Should I be concerned over these testdata for my new Lyc XIO-360?

I need some advice from you engine experts out there: in 2010 I bought a new Lyc XIO-360 from Vans for my -7.
It was run twice at the Lyc factory, then shipped to me.
As part of the paperwork with the engine, there where reports from the two test-runs.

Yesterday I was going over the paperwork in preparation for the very first engine start, and I noticed that both runs had three items which was either described or marked with "rewiew".

I'm wondering of these three items are something I schold be concerned about? Does it need fixing before first flight for example? Or is it normal variations one schould expect from a new engine?

Look in the "variations" column from test-run # 1: (upper right corner)
There's three items listed








Here's the report from test-run #2:



The same three items are marked as "rewiew" in the report.

Is this something to get fixed or be worried about?


I have little detailed knowledge of aircraft engines, so I'm hoping someone out there can tell me what these three remarks actually means?

(Mel or Malon, are you guys out there? )

I assume this is all about injector nozzle flow rates.

See what your Gami spread is.....if it were me just install a set of Gamijectors.

You can see Lycoming are not bothered at all to get your F/A ratio and flows correct.

They just were calibrating fuel system, I think the problem will be they leave it like that, but they review/fixed so just go ahead and fly your plane

It' new.

This is within limits but not uniform. 'Very few are." You will have lots of time after you get your bird up and flying to look in to fine tuning these flows. Unless you get some very bad "E.G.T." reading, I would wait till it gets 50-100 hrs. on it before you start fine tuning it. Every new one takes some time to settle down and find its own attitude. If you find that you don't like it after it settles in for the long hall, yes Gamis are a good thing to look into.
Hope this helps. Yours as always R.E.A. III # 80888

Gami's are good, but Don at Airflow Performance will treat you even better - give him a shout with your info and he'll be able to get you perfectly dialed in.

Cheers,
Stein

I'm with Stein.

+1 for Don at AFP. His injector orifices go down to half thousandths. We had .025's to start with and needed .0251/2 for the two center cylinders...amazing results.

Best,

Anybody here familiar with these charts and the dyno setup? Regarding the review items in question...

What does "Airflow@AF-1000" actually mean? I assume air in pounds per hour.

Fuel Flow Limits and Fuel Nozzle Limits appear to be quantity and pressure. At 82.68 PPH the measuring point would have to be prior to the fuel divider, as it's a little less than 14 GPH. No idea which nozzle they refer to here. The 10.9 Hg is perhaps differential pressure as compared to manifold pressure? Anybody know? Last, at what RPM is this test done? Loaded to 2700 while throttled to 1000 PPH air?

Observation...

The Rated Power figures further down the page are interesting...2712 RPM, 27.17 MP, and a "Flow Limits (PPH)" of 1041. That's too large to be a fuel flow, so it must be airflow. The theoretical air capacity of a 4-stroke is (RPM x Displacement)/3456 = CFM, so (2712 x 361)/3456 = 283 CFM. Air at the given barometer (29.2) should be about 0.075 lbs per cubic foot, so that's 21.225 lbs per minute, or 1273.5 PPH. 1041/1274 = 82% volumetric efficiency, which puts it in the "truck engine" performance category. Always nice to have real numbers.

I wonder too......

I also wonder how a recent Lycoming IO360 could have made it out the door with the FCU for an IO320. It certainly flows the wrong fuel flow

