Startup Question.

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JOhnH

Touchdown! Greaser!
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It always makes me cringe when we start up an engine after it has not run for a week or two. The procedure is full throttle and full rich, and when the engine catches, pull back on the throttle. But for a few seconds, that cold engine with little oil on the cylinder walls is running at high RPM.

Would it make any sense to turn the starter for a few seconds a couple of times first without letting it start to get some oil up on the cylinder walls?
 
what engine gets started at full rpm?....and anything warmer than 40 deg F ain't cold for an engine.
 
WhAt are you flying,only time i have seen full throttle is for a hot start,on a fuel injected engine.
 
I don't have any problem starting my engine after a winter of sitting. There's still an oil film on the metal. It's common with a new rebuild to pull the plugs and crank the starter until oil pressure registers on the oil gauge but I don't know anyone who'd do that for starting a stored or inactive engine.
 
I get concerned about it. I'll pull the prop through all cylinders if I'm really concerned. Poor engine starts are a huge pet peeve of mine. Yeah, I'm looking at you Cirrus owner/operators.

Most of the damage inside one of these engines comes from the cold engine start.
 
Why would pulling the prop be any different than twisting the key? If you're concerned about dry cylinders pull the top plugs and spray lube into the cylinders. There's nothing you can do for the bottom end other than to start it as quickly as possible.
 
JOhnH said:
It always makes me cringe when we start up an engine after it has not run for a week or two. The procedure is full throttle and full rich, and when the engine catches, pull back on the throttle. But for a few seconds, that cold engine with little oil on the cylinder walls is running at high RPM.

Would it make any sense to turn the starter for a few seconds a couple of times first without letting it start to get some oil up on the cylinder walls?
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What engine is this? Most GA engines will start just fine with the throttle closed or barely cracked. A common practice is to set the RPM to a mildly fast idle (e.g. 900 RPM) before pulling the mixture and leaving it there for the next start. If you need the throttle open further than that to start you're probably overpriming.

And to answer your specific question, with most of these engines cranking the engine will put zero oil on the cylinder walls and may actually remove any still there. Even a pre-oiler won't do much for the cylinder walls.
 
JOhnH said:
It always makes me cringe when we start up an engine after it has not run for a week or two. The procedure is full throttle and full rich, and when the engine catches, pull back on the throttle. But for a few seconds, that cold engine with little oil on the cylinder walls is running at high RPM.
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Install a pre-oiler.
 
Tom-D said:
Install a pre-oiler.
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While I agree that this would be a good idea if the OP continues to start at WOT and reach high RPM on every cold start, what's it gonna do for the cylinders?
 
gismo said:
While I agree that this would be a good idea if the OP continues to start at WOT and reach high RPM on every cold start, what's it gonna do for the cylinders?
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Wouldn't the oil being sprayed out of the crank, be hitting the cylinder walls?
 
This just goes to show, there are no stupid questions. Just stupid people asking questions. :redface:
I now believe I was taught the wrong way to start an engine and since it always worked, and nobody ever called me on it, that was the way I did it. Today I'll tryi it differently.
 
John....no need to fret, just read the POH/AFM and do what it says. No biggie. :D
 
I would never start full throttle.... In the Cirrus its full throttle, full rich, prime, then pull all the way back on the throttle. Open it a little bit and starts right up and then we throttle UP to 1000...
 
JOhnH said:
This just goes to show, there are no stupid questions. Just stupid people asking questions. :redface:
I now believe I was taught the wrong way to start an engine and since it always worked, and nobody ever called me on it, that was the way I did it. Today I'll tryi it differently.
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Checklists are your friends.
 
Only time I start full throttle is for a hot start with mixture ICO, of course the second the engine catches it's throttle idle and mixture in.


Starting WOT as a normal starting procedure :dunno:



midlifeflyer said:
Checklists are your friends.
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Depends on who wrote them, OP should read the POH cover to cover, guessing there were a few other procedures that got mistranslated by his CFI.
 
Starting a flooded engine entails pulling the mixture back all the way lean, so it gets no fuel. Then wide open throttle so it gets maximum air. That is basic for a carbureted engine. Not everyone knows this one. If you dont, you should. And understand why.

Not sure on fuel injected engines.
Anyone know if there is a "universal" flood start for fuel injected?
 
There is also something you SHOULDNT DO for a flooded engine. You should know that too.
 
coloradobluesky said:
Starting a flooded engine entails pulling the mixture back all the way lean, so it gets no fuel. Then wide open throttle so it gets maximum air. That is basic for a carbureted engine. Not everyone knows this one. If you dont, you should. And understand why.

