The reality of dry starts on a vehicle.

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Well I am here to gain knowledge so please don't throw tomatoes and trash here folks.
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I am not talking about anybody here but my own opinion on this, but is a dry start really non-existant.

Because I really understand a new engine out of the box and placed in a vehicle is a scenario where you need to worry about a dry start.

But after purchasing a vehicle isn't it already prepared and a car is already to go with all it's lubrication.

Moreover, you really don't need to worry about a dry start after changing an oil filter unless the car has been sitting a long time;
there will be enough oil left coating the internals for that brief period of time before oil is recirculated.

Oil is greasy as heck, and if you poured a bucket over your head and stood there for 2 hours, you will still be slippery. It's tough get that off your skin as it is.

So I am saying, isn't all this talk about dry start a misconception.

Do we really mean that we want that 8 tablespoons of oil in the filter to feel better.

Really mean:
Dry start = 8 tablespoon of oil start so I feel better.

I just feel TECHNICALLY there is no such thing as a dry start.
If oil fell to the bottom of the oil pan like water than the engine parts is dry like a countertop, then I would say that could be dry starting.

I really don't worry about dry starting until I came into the forums.

Personally, I thought changing the oil and filter was doing a good job in itself as a regular person trying to keep their car in good shape.
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I really want less things to worry about.

Moreover, poeple say there is a half quart in the engine still after draining.

Just bored and thinking about dry starts.
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I reference to empty oil filters , yes there is a oil already in the bearings and length of the crankshaft. MY question is always , where does the air thats in the oil filter go?? I theorize that the air is being pushed down the crankshaft displacing the oil off the bearings and journals, until the filter is filled and oil pressure returns. I fill my oil filters first.
 
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Originally Posted By: spasm3
I reference to empty oil filters , yes there is a oil already in the bearings and length of the crankshaft. MY question is always , where does the air thats in the oil filter go?? I theorize that the air is being pushed down the crankshaft displacing the oil off the bearings and journals, until the filter is filled and oil pressure returns. I fill my oil filters first.

Of course the air is pushed out through the oil galleys, but you are not eliminating this by filling the filter. This is nothing to worry about. Even if you don't fill the filter the oil is going to reach engine parts so fast that it doesn't matter. Fill it if it makes you feel good, but it doesn't do any good.
 
There have been studies that show that the bulk of wear is at startup. "Dry" or not, there is not a sufficient pressure-backed film present to allow for true hydrodynamic lubrication. You are still reliant on whatever thin film plus additives exist.

Is this a huge deal or a tiny one? Most may never know. I have a lot of seldom-used cars, and knock on wood, they have not exhibited any issues.
 
Mine are never really full anyway.

The 6 is at about a 45° angle and the PT is parallel to the ground mounted on the oil cooler.

If you filled it, you would lose half the contents when you put it on. Especially on the PT. Not all FL400S size filters are exactly the same length and some need a little extra manipulation to get in that area. (the convenient rough surface on the top of the OCOD makes it about a 1/2 mm too big to easily slide into place.
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I still like to "prime" the filter media and it gives me a small amount of oil to run around the filter gasket. And while it's settling into the filter media I get a red rag and wipe down the filter mount to make sure the old gasket came off.

I honestly don't care if it doesn't do any good. I've been doing this for so long that I can't see any reason to change now.
 
If I dont fill up my oil filter my truck will make a horrible screeching sound for a second. I always fill up the filter, which is about half a quart.
 
I've noted this over and over in many of the cars that i service regularly... the oil pressure light goes off MUCH faster if the oil filter is primed during that initial start after an oil change.

Engine noise decreases much quicker as well because oil pressure builds up faster and oil starts flowing.

There's a reason why oil filter have anti-drain back valves, to prevent the oil from draining out and minimize dry start.

If it wasn't THAT important, that valve wouldn't be there.

That said, i'm sure the engine will be "fine" without priming the oil filter but to me, priming it just making the oil change that much closer to being "the perfect, professional oil change method."
 
Originally Posted By: hisilver
If I dont fill up my oil filter my truck will make a horrible screeching sound for a second. I always fill up the filter, which is about half a quart.

Then there is something else wrong with your truck.
 
I expect the wear at start-up is due to the fact the oil is thick and not flowing the way it should. Most cars live happy long lives, and the shops that change their oil never prefill an oil filter.

As far as new engines go, they are filled with zinc rich assembly lube, so i don't think we need worry
 
Idle load doesnt present much wear in a normally clearanced engine. Worry about hard acceleration in a non-warmed up engine when the EP add are non-functional. A Moly DTC additised oil would help here as would an oil thet has some polar base component (PO, alkylated naphth or ester and di-ester). Most cold start cylinder wear is etching from acid formation from the Sulfur in the fuel. What are you going to do about that?
 
