Oil system question
Discussion
We had a bit of a discussion on the Tuscan forum about oil level checking and it appears the non-technical amongst us do not appreciate the configuration of the oiling system of the dry sump Speed 6 engine, so I thought I would ask the good and the great on this forum.
If anyone can help with a basic description of the oil system and resevoirs etc, then that would be of great help? We were simply trying to discover whether it was possible to check the oil level accurately when cold instead of when hot and got ourselves in a bit of a muddle.
If anyone can help with a basic description of the oil system and resevoirs etc, then that would be of great help? We were simply trying to discover whether it was possible to check the oil level accurately when cold instead of when hot and got ourselves in a bit of a muddle.
In a dry sump, extra oil is stored the tank outside the engine rather than in the sump.
There are two oil pumps in a SP6 dry sump, the scavenge pump pulls oil from the engine sump and sends it to the tank, and the HP Oil pump takes oil from the tank to lubricate the engine.
The minimum amount of oil possible remains in the engine, reducing oil drag on the crankshaft etc.
A dry sump does not need to have an oil sump big enough to hold all the oil under the engine, so the engine can be placed lower in the car.
Once you switch the engine off the oil from the full dry sump tank bleeds back into the engine (dependant on ambient temp & oil viscosity)through the clearances in the HP Oil pump to find its own level.
If you measure oil level when cold its dependant on how long you leave it, the oil type etc
IMO 'hot switch off level check' for most consistent method
G
There are two oil pumps in a SP6 dry sump, the scavenge pump pulls oil from the engine sump and sends it to the tank, and the HP Oil pump takes oil from the tank to lubricate the engine.
The minimum amount of oil possible remains in the engine, reducing oil drag on the crankshaft etc.
A dry sump does not need to have an oil sump big enough to hold all the oil under the engine, so the engine can be placed lower in the car.
Once you switch the engine off the oil from the full dry sump tank bleeds back into the engine (dependant on ambient temp & oil viscosity)through the clearances in the HP Oil pump to find its own level.
If you measure oil level when cold its dependant on how long you leave it, the oil type etc
IMO 'hot switch off level check' for most consistent method
G
Thanks VarleyHD.
Would I be right in thinking therefore that if you left the engine to cool overnight and checked the level the next morning that presuming there were no oil leaks the level would be accurate? I have tried this with my Tuscan MK1 4.0L and I get very consistent "cold" oil level readings.
However when I try using the "hot" method I get very varied readings, even though I use the same procedure of not switching off the engine until I have opened the small bonnet and running round to check the level as soon a I can.
Would the length of time the engine is at idle affect the level in the oil tank?
Would I be right in thinking therefore that if you left the engine to cool overnight and checked the level the next morning that presuming there were no oil leaks the level would be accurate? I have tried this with my Tuscan MK1 4.0L and I get very consistent "cold" oil level readings.
However when I try using the "hot" method I get very varied readings, even though I use the same procedure of not switching off the engine until I have opened the small bonnet and running round to check the level as soon a I can.
Would the length of time the engine is at idle affect the level in the oil tank?
Chequred Demon said:
Would I be right in thinking therefore that if you left the engine to cool overnight and checked the level the next morning that presuming there were no oil leaks the level would be accurate?
I think it would be consistent on that basis, but it will be individual to every car dependant on oil viscosity wear in pump rotor etc, and I guess you probably will not see the level on the dipstick.Chequred Demon said:
Would the length of time the engine is at idle affect the level in the oil tank?
Yes, but again individual to every car dependant of rotor wear, idle rpm, viscosity etc.The 'best yard stick' is when next doing an oil change (a full one, inc siphon the engine sump) fill with 9 litres, and check level before starting.
G
I'd concur with the 20mm cold level. I also wonder if this would be the better way of checking. Mine never used to drain back much at all, but recently you can hear it gugle backwards after switch off so you have to be quick to check it by traditional method.
Needles to say level ground is important.
Concensus is that slight overfill is better than underfill
Needles to say level ground is important.
Concensus is that slight overfill is better than underfill
VARLEYHYD said:
Chequred Demon said:
The 'best yard stick' is when next doing an oil change (a full one, inc siphon the engine sump) fill with 9 litres, and check level before starting.
Is this correct that it should be 9 litres of oil in the system. When i drained mine completetly I got 8 litres out of the engine sump and the dry sump.My handbook say 6 litres in the system which never has worked to fill the system up to the mark on the dipstick.
On my early Cerbera SP6 there is only one mark on the dipstick which I have been using as the top level, and I hope the low level is when you have some oil on the lower end of the dipstick.
Peppe said:
VARLEYHYD said:
The 'best yard stick' is when next doing an oil change (a full one, inc siphon the engine sump) fill with 9 litres, and check level before starting.
Is this correct that it should be 9 litres of oil in the system. When i drained mine completetly I got 8 litres out of the engine sump and the dry sump.Peppe said:
My handbook say 6 litres in the system which never has worked to fill the system up to the mark on the dipstick.
True but thats only the dry sump tank volume, easy cop out to change 2/3rds of the oil only! not the full change G
OK !
That explains why I have had to top up the oil after putting 7.5 litres in when I changed the oil. I have all together put in about 8.5 litres now.
I have used a bigger oil filter on my car so it probably needs a little bit more than 9 litres.
The oil filter I have used is the same size as used on a Ford 7.5 litre marine engine. The reason I wanted a bigger filter is that I think a engine of the size of a SP6 should have a bigger filter than the original one. The filter I use is recommended to me by FRAM filters when I asked them if it was possible to use a bigger filter. What you need to check is that the filter has the same internal construction with reverse valve etc. as the original, so I gave the number on the original to FRAM and they answered me with a number on a bigger filter with the same internal construction.
Varlehyd, do you know how much oil it is in the oil cooler ?
That explains why I have had to top up the oil after putting 7.5 litres in when I changed the oil. I have all together put in about 8.5 litres now.
I have used a bigger oil filter on my car so it probably needs a little bit more than 9 litres.
The oil filter I have used is the same size as used on a Ford 7.5 litre marine engine. The reason I wanted a bigger filter is that I think a engine of the size of a SP6 should have a bigger filter than the original one. The filter I use is recommended to me by FRAM filters when I asked them if it was possible to use a bigger filter. What you need to check is that the filter has the same internal construction with reverse valve etc. as the original, so I gave the number on the original to FRAM and they answered me with a number on a bigger filter with the same internal construction.
Varlehyd, do you know how much oil it is in the oil cooler ?
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