Fuel Flow Setup in NoCal

amexbmorgan · #1 06-23-23, 10:52 AM

Hello Everyone -

Does anyone know of a mechanic in the Northern California area who is familiar with setting up the fuel flow on these Continental IO-360s and the Skymaster?

Thanks,

Bryan

Learjetter · #2 06-23-23, 07:33 PM

Bryan,
We do my NA IO-360s each annual with a very cool test set my avionics shop built. If you can make it to central OK, happy to help get yours all tuned up. It can be done by any A&P who can read the procedure. Turbos are a little trickier.

The procedure is straightforward and described in the old TCM SID 97-3, and now published in the TCM M-0 manual available on the tcm site. Usually takes a couple hours and several runs to get both engines dialed in and purring.

-LJ

Joes · #3 07-04-23, 09:16 AM

A Shadin type fuel flow indicator seems to make the setup and checking a lot easier. The pressures equates to fuel flow (gph). The sid was created when the fuel flow indicator that was originally installed was a pressure type. Is this the correct way of looking at the setup and verification? Joe

Learjetter · #4 07-04-23, 10:14 PM

Joe,
Yes, on the air-breathing TCM IO-360 series (most versions) “pressure is flow” and if you’ve nothing else ensuring you get @ 50RPM max rise when leaning from full-rich at 650 RPM smooth idle, and @ 18+ GPH at 2800RPM you will be in the ballpark. Our kit measures both unmetered (into throttle body) and metered (at flow divider), and makes dialing in to the exact pressures (and flows) easy. We use sensitive pressure transducers plumbed into the fuel lines with AN fittings and put the pressure digital display in a small pelican box that sits in the cockpit while we follow the steps in the M-0.

amexbmorgan · #5 07-05-23, 02:08 PM

Yeah - I'm not getting the 18+ at 2800. At least according to the ships gauges.
I'm interested in traveling to get this resolved, but don't know anyone with the gauge and/or anyone who wants to work on it.

Thanks,

Bryan

Kim Geyer · #6 07-05-23, 02:58 PM

I would not use a Shadin or jpi to set up your fuel flows. You must/ should use a calibrated gauge to set it up. The K factor on a Shadin or jpi can get off and give you an inaccurate reading. If I remember correctly we had a past member crashed because his fuel system was adjusted using his electronic system. He didn’t survive.

Joes · #7 07-05-23, 04:51 PM

Learjetter, does your setup accommodate a tsio 360, and i would like to see pictures of the units if its possible.

n86121 · #8 07-09-23, 06:18 PM

Perhaps a bit more expensive and invasive is to have the fuel pumps pulled and then setup on lab bench. Then checked on aircraft.

I had my entire rear fuel and intake system, throttle, intake, fuel pumps pulled and overhauled when I put in GAMIs. (TCM injectors were backlogged, but GAMI were available, so easy decision to swap them all).

I noticed after that the rear engine took almost zero manual adjustment with climb and descent. Pretty much deade center all the time.

Whereas the front I had to do a lot of leaning and fidgeting.

So next annual I had the same done to the front.
Similar results as rear.

They found ancient gaskets in throttle, and spider, leaky gaskets etc.

Ballpark total was around $1-2k each engine, but now the fuel systems are like new.

amexbmorgan · #9 07-09-23, 11:08 PM

Yeah - I had both pumps and dividers rebuilt. Front is fine, rear hight pressure is low.

I guess is need to fiddle around a bit.

Joes · #10 07-10-23, 07:50 AM

Thanks for the helpful information on this issue. I found this article, hope it helps. Had been fighting this issue for a while.

Now find your engine model number on TCM SID97‑3 and verify your unmetered fuel pressures are within limits at idle and at full manifold pres*sure. Let's talk about the term "within limits". I have found that on the TSIO‑360‑GB and ‑LB engines, it is best to set the idle pressure right in the middle of the limits, but the full power pressure should be set at the maximum pressure setting. The reason? When the engine gets hot, the metered fuel flows tend to drop causing a lean engine just when you need a richer (cooler) engine. Even if you have a new engine or a recent fuel pump overhaul, don't think you are okay. Never have I seen a TCM or any other overhauled fuel pump set up for maximum pressure at maximum mani*fold pressure.

amexbmorgan · #11 07-10-23, 01:19 PM

I found this article.

Looks like I might be building testing gauge setup.

https://www.tennesseeaircraft.net/20...id97-3e-again/

Bryan

B2C2 · #12 07-11-23, 11:29 AM

I take my 1969 T337D to TriValley Aviation at KLVK. They are pretty competent and can probably do this for you.

amexbmorgan · #13 07-11-23, 01:38 PM

Perfect. I'll reach out to them.

amexbmorgan · #14 08-02-23, 04:54 PM

TriValley Aviation at KLVK got my fuel flow issue resolved. They were awesome!

Joes · #15 08-03-23, 06:43 PM

Thanks to Dan M. for the breakdown into the metered pressure analysis and for taking a look at an alternative approach to setting these pressures. Joes

ps: the articles pages are not in order.