Reading an engine monitor

Fenland_Flyer wrote:

Thank you Peter, a good simple explanation. So do GAMI all have an identical flow rate and if so why cannot the engine manufacturer achieve what seems to be a very simple engineering task? Has any one a good picture of an injector?

The GAMIjectors are tuned for you specific engine to deliver the same amount of fuel to each cylinder. Each cylinder is in effect a separate engine and the power developed in each cylinder is dependent on the fuel/air mixture. On the rich side of peak EGT, the amount of air delivered to the engine is largely responsible for determining the power and is somewhat independent of the fuel, IOW the power curve vs fuel is pretty flat. So as long as the air is evenly distributed to the 6 cylinders, you get a smooth running engine when ROP. When LOP, the power developed is a function of the amount of fuel delivered to each cylinder, so if one or more cylinders gets more fuel than the others, they develop more power and you get a rough running engine due to the uneven power from the various cylinders.

With the GAMIjectors, each injector is tuned (sized) for the individual cylinder to match the fuel flows. You run a test before you order the GAMIjectors or provide data. The test is to lean the engine in small increments of 0.5 GPH or less and record the 6 EGT and CHT values along with the overall fuel flow. Then you circle the peak EGT for each cylinder. Ideally all of the cylinders peak at the same fuel flow, but usually they don’t. If the cylinders have peak EGT values more than 0.5 GPH different from each other, those that differ are precisely adjusted by increasing/decreasing the injector orifice for that cylinder. GAMI sends you a set of injectors that are marked for each cylinder.

The actual EGT temperatures are not meaningful, what is important is what fuel flow that they achieve peak EGT. TCM has an offering of tuned injectors, but in my experience, they are inferior to GAMI.

Most often it is a clogged injector if CHT runs high for a specific cylinder.

Not without a corresponding abnormally high EGT.

Also the OP’s temps (see post 1) are normal. #3,4 tend to run hottest. #1,2 tend to be cool for obvious reasons, #5,6 tend to be cooler than 3,4 because the air is rammed against the rear wall an forced to flow through these two.

I hope your mechanic knows about it…

Teledyne Continental Motor’s (TCM) Position-Tuned Fuel Injection Nozzles
TCM_InjectorSID05_7_pdf

Easy to detect problems if you upload your data on Savvy and look at the CHT lines.
Most often it is a clogged injector if CHT runs high for a specific cylinder.

GAMI injectors are mostly the manufacturer’s injectors. They are measured by GAMI for the precise fuel flow at a given pressure. So when you buy a set of GAMIs, they are merely selling you standard Lyco or Conti injectors, selected to even up the power delivery of your respective cylinders.

So you may ask: why do GAMI need an STC, when all they are doing is what you might get with a standard engine, purely by accident?

They need an STC because in some cases they can’t get the required flow rate with a standard injector, or they don’t have any handy of that size. So they bore one out. That is a modification.

The other reasonf for an STC is that many mechanics are illiterate/obstinate and can’t (or won’t) read the regs, and an STC gives them a nice warm feeling It’s like an STC for a Concorde battery; their STCs are also purely for what is basically marketing.

With good baffling you should be able to keep CHTs below 400F at all times. I used to struggle to keep mine below 450F in Greece during climbs at +35C but since I reworked the baffles (link above) this dropped a lot.

cessnatraveller wrote:

The Continental IO 360 already has balanced injectors when it leaves the factory. NO need for GAMIs!

Are you positive about that? I don’t see it specified in the TCM spec sheet. The air delivery is an improvement over the IO520 series because it is overhead and individual plenums so fuel doesn’t get transported from one cylinder to an adjacent cylinder. So it should have a lower requirement for balanced injectors, but from the evidence in the OP engine analyzer, fuel flow balance isn’t working with the existing injectors.

Fenland_Flyer wrote:

Continental IO360 KB1B

Gami supports this engine with custom injectors. I would expect much improved performance and smoother operations with the Gamijectors.

The Continental IO 360 already has balanced injectors when it leaves the factory.

Very unlikely to have been actually done deliberately.

how does one get a “pattern” to manufacture from

With the lower cowling in place, by visual inspection of where the gaps are.