Burning Oil

I have a newly acquired 85 QV which needed a lot of TLC and hadn't moved for years. It has about 92,000 miles on it. First items for replacement were the starter motor and fuel pump and a cleanout of the fuel system in order to get it running last year. It ran ok but one of the cylinders wasn't firing -- no fuel due to a plugged injector. It received 8 new injectors, spark plugs and new ignition wires and ran well on all 8 cylinders. So I decided to put more money into it. Lots of cosmetic items. Then it was on to new timing belts and bearings, a new fuel filter and new coolant. Another test drive and still ran well. Engine temp came up promptly but didn't overheat. Electric cooling fans turned on when they needed to (they got a new thermo switch). New brakes all around, new wheels. Another test drive, no problems. Altogether I put about 100 miles on it for test drives. The last thing I did to it was to change the engine oil (Shell Rotella 15w40 conventional) and filter (not a fram) and change the gearbox lube to redline last week.

Now the @#$%^&* decides it's time to start burning oil. Lots. It doesn't start burning it right away on start up but rather takes a few minutes to show up. If it were the valve stem seals, I would expect a more immediate puff of blue smoke on start up but there is no smoke until a few minutes of running. Could be the rings which doesn't make me happy but it's odd to me that the smoke started happening so suddenly. It's not leaking oil onto a hot manifold, the smoke is certainly coming out of the engine exhaust. I don't think the oil is overfull although I did put in 10 quarts initially, I took 2 out when it looked like it was too high on the dipstick. Still has good oil pressure.

The only paths I know of for oil to get into the cylinder would past the valve stem seals, past the rings or through the crankcase ventilation system. The inside of the hose for the crankcase ventilation system which connects to the air filter box doesn't appear to have oil residue on it. Does anyone know of another way for oil to get into the cylinder?

The other clue is that now the engine doesn't warm up quickly and might not even get to the running temp of 195 unless run for 15-20 minutes. That might be an unrelated thermostat issue but it, too, has just started suddenly after the oil change.

Maybe should have left the old oil and fram filter alone.

Any great ideas why the sudden oil burning?

 

I think I have put about 50 miles on it since it started burning oil. The only change between not observing oil burning and oil burning was changing the oil. I'll admit I'm not too sure where the "full" mark is on the dipstick but I only have 8 quarts in it and the level appears to be at the notch near the top of the copper part of the dipstick which I think is the full mark.

 

Pretty sure its oil smoke. Blue and a definite smell of oil.

 

That's my plan. I have the results from a prior compression test so it will be interesting to see if there is any difference. I was just hoping that there was some stupid Italian engineering item on the car which could accidentally introduce oil into the cylinder.

 

I have heard of the shaft failure issue. If that happens, does the gearbox flow into the engine oil or is it vice versa? In other words, which level is supposed to be higer?

 

Here's where I am so far:
Compression check -- results similar to test done a few months ago with pressures ranging from 125 to 140. Seems a little low to me but the numbers are fairly even between the cylinders. No pressure decreases in any of the cylinders when comparing first test result to most recent test. So, no new broken rings or leaky valves.
Blow-by system is clean and not putting oil in the air intake. That's not where the oil is coming from.
Gearbox oil level is consistent so I'm not getting gear lube into the engine or vice versa. I don't smell any gear lube in the engine oil. Engine oil level increase not coming from gearbox.
Spark plugs are black but not wet except for one cylinder that hasn't been firing. That cylinder has spark and compression and I think way too much fuel. Overall, the engine seems to be running rich. Adjustment of the mixture screw on the fuel distributor is ineffective to lean out the mixture.
Fuel pressure test. 60 psi consistently whether at idle or on the road. Will hold pressure for at least 1/2 hour when not running. Doesn't seem like the system is leaking fuel thru the injectors when not running but I am suspicious that its dumping fuel, especially into one particular cylinder which isn't firing, while its running.
Engine oil is gasoline contaminated and level increases rather rapidly. It's over-filled by more than a quart after a 1/2 hour of running. I'm on my second oil change in 60 miles.
The only way I see that fuel gets into the engine is through the cold-start injector or the 8 other main injectors. I disconnected the cold start injector and it's still too rich.
After sitting unused for more than 10 years and being almost 40 years old, I think the little o-rings, gaskets and seals on the fuel distributor have failed and fuel is just going anywhere it wants to inside the distributor. I'm going to give rebuilding the fuel distributor a try. There are some instructions on cis-jetronic website and I have a Bosch book on the cis system.
Does anyone have any hints or tips on fuel distributor rebuilds?
Does anyone know what the fuel pressure setting should be?

 

Thank you for the documents. Looks like the primary pressure should be between 4.7 and 5.4 bar so I'm low at 4.1 bar. It doesn't look like one can adjust the fuel pressure externally but rather its controlled by the primary circuit pressure regulator and perhaps adjustable by adding or removing shims. I plan on doing a rebuild of the mixture control unit so hopefully new o-rings on the pressure regulator will cure my low-pressure situation.

 

So the smoke has been resolved. The culprit was the fuel distributor. After a rebuild of the distributor and a third oil change in 63 miles, it runs well and no smoke. I didn't find anything grossly wrong with the distributor but the various o-rings weren't as soft as they were 39 years ago. After I rebuilt the distributor, I went to do my first startup and it wouldn't fire. After a little diagnosis, it wasn't getting fuel. I found out that the tank was empty. My fuel gauge doesn't work but I didn't expect that. It used a full tank of gas in 63 miles and appears to have dumped most of that into the crankcase. Now all 8 cylinders are firing and it comes up to temp quickly.

The cause of the smoke was a high oil level which was mostly gas, Now the oil level is constant and no longer gassy.

Previously, I had only driven a 7 cylinder Ferrari. They're better with 8.