Engine start procedure

[PT20J]

51 minutes ago, N201MKTurbo said:

My wife’s Toyota does it effortlessly every time you come to a stop.

I’ve had a few rental cars that did that and I was always amazed at how well it worked. I guess software engineers are the best at figuring out how to start internal combustion engines. 

[PT20J]

6 hours ago, PeteMc said:

So you're on the Prime and Crank team...  No waiting? 

 

I usually just prime and crank. I have tried waiting a bit and haven’t noticed a reproducible difference. I am going to try Rich’s method though. I have used it for hot starts and it seems to avoid the problem of the engine wanting to die when it uses up the gas remaining in the lines. But, I’ve never tried it on a really cold engine.

[N201MKTurbo]

20 minutes ago, PT20J said:

I’ve had a few rental cars that did that and I was always amazed at how well it worked. I guess software engineers are the best at figuring out how to start internal combustion engines. 

Considering it is done to conserve fuel, I can’t imagine they are putting excess fuel into the engine before cranking. I’m sure their engineers did thousands of starts in every imaginable (not necessarily all) situation to come up with the best method.

That being said I need to work on the software for the pipetter and oil pump before the game….

[EricJ]

1 hour ago, PT20J said:

I’ve had a few rental cars that did that and I was always amazed at how well it worked. I guess software engineers are the best at figuring out how to start internal combustion engines. 

When the 'puter has complete control over each injector, ignition, and sometimes even the valve timing, it gets easier.   These days with direct injection it's apparently even more reliable.

Our airplane motors are still in the stone age in comparison, which is good and bad. 

[Shadrach]

5 hours ago, N201MKTurbo said:

My wife’s Toyota does it effortlessly every time you come to a stop.

Yes. More than 100 years of advancements in materials science, combustion science and applied information technology…effortless.

[Shadrach]

2 hours ago, EricJ said:

When the 'puter has complete control over each injector, ignition, and sometimes even the valve timing, it gets easier.   These days with direct injection it's apparently even more reliable.

Our airplane motors are still in the stone age in comparison, which is good and bad. 

Yes until the intake ports foul from from the EGR system because there is no fuel cleaning off the components.

[N201MKTurbo]

31 minutes ago, Shadrach said:

Yes until the intake ports foul from from the EGR system because there is no fuel cleaning off the components.

Back in the 80s the EGR clogging with carbon was common. I haven’t heard much about it lately. I think the exhaust is so clean now that there are no deposits to clog anything.

[Shadrach]

26 minutes ago, N201MKTurbo said:

Back in the 80s the EGR clogging with carbon was common. I haven’t heard much about it lately. I think the exhaust is so clean now that there are no deposits to clog anything.

Some cars are worse than others. Walnut media blasting is a common practice for some DFI intakes (some of the Audi S cars are particularly bad).  It’s not that the EGRs clog, it’s that fuel being sprayed into the intake port is what keeps EGR deposits from building up in the intake and valve stems. With the injectors moved into the cylinders (DFI) there is nothing to clean away deposits. Diesels can be really bad.  The life of some of these engine could be dramatically extended if the weren’t forced to breath their own emissions.

[N201MKTurbo]

1 hour ago, Shadrach said:

Some cars are worse than others. Walnut media blasting is a common practice for some DFI intakes (some of the Audi S cars are particularly bad).  It’s not that the EGRs clog, it’s that fuel being sprayed into the intake port is what keeps EGR deposits from building up in the intake and valve stems. With the injectors moved into the cylinders (DFI) there is nothing to clean away deposits. Diesels can be really bad.  The life of some of these engine could be dramatically extended if the weren’t forced to breath their own emissions.

“There is always something, If it’s not one thing, it’s another” Rosanne Rosannadanna

[Shadrach]

On 2/10/2024 at 9:46 PM, PeteMc said:

I believe you're talking about a running engine where the cylinder also PULLS the fuel AND air in together.  Not a stationary non running engine you're just pumping fuel into.  Sure there is always some mixing/atomization when you shoot the fuel in.  But I think there may be more wet fuel that just sprays in too. 

I'll defer to one of the real engine mavins here to weigh in, but my mechanic was pretty good.  (Where's George Braly when you need him?!  )

 

 

He’s on YouTube and by the looks of their injector testing, you’re correct.