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Originally Posted By: JHZR2
"Dry" or not, there is not a sufficient pressure-backed film present to allow for true hydrodynamic lubrication.


Exactly.

On a run of the mill street car, this may not be that big of a deal, though I always fill the filter during an oil change on any vehicle. When it comes to my race car, I rely on a 1 qt. oil accumulator to provide pressurized oil to the bearings before every startup.

-Rod
 
Originally Posted By: spasm3
I reference to empty oil filters , yes there is a oil already in the bearings and length of the crankshaft. MY question is always , where does the air thats in the oil filter go?? I theorize that the air is being pushed down the crankshaft displacing the oil off the bearings and journals, until the filter is filled and oil pressure returns. I fill my oil filters first.


To answer that question... I remember reading a book by a Rolls-Royce engineer talking about their work with airplane engines during WWII, and what would sometimes cause sudden bearing failure. They found that if they were running an engine under load and simply stopped the oil pump and oil flow, the engine would be fine for a surprisingly long time- minutes if I remember right. If on the other hand they stopped the oil flow and blew compressed air into the oiling system, the bearings would fail almost immediately (reference: "The Merlin in Perspective: the War Years" by Wilfred Hyde-White).

Now- your oiling system on most cars is probably set up so that when you start the engine, most of the air in the filter winds up going upward to the lifters and head, not to the bearings, and its also not being forced in under extremely high pressure, AND the bearings aren't heavily loaded since you do this at idle, not on a dyno with the engine at full power and under load the way the Rolls-Royce guys were doing it. But I think limiting the amount of air forced out of the filter and into the oiling system on startup by pre-filling the filter is a good thing. And its also a good idea to start the engine and just let it idle until the pressure comes up, even if that takes longer than revving it up a bit.
 
Agree with new engines being prelubed with, as they call it, "Assembly Lube".

There's a reason that good oil filters have anti-drainback valves. Having a ready supply of oil to pump to a newly started engine is, IMO, better than pumping air - backed up by having had the same things occur as other members above (more noise from engine and longer for oil pressure to come up with non-filled filter.

So I guess I'm part of the "fill the filter" club.
 
Exactly, limiting engine noise during start up and faster build up of oil pressure is good enough for me to spend a few seconds and pour a little oil into the oil filter.

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If you don't prime the oil filter, the engine will self destruct in less than 500,000 miles :) Are you prepared to take that chance? If you take routine care of engine lubrication, it will outlast the rest of the vehicle.

- Vikas
 
Originally Posted By: 440Magnum
To answer that question... I remember reading a book by a Rolls-Royce engineer talking about their work with airplane engines during WWII, and what would sometimes cause sudden bearing failure. They found that if they were running an engine under load and simply stopped the oil pump and oil flow, the engine would be fine for a surprisingly long time- minutes if I remember right. If on the other hand they stopped the oil flow and blew compressed air into the oiling system, the bearings would fail almost immediately (reference: "The Merlin in Perspective: the War Years" by Wilfred Hyde-White).


Rings pretty true.

In the 70's the Ford V-8s racing at Bathurst were reporting significant sections of the track with zero oil pressure due to surge in the sump...for 500 miles.
 
I talked to a guy at a boat show once who was selling a gizmo that tapped into the engine someplace so you could run the engine and pump out all the old oil for an oil change. I can't remember the details, but I vividly remember him saying that at idle you could run the engine for quite a awhile (maybe minutes) until there was no oil whatsoever and there was very little danger of hurting anything. Seemed like a wacky way to me to get the oil out, but a lot of boat engines are very difficult to drain. Every boat show has someone selling some new device to accomplish the task. My current boat engine came with a handy pump that removes the oil from the sump, so I don't have the problem anymore.
 
Some old diesel trucks have a diverter valve to bleed some oil off to the fuel tanks, with an auto shutdown for when the oil pressure dropped. Then, change filter, fill it up with oil, and you're good to go.
 
Originally Posted By: spasm3
I reference to empty oil filters , yes there is a oil already in the bearings and length of the crankshaft. MY question is always , where does the air thats in the oil filter go?? I theorize that the air is being pushed down the crankshaft displacing the oil off the bearings and journals, until the filter is filled and oil pressure returns. I fill my oil filters first.
The engine oil passages and bearings do not hold oil. When the engine stops running , there is only an oil film on the parts, the oil drains out.
 
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