaust studs, so I can see that, but why 2 washers each, in addition to the flange nut?

I got exhaust gaskets from cyl to HEs that are thinner than those I removed. The Victor Reinz, pn works. I don’t think it’s an issue, but curious. Also, I thought about reusing the previous ones. They seem to be in good shape.

So, what did I miss?

[LuvNH]

The HEs

[Otter74]

If your car is still smoking, take it to Chicago and get on the CTA with it. The Mayor will send social workers to encourage it to quit smoking and point it towards smoking-cessation programs. Should fix the smoking right away.