Whats your defination of clean oil tank?

[911Tsilver]

What is your definition of a clean oil tank?
I’m trying to clean the oil tank on my 911.
Is any debris acceptable at all in the tank or must it be clinical clean?
I suppose some dirt particles must be acceptable since if not you should not be able to do any reparations on the engine. Theoretically it’s possible for foreign particles to enter the oil system and destroy the engine every time you open the engine.
This is however really rare because most workshops are extremely dirty compared to a "clean room".

[DanielDudley]

POR 15 has a product called Marine Clean that will get that sucker clean like you read about.

Clean is clean. Dirty is not clean.

[RWebb]

no debris

unless you want to destroy the motor

[dad911]

Originally Posted by 911Tsilver

What is your definition of a clean oil tank?
I’m trying to clean the oil tank on my 911.
Is any debris acceptable at all in the tank or must it be clinical clean?
I suppose some dirt particles must be acceptable since if not you should not be able to do any reparations on the engine. Theoretically it’s possible for foreign particles to enter the oil system and destroy the engine every time you open the engine.
This is however really rare because most workshops are extremely dirty compared to a "clean room".

Only shops I would let rebuild my motor do have 'clean rooms'.

All debris must be removed, or you WILL destroy the engine.

Oil is filtered going into the tank, why is your tank dirty?

[Formerly Steve Wilkinson]

I think what 911T means by a true clean room is an electronics-industry clean room, which is orders of magnitude cleaner than anything you'd find even at Ferrari's F1 shop, much less a good Porsche facility.

[Steve@Rennsport]

Oil tanks (and coolers ) should all get ultrasonically cleaned.

[GaryR]

Is the oil in the tank just dirty (black) or is there debris? I just flushed my tank with fresh Mineral Spirits until it came out clean. I'll put some fresh oil in, slop that around, and dump that out before mounting it to be sure all the MS is gone. I had zero debris of any kind in the filter cloth I used but the oil/sludge in the tank took a couple gallons of MS to get it out.. They also make an in-line filter for the line between the tank and the engine if you want extra protection..

[Walt Fricke]

Agree oil tanks should have zero debris. The first place the oil TO the tank goes is through the filter. But after that there is, for 911s through '89, no further filtering. So dropping a load of sand into the oil filler opening would be bad news.

Of course, if an engine was about to blow up, and the filter clogged with bearing debris, and the filter bypass opened, then stuff would get into the tank. And reuse would be a problem unless the filter were clean, or clean enough that it wasn't likely that the bypass had opened. So one would be especially careful about a tank with a known bad history, or an unknown one.

Early factory 911 race cars had an oil filter instead of an engine oil cooler (cooling was done with a front cooler). So oil after the pressure pump got filtered. As long as debris wasn't sufficient to damage the pump, it wasn't likely to get to the bearings/smaller oil passages in the engine. 964s (and later 911s?) got these, along with much more efficient front oil coolers, ducting, fans, etc.

But you need good front cooling to dispense with the engine oil cooler. Maybe a cooler fan as well, for stuck in traffic idling. A lot of extra effort to deal with a worry.

I don't think adding a filter between the tank and the engine is a good idea. If it is a fine enough filter to catch anything bad, it will be quite a flow restrictor. ~15 psi is about the most you can expect for fluid flowing under suction, is it not? If you dropped a 10mm nut into your oil tank by mistake, maybe a coarse filter if draining the oil did not get it out. But othewise who sells a filter for this location? I've never seen this recommended, and have seen several warnings not to do it.

Steve has been at this so long that I think he has seen about everything that could, under the worst circumstances, happen, happen. And his reputation/living is on the line if anything he touches goes sour. Can you spell meticulous? But rest assured a lot of us are willing to roll a few more dice with our own engines, and have gotten away with it, at least for the moment. If the odds catch up, we know who to blame.

So you are in good (or perhaps that is bad?) company if you slosh various cleaners around, and call it good when they come out clean.

The question of why you are worrying is also a pertinent one. No one goes through all this just to change oil. Engines can operate well enough as long as particles are smaller than some small micron number. Bearing material is soft, I understand, so it can allow small particles to be squashed into it, which gets them out of harm's way. You can keep things quite clean enough in a dirty garage as long as you are careful (and you don't have dust and dirt actually blowing around) when you need to be.

Walt Fricke

[baruch mor]

sorry mistake

[911Tsilver]

Thanks for all replays!
Let me put the question this way:
If you start with a clean oil tank, how much sand can you put in the tank before you have to clean the tank again?
Well, I would say that if you put a spoon of sand in it you definitely have to start from the beginning again. But what about a few sand corn? A corn of sand is bigger than a few microns and hence above the limit Walt Fricke mention.

A “clean room” is a room where you have absolute vacuum. This only exists in theory so all “clean room” are in some sense dirty.

Not all engines have been rebuilt in “clean rooms” and work perfectly well. Since the rebuilt not have been done in “Clean rooms “ the mechanics never can be sure that no dust, sand, debris was falling into the engine during the rebuilt

[JohnJL]

Ask GXXXX GXXXXX how he feels about spending >$100,000 building an engine and prepping a shell, hauling an entire race team to Targa Tasmania, then crapping out on Day 1 due to a plugged bearing journal.

The only amount of acceptable dirt is zero.

[Langers]

Ask GXXXX GXXXXX how he feels about spending >$100,000 building an engine and prepping a shell, hauling an entire
race team to Targa Tasmania, then crapping
out on Day 1 due to a plugged bearing
journal.




The only amount of acceptable dirt is
zero.

and on the other hand his company's namesake built plenty of race winning engines in the same workshop without the separate engine building room without issue. Luck of the draw I guess.