Cranking the engine before starting?

[Ben99GT]

I do just that every oil change to prime the oil system before starting. Pre-fill the filter as much as possible then crank until I get an oil pressure reading (usually 10 seconds or so).

That's the only time I do it though, once the system is primed and the ADBV is doing its job I don't see much of an advantage.

 

[Ben99GT]

Originally Posted By: Chris142
Most oil pumps wont pump oil at cranking speeds. So your just cranking a dry engine over and over.


Eh, most do. In fact that is precisely why most manufacturers require priming the oil system before firing off a new engine.

 

[Craig in Canada]

Originally Posted By: mechtech2
Start the car normally.
Cranking and not starting does not build pressure like a running engine. Not nearly the same.


No, not the same, but my Porsche could build an indicated 4.5-5.0 bar of oil pressure on the starter with the plugs removed. This was M1 15W50 red cap (probably SJ) in the early 2000s coming out of winter storage so it was pretty cool. As I mentioned, on a post-storage start when I had the plugs out anyways it didn't seem like a bad idea.

(I'm not advocating making a daily habit of this)

 

[Bigsyke]

Originally Posted By: Ben99GT
Originally Posted By: Chris142
Most oil pumps wont pump oil at cranking speeds. So your just cranking a dry engine over and over.


Eh, most do. In fact that is precisely why most manufacturers require priming the oil system before firing off a new engine.


This is true. After taking my cars out of storage, I can start it up right away and wait 5 seconds for the oil light to turn off, or crank it for 5 seconds with the kill switches disengaged and the oil pressure light goes off instantly on start up.

Ive done it both ways, I prefer to prime the oil pressure before starting it up after they sit for too long.

 

[Chris142]

Originally Posted By: Ben99GT
Originally Posted By: Chris142
Most oil pumps wont pump oil at cranking speeds. So your just cranking a dry engine over and over.


In fact that is precisely why most manufacturers require priming the oil system before firing off a new engine.
They don't recomend that you prime the engine by cranking it. They recomend spinning oiil pump or presurizing the oil galleys with a pressurized tank of oil.

 

[Ben99GT]

Originally Posted By: Chris142
Originally Posted By: Ben99GT
Originally Posted By: Chris142
Most oil pumps wont pump oil at cranking speeds. So your just cranking a dry engine over and over.


In fact that is precisely why most manufacturers require priming the oil system before firing off a new engine.
They don't recomend that you prime the engine by cranking it. They recomend spinning oiil pump or presurizing the oil galleys with a pressurized tank of oil.


Want to bet?

Ford TSB 01-24-6 ENGINE — ENGINE OIL SYSTEM PRIMING
PROCEDURES — SERVICE TIPS

Overhead cam engines, whether overhauled or remanufactured, prior to starting the engine, ensure the the engine crankcase is filled to specification with engine oil. Disable the fuel supply to the fuel injectors (disable inertia fuel shut-off switch) and crank the engine in fifteen (15) second increments, until the oil pump is primed. An oil pressure gauge can be used to assist in determining when oil pressure is obtained.

 

[Chris142]

Thats definatly a new one to me. You win. I still prefer spinning the oil pump.

 

[Durango]

Originally Posted By: CharlieJ
Hi everyone,

Realizing that I can crank the engine without starting it while holding the accelerator to the floor when turning the key, I wondered if this can be beneficial for a cold dry start. I think this would prelube the bearings before actually starting the engine. What does everyone else think? Can this beneficial? Or, is it a waste of energy?


CharlieJ,

When I was a kid my saw my dad do this many times in the family car but didn't understand why. I beleive it's a truckers thing then he worked for Vons.

Durango