Gami Injectors?

[Cyril Gibb]

2 hours ago, mike_elliott said:

I One might have to "juggle" the injectors around (swap the leanest with the richest cylinder after a Gami spead test, and make sure you know the correct torque value of the injectors so you don't introduce a crack in the cyl head.) but if all else is right, you should have a nice running engine at 25 LOP.

+1

Clarence noticed the injector bleed holes were mostly oriented incorrectly (lycoming 1275), so we did the GAMI juggle at the same time.  0.0 spread at 7ish GPH and 0.1 at cruise fuel flow.

[DAVIDWH]

And of course, talking about Gami's,  how could we fail to mention Fine Wire Plugs?

Just installed both at annual.

Anything to keep the purr going smoothly.

[MV Aviation]

@all:

Has anyone ever sent back their GAMIs because they needed more fine tuning? GAMI offers re-calibration, if the results are not satisfying. And, did you buy your GAMIs just according to your engine model or did you provide the company with detailed leaning data of your setup beforehand?

Currently I'm wondering whether it makes more sense to go for GAMIs or an EDM-830 first. I do have an analog 4xEGT, 1xCHT, and FF on board already. GAMIs first might make the EDM unnecessary, if they are perfectly calibrated from the factory already. EDM first might make the GAMIs unnecessary, if I find out that my current setup works well as is. With the analog 4xEGT I did make two independent GAMI spread test (with .5 Gph increments), which is rather imprecise. The data suggests that the spread is in the area of 1-1.5 Gph. Yesterday I flew about half an hour LOP with my setup. My (unexperienced) feeling is that I'm better off getting GAMI's first and postpone the EDM.

Any suggestions and opinions?

Edited April 10, 2017 by MV Aviation

[ArtVandelay]

Engine monitor.
Then you can just try swapping your current injectors between the leanest and richest cylinders.

[carusoam]

Looking objectively as possible...

1) Is the data you are getting reliable?

2) not having 4 CHTs is not getting the whole picture.

3) cleaning the fuel injectors can be a good starting place.

4) some Gami spreads are pretty tight. Tenths of a gallon.

5) Having a gami spread over a GPH is quite large.

6) swapping injectors has resulted in tighter spreads.

7) getting reliable data, EGT, CHTs, FF makes life easier.

8) cleaning and testing the FF of the FIs into glass baby food jars might be a good way to start.

9) The existing EGT data that has been collected indicates the FF to each FI is less than ideal.

10) Inspecting, cleaning and testing the FIs will tell you if there is something in the fuel system causing the large gami spread.

11) Bad (less than ideal) FIs mixed with good air flow is how GAMI earns their Keep.

12) it can be expected that the airflow in each cylinder is not perfectly matched.

PP ideas only, not a mechanic...

Best regards,

-a-

Edited April 10, 2017 by carusoam

[CaptRJM]

Yes,  I sent my GAMIs back for recalibration about 5 years ago as I was having a hard time running LOP.  The people at GAMI were very accommodating.

After talking to them they asked that I email data from my JPI 830 for several flights in excess of an hour to look at.  They called me and asked me to remove and send them 2 injectors for recalibration.  They must have worked on them the day that they arrived because I got them back 5 business days after I sent them out.  Recalibration worked perfectly for me,  when going LOP my current GAMI Spread is typically 0.1 GPH.  All 6 injectors go from leanest to richest within 1/8 turn of the mixture knob.

Since my injectors were out of warranty, GAMI charged me around $100 which included shipping and a new warranty on all injectors.  I couldn't be more pleased.

[jlunseth]

On 10/6/2016 at 7:07 PM, clh said:

Are you talking CHT or EGTs?

For EGT's the Gami's will most likely even the flow of fuel to the cylinders.  

The same is true for the CHT's if the problem is fuel distribution, but, it could also could be an airflow issue.  Make sure all of the baffling has not changed.  This includes plugging unwanted air leaks.

Fixing airflow is a lot cheaper than GAMI's.  

 

This is the right answer.  I have the TSIO360LB, which is a six cylinder Continental, turbocharged.  I have GAMIs and the fuel flows are acceptable - within .5 GPH of each other.  But I have an approximately 85 degree difference between CHTs at cruise.  The reason is not fuel flow but air flow.  Cyl 6 sits right in the cowl entrance hole at the right front and gets quite a bit of cooling air.  Cyl 5 sits at the left front, but is partially obstructed, so it is always warmer.  Cyls 1 & 2 sit at the back of the engine and are generally the hottest, usually Cyl 2 because they get the least air and it is already warmed.  There is no harm or consequence as a result of this, unless for some reason the hottest cylinder is too hot, which I consider to be over 400 dF (380 is the best target).  Same with cyl 2, it is fine unless its temps falls under the normal operating temp. range, which is 250 dF, and I am fine with it running 220 since it is so much cooler than the other cylinders, so long as oil temp and the other engine parameters are good.  

I would do something about it, rebuild or put in new baffles, but my engine is nearing TBO so why bother at this point.  There is no issue created by the difference, so long as it is not a fuel flow problem.

In the summer I have the cowl flaps set to trail slightly, this helps the rear cylinders with cooling.

[wishboneash]

IMHO, the engine monitor is much more valuable than GAMIs. I can achieve 0.1-0.2 gph spread with stock injectors in the J. As some have pointed out, I am more concerned with CHT differences (cyl #3 tends to be hottest in my case). I  have discovered morning sickness with an engine monitor which might have prevented an engine failure in the future. Also, I see no reason to go excessive LOP since power drops off sharply beyond a certain point. At low altitudes, I maintain 65% power or lower using prop/throttle then lean as needed (economy/power).

[gsxrpilot]

One point to note here... I've found, and other's as well, that GAMI is very ethical and a good company to do business with. They will not sell you a set of injectors if you don't need them. I've found its just easier to go straight to GAMI with any questions. They will give you straight answers based on real data. They will not sell you parts or service you won't benefit from.

Just my $0.02