REFLECTOR: Engine backfiring
Dave Philipsen
velocity at davebiz.com
Wed Aug 16 12:19:36 CDT 2006
Mine *is* an updraft engine. The spider is up on top somewhere so it
makes sense that it could overheat. I will do some experimenting with
insulation and perhaps even a cooling duct when I get a chance.
The oil line sounds like a neat idea. Can't imagine that the oil would
ever get warm enough that you'd have vaporization. In effect, it would
keep the fuel in a fairly tight temp. range.
Scott Derrick wrote:
> This is usually a common problem caused by overheating the injection
> lines and spider, its especially prevalent in updraft engines. Heating
> the injection system can help when running at cruise but can be a
> problem at idle if its too hot.
>
> If the problem is just a hot injection system you can sometimes
> alleviate it by doing a couple things.
>
> 1.) Run your aux fuel pump while taxing if the engine is hot. The
> higher pressure can prevent some of the fuel from vaporizing.
>
> 2.) Put an insulated baffle under the spider so it doesn't absorb as
> much ambient heat from the engine case.
>
> 3.) some folks run a 1/2 inch cooling duct to the spider and build a
> shroud around the spider to direct the air. This can help with the over
> heating problem but it also cools the fuel when running which may lower
> fuel efficiency, probably by not much though.
>
> My TSIO520 has a heated spider that is heated with an oil line. This
> keeps the spider at oil temp which is good for fuel burn but also helps
> prevent it from getting so hot the fuel vaporizes.
>
> Scott
>
> Dave Philipsen wrote:
>
>> Here's a question perhaps for some of the engine experts: I've got a
>> STD FG with IO360-A1A engine.
>> It has one standard magneto and one Jeff Rose electronic ignition. The
>> engine and oil cooling are not a
>> problem even with OATs in the low 90s. But, I have a problem (it's not a
>> huge problem) with backfiring
>> during taxi *after* I land. Taxiing before takeoff seems to be ok. The
>> backfiring happens maybe once
>> every 30 seconds or so. The engine also seems to run a little rough at
>> this time. I've tried running lean,
>> running rich, running on just the magneto, running on just the
>> electronic ignition. None of these seems to
>> prevent the backfiring during taxi. The engine never seems to have
>> problems before or during takeoff or
>> during cruise or descent...just taxiing back after landing.
>>
>> I'm starting to think it's a vapor lock problem or something since the
>> fuel flow is way down and the fuel is
>> sitting in the lines longer and heating up. I had the cowling off the
>> other day and was checking the routing
>> of the fuel injector lines and they don't appear to be routed near the
>> exhaust manifolds or anything like that.
>> I was thinking of maybe experimenting with some insulating material
>> around the individual injector lines as
>> well as the main fuel line. Any ideas?
>>
>>
>>
>
>
--
Dave Philipsen
STDFG
N171SP
More information about the Reflector
mailing list