Not sure on fuel injected engines.
Anyone know if there is a "universal" flood start for fuel injected?
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Starting a flooded engine is starting a flooded engine. Run air through it and no more fuel.

Now starting a hot, fuel injected engine...that can get some arguments going...and the good news is that everyone's method is correct if it works for them...of course there are factory recommendations which should be followed.
 
coloradobluesky said:
Starting a flooded engine entails pulling the mixture back all the way lean, so it gets no fuel. Then wide open throttle so it gets maximum air. That is basic for a carbureted engine. Not everyone knows this one. If you dont, you should. And understand why.

Not sure on fuel injected engines.
Anyone know if there is a "universal" flood start for fuel injected?
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For my fuel injected, you open the throttle and close the mixture and run the fuel pump for about 30 seconds. Then you try a normal start.

Oh, wait. That is for a hot start.

To be honest, my original question was posted mostly for my wife. Since I lost my medical ages ago, she is the family pilot. And she is a great pilot, but she is not an "engine person". We disagree on leaning techniques, and until today on startup procedures. What she was doing was opening the throttle just a little prior to start and go full rich (we are at sea level). But as soon as she turned the key, she started pushing the throttle in until it would catch. When it did catch, it was at "high" throttle if not full. And she wasn't as fast as I wanted in reducing engine speed.

Today, after reading this thread, she started it with the throttle open slightly and it was much better. Sometimes a woman has to hear something from someone besides her husband.

Now if I could just get her over her fear of the red knob. But at least with the Gamis, she is doing better.
 
Start per the POH guidelines. Don't rev hard after starting. I see this daily where people start and immediately run high rpm. That is not needed, not per guidelines, and certainly not the best for your motor.
 
I'm skeptical that a few low RPM revs are causing significant wear. The thing that kills cylinders is HEAT and that usually comes from AFTER the start procedure.
 
flyingron said:
I'm skeptical that a few low RPM revs are causing significant wear. The thing that kills cylinders is HEAT and that usually comes from AFTER the start procedure.
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Believe it or not....cold starts are horrible for cylinders (temps way-way lower than 40 deg F). :yes:

...but, he's in Florida and probably not ever seeing that.:no:
 
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Running it hard when cold definitely reduces top end life. You should never hit more than 1500rpm on a start. I might hit 12-1300 rpm on the start and then bring it back quickly to a fast idle.
 
TCM preheat recommendation is below 20*. Lycoming's is 10*. Where does the <40* cold starts are bad for cylinders info come from?
 
Tom-D said:
Wouldn't the oil being sprayed out of the crank, be hitting the cylinder walls?
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Nope. It's too thick and the flow is far too low from any preoiler. The oil is thrown off the rotating crank onto the cylinder walls once the engine is running. A preoiler will make sure that there's oil there to reach the cylinders sooner after start, though.

The cylinders don't suffer from a lack of oil nearly as much as the bearings. There's just too little pressure between the rings and cylinder walls to do damage in short order. It's the crankshaft rod and main bearings that get damaged by a lack of oil. Anytime an engine is run dry it's usually the bottom end that fails first.
 
Stewartb said:
TCM preheat recommendation is below 20*. Lycoming's is 10*. Where does the <40* cold starts are bad for cylinders info come from?
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I was a reliability/test engineer guy for a powerplant development project....and one of my co-workers was an ex-Lycoming engineer. He did a stackup analysis and determined that there was a slim, but, a possible interference in the main journal bearing at temps as warm as 40 deg F.

So....dat's my story, and I'm stick'n with it. Now I have a CMI and I still prefer to preheat around 40 deg F or cooler.

the guy wasn't Ted....but, paging Ted to the white phone.:goofy::D
 
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Your choice. I admit that engine starts are faster and easier with a preheated engine but I don't hesitate to start my TCM in mid-20s temps if I have someplace to go and limited time to prepare. I park outdoors in Alaska so I get my opportunities to play in the cold. My preheat is defined by whether my little Odyssey battery has the juice to spin that big, cold motor. Modern times provide us good multi-vis oils and aftermarket additives but old stories persist. Honestly after years of watching guys use ****-poor preheat routines most of the preheat stories are BS anyway.
 
Stewartb said:
Your choice. I admit that engine starts are faster and easier with a preheated engine but I don't hesitate to start my TCM in mid-20s temps if I have someplace to go and limited time to prepare. I park outdoors in Alaska so I get my opportunities to play in the cold. My preheat is defined by whether my little Odyssey battery has the juice to spin that big, cold motor. Modern times provide us good multi-vis oils and aftermarket additives but old stories persist. Honestly after years of watching guys use ****-poor preheat routines most of the preheat stories are BS anyway.
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I have a pad heater....so pre-heat ain't all that hard. Just leave it plugged in and yes it does start easier. :rolleyes2:

But....what you do just produces a lil more wear in the choke area of the cylinders and possibly other areas. None of which are catastrophic....but just more wear.
 