No problem here

What Lycoming does when they dyno an engine is to (correctly) set a given mass airflow through the engine then read the hp output. This method was established in conjunction with the Bendix Corporation beck in the 50?s. I actually spent many days in the engineering air box, calibrating their airflow measuring equipment, then made from PS-7 throttle bodies. Today I?m sure all their test cells use electronic airflow measuring equipment. Additionally they measure the fuel flow in PPH. This of course can be directly related to BSFC a measurement of the engine?s health and efficiency. The limits for fuel flow for this engine at 1000 PPH air flow show 83.1 to 92.1 PPH or a .083-.092 fuel air ratio). The engine was at 82.68 PPH, so it?s 0.5% out of the lean limit. Personally I wouldn?t worry about it. The other limits for review are nozzle backpressure measurements. These are pretty much meaningless to the operation of the engine, and are strictly a result of the nozzle size. Back in the day there wasn?t electronic fuel flow measuring devices, so since we knew the nozzle size, you could establish a relationship between nozzle back pressure and fuel flow. These were given to Lycoming and they established fuel flow limits for the engines off of these charts. They still use them today even though they have digital or on the older dyno stands they had Cox flow meters. I guess you could use this as a trouble-shooting device if you had a clogged nozzle. The reality of it is if you are running Bendix (Precision) or Airflow Performance fuel injection, it doesn?t matter what the nozzle back pressure is because the fuel control establishes the fuel air ratio that is delivered to the engine. If the nozzles were bigger or smaller (which would change the nozzle back pressure reading for a given fuel flow) the fuel flow delivered to the engine would still be the same.

On another note if you had a fuel control for a 320 and installed it on a 360 the engine would still run fine. The fuel air ratio for the setting for the IO-320 is around .085. The fuel air ratio setting for the 360 is around .085. So basically either unit would run either engine. There is a parts list RSA-5AD1 that is used on an IO-360 and IO-540 with no change in the parts list or calibration.

Don

Thanks..

.... for the replies guys! Now I feel alot better!
A special thank you to Don at Airflow for taking the time to write the long comment. I'm learning something new every day in this RV-building business!

Now I'll get this bird in the air and see how things work. It'll be interesting to observe CTH's ang EGT's as well as the other numbers.

Hopefully first engine start is in a couple of weeks and first flight just after New Year.

Regards Alf Olav

Don,

the IO320 and IO360 are different. You wouldn't happen to know why or what the actual differences are?

My APS partner down here in Oz (Andrew Denyer - Riverina Airmotive) overhauls and calibrates these things and his comment is the likely difference is the idle valve and they are calibrated for their max fuel flow. And the calibration tables are different.

So it could be that a wrong servo is fitted.

Would you believe it.

I have just had one local guy down here, RV7 builder with an IO360 send me his data sheets, the same guy where I suspect the FCU is set up for an IO320.

The flow data and EGT data confirms the rows are too low. End of Story!!

But guess what the Lycoming sheet shows, rock bottom flow rates just the same as this thread starter posted.

Something is not right. The certification limits for detonation are at -10% and these are on that level, -10% so they are "passed" as far as flow goes. Does not make it right.

ao.frog, it is your engine and your investment, but believe me if you accept those flows, you are not doing your engine, or yourself long term (or a subsequent owner) any favours.

If Lycoming refuse to do anything about it, remove the FCU and send it to a reputable shop and request that it flows 17.5GPH at the top end of the data tables.

If you cant find anyone, PM me and I can find someone for you.

I found this from a simple bit of info from a EMS data file. I wonder how many people have this problem and never know about it.

Any Concern??

Am I correctly reading the second engine run data?? When running at "Rated" power for 15 minutes the cht's were 490+ degrees F?? With a new engine doesn't this high temp increase the possibility of cylinder glazing----or is this not as critical when run in a test chamber?? Just curious if some of our experienced engine builders saw this and can comment?

Cheers,

db

Hi again.

Now, I'm REALLY getting worried.... I have contacted both Lycoming and Vans, so hopefully I'll get a course of action from them.

David: what's the "FCU"? Flow Control Unit maybe?
If so, how does it look like and where is it mounted on the engine?
Is it the fuel injector unit maybe?

I certainly won't risk anything with my brand new Lyc, and so far I haven't started it yet. Looks like that will be a while for that to happen...

RV10inOz said:

Don,

the IO320 and IO360 are different. You wouldn't happen to know why or what the actual differences are?

