A1Skinner wrote:

Zzz wrote:Well, Bob talked me out of injection again the other day. Every time I call him.

Can we know why?

The same old reasons: Simplicity, no need for fuel pumps, nearly equal performance. I made the argument to him about the balanced temps on the cylinders but he's a creature of simplicity and I think he just likes carbs more. Maybe let's bump another thread about it.

Zzz wrote: The same old reasons: Simplicity, no need for fuel pumps, nearly equal performance. I made the argument to him about the balanced temps on the cylinders but he's a creature of simplicity and I think he just likes carbs more.....

Are "balanced temps" really that big of a deal? If one head's at 290, one's at 340, and the rest are at 325...who cares? Even if you only run a single-point CHT gauge, just make sure you have the probe on the hottest one. Sometimes I think we overthink this stuff. IMHO simpler is usually better....and carbs are simple.

This is what a Lycoming IO-540, will look like, after an EPA review and recommendations. It has perfect temps to within one degree F

another IA I talked to said I should be concerned with the seals in the continental io360d fuel injection system deteriorating from the mogas. I know this is true in the lower 48 with ethanol but we don't add that to our fuels in alaska. which seal could be a problem and is it possible for a seal failure to possibly cause a fuel stoppage or engine shut down /plugged throttle orifice, etc... Also perhaps we can compare injection seals and parts to the new io360F model derated for mogas and 2600rpm redline.

akholland wrote:.... perhaps we can compare injection seals and parts to the new io360F model derated for mogas and 2600rpm redline.

Derated to what horsepower? As I recall, the Cessna Hawk XP had a TCM IO-360, one model had a fixed prop & 195hp, the other a constant speed and 210hp. Or was that the Isham conversion?

hotrod180 wrote:

akholland wrote:.... perhaps we can compare injection seals and parts to the new io360F model derated for mogas and 2600rpm redline.

Derated to what horsepower? As I recall, the Cessna Hawk XP had a TCM IO-360, one model had a fixed prop & 195hp, the other a constant speed and 210hp. Or was that the Isham conversion?

I rented a Hawk XP for a while, it was 195hp with constant speed prop. I think they targeted that power rating to allow use without a High Performance endorsement.

The IO-360-AF (alternative fuel) is 195hp at 2800 rpm. It uses 7.5:1 pistons. It is rated for 91UL not mogas. A manufacture has selected it for use in their plane but derated to 180hp at 2550 rpm.

While possible I doubt TCM uses different seal material in the IO360 than they do in the IO470. It would be something to watch for but it isn't going to stop me from running mogas.

$00.02. ...

Try taking a seal and soaking it the fuel you intended to burn for a month. Does it bleed, melt, break up (into hard particles)?

You may find it is no big deal. The beauty of the experimental market.

In response to the guys that had issues with Cessna 150/150's...
There is one I know of that got destroyed over vapor lock... Sat at the end of the runway at idle for 20 mins in the heat with a student... Took off, quit... Ran it across the road at the end of the runway tearing the nose gear off...

After looking at the system, we determined that the main culprit with that system was having the mechanical and electric fuel pumps plumbed in series.. It would vaper lock between the pumps... Plumped in parallel and the issue went away... Our 0-360 STC convention for the PA-22 is plumped in parallel because of that Cessna.... I also recommend anyone who is building an experimental with pumps to do the same thing...

Also, there are a couple of comments of flying somewhere, parking for a few minutes and then taking back off and having fuel problems.... Especially in the heat... I have personally seen fuel boiling In a glass bowl gascolator after a Super Cub flew in and shut the engine off. This was during a nice warm summer day, about 90 degrees out.... We opened the cowling about 5 minutes after shut down and watched it boil for 20 minutes.... So whenever we fly during the summer we make it a point to open the cowl when we stop to let the heat out AND stick around for at least 20 to 30 minutes...

Brian

Brian-StevesAircraft wrote:......After looking at the system, we determined that the main culprit with that system was having the mechanical and electric fuel pumps plumbed in series.. It would vaper lock between the pumps... Plumped in parallel and the issue went away... ......

My C150/150 was converted using the Aircraft Conversion Technologies (aka "Texas") STC. When I bought it, I discovered that the two fuel pumps were plumbed in parallel. After checking out the STC paperwork, which called for them to be plumbed in series, I redid the fuel lines. In hindsight, since my possible / probably vapor lock issues took place after this, I probably should have left well enough alone.