 

[PT20J]

16 minutes ago, Shadrach said:

Where's George Braly when you need him?!  )

He hangs out on BeechTalk 

FWIW, I’ve been to the Precision Airmotive factory and watched them flow test nozzles. They don’t flow match them. What they do is test each nozzle to make sure the fluid comes out in a steady stream about the size of a #2 pencil lead. If not, they swap inserts and nozzle bodies until it does. When removing and cleaning, you are supposed to keep the nozzle bodies and inserts together and not mix them up. 

[PeteMc]

3 hours ago, PT20J said:

He hangs out on BeechTalk 

Yea, I actually knew that.  Just teasing.   

Back in the day we had MANY a B vs M debate.  Remember when he was so proud of his first flights with the GAMIs and how much fuel he saved...  We on the M team pointed out that of course he needed them for that "B"east he was flying.  And now I look back and think that had he been fly a Mooney all those years, GAMI Injectors may have never come to be!!! 

 

 

[jaylw314]

On 2/10/2024 at 7:41 PM, PT20J said:

Liquid gasoline will not burn. Only gasoline vapor burns. Gasoline will vaporize at any temperature above its flash point which is about -40 deg C, but the higher the temperature the faster the vaporization. Carburetors and fuel injection nozzles atomize the fuel (i.e., break the metered fuel stream into small droplets mixed with air) to facilitate vaporization but atomization and vaporization are not the same thing. So, given these facts, the colder it is (as long as it is above -40 deg C), the more beneficial it may be to wait a bit after priming before cranking because this gives the atomized fuel some time to absorb heat from the metal and vaporize leading to a faster start. But the benefit is probably small. The heat from compression during the compression stroke probably has a much bigger effect. 

I'd suspect the movement of air when the pistons start sucking also helps vaporize a fair amount of the liquid gasoline in the intake (and is probably a larger effect the faster the starter turns).

 

Edited February 12, 2024 by jaylw314

[Ibra]

Does anyone know how to start Mooney (for ground run) if they suspect water in the tanks? 

I was helping a fellow Mooniac this weekend, we sampled the main tanks and the gascalator and found lot of water in tanks: allmost 1/8 of a gallon ! 

Aircraft did not start after load of attemps, even on auxiliary power...it's finally, in hangar now and we are giving it a go in two weeks (we did drain all fuel and we plan to refuel it again with pre-heat next time)

We are not planning to fly it anytime soon until everything is checked, sadly, that beauty has been sitting for a while under rain and dirt, way too much this year and has too much gremlins...

Edited February 12, 2024 by Ibra

[N201MKTurbo]

4 hours ago, Ibra said:

Does anyone know how to start Mooney (for ground run) if they suspect water in the tanks? 

I was helping a fellow Mooniac this weekend, we sampled the main tanks and the gascalator and found lot of water in tanks: allmost 1/8 of a gallon ! 

Aircraft did not start after load of attemps, even on auxiliary power...it's finally, in hangar now and we are giving it a go in two weeks (we did drain all fuel and we plan to refuel it again with pre-heat next time)

We are not planning to fly it anytime soon until everything is checked, sadly, that beauty has been sitting for a while under rain and dirt, way too much this year and has too much gremlins...

You need to remove the spark plugs and dry them with compressed air. Your cylinders are full of water. You should do this sooner than later.

[Fly Boomer]

8 hours ago, Ibra said:

Does anyone know how to start Mooney (for ground run) if they suspect water in the tanks? 

If I found water in the gascolator or wing drains, I would violently shake the wings, wait a while, and sump the various drains.  Repeat until nothing found.  Then I would probably add some alcohol to help absorb any remaining water.  A few years ago, someone here suggested an automotive product called iso-HEET (red bottle), which is reportedly 100% isopropyl alcohol.

[Pinecone]

My POH (252) allows 1% isopropyl alcohol in the tanks.  You want 91% or higher.

I would add it first, then add fuel to mix it up.

But this is AFTER you completely drain the tanks and lines and flush with a bit of fresh fuel.

If you tried to start it on water, you need to pull the plugs and dry out the cylinders NOW.  They are rusting as we speak.  

I would probably pull the injectors and once you have fresh fuel, run them into baby food bottles to ensure you are getting only fuel.

[Ibra]

Thanks, I passed the info to my friend (we drained all of it last weekend, however, we have not removed the spark plugs, he needs to act on this urgently) 

[N201MKTurbo]

28 minutes ago, Ibra said:

Thanks, I passed the info to my friend (we drained all of it last weekend, however, we have not removed the spark plugs, he needs to act on this urgently) 

When he gets it going, he needs to go fly it for an hour or so to cook all the water out of the engine. When he gets back, it would be wise to change the oil.

