Diesel starting after storage?

[TUT]

After a year in storage how’s best to start a Fiat Ducati 2.3, considering the Oil which was new just before storage has drained to the bottom of the engine?

 

[PP Bear]

The oil pump turns whether the engine fires or not. It's perfectly possible to achieve full oil pressure using the starter alone. I do it every time I change the oil filter on a non-ECU vehicle.

Each to their own dear Funster, each to their own

 

[Fontie]

Your all wrong the pressure is caused when the gangle pin moves and closes the foo foo valve.

 

[L' Hobo]

Hmm well, I may not be totally correct however this guy has a thing to say about pressure so
I guess I little knowledge is a Dangerous thing, I do agree with you "The pumping action of the journal forces the oil to squeeze through the wedge shaped gap generating a pressure."

I am sure we are all right and wrong, I think this helps to explain why all the oil does not all pour out of the sides of the shells.

http://www.kingbearings.com/wp-content/uploads/2014/10/Engine-Bearings-and-how-they-work.pdf

As a VERY old engineer who has worked on engines from 1960s ships to 2010 plant engines, I think you should have posted the 'link' long ago but even, with the link, one still needs more than a 'little knowledge'. One has to realise that there is a big difference between older engines and the new ones (which I know very little about) Older car engines, usually, produced pressure in the system by squeezing oil between two cogs, driven by a shaft, enclosed in a oil pump until the complete system was charge up to the pressure of the relief valve. Restrictor valve were, sometimes, incorporated into the system. I thought that new engines had a similar system, just more sophisticated. Maybe I'm wrong! Also, something that has been mentioned a number of time, fluid CAN be compressed, just at different rates, which is why you get a 'spongy' brake pedal when water gets absorbed in your brake fluid. In answer to the OP's question, charge the battery, check the oil and water level, and just start it!

 

[L' Hobo]

I'm speaking from admittedly limited experience. The vehicle with an oil gauge was a Reliant Scimitar with a 3 litre V6 Ford engine. Idle pressure on a cold engine was around 50 - 60 psi. It would reach 50+ on the starter motor. Whenever possible, if starting with a new and partially filled oil filter, I crank the engine without starting it until I see the pressure gauge move or at least the oil light go out. Nowadays that isn't easy or possible and no it doesn't worry me. Starting an engine that has stood for while wouldn't worry me at all - the oil filter is full anyway. I'd simply start it without a second thought. As I have always done.

Here's a few:

I agree with the last part! New oils have made things much easier, just get the right one for the right engine.

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[tacr2man]

"New oils" have been around for quite while now , and quite a few engines have been specced oils to aid with meeting emissions testing requirements . This has led to other problems , one particular example was found in Australia where the V6 GM engine would have the oil low pressure warning light come on when idling as the oil was that thin when hot it couldn't maintain pressure . Oil spec (viscosity )changed problem solved . Lubrication on "new engines" operates on the same principle as old engines .

 

[tonyidle]

As a VERY old engineer who has worked on engines from 1960s ships to 2010 plant engines, I think you should have posted the 'link' long ago but even, with the link, one still needs more than a 'little knowledge'. One has to realise that there is a big difference between older engines and the new ones (which I know very little about) Older car engines, usually, produced pressure in the system by squeezing oil between two cogs, driven by a shaft, enclosed in a oil pump until the complete system was charge up to the pressure of the relief valve. Restrictor valve were, sometimes, incorporated into the system. I thought that new engines had a similar system, just more sophisticated. Maybe I'm wrong! Also, something that has been mentioned a number of time, fluid CAN be compressed, just at different rates, which is why you get a 'spongy' brake pedal when water gets absorbed in your brake fluid. In answer to the OP's question, charge the battery, check the oil and water level, and just start it!

A liquid of any sort is effectively non-compressible. The reason brakes become spongy when the fluid is contaminated with water is that the mixture has a much lower boiling point than pure brake fluid. It's the vapour produced by the mixture when heated by the pads / shoes that makes the pedal go soft. When cold the brakes will operate normally with only water as an hydraulic fluid.

 

[Driventemple]

Older car engines, usually, produced pressure in the system by squeezing oil between two cogs,

Nooo! The oil is pushed around the the outsides of the 'cogs'. It does not get mangled through the middle.

 

[jockaneezer]

....and don't forget, your oil pump doesn't create pressure, only flow !

 

[Coolcats]

....and don't forget, your oil pump doesn't create pressure, only flow !

Exactly it is when it goes through the oil galleries which then help to produce pressure amongst the other things mentioned (including the pressure from the Crank! as described by Dr Dimitri in the link I posted)

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[eurajohn]

Interestingly the oil pump in an engine only provides a few pounds of pressure, the rest comes from the con rod and the mains bearings as the engine runs ( hence lower oil pressure wen the mains bearings wear as this is where the oil escapes under pressure)

There are some mistakes and suppositions in your replies.
It would appear from your replies (that appear to come directly from this link [here]) the oil pump in question is only capable of producing 10 lbs of pressure, not so.