My APS partner down here in Oz (Andrew Denyer - Riverina Airmotive) overhauls and calibrates these things and his comment is the likely difference is the idle valve and they are calibrated for their max fuel flow. And the calibration tables are different.

So it could be that a wrong servo is fitted.

Click to expand...

Yes there are differences between an IO-320 and IO-360. One is three hundred and twenty cubic inches and the other is three hundred and sixty cubic inches. Oh you mean the fuel control unit. Depends which parts list you?re talking about. If you guy overhauls these systems then he should know what the differences are. No, the idle valves in a 320 unit and a 360 unit are the same. Just in some of the 320 units their clocked different because the throttle rotates the opposite direction. Again as hard as this concept is to grasp (for some people) engines are just air pumps. They run based on a fuel air ratio. If the metering device sets the correct fuel air ratio then the engine will run no matter how big it is or how many RPM?s it turns. So again have your friend look at the flow sheets for the IO-320 and IO-360. Look on the flow sheet where it says ?Corresponding Air Flow LBS/HR?. Then calculate the fuel air ratio based on the published fuel flow limits. You will see that while not exact the fuel air ratios overlap for the IO-320 and IO-360 engines. There are some settings of IO-360?s that are leaner and some that are richer than IO-320?s. And yes, some 320 units run a different venturi than the 360 units, but unless they put a 320 venturi in a 360 unit and only bench checked it, that could be a problem. We have an Air Box flow test stand so we actually flow air through the fuel control when we run the calibration. This would find an incorrect venturi in a unit.

So it really depends on the installation the engine was put in based on the flight tests from the airframe manufacture that establishes the final fuel flow limits. Basically in the test cell, all the parallel valve 4 cylinder engines would run on the same fuel air ratio. Since that?s how the Bendix and Airflow fuel controls work, the same unit will correctly run different engines at different hp outputs, RPM?s and displacements. For some reason people really get hung up on fuel flow. We hear it all the time ? My engine doesn?t flow enough fuel. Joe says I should be flowing 35 GPH and my engine only flows 28 GPH?. We would like to answer: ?Well, maybe you engine isn?t making 381 HP?, but we don?t. What we usually say is; ?What is the change in EGT at 24 square from full rich to peak EGT on one cylinder. This is the indicator of fuel air ratio and the indication if the fuel control is flowing enough fuel to the engine?. FUEL FLOW DOESN?T MATTER. FUEL AIR RATIO DOES MATTER.

Don

Agreed,and given that the RPM and MP are near the full power rating the flow being a lot less means the F/A ratio is not what it should be. So the calibration of the offending FCU is clearly at the bottom end and not really acceptable.

Turns out the FCU is an AVSTAR not Precission.

Thanks anyway.

Don at Airflow said:

What we usually say is; ?What is the change in EGT at 24 square from full rich to peak EGT on one cylinder. This is the indicator of fuel air ratio...

Click to expand...

Thank you Don.

Regarding EGT change, full rich to peak at 24/2400...ballpark, what should we look for in the field?

Just be aware that if you have a constant speed prop, looking at fuel flow is not the only answer. You can have a sick engine, incorrect timing, bad ignition and you will still get full RPM and 30? MAP at WOT and still not make the rated fuel flow. The fuel air ratio that the fuel control is giving the engine can be right on. This is why airflow-testing equipment, not just a flow bench, is required to effectively trouble shoot and design these devices.

To check mixture strength, we look for around 180 to 220 degrees F change from peak EGT on one cylinder to full rich. This gives a fuel air ratio of .084-.090.


Don

I agree.

I agree with Don and it has always been my understanding that the "F.C.U." with a venture and that are diaphragm modulated worked just as he described. Thanks Don, it will be interesting to see were this go's. I hope we hear the long answer back out of this one. OH, I picked the throttle body from "E.C.I." I spent a lot of time behind an IO-470 S and grew to like how bullet prof they could be. Yours as always R.E.A.III #80888