[Pinecone]

I would check the dipstick immediately after flying.

If it looks like clear oil, you are OK.  If it looks milky CHANGE IT

[N201MKTurbo]

5 hours ago, Pinecone said:

I would check the dipstick immediately after flying.

If it looks like clear oil, you are OK.  If it looks milky CHANGE IT

I only suggested  changing the oil because when water and combustion products mix it forms acids. And you don’t want your engine bathed in acid any longer than necessary. After flying, any water in the engine will be emulsified in the oil. And if there is enough, yes it will look milky, but either way, it would be good to get some fresh oil in there.

[Pinecone]

Not disagreeing that an oil  change would be a good idea. 

[PeteMc]

5 hours ago, Pinecone said:

oil  change would be a good idea. 

Because my mind always goes down into the weeds...   

So how much water would get into the oil through the cylinders from the minimal amount of water sprayed through the injectors?  And how long would it take to boil off once the engine was started and gets to temp?   Would it be much more or less than a plane in the spring or fall that sits for a say a week as the temps go up and down over a pretty broad range and there is a fair amount of condensation in the engine every day? 

I'm not disputing if the oil should be changed (or not), I had just never heard of major water getting into the oil because of water in the tanks.  I certainly would not have thought it was enough to matter.  When I first got my plane and I hadn't flown in a while I used to take off the oil cap to let the moisture out when I got to our lunch or whatever destination, and I'd fold over the cowling door (not locked) just to keep debris from getting in there.  One day an afternoon T-Strom passed through and I got back to the plane with the door blown open and I assumed a tone of rain went into the oil.  Called my mechanic who had a good laugh and said I could poor more water in there than rain would go in the filler and it would boil off before it would matter.  Granted, we were talking about starting up the engine and flying back an hour or so, not letting it sit with the water in there. 

 

[EricJ]

16 minutes ago, PeteMc said:

Because my mind always goes down into the weeds...   

So how much water would get into the oil through the cylinders from the minimal amount of water sprayed through the injectors?  And how long would it take to boil off once the engine was started and gets to temp?   Would it be much more or less than a plane in the spring or fall that sits for a say a week as the temps go up and down over a pretty broad range and there is a fair amount of condensation in the engine every day? 

I'm not disputing if the oil should be changed (or not), I had just never heard of major water getting into the oil because of water in the tanks.  I certainly would not have thought it was enough to matter.  When I first got my plane and I hadn't flown in a while I used to take off the oil cap to let the moisture out when I got to our lunch or whatever destination, and I'd fold over the cowling door (not locked) just to keep debris from getting in there.  One day an afternoon T-Strom passed through and I got back to the plane with the door blown open and I assumed a tone of rain went into the oil.  Called my mechanic who had a good laugh and said I could poor more water in there than rain would go in the filler and it would boil off before it would matter.  Granted, we were talking about starting up the engine and flying back an hour or so, not letting it sit with the water in there. 

Yes, there's often condensation inside the crankcase after shutdown and some of it winds up in the oil, so small quantities of water getting in the oil is a pretty normal thing.    The usual advice for most ICE motors is that if the oil gets up to full temp once in a while any water present will vaporize and go out the breather or through the PCV (for cars) and will no longer be an issue.   Too much water, though, and it just degrades the oil, which is when it turns into the ugly milkshake color and texture, and at that point it's well past needing to be changed.

I think the bigger problem with water going through the injectors is that if some of it winds up sitting in the cylinder in the right conditions it can damage the cylinder finish pretty quickly.   I'd also check the filters at the boost pump and the finger filter at the fuel servo (if either is present).   One of the big issues with my airplane when I bought it was that it had (apparently) had a chronic problem with water.   The finger filter at the fuel servo was full of rusty-looking crap.   I don't know what it was, but there was a lot of it.   I eventually had to have the servo overhauled and one of the diaphragms had a waterline on it about halfway up, and that's apparently not unusual for servos that have had significant water ingestion.   It's better to not leave stuff with any water in it if at all possible.

[PeteMc]

1 hour ago, EricJ said:

I think the bigger problem with water going through the injectors is that if some of it winds up sitting in the cylinder in the right conditions it can damage the cylinder finish pretty quickly. 

That makes sense on the cylinders.  But I was going off the comment that the oil should be changed as soon as possible.  That's what didn't track for me.