JK Pre-Start Oil Trick

[JerryD]

Anyone else know about this? Am I late to the party? I just came across this video.

Basically, if you hold the skinny pedal down while cranking, the engine won't fire but it the oil WILL prime. Release the ignition, release the pedal and then crank as normal and engine starts.

Down side is the starter has a bit more stress, but starters are cheaper than engines. This sounds like a great trick for those cold winter mornings...

 

[BLACKJKU]

Anyone else know about this? Am I late to the party? I just came across this video.

Basically, if you hold the skinny pedal down while cranking, the engine won't fire but it the oil WILL prime. Release the ignition, release the pedal and then crank as normal and engine starts.

Down side is the starter has a bit more stress, but starters are cheaper than engines. This sounds like a great trick for those cold winter mornings...

No I've never heard of that trick but my JK has a block heater from the factory.

 

[Dirty Dog]

Never heard of it, but I'll have to try it.

 

[Dirty Dog]

I can confirm that this does prevent starting both the 3.8L and 3.6L engines.

 

[JeepJeezy]

Confirmed it works on my 2015.

 

[Leadhead1]

Read the thread yesterday, tried it today and it works.

 

[1o1Proof]

Engine revolutions are engine revolutions….

 

[Speartip]

Engine revolutions are engine revolutions….

Yeah that is what I was thinking .
Generally the term priming or pressuring up an
oil pump and getting oil in the system is
done without turning the engine over .
As you want critical components oiled up
before turning over .ie. New Rebuild .
Just start the engine seems the most logical .
If In cold climate just plug in as @BLACKJKU
mentioned .

 

[BLACKJKU]

Yeah that is what I was thinking .
Generally the term priming or pressuring up an
oil pump and getting oil in the system is
done without turning the engine over .
As you want critical components oiled up
before turning over .ie. New Rebuild .
Just start the engine seems the most logical .
If In cold climate just plug in as @BLACKJKU
mentioned .

Do all the JK's have a block heater or just the Canadian Jeeps?

 

[Speartip]

Do all the JK's have a block heater or just the Canadian Jeeps?

Not sure TBH . Mine does but it’s never cold enough on Vancouver Island to use .
I do know if living in Alberta, Saskatchewan, Manitoba , Northern BC it’s pretty much standard equipment to have a block heater.
Can get very cold in the winter . But even than while living in Edmonton I remember over the years hearing a couple friends complaining that had to pay to have block heater installed on new vehicle ?
So it’s not a guarantee that all new vehicles have them in colder area’s but most do.

 

[BLACKJKU]

Not sure TBH . Mine does but it’s never cold enough on Vancouver Island to use .
I do know if living in Alberta, Saskatchewan, Manitoba , Northern BC it’s pretty much standard equipment to have a block heater.
Can get very cold in the winter . But even than while living in Edmonton I remember over the years hearing a couple friends complaining that had to pay to have block heater installed on new vehicle ?
So it’s not a guarantee that all new vehicles have them in colder area’s but most do.

Reason I asked was because mine is a Canadian made Jeep.

 

[Speartip]

Reason I asked was because mine is a Canadian made Jeep.

I Quote

Originally, the Wrangler was built in Canada, but in 1993, production of all Wranglers was moved to Toledo, Ohio.

All JK’s , JL’s etc built in Toledo for N America . I’m assuming they have plants in Europe for that part of the world

 

[JerryD]

Yeah that is what I was thinking .
Generally the term priming or pressuring up an
oil pump and getting oil in the system is
done without turning the engine over .
As you want critical components oiled up
before turning over .ie. New Rebuild .
Just start the engine seems the most logical .
If In cold climate just plug in as @BLACKJKU
mentioned .

I do agree with you. Reflecting on this, the only argument I can see rationalizing this is that doing this turns it over for a few seconds at a lower rpm than when it actually fires. ???

So this is more likely along the lines of Lettermans old "stupid pet tricks"

 

[JeepJeezy]

I do agree with you. Reflecting on this, the only argument I can see rationalizing this is that doing this turns it over for a few seconds at a lower rpm than when it actually fires. ???

So this is more likely along the lines of Lettermans old "stupid pet tricks"

Weird thing thing for me is, when I start my Jeep, the valves chatter for like 2 seconds. When I did the peddle thing a couple times there was no chatter on startup each time.

 

[Dirty Dog]

Weird thing thing for me is, when I start my Jeep, the valves chatter for like 2 seconds. When I did the peddle thing a couple times there was no chatter on startup each time.

The thinking is that the starter turns at a much lower RPM, which means there's less inertia in the bits and pieces that rattle, so they don't rattle.

Does this impact actual wear? Nobody really knows, other than as a purely theoretical exercise.

 

[Dirty Dog]

I'm texting the PhD engineer about this. I suspect what he will tell me is that building oil pressure while dead cranking will result in less friction wear than just starting the engine and then letting pressure build. But I also suspect he's going to say that the difference will not make any real world difference in longevity of engine components. I'll update after he replies.

 

[WestCoastDan]

I get the idea behind it. Not unlike getting oil pressure to the heads on a freshly built motor by removing the coil wire from the distributor during the initial turn over.
IF this trick would also magically remove the metal-to-metal contact that occurs it would make sense, BUT... all of the moving parts are still contacting each other BEFORE the oil gets there, so I have to ask... "Why bother"?

 

[JerryD]

I get the idea behind it. Not unlike getting oil pressure to the heads on a freshly built motor by removing the coil wire from the distributor during the initial turn over.
IF this trick would also magically remove the metal-to-metal contact that occurs it would make sense, BUT... all of the moving parts are still contacting each other BEFORE the oil gets there, so I have to ask... "Why bother"?

So the Bronco guys can point and say "look at the doofus that can't start his Jeep"

 

[Dirty Dog]

I get the idea behind it. Not unlike getting oil pressure to the heads on a freshly built motor by removing the coil wire from the distributor during the initial turn over.
IF this trick would also magically remove the metal-to-metal contact that occurs it would make sense, BUT... all of the moving parts are still contacting each other BEFORE the oil gets there, so I have to ask... "Why bother"?

Because 5 seconds without oil pressure at 200 RPM from the starter motor is less than 5 seconds at 1000 RPM when the engine cold starts. And there's more to consider than just inherent friction. After the cold start, the pressures are much much higher inside the cylinders (thanks to the miracle of internal combustion), which also increases the pressure on all the other bits involved.

And as I said, that may well be one of those statements that is completely correct and still completely irrelevant. It is certainly true, but does it have any impact in the real world?

 

[Dirty Dog]

So I heard back from the nerd...err.... engineer this morning. He confirmed what I expected. Spinning it with the starter will causes less friction wear than cold starting, but that in something that easily lasts 200,000 miles the difference in lifespan will be negligible.

But this is certainly handy if that cold start rattle bothers you.