TSIO-360-LB

[Q The Engineer]

25 minutes ago, jlunseth said:

GAMI is General Aviation Modifications Inc. They sell tuned injectors. https://gami.com. One runs a lean test that is described on GAMI’s website. The idea is to determine at what fuel flows each factory injector causes its cylinder to hit peak EGT. With that information, GAMI sells you a set of injectors that brings the range of fuel flows at which peak is reached to within 0.5 GPH or less. This helps the engine run more smoothly. It also is very helpful if you want to operate your engine lean of peak. 

Thanks man, I appreciate it.  .5 gph is not very good, it's really bad actually, and it all depends on the feed pressure that changes the flow.  I'll work my own injectors.  It's really interesting how aviation does it's deal. 

[Z W]

Some basic info nobody has really posted yet - Many (most?) piston aircraft engines will foul a plug if they are not leaned out on the ground immediately after starting.  Standard operating procedure after engine start is 1) verify oil pressure, and 2) lean the mixture.  You want it leaned aggressively to the point where you can taxi, but if you put in any more throttle than required for taxi, the engine will die.  Keep it there for the run-up.  Sometimes you have to add a little mixture to make run-up power if you're doing it right.

This accomplishes at least three goals: 1) you will not foul a plug, 2) the engine warms up to operating temperatures faster, and 3) you can't forget to go full rich for takeoff, because your engine will die if you try to push in the throttle.  I was taught this as best practice in anything, from a 172 trainer to a high power Mooney. It also makes you teach yourself to always go full prop and mixture before full throttle, which is important for your engine.  Note that naturally aspirated engines are sometimes leaned for takeoff, but never a turbocharged engine.

If you ever forget to lean for taxi and foul a plug, you'll discover it during the mag check on your run up.  The engine will run rough, sound awful, and scare your non-pilot passengers.  The fix is to do a higher power run-up (something like 2200 RPM), then lean the mixture until the RPM starts to drop, and hold it there for 1 minute or so.  This burns off the fouling you've created on the plug.  Repeat until you get a good mag check and you're good to go.

If you were starting the engine, taxiing, doing run ups, and doing pattern work with a full rich mixture, I'm surprised you made it 10 hours before your engine started acting up.  I believe this is just a symptom of the fact that aircraft engines have to be set rich enough to stay cool on climb, which is too rich for taxi operations.  If it's a design flaw, it's not unique to the TSIO360.

[Pinecone]

GMAIjectors were developed due to two issues.

1)  The airflow in the big bore Continental engines are not even.  And that due to the pressure pulses, as described, there is fuel injected for one cylinder that gets carried out into the log and into another cylinder.  So even with perfect injectors, different cylinders would be at a different fuel-air mixture.

2)  At the time, the Continental injectors were NOT consistent in fuel flow.  So you could have a great LOP running engine, by chance, and when the injectors were cleaned and put back into different cylinders, it would run horribly.  I was around on AVSIG when the first testing and development was occurring the test data on stock injectors was eye opening.  So GAMIjectors are also held to very close tolerances and each injector it tested for the actual flow rate.  In about 2003, Continental went to a higher tolerance on their fuel injectors and some tuning to even out mixtures.  But GAMIjectors are still better.

0.5 gallon per minute difference is not in the injector flow rate, but the fuel flow where each cylinder EGT peaks when leaning.  So you start leaning and cylinder A peaks at say 12.0 GPH (total flow for the engine), the other cylinders peak as you lean further, and the last cylinder peaks at 11.5 GPH flow.  And it is VERY good for a stock engine.  With GAMIjectors and some testing and tuning, you can get the spread to 0.2 or less.

And realize, you cannot just do this to your injectors.  The FAA will need to be involved.  GAMI has done the work and has the approvals (STC).

[Q The Engineer]

15 hours ago, Z W said:

Some basic info nobody has really posted yet - Many (most?) piston aircraft engines will foul a plug if they are not leaned out on the ground immediately after starting.  Standard operating procedure after engine start is 1) verify oil pressure, and 2) lean the mixture.  You want it leaned aggressively to the point where you can taxi, but if you put in any more throttle than required for taxi, the engine will die.  Keep it there for the run-up.  Sometimes you have to add a little mixture to make run-up power if you're doing it right.