As the piston hurtels up and down the bore the forces created try and squeeze the oil between the Conrod bearing And the crankshaft trying to squeeze the oil out of the gap between the bearing and crank, a liquid cannot be compressed so the oil is forced back up through the oil galleries, it is this that creates pressure an oil pump only produces around 4lb of pressure the rest is done by the pressure created around the crank and is why I change the oil every year.

The oil is not forced back up through the galleries the controlled clearances between the bearing and the journal causes a restriction to the FLOW of oil which creates the pressure

Interesting I have a car that displays 70lb of pressure at 70 mph and the water temp is 70 degrees @2,500rpm. If the water temp goes up the pressure drops a few lbs this is due to viscosity (not thickness or thinness of the oil) Visosity is the rate of flow at a given temperature

You obviously like Wiki for your info [here] but to the layman viscosity is very closely linked to thickness.

Just as important as pressure is the flow of oil as without sufficient flow no matter how much your bearings squash the oil there will not be sufficient lubrication further around the engine to keep it alive.

 

[Coolcats]

As a VERY old engineer who has worked on engines from 1960s ships to 2010 plant engines, I think you should have posted the 'link' long ago but even, with the link, one still needs more than a 'little knowledge'. One has to realise that there is a big difference between older engines and the new ones (which I know very little about) Older car engines, usually, produced pressure in the system by squeezing oil between two cogs, driven by a shaft, enclosed in a oil pump until the complete system was charge up to the pressure of the relief valve. Restrictor valve were, sometimes, incorporated into the system. I thought that new engines had a similar system, just more sophisticated. Maybe I'm wrong! Also, something that has been mentioned a number of time, fluid CAN be compressed, just at different rates, which is why you get a 'spongy' brake pedal when water gets absorbed in your brake fluid. In answer to the OP's question, charge the battery, check the oil and water level, and just start it!

I read that as a very experienced engineer (age +Wisdom) and yes I guess if you are working on plant and Marine engines the Oil pump, and oil pressures may be different to run of the mill vans and cars so I cant comment.

Maybe you can compress a liquid but the forces involved would be far greater than a braking system or engine can generate. I think you will find that 'spongey brakes' are normally associated with air, water in the braking system is an issue if your coming down a mountain pass as the brake fluid essentially has a lower boiling point and gasses are being generated by braking and a lot of heat can be generated causing the brake fluid to 'boil' creating that spongey feeling underfoot. (I suspect that is what you meant)

Top tips Change the oil regularly, change the brake fluid regularly and I totally agree with you regarding the OP's question

 

[Pausim]

I read Dr Dimitri’s explanation very differently, yes the bearing is supported by hydrodynamic pressure at the 180 degree point but this is transitory and cancelled out by the time that part of the crank completes 360 degrees, where the oil enters the bearing. So it seems to me that the constant pressure of the oil in the rest of the system depends on the oil pump, otherwise oil would not flow into the bearing but be forced back.

 

[mitzimad]

Interestingly the oil pump in an engine only provides a few pounds of pressure, the rest comes from the con rod and the mains bearings as the engine runs ( hence lower oil pressure wen the mains bearings wear as this is where the oil escapes under pressure)

that isnt correct only the pump provides oil pressure it goes low when shells are worn as the oil is just running through them bit like putting your finger over the end of a hose

 

[Coolcats]

I read Dr Dimitri’s explanation very differently, yes the bearing is supported by hydrodynamic pressure at the 180 degree point but this is transitory and cancelled out by the time that part of the crank completes 360 degrees, where the oil enters the bearing. So it seems to me that the constant pressure of the oil in the rest of the system depends on the oil pump, otherwise oil would not flow into the bearing but be forced back.

I haven't read anywhere that the flow from an oil pump is not essential, many engines have multiple pistons but even a single piston engine rotating at 1,000 rpm would keep oil pressure up, as the oil flows around an engine it get restricted by various galleries and increases pressure at various points (just think of a hose pipe when open the water flows out and you can create a more powerful jet by closing the end) if reverse flow was an issue I suspect some bright spark would place a non-reverse valve in.

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[Pausim]

All I am saying is that the hydrodynamic pressure at the crank does not contribute to the pressure elsewhere in the oil system, this is provided by the oil pump.

 

[tonyidle]

that isnt correct only the pump provides oil pressure it goes low when shells are worn as the oil is just running through them bit like putting your finger over the end of a hose

The crank can, under certain circumstances, produce negative pressure (suction) if the oil feed drillings that feed the big end bearings emerge vertically at top dead centre. Hence cross-drilling to prevent the effect.

 

[mitzimad]

note to self read the whole thread yes bearings do float but they float on the oil pressurised by the pump
#

 

[Coolcats]

All I am saying is that the hydrodynamic pressure at the crank does not contribute to the pressure elsewhere in the oil system, this is provided by the oil pump.

