DDK - Die Deutschen Klassiker

The problem is that the wing cooler is on the return side of the oil system and if the thermostat was open the first oil scavenged by the suction side of the pump will contain debris and will be fed straight to the external cooler. If there is debris in the engine cooler it will most likely have travelled there via the wing cooler unless the thermostat was completely closed. This is unlikely if the car was being driven hard.

The return oil from the wing cooler is then filtered on its its way back into the tank and is then drawn though the pressure section of the pump into the engine mounted cooler and onwards to the bearings, cams etc.

If the wing cooler is a simple trombone type you may be OK and be able to clean it out but if it is a fin and plate type cooler I would just throw it away.

fetuhoe wrote: If the wing cooler is a simple trombone type you may be OK and be able to clean it out but if it is a fin and plate type cooler I would just throw it away.

nooooooo, it's an original 69 S one....

I actually didn't see any swarf in the engine cooler, which makes sense given what you say about the oil having to go all the way round the system before getting there. maybe it's all in the front one

tim69s wrote:

fetuhoe wrote: If the wing cooler is a simple trombone type you may be OK and be able to clean it out but if it is a fin and plate type cooler I would just throw it away.

nooooooo, it's an original 69 S one....

What a nightmare.

I really don't think you willn ever clean it successfully.

Is there any way of running oil through the pipes and front cooler under pressure (off the car) and fitting a magnetic strainer or strainers in one or more of the pipe joints to collect the swarf?

Regards
Mike

There will be steel and alum swarf in this engine, but worth a try!
Also, contact a leading rad restorer such as Serk and do not discount a supplier/refurb of industrial coolers too. They would be better equipped than a car rad company.

For example: (plucked from Google, check out Motor Vehicles)

http://www.google.co.uk/url?sa=t&rct=j& ... 4ZedpLSYGF

You could make a flushing rig but you would need to use hot oil - say 90 degC and achieve a flow rate that ensured that you could fill the cooler and move oil around any parts of the cooler where flow would normally be limited.

Filtering the output would be important as you need to remove particles down to at least a 10 micron level.

Front coolers are not really pressure rated as they are on the scavenge side of the system so I would tend to avoid pressures much greater that 1 bar.

One way to try to clean the cooler would be to ultrasonically clean with the cooler part filled with a good chemical cleaner and close off the inlet and outlet.

If you use a heated cleaning system it would help.

The good news is that the cooler is mounted before the filter and this helps but it is the small particles that can take several 'passes' through the filter that are the worry.

Just as a side question, how well does an engine oil filter do in regard to the sizes of particles from a typical engine blowup? Are there particles too small for the engine filter to filter out that would still be damaging to a healthy engine? Just curious really.
Graham

Oil lines go through the sill, no taking them off.
I plan to do some detailed forensics to find out where the swarf got to. The first time I saw it was when I was stripping the engine.



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Ok Tim, I was forgetting on a 69 they run through the body. I was visualising my own external RS system. No matter, you wouldn’t need to take them off just isolate them and put the magnetic trap at one (or both) ends of the pipe.

Regards
Mike

.
As Graham said earlier - there will be non-ferrous (aluminium/alloy) swarf too though ...

Mmmm...
need a second type of filter as well then,
Would that alloy warf sink or swim in a vat of hot oil Andy?

It may not be possible but I’m thinking out loud because those 69 oil cooler systems are nigh on impossible to get and megabucks so it could be worth at least an attempt to try to salvage.



Regards
Mike

The specific gravity of an engine oil is typically between 0.85 and 0.87 depending on detailed formulation.

Magnesium is around 1.8 and Aluminium is around 2.7.

Filtering out large particles shouldn't prove difficult as car Oil filters are normally quite good at levels down to 40 microns.

It is worth bearing in mind that not all large particles are removed by a single pass through a filter. Typical filtrations removes around 98% of a 40micron particle size in a single pass and this can drop to around 50% at 10 microns.

The real issue with engine blow ups is often more about the amount of fine particles that may be in the oil.

Automotive filters are often quite crude and commonly only filter down to 40 microns at a decent Beta Ratio and this is the smallest particle that can typically be seen by a naked eye.

Wear due to fine particles can be more damaging and it has been found that particles of smaller than 10 microns cause 3-4 times the than 40 micron particles.

This isn't much of an issue as the number of fine particles is often very small hence the wear they cause is limited.

If there is a relatively high concentration of small hard particles then wear can accumulate rapidly and wreck a set of bearings.

Getting the large pieces of swarf out of the cooler shouldn't be much of an issue but the concern is that small amounts of fine debris that are trapped in the cooler may tend to migrate into the oil over time and as the level of contamination build up the wear will accelerate.

I would almost certainly send it to Serck Motorsport in Hayes.

Just to finish off documenting the full horror show.








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Amazing, first time I've seen a 911 break this way.
Good luck on the next engine and that cooler.
Graham.

Sorry to see this in all it's gory detail now. As others have said, it is really unusual to see a 911 crank fail like this.

Good luck with the hunt for another unit and the rebuild.