This accomplishes at least three goals: 1) you will not foul a plug, 2) the engine warms up to operating temperatures faster, and 3) you can't forget to go full rich for takeoff, because your engine will die if you try to push in the throttle.  I was taught this as best practice in anything, from a 172 trainer to a high power Mooney. It also makes you teach yourself to always go full prop and mixture before full throttle, which is important for your engine.  Note that naturally aspirated engines are sometimes leaned for takeoff, but never a turbocharged engine.

If you ever forget to lean for taxi and foul a plug, you'll discover it during the mag check on your run up.  The engine will run rough, sound awful, and scare your non-pilot passengers.  The fix is to do a higher power run-up (something like 2200 RPM), then lean the mixture until the RPM starts to drop, and hold it there for 1 minute or so.  This burns off the fouling you've created on the plug.  Repeat until you get a good mag check and you're good to go.

If you were starting the engine, taxiing, doing run ups, and doing pattern work with a full rich mixture, I'm surprised you made it 10 hours before your engine started acting up.  I believe this is just a symptom of the fact that aircraft engines have to be set rich enough to stay cool on climb, which is too rich for taxi operations.  If it's a design flaw, it's not unique to the TSIO360.

No they won't, no engine will foul a plug based on being lean, none.  They will foul a plug being rich or in oil.  I'm not sure who you are but you lost me with this incorrect information.  

[Q The Engineer]

15 hours ago, Pinecone said:

GMAIjectors were developed due to two issues.

1)  The airflow in the big bore Continental engines are not even.  And that due to the pressure pulses, as described, there is fuel injected for one cylinder that gets carried out into the log and into another cylinder.  So even with perfect injectors, different cylinders would be at a different fuel-air mixture.

2)  At the time, the Continental injectors were NOT consistent in fuel flow.  So you could have a great LOP running engine, by chance, and when the injectors were cleaned and put back into different cylinders, it would run horribly.  I was around on AVSIG when the first testing and development was occurring the test data on stock injectors was eye opening.  So GAMIjectors are also held to very close tolerances and each injector it tested for the actual flow rate.  In about 2003, Continental went to a higher tolerance on their fuel injectors and some tuning to even out mixtures.  But GAMIjectors are still better.

0.5 gallon per minute difference is not in the injector flow rate, but the fuel flow where each cylinder EGT peaks when leaning.  So you start leaning and cylinder A peaks at say 12.0 GPH (total flow for the engine), the other cylinders peak as you lean further, and the last cylinder peaks at 11.5 GPH flow.  And it is VERY good for a stock engine.  With GAMIjectors and some testing and tuning, you can get the spread to 0.2 or less.

And realize, you cannot just do this to your injectors.  The FAA will need to be involved.  GAMI has done the work and has the approvals (STC).

That makes sense, just like on my LB, it gets richer as it goes rearward.  Fair enough, I appreciate you clarifying and for my lack of experience. I thought you were talking injector flow, not fuel flow.  I realize what needs to happen.  However, I won't compromise what makes sense to satisfy anyone.  It's my ass in the seat and I'll do what's right for me and my airplane.   You'd be wise to do the same. 

[Z W]

7 hours ago, Q The Engineer said:

No they won't, no engine will foul a plug based on being lean, none.  They will foul a plug being rich or in oil.  I'm not sure who you are but you lost me with this incorrect information.  

Well, I don't know who you are either, other then it sounds like you are new to running the TSIO-360 and maybe to flying.  I'm just a stranger on the internet trying to help, for some reason.

I did not say an engine will foul a plug by being lean.  In fact I said the opposite.  I suggest re-reading what I wrote.

Good luck.

[Guest]

11 minutes ago, Z W said:

Well, I don't know who you are either, other then it sounds like you are new to running the TSIO-360 and maybe to flying.  I'm just a stranger on the internet trying to help, for some reason.

I did not say an engine will foul a plug by being lean.  In fact I said the opposite.  I suggest re-reading what I wrote.

Good luck.

I’ve noted in my years here that reading, understanding and comprehension are things missed by many.

[Pinecone]

8 hours ago, Q The Engineer said:

No they won't, no engine will foul a plug based on being lean, none.  They will foul a plug being rich or in oil.  I'm not sure who you are but you lost me with this incorrect information.  

That is what he said.

"Many (most?) piston aircraft engines will foul a plug if they are not leaned out on the ground"

[Pinecone]

30 minutes ago, M20Doc said:

I’ve noted in my years here that reading, understanding and comprehension are things missed by many.

It happens.  Multi tasking, reading and posting in the morning before coffee, or in the evening after an adult beverage.