A pad heater is half a solution. See my final comment in post 28. But it all comes down to your operating temps. +30 is a lot different than -30.
 
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Stewartb said:
A pad heater is half a solution. See my final comment in post 28. But it all comes down to your operating temps. +30 is a lot different than -30.
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Your opinion...thanks.;)

The pad heater brings everything up to +60 deg....yup, I measure this kinda stuff, even the cylinder heads. Yes, I use the latest in lubrication technology....Phillips XC multi weight and CamGuard. :yes:
 
Out of curiosity, how many failed starts have you personally had and what were the symptoms? What was the ambient when you found CHTs at 60* after using only a pad heater? Have you ever had frosted plugs? Do you leave the pad heater on continuously? How's your top end corrosion been when you're torn down your engines?
 
Stewartb said:
Out of curiosity, how many failed starts have you personally had and what were the symptoms? What was the ambient when you found CHTs at 60* after using only a pad heater? Have you ever had frosted plugs? Do you leave the pad heater on continuously? How's your top end corrosion been when you're torn down your engines?
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No failed starts lately. Ambients were probably a lil below freezing, not nearly as cold as yours. No frosted plugs at 60 deg F. ...and my CMI starter adapter is happy warm. :yes:

I turn the heater on the night before. It does not run continuously. ....and no top end corrosion. The pad heater (~250-300watts) provides 60-70 deg temp rise and is more than adequate to heat the entire engine.


I borescope frequently....every time a plug comes out. :D
 
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My experience with pad heaters is in colder temps. The oil is warm but the cylinders are cold. Frosted plugs are the result. That's a show stopper. I've used warm air, too. Cylinders are warm and fire easily but oil pressure takes way too long. Most guys don't use either of those methods for long enough and that requires suitable outside temps. Sometimes there is no "long enough". I use the Reiff Turbo XP system these days. It's the fastest way I know to adequately heat cylinders and oil, and nearly 100% of my preheating is done from a 1000w generator in the hours prior to flight. The balance is from a combustion heater that uses an MSR camp stove. That's painfully slow and must be attended. I like the Reiff much better.
 
Stewartb said:
The balance is from a combustion heater that uses an MSR camp stove. That's painfully slow and must be attended.
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And pumps tons of water onto a cold engine where it condenses and can eventually cause corrosion.
 
The stove(s) I use are white gas, not propane or butane, so no moisture issues.
 
Stewartb said:
The stove(s) I use are white gas, not propane or butane, so no moisture issues.
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Combustion products, H2O, CO, CO2, some NOx from all hydrocarbons are similar. When the water vapor condenses in the presence of CO2, the pH can drop into the acidic range. Of course if you go fly chances are that all of the water will re-vaporize. If you don't go fly it can lead to problems.

Even electric heaters can be bad just because they can vaporize the water in the oil and that water vapor can condense when it contacts the cold top of the engine case.

Fire up the pre-heater? try real hard to go fly...
 
Stewartb said:
The stove(s) I use are white gas, not propane or butane, so no moisture issues.
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White gas can mean a couple different things, but all of them will produce about a gallon of water for each gallon of gas burned.
 
Checkout_my_Six said:
what engine gets started at full rpm?....and anything warmer than 40 deg F ain't cold for an engine.
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That's how all Bo owners start their plane. Full throttle. It's a bit tongue in cheek, but I've heard it from different people in different circles.
 
JOhnH said:
It always makes me cringe when we start up an engine after it has not run for a week or two. The procedure is full throttle and full rich, and when the engine catches, pull back on the throttle. But for a few seconds, that cold engine with little oil on the cylinder walls is running at high RPM.

Would it make any sense to turn the starter for a few seconds a couple of times first without letting it start to get some oil up on the cylinder walls?
Click to expand...

Not much of a problem, however it's unnecessary with your engine to have full throttle at start. On Continentals I go full throttle, full rich, hit "High" on the boost pump, as soon as the fuel flow needle comes off the peg I start counting, using "4" as my 'pump off' count in warm weather, and going up to "9" in very cold weather. Then the throttle comes back to just cracked open 3/4" or so, mixture comes back to my ground idle setting, and hit the starter. I use the same procedure with a hot or cold engine and it always fires in a couple of blades max.
 
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