No oil in oiltank or filter!? first start in 20+ years

[elgh33]

Hi just started up my 911T 2.0 engine for the first time. have running it for a couple of minutes maybe 10-15 in total (with new oil) i have only connected the oil pressure light on the engine and it goes out when starting so there should be pressure.

however, I change the oil immediately after this start to flush out the engine as it has been standing for 20+ years

to my surprise, I got a maximum of 0.3 liters out of my oil tank, and that the oil filter looked like new, so no oil has passed through it??!!

the car is filled with 11L (about 12quarts?) of new oil before starting.

should I be worried or does the oil not reach the filter until you are at operating temp?

Am I running too little oil?

I feel right now that it doesn't feel right to go out on a first trip

[Tea Tray]

If you put 11L in then it still has to be there. Drain the sump and see how much comes out. The oil pump has two sections, pressure and scavenge. The scavenge side pumps roughly 1.7 times the volume as the pressure side (to prevent flooding of the sump while running) and routes the oil back through the filter/tank.
Installing a mechanical oil pressure gauge would be a step to consider as well as disconnecting the oil return line to verify the scavenge side is working. Try disabling the ignition and cranking the engine to see if you have oil coming out of the (removed) oil pressure light switch. Do the same with the oil return line.
Remove the sump plate to make sure there’s not some strange surprise at the oil pick up.
Very interesting problem.

[elgh33]

Originally Posted by Tea Tray

If you put 11L in then it still has to be there. Drain the sump and see how much comes out. The oil pump has two sections, pressure and scavenge. The scavenge side pumps roughly 1.7 times the volume as the pressure side (to prevent flooding of the sump while running) and routes the oil back through the filter/tank.
Installing a mechanical oil pressure gauge would be a step to consider as well as disconnecting the oil return line to verify the scavenge side is working. Try disabling the ignition and cranking the engine to see if you have oil coming out of the (removed) oil pressure light switch. Do the same with the oil return line.
Remove the sump plate to make sure there’s not some strange surprise at the oil pick up.
Very interesting problem.

ive got about 10.5L from the engine sump, and 0.5 from the tank. car was also smoking heavely. but thought it was ok due to been sitting

i will check the sump plate today first.

then fill it upp again and try your suggested things thanks

[stownsen914]

It sounds like something may be wrong with your engine's oil scavenge system that returns oil to the tank from the engine. This goes through the filter on the tank, so it could explain why the filter is dry. Under normal operation the scavenge system operates all the time, including when cold. So the filter shouldn't be dry. But it ran 10+ minutes like this? That isn't believable to be honest. If oil weren't being returned to the tank, its contents would be used up in less than 10 minutes.

I'd suggest some diagnosis to figure out what's going on with the scavenge system causing it to operate inefficiently.

Here's a post showing a 911 oil system for reference
http://forums.pelicanparts.com/porsche-911-technical-forum/145705-oil-system-drawing.html

[elgh33]

Originally Posted by stownsen914

It sounds like something may be wrong with your engine's oil scavenge system that returns oil to the tank from the engine. This goes through the filter on the tank, so it could explain why the filter is dry. Under normal operation the scavenge system operates all the time, including when cold. So the filter shouldn't be dry. But it ran 10+ minutes like this? That isn't believable to be honest. If oil weren't being returned to the tank, its contents would be used up in less than 10 minutes.

I'd suggest some diagnosis to figure out what's going on with the scavenge system causing it to operate inefficiently.

Here's a post showing a 911 oil system for reference
http://forums.pelicanparts.com/porsche-911-technical-forum/145705-oil-system-drawing.html

my engine should have burned all the oil in 10 mins? if all oil stays in the crankcase?

i will try to crank the engine with new oil and disconect the line to the tank

[mikedsilva]

Originally Posted by elgh33

Hi just started up my 911T 2.0 engine for the first time. have running it for a couple of minutes maybe 10-15 in total (with new oil) i have only connected the oil pressure light on the engine and it goes out when starting so there should be pressure.

however, I change the oil immediately after this start to flush out the engine as it has been standing for 20+ years

to my surprise, I got a maximum of 0.3 liters out of my oil tank, and that the oil filter looked like new, so no oil has passed through it??!!

the car is filled with 11L (about 12quarts?) of new oil before starting.

should I be worried or does the oil not reach the filter until you are at operating temp?

Am I running too little oil?