The oil pump provides flow at a lowish pressure, without flow there is no pressure, the higher pressures are generated within the engine by constricting flow (as a liquid cannot be compressed) and the other forces within the engine itself. The force within the crank is not a neutral or negative one therefore it will effect the pressure within the rest of the unit, the oil in the crank is not a separate system therefore it is systemic by nature, if the bearings wear, the forces become less (across all area's within the unit) and oil pressure falls.

 

[Vipar]

Is this thread only relevant until 2035 just asking ?

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[Pausim]

The oil pump provides flow at a lowish pressure, without flow there is no pressure, the higher pressures are generated within the engine by constricting flow (as a liquid cannot be compressed) and the other forces within the engine itself. The force within the crank is not a neutral or negative one therefore it will effect the pressure within the rest of the unit, the oil in the crank is not a separate system therefore it is systemic by nature, if the bearings wear, the forces become less (across all area's within the unit) and oil pressure falls.

I don’t agree, because the cavitation referred to by Dr D cancels out the pressure at the single point where the bearing connects to the rest of the oil system.

 

[Coolcats]

Is this thread only relevant until 2035 just asking ?

Probably not but i'm bored..... ? Le Hobo post above is probably the most relevant

" In answer to the OP's question, charge the battery, check the oil and water level, and just start it!"

 

[Coolcats]

I don’t agree, because the cavitation referred to by Dr D cancels out the pressure at the single point where the bearing connects to the rest of the oil system.

OK that's fine, ?

 

[Coolcats]

The crank can, under certain circumstances, produce negative pressure (suction) if the oil feed drillings that feed the big end bearings emerge vertically at top dead centre. Hence cross-drilling to prevent the effect.

Just a pause for thought, and I am not saying your wrong if negative pressure can be created, then conversely positive pressure can also occur.

 

[tonyidle]

Just a pause for thought, and I am not saying your wrong if negative pressure can be created, then conversely positive pressure can also occur.

No . The negative pressure is caused by the oil being drawn from the big end drilling by centrifugal force as the crank spins. The effect can result in main bearing oil starvation.

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[Tykatem]

Probably not but i'm bored..... ? Le Hobo post above is probably the most relevant

" In answer to the OP's question, charge the battery, check the oil and water level, and just start it!"

And if it does'nt fire up try

Pete

 

[tonyidle]

The oil pump provides flow at a lowish pressure, without flow there is no pressure, the higher pressures are generated within the engine by constricting flow (as a liquid cannot be compressed) and the other forces within the engine itself. The force within the crank is not a neutral or negative one therefore it will effect the pressure within the rest of the unit, the oil in the crank is not a separate system therefore it is systemic by nature, if the bearings wear, the forces become less (across all area's within the unit) and oil pressure falls.

The pump generates zero pressure. Pressure is generated by restriction of its outlet by the interface between oil drillings and bearings. Provided that pump throughput exceeds the ability of the bearings to leak oil then pressure is generated. As bearing clearances increase due to wear oil dispersal from the bearings increases and less restriction is offered to the pump. Once the pump excess flow is used up the pressure will drop.

 

[John Barrett]

Absolutely spot on Tony!
Incidentally, finding and quoting a source and attempting to discuss it with real engineers who actually know what they are talking about can potentially cause some embarrassment!
Didn't the OP just want to know if he could start the thing?
John

 

[tonyidle]

Absolutely spot on Tony!
Incidentally, finding and quoting a source and attempting to discuss it with real engineers who actually know what they are talking about can potentially cause some embarrassment!
Didn't the OP just want to know if he could start the thing?
John

Yep - PP Bear answered the question perfectly (post 2 I think) ?.

 

[68c]

Oil is most certainly compressible. The Army Auster spotter aircraft had Dowty Liquid Spring undercarriage suspension. A small piston, by memory about 1/2" in diameter with 2" stroke, was completely charged with hydraulic oil and pressurised to some 2000PSI. The suspension arm was about 3ft long and pivoted around its attachment pin, the piston being anchored to fuselage and attached to the suspension arm a short distance from the pivot, so good mechanical advantage against the liquid spring.

During my apprenticeship the instructor first taught us hydraulics then the liquid spring. He did it that way to stop any smart Alec asking how hydraulics work if oil is compressible. The answer of course it takes tens of thousands of PSI to compress the liquid.

Just start the engine, warm it up then change the oil.

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[John Barrett]

Oil is most certainly compressible. The Army Auster spotter aircraft had Dowty Liquid Spring undercarriage suspension. A small piston, by memory about 1/2" in diameter with 2" stroke, was completely charged with hydraulic oil and pressurised to some 2000PSI. The suspension arm was about 3ft long and pivoted around its attachment pin, the piston being anchored to fuselage and attached to the suspension arm a short distance from the pivot, so good mechanical advantage against the liquid spring.

During my apprenticeship the instructor first taught us hydraulics then the liquid spring. He did it that way to stop any smart Alec asking how hydraulics work if oil is compressible. The answer of course it takes tens of thousands of PSI to compress the liquid.

Just start the engine, warm it up then change the oil.

Here's the original patent with drawings. Very interesting!

US2563194A - Liquid spring resilient unit - Google Patents