Oil change procedure on a Duratec with Cosworth dry sump

[Doc007]

I need to change the oil on my Duratec which now has a Cosworth dry sump (see photos), a standard 420 style triangular tank ahead of the engine and an oil cooler that sits in front of the lower part of the radiator. 
I can't find a blow by blow instructions that seem to fit my set up. Some descriptions suggest there is a mesh filter somewhere.
I presume the hex key plug on the right side of the engine is the drain plug?

Do I need to drain the dry sump tank? I think there is a plug in the middle at the bottom?

Will there be any O-rings/washers that need replacing?

How much oil will it take?

Thanks in advance.

[KnifeySpoony]

I'm not sure about draining the sump (my 420R sump is a little different), but most of the oil is in the tank. You will need to drain it - you can use the drain plug at the bottom, but most people don't use it as it is prone to stripping, as it's in soft aluminum. Many people use a fluid extractor to suck the fluid out of the tank.

[Doc007]

Thanks Knifey.

Does that not leave a large quantity of oil that has leaked down into the sump? And in the oil cooler and pipe work?

[ScottR400D]

With the Raceline dry sump you suck the oil from the tank with a Pela as said above then remove the finger filter cover (1 M5 cap head) and the rest drains from the sump, quite a lot. 

You could unfasten the pipes and cooler but very little seems to stay in there so I guess it drains back to the sump.  

So, empty tank, remove oil filter, remove finger filter cover and you'll end up with about 7L. Again with Raceline sump but does suggest that quite a lot drains back to the sump. 

[KnifeySpoony]

With my setup (raceline sump), there's probably about a liter that drains from the finger filter hole.

[7 wonders of the world]

If yours has the vetical oil cooler aside the coolant rad then maybe worth taking the hoses of since this wont drain, as the lower hose form the cooler goes to the top of the DS tank, 

 

 

Alternatively you could do a 'rally' style oil change...... remove scavenge hose to DS tank and place in a 20ltr container, start engine and keep topping up the tank until you've pushed about 8ltrs thro, oil changed in minutes  

The shallow filter you need is Mann W77

[Doc007]

Thanks chaps.

And with regards to filling, do you just pour the same volume you removed into the DS tank. Then run it up to temperature and ensure the level is 5mm below the baffle plate (I presume this measure is irrespective of the DS type)?

[ScottR400D]

#7 I guess you're right with your last question and yes, just pour the oil into the tank. Hold the last litre maybe till you've run the engine up and add it then.

For me, I do measure what's come out and put the same amount straight back in.

[Geoff Brown]

On refill I split the oil quantity 50/50 between tank & engine but 'dry' start crank the engine with the inertia switch disconnected to establish good oil pressure.

BUT, quote from my build manual: 'with all variants the engine oil should be filled via the screw cap on top of the engine. Remove the cap from the cam cover and slowly pour in the oil allowing time for the oil to run to the bottom of the engine.'

The annoyingly tricky thing is establishing the correct oil level in the tank once the engine is hot. The initial fill is 6L but this is usually at least half a litre less than required. All the owners hand book states is to establish a tank oil level just below the first visible baffle!

[7 wonders of the world]

Pointless Geoff, the pump receives a positive charge of oil form the DS tank and theres more than sufficient oil in the scavenge to mange a start, you can drop a litre in the engine if you want but just start the engine and check for leaks, warm it up and top up the level 15mm below top plate.

[Geoff Brown]

May appear pointless but we all have our individual ways of doing things based on previous experiences both professional & personal. 

So my best practice will remain the same.

[7 wonders of the world]

As have I.....

But what exactly are you achieving by doing this Geoff in this specific application...?

[Doc007]

Probably a stupid question  but does the engine take its feed from the bottom of the DS tank? And what stops the oil draining from the DS tank into the sump when left over time?

[KnifeySpoony]

Yes, it feeds from the bottom of the tank. I have read about some people having issues with oil siphoning back into the sump when sitting, but I haven't seen that issue. At least, if I look in the tank after the car has been sitting a while, there is still a fair bit of oil in the tank. No issues on cold start.

[SKC]

Hi Doc007,

A good question and one I've thought about myself.  Having worked on several of these cars now and replaced the dry sump system, generally due to engine failures caused by lack of oil, I've written a process and put it on our website.

https://premierpowerengines.com/csr-oil-change-process/

The issue with this oil system is that carrying out an oil change, doesn't drain all of the old oil.  Because there isn't a proper drain on the sump, a quantity of oil is left in the sump.  The only way to try and drain this oil, is to use the engine, to pump it back to the tank and drain it from there.  But you need to ensure there is adequate lubrication to the crankshaft bearing shells to do this.  Please read the process carefully and take your time doing this.  This really is a two person job, one on the ignition key and the other watching the oil coming out of the drain plug at the base of the tank.

Good luck.

SKC.

 

[Doc007]

Thanks Stuart. Sounds scary!