I feel right now that it doesn't feel right to go out on a first trip

Is this a brand new build?

[elgh33]

Originally Posted by mikedsilva

Is this a brand new build?

absolutly not, been sitting since the 90s, just done valve adjustment and carburator rebuilds..

[Bill Douglas]

Originally Posted by mikedsilva

Is this a brand new build?

Originally Posted by elgh33

however, I change the oil immediately after this start to flush out the engine as it has been standing for 20+ years

It's a ar that has been parked up.

[stownsen914]

Originally Posted by elgh33

my engine should have burned all the oil in 10 mins? if all oil stays in the crankcase?

i will try to crank the engine with new oil and disconect the line to the tank

It wouldn't consume it, per se. Remember that with a dry sump system there are essentially two reservoirs - the tank and the engine. and a two stage oil pump. The two reservoirs aren't directly connected, at least not exactly. So an issue in scavenging could cause the tank to essentially drain into the engine, if oil isn't being returned to the tank properly by your scavenge system. It sounds like you might be experiencing something like this.

Disconnecting some oil lines may help troubleshooting. Take a look at the diagram I linked above. Hopefully it will help figure out where to start looking.

[6cylboxer]

Look at the simple things first - Have you checked the screen at the sump screen? if it is clogged, the scavenge pump will not take any oil out to the tank
my 2 cts

[elgh33]

Originally Posted by 6cylboxer

Look at the simple things first - Have you checked the screen at the sump screen? if it is clogged, the scavenge pump will not take any oil out to the tank
my 2 cts

yes i had it out and it looks good (if you meen the net thing thats surounds the oil pickup pipe

[stownsen914]

If you've looked at the screen, does that mean you already drained the oil from the engine? How much came out?

[H-viken]

Quote
ive got about 10.5L from the engine sump, and 0.5 from the tank. car was also smoking heavely. but thought it was ok due to been sitting
Unquote

[David Inc.]

Probably smoking heavily because the pistons are in a bath of oil. Something's up with the scavenging. You know why the car was parked originally?

I might pull the return line from the sump to the oil tank to see if there's a clog.

[Tyson Schmidt]

Sounds to me like the pressure relief valve, and/or the safety valve are stuck open.

If this happens, oil from the pressure pump is dumped into the crankcase. You’d still have just enough oil pressure (7psi) to turn off the idiot light.

It’s easy to access the pressure relief valve on the bottom of the engine to check for this. The safety valve on the drivers side of the case is more difficult and probably requires heat exchanger removal.

[elgh33]

Originally Posted by David Inc.

Probably smoking heavily because the pistons are in a bath of oil. Something's up with the scavenging. You know why the car was parked originally?

I might pull the return line from the sump to the oil tank to see if there's a clog.

engine is from a 912 (was swapped to an 911T engine 901 trans) it was a parts car i bought, car was pulled apart and was i boxes, they was going to start a resto back in the 90s but the shell was to bad and everything was just left in an barn, but he told me it ran before they took the car apart, so i dont know much about this

[MAH77]

Is the engine a 4 cylinder, or 6 cylinder, motor?

Originally Posted by elgh33

engine is from a 912 (was swapped to an 911T engine 901 trans) it was a parts car i bought, car was pulled apart and was i boxes, they was going to start a resto back in the 90s but the shell was to bad and everything was just left in an barn, but he told me it ran before they took the car apart, so i dont know much about this

[stownsen914]

Originally Posted by Tyson Schmidt

Sounds to me like the pressure relief valve, and/or the safety valve are stuck open.

If this happens, oil from the pressure pump is dumped into the crankcase. You’d still have just enough oil pressure (7psi) to turn off the idiot light.

It’s easy to access the pressure relief valve on the bottom of the engine to check for this. The safety valve on the drivers side of the case is more difficult and probably requires heat exchanger removal.

It wouldn’t explain why none of the oil is making it back to the tank though. Filter was dry and tank is empty, so somehow no scavenging is happening.

[RSTarga]

I don't think the 912 had a dry sump. Are you trying to connect a 4 cyl. to the 6cyl system?
I would be worried of hydro locking the engine with that much oil in the block.

[Tea Tray]

I don’t think pulling oil lines to verify scavenge oil flow back to the tank is needed if the oil filter is dry.
I’m not sure about the 2.0 but my 3.2 doesn’t have and relief or safety valves on the scavenge side of the pump.
For some crazy reason, the scavenge side of the pump isn’t working.