Dry Start A Good Idea?

[roaniecowpony]

Dry cranking = Waste of time, IMO

The cam/rockers are the focus. The pressures on the cam/rocker surface don't change much from dry cranking to idle. The little that the pressures do increase is offset by the higher speed of the oil pump, which makes it more efficient and gets oil to the top end more quickly, in less engine revolutions, IMO, than slower dry cranking. I just don't see spit difference either way.

And it seems to me that a lot of intake rockers/cam lobes were going bad, and those shouldn't have much different pressures while idling, even fast idle.

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[Redcanyon77]

Kinda like dry humping, feels good but nothing happens.

In this case it probably causes more friction and in some case more environmental friendly.

 

[Mudduck]

My jeep sits for 5-12 weeks at a time. on start up, there's no excessive noise, prolonged clatter or anything. Sounds the same as if it only sat overnight. But, that's probably because I run Amsoil... (Just Kidding).

 

[coupedncal]

Ok this explanation helps. The correct term in that case is not dry start but dry crank.

I was not aware pressing the accelerator and hitting the start cranks the engine but does not start the car. Why would they build this capability? What is the use case they did this feature for?

 

[gsbrockman]

Why would they build this capability? What is the use case they did this feature for?

In the rare instance that the engine flooded, that procedure would aid in clearing a flooded engine.

 

[richk225]

They have been around for a while and worth checking out
The issue is not just with Jeeps, but it does keep oil up in the top end. May have to read about it to understand it better but it retains oil instead of draining out so it can deliver it up until the oil pup develops pressure, in a round about way, it was on 2 guys garage and it made sense


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[richk225]

My jeep sits for 5-12 weeks at a time. on start up, there's no excessive noise, prolonged clatter or anything. Sounds the same as if it only sat overnight. But, that's probably because I run Amsoil... (Just Kidding).

First, Your Jeep battery has enough juice after sitting for 5-12 weeks to actually start it? That alone is pretty amazing

And why is everyone against Amsoil? Just wondering

 

[Mudduck]

First, Your Jeep battery has enough juice after sitting for 5-12 weeks to actually start it? That alone is pretty amazing

And why is everyone against Amsoil? Just wondering

I have no issues with my battery starting my Jeep after sitting 3 months on occasion. 5-7 weeks is most common. I wonder what is going on with some jeeps that don't start after shorter time periods? I do not disconnect my battery or accessories either. and I do not put a trickle charger on it. My current battery is an AGM and its 2 years old.

The Amsoil thing is a running joke for some, and a source of oxygen and reproduction for others.

 

[richk225]

I have no issues with my battery starting my Jeep after sitting 3 months on occasion. 5-7 weeks is most common. I wonder what is going on with some jeeps that don't start after shorter time periods? I do not disconnect my battery or accessories either. and I do not put a trickle charger on it. My current battery is an AGM and its 2 years old.

The Amsoil thing is a running joke for some, and a source of oxygen and reproduction for others.

That is something that you and probably others don't have battery issues. My 21 392 was starting to show signs about a month or so ago and I was putting it on a 10 amp charger but the bottom line was that I didn't want to get stuck somewhere and have to wait so I went ahead and bought a good AGM battery and all has been well since. I really feel for the owners that are having issues and the dealers not being much of a help to them, not all have the meters or knowledge and sometimes there is a little too much on the forum

I`ll have to keep an eye out on the Amsoil oil, some of the guys here definitely know how to make you laugh

 

[Tncdrew]

This whole thing is a non-issue.
I would be more concerned about dry steering your Jeep. Dry steering will definitely wear out your steering joints a lot sooner.

 

[Yawnie'sPapa]

It's only turning over at a few hundred RPMs while building oil pressure is my theory. I'm more concerned with the valve train being dry, than the bottom end which is already sitting in an oil bath.

Bottom end better not be sitting in an oil bath.
The modern 3.6 starts with the oil pump in high volume mode and pressure builds in just a second or two after the start. You can monitor this pretty easily.
Think of the millions of 3.6s on the road with no troubles - many 3.6s have way over 100,000 trouble-free miles, but then there's armchair engineers who know better..........

 

[Mudduck]

Bottom end better not be sitting in an oil bath.
The modern 3.6 starts with the oil pump in high volume mode and pressure builds in just a second or two after the start. You can monitor this pretty easily.
Think of the millions of 3.6s on the road with no troubles - many 3.6s have way over 100,000 trouble-free miles, but then there's armchair engineers who know better..........

MY work van is a 2017 Caravan. 3.6 and has 202,774 miles. No issues. The transmission is another shit show, engine is still solid.

 

[roaniecowpony]

Oil level in the pan is well below the crankshaft and there's a windage tray between the crankshaft and the the oil.

 

[Flip]

So I happened on a YouTube just after I took delivery of the JL and they were describing how the 3.6 does not have a one way valve in the oil filter assembly, so when you switch off, all the oil drains out of the top half of the engine, so when you start up from cold, there is no oil up there for a few seconds, hence problems down the track with lifters etc. Sounded reasonable to me, and they were pushing their own oil filter assembly that incorporated a one way check valve, which sounded good, except would give the dealer an out if it ever came to a power train warranty issue.
So every morning, I have been dry starting - foot flat on the gas and brake - motor will crank but does not start. figuring that this will oil the top half of the motor, then I start normally.
Dumb idea or not?

How much oil is left in the top half of the engine after draining? I don't know.

I remove 5 quarts of oil, I put in 5 quarts of oil, the dip stick level is correct. The 5 quarts I remove goes back into the empty 5 quart container. Does this seem logical or am I missing something?

If you're worried about burning off the teaspoon of oil left in the top half of the engine, by all means dry fire it.

How did changing the oil become so complicated? I'm really starting to see what Ted Kaczynski was on too.

 

[Bandit59]

So I happened on a YouTube just after I took delivery of the JL and they were describing how the 3.6 does not have a one way valve in the oil filter assembly, so when you switch off, all the oil drains out of the top half of the engine, so when you start up from cold, there is no oil up there for a few seconds, hence problems down the track with lifters etc. Sounded reasonable to me, and they were pushing their own oil filter assembly that incorporated a one way check valve, which sounded good, except would give the dealer an out if it ever came to a power train warranty issue.
So every morning, I have been dry starting - foot flat on the gas and brake - motor will crank but does not start. figuring that this will oil the top half of the motor, then I start normally.
Dumb idea or not?

In my opinion there is not much difference in this and any other engine. There is always some there. It don’t have to be floating in oil to be protected. Now if it sat for days or weeks then maybe. I probably would not do it then. I have a 5.7 Ram. I had lifter tick after it set for maybe an hour.

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